Add ODDMU_FILTER environment variable

This is used to hide secret subdirectories from search since search
includes subdirectories.

Makefile

@@ -8,21 +8,40 @@ help:
 	@echo "    runs program, offline"
 	@echo
 	@echo make test
-	@echo "    runs the tests"
+	@echo "    runs the tests without log output"
 	@echo
-	@echo make upload
-	@echo "    this is how I upgrade my server"
+	@echo make docs
+	@echo "    create man pages from text files"
 	@echo
 	@echo go build
 	@echo "    just build it"
+	@echo
+	@echo make install
+	@echo "    install the files to ~/.local"
+	@echo
+	@echo make upload
+	@echo "    this is how I upgrade my server"
 
 run:
 	go run .
 
 test:
-	go test
+	go test -shuffle on .
 
 upload:
 	go build
-	rsync --itemize-changes --archive oddmu oddmu.service *.html README.md sibirocobombus.root:/home/oddmu/
-	ssh sibirocobombus.root "systemctl restart oddmu; systemctl restart alex"
+	rsync --itemize-changes --archive oddmu sibirocobombus.root:/home/oddmu/
+	ssh sibirocobombus.root "systemctl restart oddmu; systemctl restart alex; systemctl restart claudia; systemctl restart campaignwiki"
+	@echo Changes to the template files need careful consideration
+
+docs:
+	cd man; make
+
+install:
+	make docs
+	for n in 1 5 7; do install -D -t $$HOME/.local/share/man/man$$n man/*.$$n; done
+	go build
+	install -D -t $$HOME/.local/bin oddmu
+
+missing:
+	for f in man/*.txt; do grep --quiet "$$f" README.md || echo $$f is not in the README; done

README.md

@@ -1,163 +1,98 @@
 # Oddµ: A minimal wiki
 
-This program runs a wiki. It serves all the Markdown files (ending in
-`.md`) into web pages and allows you to edit them. If your files don't
-provide their own title (`# title`), the file name (without `.md`) is
-used for the title. Subdirectories are created as necessary.
+This program helps you run a minimal wiki. There is no version
+history. It's well suited as a *secondary* medium: collaboration and
+conversation happens elsewhere, in chat, on social media. The wiki
+serves as the text repository that results from these discussions.
 
-This is a minimal wiki. There is no version history. It's well suited
-as a *secondary* medium: collaboration and conversation happens
-elsewhere, in chat, on social media. The wiki serves as the text
-repository that results from these discussions.
+If you're the only user and it just runs on your laptop, then you can
+think of it as a [memex](https://en.wikipedia.org/wiki/Memex), a
+memory extender.
 
-The wiki lists no recent changes. The expectation is that the people
-that care were involved in the discussions beforehand.
+Oddµ can be used as a web server behind a reverse proxy such as Apache
+or it can be used as a static site generator.
 
-The wiki also produces no feed. The assumption is that announcements
-are made on social media: blogs, news aggregators, discussion forums,
-the fediverse, but humans. There is no need for bots.
+When Oddµ runs as a web server, it serves all the Markdown files
+(ending in `.md`) as web pages and allows you to edit them.
 
-As you'll see below, the idea is that the webserver handles as many
-tasks as possible. It logs requests, does rate limiting, handles
-encryption, gets the certificates, and so on. The web server acts as a
-reverse proxy and the wiki ends up being a content management system
-with almost no structure – or endless malleability, depending on your
-point of view.
+If your files don't provide their own title (`# title`), the file name
+(without `.md`) is used for the title. Subdirectories are created as
+necessary.
 
-And last but not least: µ is the letter mu, so Oddµ is usually written
-Oddmu. 🙃
+Oddµ uses a [Markdown library](https://github.com/gomarkdown/markdown)
+to generate the web pages from Markdown. Oddmu adds the following
+extensions: local links `[[like this]]`, hashtags `#Like_This` and
+fediverse account links like `@alex@alexschroeder.ch`.
 
-## Markdown
+The [lingua](https://github.com/pemistahl/lingua-go) library detects
+languages in order to get hyphenation right.
 
-This wiki uses a [Markdown
-library](https://github.com/gomarkdown/markdown) to generate the web
-pages from Markdown. There is no additional wiki markup. Most
-importantly, double square brackets are not a link. If you're used to
-that, it'll be strange as you need to repeat the name: `[like
-this](like this)`.
+The standard [html/template](https://pkg.go.dev/html/template) library
+is used to generate HTML.
 
-The Markdown processor comes with a few extensions, some of which are
-enable by default:
+## Documentation
 
-* emphasis markers inside words are ignored
-* tables are supported
-* fenced code blocks are supported
-* autolinking of "naked" URLs are supported
-* strikethrough using two tildes is supported (`~~like this~~`)
-* it is strict about prefix heading rules
-* you can specify an id for headings (`{#id}`)
-* trailing backslashes turn into line breaks
-* definition lists are supported
-* MathJax is supported (but needs a separte setup)
+This project uses man(1) pages. They are generated from text files
+using [scdoc](https://git.sr.ht/~sircmpwn/scdoc). These are the files
+available:
 
-A table with footers and a columnspan:
+[oddmu(1)](/oddmu.git/blob/main/man/oddmu.1.txt): This man page has a
+short introduction to Oddmu, its configuration via templates and
+environment variables, plus points to the other man pages.
 
-```text
-Name    | Age
---------|------
-Bob     ||
-Alice   | 23
-========|======
-Total   | 23
-```
+[oddmu(5)](/oddmu.git/blob/main/man/oddmu.5.txt): This man page talks
+about the Markdown and includes some examples for the non-standard
+features such as table markup. It also talks about the Oddmu
+extensions to Markdown: wiki links, hashtags and fediverse account
+links. Local links must use percent encoding for page names so there
+is a section about percent encoding. The man page also explains how
+feeds are generated.
 
-A definition list:
+[oddmu-list(1)](/oddmu.git/blob/main/man/oddmu-list.1.txt): This man
+page documents the "list" subcommand which you can use to get page
+names and page titles.
 
-```text
-Cat
-: Fluffy animal everyone likes
+[oddmu-search(1)](/oddmu.git/blob/main/man/oddmu-search.1.txt): This
+man page documents the "search" subcommand which you can use to build
+indexes – lists of page links. These are important for feeds.
 
-Internet
-: Vector of transmission for pictures of cats
-```
+[oddmu-search(7)](/oddmu.git/blob/main/man/oddmu-search.7.txt): This
+man page documents how search and scoring work.
 
-There is another extension made: hashtags link to searches for the
-hashtag. Hashtags are separate from titles because there is no space
-after the hash. Use the underscore to use hashtags consisting of
-multiple words.
+[oddmu-replace(1)](/oddmu.git/blob/main/man/oddmu-replace.1.txt): This
+man page documents the "replace" subcommand to make mass changes to
+the files much like find(1), grep(1) and sed(1) or perl(1).
 
-```
-# Title
+[oddmu-missing(1)](/oddmu.git/blob/main/man/oddmu-missing.1.txt): This
+man page documents the "missing" subcommand to list local links that
+don't point to any existing pages or files.
 
-Text
+[oddmu-html(1)](/oddmu.git/blob/main/man/oddmu-html.1.txt): This man
+page documents the "html" subcommand to generate HTML from Markdown
+pages from the command line.
 
-#Tag #Another_Tag
-```
+[oddmu-static(1)](/oddmu.git/blob/main/man/oddmu-static.1.txt): This
+man page documents the "static" subcommand to generate an entire
+static website from the command line, avoiding the need to run Oddmu
+as a server. Also great for archiving.
 
-## Templates
+[oddmu-notify(1)](/oddmu.git/blob/main/man/oddmu-notify.1.txt): This
+man page documents the "notify" subcommand to add links to hashtag
+pages, index and changes for a given page. This is useful when you
+edit the Markdown files locally.
 
-The template files are the HTML files in the working directory:
-`add.html`, `edit.html`, `search.html`, `upload.html` and `view.html`.
-Feel free to change the templates and restart the server. The first
-change you should make is to replace the email address in `view.html`.
-😄
+[oddmu-templates(5)](/oddmu.git/blob/main/man/oddmu-templates.5.txt):
+This man page documents how the templates can be changed (how they
+*must* be changed) and lists the attributes available for the various
+templates.
 
-See [Structuring the web
-with HTML](https://developer.mozilla.org/en-US/docs/Learn/HTML) to
-learn more about HTML.
+[oddmu-apache(5)](/oddmu.git/blob/main/man/oddmu-apache.5.txt): This
+man page documents how to set up the web server for various common
+tasks such as using logins to limit what visitors can edit.
 
-Modifying the styles in the templates would be another good start to
-get a feel for it. See [Learn to style HTML using
-CSS](https://developer.mozilla.org/en-US/docs/Learn/CSS) to learn more
-about style sheets.
-
-The templates can refer to the following properties of a page:
-
-`{{.Title}}` is the page title. If the page doesn't provide its own
-title, the page name is used.
-
-`{{.Name}}` is the page name, escaped for use in URLs. More
-specifically, it is URI escaped except for the slashes. The page name
-doesn't include the `.md` extension.
-
-`{{.Html}}` is the rendered Markdown, as HTML.
-
-`{{printf "%s" .Body}}` is the Markdown, as a string (the data itself
-is a byte array and that's why we need to call `printf`).
-
-For the `search.html` template only:
-
-`{{.Results}}` indicates if there were any search results.
-
-`{{.Items}}` is an array of pages, each containing a search result. A
-search result is a page (with the properties seen above). Thus, to
-refer to them, you need to use a `{{range .Items}}` … `{{end}}`
-construct.
-
-For search results, `{{.Html}}` is the rendered Markdown of a page
-summary, as HTML.
-
-`{{.Score}}` is a numerical score for search results.
-
-The `upload.html` template cannot refer to anything.
-
-When calling the `save` action, the page name is take from the URL and
-the page content is taken from the `body` form parameter. To
-illustrate, here's how to edit a page using `curl`:
-
-```sh
-curl --form body="Did you bring a towel?" \
-  http://localhost:8080/save/welcome
-```
-
-The wiki uses the standard
-[html/template](https://pkg.go.dev/html/template) library to do this.
-There's more information on writing templates in the documentation for
-the [text/template](https://pkg.go.dev/text/template) library.
-
-## Non-English hyphenation
-
-Automatic hyphenation by the browser requires two things: The style
-sheet must indicate `hyphen: auto` for an HTML element such as `body`,
-and that element must have a `lang` set (usually a two letter language
-code such as `de` for German). This happens in the template files,
-such as `view.html` and `search.html`.
-
-Oddmu uses the [lingua](github.com/pemistahl/lingua-go) library to
-detect languages. If you know that you're only going to use a small
-number of languages – or just a single language! – you can set the
-environment variable ODDMU_LANGUAGES to a comma-separated list of ISO
-639-1 codes, e.g. "en" or "en,de,fr,pt".
+[oddmu.service(5)](/oddmu.git/blob/main/man/oddmu.service.5.txt): This
+man page documents how to setup a systemd unit and have it manage
+Oddmu. “Great configurability brings great burdens.”
 
 ## Building
 
@@ -165,7 +100,7 @@ environment variable ODDMU_LANGUAGES to a comma-separated list of ISO
 go build
 ```
 
-## Test
+## Running
 
 The working directory is where pages are saved and where templates are
 loaded from. You need a copy of the template files in this directory.
@@ -176,289 +111,65 @@ go run .
 ```
 
 The program serves the local directory as a wiki on port 8080. Point
-your browser to http://localhost:8080/ to get started. This is
-equivalent to http://localhost:8080/view/index – the first page
-you'll create, most likely.
-
-If you ran it in the source directory, try
-http://localhost:8080/view/README – this serves the README file you're
-currently reading.
-
-You can change the port by setting the ODDMU_PORT environment
-variable.
-
-## Deploying it using systemd
-
-As root, on your server:
-
-```sh
-adduser --system --home /home/oddmu oddmu
-```
-
-Copy all the files into `/home/oddmu` to your server: `oddmu`,
-`oddmu.service`, and all the template files ending in `.html`.
-
-Edit the `oddmu.service` file. These are the three lines you most
-likely have to take care of:
-
-```
-ExecStart=/home/oddmu/oddmu
-WorkingDirectory=/home/oddmu
-Environment="ODDMU_PORT=8080"
-Environment="ODDMU_LANGUAGES=en,de"
-```
-
-Install the service file and enable it:
-
-```sh
-ln -s /home/oddmu/oddmu.service /etc/systemd/system/
-systemctl enable --now oddmu
-```
-
-Check the log:
-
-```sh
-journalctl --unit oddmu
-```
-
-Follow the log:
-
-```sh
-journalctl --follow --unit oddmu
-```
-
-Edit the first page using `lynx`:
-
-```sh
-lynx http://localhost:8080/view/index
-```
-
-## Web server setup
-
-HTTPS is not part of the wiki. You probably want to configure this in
-your webserver. I guess you could use stunnel, too. If you're using
-Apache, you might have set up a site like I did, below. In my case,
-that'd be `/etc/apache2/sites-enabled/500-transjovian.conf`:
-
-```apache
-MDomain transjovian.org
-MDCertificateAgreement accepted
-
-<VirtualHost *:80>
-    ServerName transjovian.org
-    RewriteEngine on
-    RewriteRule ^/(.*) https://%{HTTP_HOST}/$1 [redirect]
-</VirtualHost>
-<VirtualHost *:443>
-    ServerAdmin alex@alexschroeder.ch
-    ServerName transjovian.org
-    SSLEngine on
-    ProxyPassMatch ^/(search|(view|edit|save|add|append|upload|drop)/(.*))?$ http://localhost:8080/$1
-</VirtualHost>
-```
-
-First, it manages the domain, getting the necessary certificates. It
-redirects regular HTTP traffic from port 80 to port 443. It turns on
-the SSL engine for port 443. It proxies the requests for the wiki to
-port 8080.
-
-Thus, this is what happens:
-
-* The user tells the browser to visit `transjovian.org`
-* The browser sends a request for `http://transjovian.org` (on port 80)
-* Apache redirects this to `https://transjovian.org/` by default (now on port 443)
-* This is proxied to `http://transjovian.org:8080/` (no encryption, on port 8080)
-
-Restart the server, gracefully:
-
-```
-apachectl graceful
-```
-
-To serve both HTTP and HTTPS, don't redirect from the first virtual
-host to the second – instead just proxy to the wiki like you did for
-the second virtual host: use a copy of the `ProxyPassMatch` directive
-instead of `RewriteEngine on` and `RewriteRule`.
-
-## Access
-
-Access control is not part of the wiki. By default, the wiki is
-editable by all. This is most likely not what you want unless you're
-running it stand-alone, unconnected to the Internet.
-
-You probably want to configure this in your webserver. If you're using
-Apache, you might have set up a site like the following.
-
-Create a new password file called `.htpasswd` and add the user "alex":
-
-```sh
-cd /home/oddmu
-htpasswd -c .htpasswd alex
-```
-
-To add more users, don't use the `-c` option or you will overwrite it!
-
-To add another user:
-
-```sh
-htpasswd .htpasswd berta
-```
-
-To delete remove a user:
-
-```sh
-htpasswd -D .htpasswd berta
-```
-
-Modify your site configuration and protect the `/edit/`, `/save/`,
-`/add/`, `/append/`, `/upload/` and `/drop/` URLs with a password by
-adding the following to your `<VirtualHost *:443>` section:
-
-```apache
-<LocationMatch "^/(edit|save|add|append|upload|drop)/">
-  AuthType Basic
-  AuthName "Password Required"
-  AuthUserFile /home/oddmu/.htpasswd
-  Require valid-user
-</LocationMatch>
-```
-
-## Serve static files
-
-If you want to serve static files as well, add a document root to your
-webserver configuration. Using Apache, for example:
-
-```apache
-DocumentRoot /home/oddmu/static
-<Directory /home/oddmu/static>
-    Require all granted
-</Directory>
-```
-
-Create this directory, making sure to give it a permission that your
-webserver can read (world readable file, world readable and executable
-directory). Populate it with files.
-
-Make sure that none of the static files look like the wiki paths
-`/view/`, `/edit/`, `/save/`, `/add/`, `/append/`, `/upload/`, `/drop/`
-or `/search`. For example, create a file called `robots.txt`
-containing the following, tellin all robots that they're not welcome.
-
-```text
-User-agent: *
-Disallow: /
-```
-
-You site now serves `/robots.txt` without interfering with the wiki,
-and without needing a wiki page.
-
-[Wikipedia](https://en.wikipedia.org/wiki/Robot_exclusion_standard)
-has more information.
-
-## Different logins for different access rights
-
-What if you have a site with various subdirectories and each
-subdirectory is for a different group of friends? You can set this up
-using your webserver. One way to do this is to require specific
-usernames (which must have a password in the password file mentioned
-above.
-
-This requires a valid login by the user "alex" or "berta":
-
-```apache
-<LocationMatch "^/(edit|save|add|append|upload|drop)/intetebi/">
-  Require user alex berta
-</LocationMatch>
-```
-
-## Private wikis
-
-Based on the above, you can prevent people from reading the wiki, too.
-The `LocationMatch` must cover the `/view/` URLs. In order to protect
-*everything*, use a [Location directive](https://httpd.apache.org/docs/current/mod/core.html#location)
-that matches everything:
-
-```apache
-<Location />
-  AuthType Basic
-  AuthName "Password Required"
-  AuthUserFile /home/oddmu/.htpasswd
-  Require valid-user
-</Location>
-```
-
-## Virtual hosting
-
-Virtual hosting in this context means that the program serves two
-different sites for two different domains from the same machine. Oddmu
-doesn't support that, but your webserver does. Therefore, start an
-Oddmu instance for every domain name, each listening on a different
-port. Then set up your web server such that ever domain acts as a
-reverse proxy to a different Oddmu instance.
-
-## Understanding search
-
-The index indexes trigrams. Each group of three characters is a
-trigram. A document with content "This is a test" is turned to lower
-case and indexed under the trigrams "thi", "his", "is ", "s i", " is",
-"is ", "s a", " a ", "a t", " te", "tes", "est".
-
-Each query is split into words and then processed the same way. A
-query with the words "this test" is turned to lower case and produces
-the trigrams "thi", "his", "tes", "est". This means that the word
-order is not considered when searching for documents.
-
-This also means that there is no stemming. Searching for "testing"
-won't find "This is a test" because there are no matches for the
-trigrams "sti", "tin", "ing".
-
-These trigrams are looked up in the index, resulting in the list of
-documents. Each document found is then scored. Each of the following
-increases the score by one point:
-
-- the entire phrase matches
-- a word matches
-- a word matches at the beginning of a word
-- a word matches at the end of a word
-- a word matches as a whole word
-
-A document with content "This is a test" when searched with the phrase
-"this test" therefore gets a score of 8: the entire phrase does not
-match but each word gets four points.
-
-Trigrams are sometimes strange: In a text containing the words "main"
-and "rail", a search for "mail" returns a match because the trigrams
-"mai" and "ail" are found. In this situation, the result has a score
-of 0.
-
-## Limitations
-
-Page titles are filenames with `.md` appended. If your filesystem
-cannot handle it, it can't be a page name.
-
-The pages are indexed as the server starts and the index is kept in
-memory. If you have a ton of pages, this surely wastes a lot of
-memory.
-
-Files may not end with a tilde (`~`) – these are backup files.
-
-You cannot edit uploaded files. If you upload a file called
-`hello.txt` and attempt to edit it by using `/edit/hello.txt` you will
-create a page with the name `hello.txt.md` instead.
-
-You cannot delete uploaded files via the web.
+your browser to http://localhost:8080/ to use it.
 
 ## Bugs
 
 If you spot any, [contact](https://alexschroeder.ch/wiki/Contact) me.
 
+## Source
+
+If you're interested in making changes to the code, here's a
+high-level introduction to the various source files.
+
+- *_test.go are the test files; a few library functions are defined in
+  wiki_test.go.
+- *_cmd.go are the files implementing the various subcommands with
+  matching names
+- accounts.go implements the webfinger code to fetch fediverse account
+  link destinations with the URI provided by webfinger
+- add_append.go implements the /add and /append handlers
+- diff.go implements the /diff handler
+- edit_save.go implements the /edit and /save handlers
+- feed.go implements the feed for a page based on the links it lists
+- highlight.go implements the bold tags for matches when showing
+  search results
+- index.go implements the index of all the hashtags
+- languages.go implements the language detection
+- page.go implements the page loading and saving
+- parser.go implements the Markdown parsing
+- score.go implements the page scoring when showing search results
+- search.go implements the /search handler
+- snippets.go implements the page summaries for search results
+- templates.go implements template loading and reloading
+- tokenizer.go implements the various tokenizers used
+- upload_drop.go implements the /upload and /drop handlers
+- view.go implements the /view handler
+- watch.go implements the filesystem notification watch
+- wiki.go implements the main function
+
+If you want to change the exact markup rules, your starting point
+should be `parser.go`. Make sure you read the documentation of [Go
+Markdown](https://github.com/gomarkdown/markdown) and note that it
+offers MathJax support (needs a change to the `view.html` template so
+that the MathJax Javascript gets loaded) and
+[MMark](https://mmark.miek.nl/post/syntax/) support, and it shows how
+extensions can be added.
+
+One of the sad parts of the code is the distinction between path and
+filepath. On a Linux system, this doesn't matter. I suspect that it
+also doesn't matter on MacOS and Windows because the file systems
+handle forward slashes just fine. The code still tries to do the right
+thing. A path that is derived from a URL is a path, with slashes.
+Before accessing a file, it has to turned into a filepath using
+filepath.FromSlashes and in the rare case where the inverse happens,
+use filepath.ToSlashes.
+
+In the rare cases where you need to access the page name in code that
+is used from a template, you have to decode the path. See the code in
+diff.go for an example.
+
 ## References
 
 [Writing Web Applications](https://golang.org/doc/articles/wiki/)
 provided the initial code for this wiki.
-
-For the proxy stuff, see
-[Apache: mod_proxy](https://httpd.apache.org/docs/current/mod/mod_proxy.html).
-
-For the usernames and password stuff, see
-[Apache: Authentication and Authorization](https://httpd.apache.org/docs/current/howto/auth.html).

TODO.md

@@ -1,6 +0,0 @@
-Upload files should use path info so that we can use Apache to
-restrict access to directories.
-
-Automatically scale or process files.
-
-Post by Delta Chat? That is, allow certain encrypted emails to post.

accounts.go

@@ -0,0 +1,153 @@
+package main
+
+import (
+	"encoding/json"
+	"github.com/gomarkdown/markdown/ast"
+	"github.com/gomarkdown/markdown/parser"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"sync"
+)
+
+// useWebfinger indicates whether Oddmu looks up the profile pages of fediverse accounts. To enable this, set the
+// environment variable ODDMU_WEBFINGER to "1".
+var useWebfinger = false
+
+// Accounts contains the map used to set the usernames. Make sure to lock and unlock as appropriate.
+type Accounts struct {
+	sync.RWMutex
+
+	// uris is a map, mapping account names likes "@alex@alexschroeder.ch" to URIs like
+	// "https://social.alexschroeder.ch/@alex".
+	uris map[string]string
+}
+
+// accounts holds the global mapping of accounts to profile URIs.
+var accounts Accounts
+
+// This is called once at startup and therefore does not need to be locked. On every restart, this map starts empty and
+// is slowly repopulated as pages are visited.
+func init() {
+	if os.Getenv("ODDMU_WEBFINGER") == "1" {
+		accounts.uris = make(map[string]string)
+		useWebfinger = true
+	}
+}
+
+// account links a social media account like @account@domain to a profile page like https://domain/user/account. Any
+// account seen for the first time uses a best guess profile URI. It is also looked up using webfinger, in parallel. See
+// lookUpAccountUri. If the lookup succeeds, the best guess is replaced with the new URI so on subsequent requests, the
+// URI is correct.
+func account(p *parser.Parser, data []byte, offset int) (int, ast.Node) {
+	data = data[offset:]
+	i := 1 // skip @ of username
+	n := len(data)
+	d := 0
+	for i < n && (data[i] >= 'a' && data[i] <= 'z' ||
+		data[i] >= 'A' && data[i] <= 'Z' ||
+		data[i] >= '0' && data[i] <= '9' ||
+		data[i] == '@' ||
+		data[i] == '.' ||
+		data[i] == '_' ||
+		data[i] == '-') {
+		if data[i] == '@' {
+			if d != 0 {
+				// more than one @ is invalid
+				return 0, nil
+			} else {
+				d = i + 1 // skip @ of domain
+			}
+		}
+		i++
+	}
+	for i > 1 && (data[i-1] == '.' ||
+		data[i-1] == '-') {
+		i--
+	}
+	if i == 0 || d == 0 {
+		return 0, nil
+	}
+	user := data[0 : d-1] // includes @
+	domain := data[d:i]   // excludes @
+	account := data[1:i]  // excludes @
+	accounts.RLock()
+	uri, ok := accounts.uris[string(account)]
+	defer accounts.RUnlock()
+	if !ok {
+		log.Printf("Looking up %s\n", account)
+		uri = "https://" + string(domain) + "/users/" + string(user[1:])
+		accounts.uris[string(account)] = uri // prevent more lookings
+		go lookUpAccountUri(string(account), string(domain))
+	}
+	link := &ast.Link{
+		AdditionalAttributes: []string{`class="account"`},
+		Destination:          []byte(uri),
+		Title:                data[0:i],
+	}
+	ast.AppendChild(link, &ast.Text{Leaf: ast.Leaf{Literal: data[0 : d-1]}})
+	return i, link
+}
+
+// lookUpAccountUri is called for accounts that haven't been seen before. It calls webfinger and parses the JSON. If
+// possible, it extracts the link to the profile page and replaces the entry in accounts.
+func lookUpAccountUri(account, domain string) {
+	uri := "https://" + domain + "/.well-known/webfinger"
+	resp, err := http.Get(uri + "?resource=acct:" + account)
+	if err != nil {
+		log.Printf("Failed to look up %s: %s", account, err)
+		return
+	}
+	defer resp.Body.Close()
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		log.Printf("Failed to read from %s: %s", account, err)
+		return
+	}
+	var wf WebFinger
+	err = json.Unmarshal([]byte(body), &wf)
+	if err != nil {
+		log.Printf("Failed to parse the JSON from %s: %s", account, err)
+		return
+	}
+	uri, err = parseWebFinger(body)
+	if err != nil {
+		log.Printf("Could not find profile URI for %s: %s", account, err)
+	}
+	log.Printf("Found profile for %s: %s", account, uri)
+	accounts.Lock()
+	defer accounts.Unlock()
+	accounts.uris[account] = uri
+}
+
+// Link a link in the WebFinger JSON.
+type Link struct {
+	Rel  string `json:"rel"`
+	Type string `json:"type"`
+	Href string `json:"href"`
+}
+
+// WebFinger is a structure used to unmarshall JSON.
+type WebFinger struct {
+	Subject string   `json:"subject"`
+	Aliases []string `json:"aliases"`
+	Links   []Link   `json:"links"`
+}
+
+// parseWebFinger parses the web finger JSON and returns the profile page URI. For unmarshalling the JSON, it uses the
+// Link and WebFinger structs.
+func parseWebFinger(body []byte) (string, error) {
+	var wf WebFinger
+	err := json.Unmarshal(body, &wf)
+	if err != nil {
+		return "", err
+	}
+	for _, link := range wf.Links {
+		if link.Rel == "http://webfinger.net/rel/profile-page" &&
+			link.Type == "text/html" {
+			return link.Href, nil
+		}
+	}
+	return "", err
+}

accounts_test.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestWebfingerParsing(t *testing.T) {
+	body := []byte(`{
+  "subject": "acct:Gargron@mastodon.social",
+  "aliases": [
+    "https://mastodon.social/@Gargron",
+    "https://mastodon.social/users/Gargron"
+  ],
+  "links": [
+    {
+      "rel": "http://webfinger.net/rel/profile-page",
+      "type": "text/html",
+      "href": "https://mastodon.social/@Gargron"
+    },
+    {
+      "rel": "self",
+      "type": "application/activity+json",
+      "href": "https://mastodon.social/users/Gargron"
+    },
+    {
+      "rel": "http://ostatus.org/schema/1.0/subscribe",
+      "template": "https://mastodon.social/authorize_interaction?uri={uri}"
+    }
+  ]
+}`)
+	uri, err := parseWebFinger(body)
+	assert.NoError(t, err)
+	assert.Equal(t, "https://mastodon.social/@Gargron", uri)
+}

add.html

@@ -1,19 +1,20 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
   <head>
     <meta charset="utf-8">
     <meta name="format-detection" content="telephone=no">
     <meta name="viewport" content="width=device-width">
     <title>Add to {{.Title}}</title>
     <style>
-html { max-width: 70ch; padding: 2ch; margin: auto; color: #111; background: #ffe; }
+html { max-width: 70ch; padding: 2ch; margin: auto; color: #111; background-color: #ffe; }
 form, textarea { width: 100%; }
     </style>
   </head>
   <body>
     <h1>Adding to {{.Title}}</h1>
     <form action="/append/{{.Name}}" method="POST">
-      <textarea name="body" rows="20" cols="80" placeholder="Text" autofocus required></textarea>
+      <textarea name="body" rows="20" cols="80" placeholder="Text" lang="" autofocus required></textarea>
+      <p><label><input type="checkbox" name="notify" checked> Add link to <a href="/view/changes">the list of changes</a>.</label></p>
       <p><input type="submit" value="Add">
         <a href="/view/{{.Name}}"><button type="button">Cancel</button></a></p>
     </form>

add_append.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"bytes"
+	"log"
 	"net/http"
 )
 
@@ -14,24 +16,48 @@ func addHandler(w http.ResponseWriter, r *http.Request, name string) {
 	} else {
 		p.handleTitle(false)
 	}
-	renderTemplate(w, "add", p)
+	renderTemplate(w, p.Dir(), "add", p)
 }
 
-// appendHandler takes the "body" form parameter and appends it. The
-// browser is redirected to the page view.
+// appendHandler takes the "body" form parameter and appends it. The browser is redirected to the page view. This is
+// similar to the saveHandler.
 func appendHandler(w http.ResponseWriter, r *http.Request, name string) {
 	body := r.FormValue("body")
 	p, err := loadPage(name)
 	if err != nil {
-		p = &Page{Title: name, Name: name, Body: []byte(body)}
+		p = &Page{Name: name, Body: []byte(body)}
 	} else {
-		p.handleTitle(false)
-		p.Body = append(p.Body, []byte(body)...)
+		p.append([]byte(body))
 	}
+	p.handleTitle(false)
 	err = p.save()
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
+	username, _, ok := r.BasicAuth()
+	if ok {
+		log.Println("Save", name, "by", username)
+	} else {
+		log.Println("Save", name)
+	}
+	if r.FormValue("notify") == "on" {
+		err = p.notify()
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	}
 	http.Redirect(w, r, "/view/"+name, http.StatusFound)
 }
+
+func (p *Page) append(body []byte) {
+	// ensure an empty line at the end
+	if bytes.HasSuffix(p.Body, []byte("\n\n")) {
+	} else if bytes.HasSuffix(p.Body, []byte("\n")) {
+		p.Body = append(p.Body, '\n')
+	} else {
+		p.Body = append(p.Body, '\n', '\n')
+	}
+	p.Body = append(p.Body, body...)
+}

add_append_test.go

@@ -6,14 +6,25 @@ import (
 	"os"
 	"regexp"
 	"testing"
+	"time"
 )
 
-// wipes testdata
+func TestEmptyLineAdd(t *testing.T) {
+	p := &Page{Name: "testdata/add/fire", Body: []byte(`# Coal
+Black rocks light as foam
+Shaking, puring, shoveling`)}
+	p.append([]byte("Into the oven"))
+	assert.Equal(t, string(p.Body), `# Coal
+Black rocks light as foam
+Shaking, puring, shoveling
+
+Into the oven`)
+}
+
 func TestAddAppend(t *testing.T) {
-	_ = os.RemoveAll("testdata")
+	cleanup(t, "testdata/add")
 	index.load()
-	
-	p := &Page{Name: "testdata/fire", Body: []byte(`# Fire
+	p := &Page{Name: "testdata/add/fire", Body: []byte(`# Fire
 Orange sky above
 Reflects a distant fire
 It's not `)}
@@ -23,14 +34,39 @@ It's not `)}
 	data.Set("body", "barbecue")
 
 	assert.Regexp(t, regexp.MustCompile("a distant fire"),
-		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/fire", nil))
+		assert.HTTPBody(makeHandler(viewHandler, true),
+			"GET", "/view/testdata/add/fire", nil))
 	assert.NotRegexp(t, regexp.MustCompile("a distant fire"),
-		assert.HTTPBody(makeHandler(addHandler, true), "GET", "/add/testdata/fire", nil))
-	HTTPRedirectTo(t, makeHandler(appendHandler, true), "POST", "/append/testdata/fire", data, "/view/testdata/fire")
-	assert.Regexp(t, regexp.MustCompile("It’s not barbecue"),
-		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/fire", nil))
-
-	t.Cleanup(func() {
-		_ = os.RemoveAll("testdata")
-	})
+		assert.HTTPBody(makeHandler(addHandler, true),
+			"GET", "/add/testdata/add/fire", nil))
+	HTTPRedirectTo(t, makeHandler(appendHandler, true),
+		"POST", "/append/testdata/add/fire", data, "/view/testdata/add/fire")
+	assert.Regexp(t, regexp.MustCompile(`not</p>\s*<p>barbecue`),
+		assert.HTTPBody(makeHandler(viewHandler, true),
+			"GET", "/view/testdata/add/fire", nil))
+}
+
+func TestAddAppendChanges(t *testing.T) {
+	cleanup(t, "testdata/append")
+	today := time.Now().Format(time.DateOnly)
+	p := &Page{Name: "testdata/append/" + today + "-water", Body: []byte(`# Water
+Sunlight dancing fast
+Blue and green and pebbles gray
+`)}
+	p.save()
+	data := url.Values{}
+	data.Set("body", "Stand in cold water")
+	data.Add("notify", "on")
+	HTTPRedirectTo(t, makeHandler(appendHandler, true),
+		"POST", "/append/testdata/append/"+today+"-water",
+		data, "/view/testdata/append/"+today+"-water")
+	// The changes.md file was created
+	s, err := os.ReadFile("testdata/append/changes.md")
+	assert.NoError(t, err)
+	assert.Equal(t, "# Changes\n\n## "+today+"\n* [Water]("+today+"-water)\n", string(s))
+	// Link added to index.md file
+	s, err = os.ReadFile("testdata/append/index.md")
+	assert.NoError(t, err)
+	// New index contains just the link
+	assert.Equal(t, string(s), "* [Water]("+today+"-water)\n")
 }

changes.go

@@ -0,0 +1,187 @@
+package main
+
+import (
+	"log"
+	"path"
+	"regexp"
+	"strings"
+	"time"
+)
+
+// notify adds a link to the "changes" page, the "index" page, as well as to all the existing hashtag pages. The link to
+// the "index" page is only added if the page being edited is a blog page for the current year. The link to existing
+// hashtag pages is only added for blog pages. If the "changes" page does not exist, it is created. If the hashtag page
+// does not exist, it is not. Hashtag pages are considered optional. If the page that's being edited is in a
+// subdirectory, then the "changes", "index" and hashtag pages of that particular subdirectory are affected. Every
+// subdirectory is treated like a potentially independent wiki. Errors are logged before being returned because the
+// error messages are confusing from the point of view of the saveHandler.
+func (p *Page) notify() error {
+	p.handleTitle(false)
+	if p.Title == "" {
+		p.Title = p.Name
+	}
+	esc := nameEscape(path.Base(p.Name))
+	link := "* [" + p.Title + "](" + esc + ")\n"
+	re := regexp.MustCompile(`(?m)^\* \[[^\]]+\]\(` + esc + `\)\n`)
+	dir := path.Dir(p.Name)
+	err := addLinkWithDate(path.Join(dir, "changes"), link, re)
+	if err != nil {
+		log.Printf("Updating changes in %s failed: %s", dir, err)
+		return err
+	}
+	if p.isBlog() {
+		// Add to the index only if the blog post is for the current year
+		if strings.HasPrefix(path.Base(p.Name), time.Now().Format("2006")) {
+			err := addLink(path.Join(dir, "index"), true, link, re)
+			if err != nil {
+				log.Printf("Updating index in %s failed: %s", dir, err)
+				return err
+			}
+		}
+		p.renderHtml() // to set hashtags
+		for _, hashtag := range p.Hashtags {
+			err := addLink(path.Join(dir, hashtag), false, link, re)
+			if err != nil {
+				log.Printf("Updating hashtag %s in %s failed: %s", hashtag, dir, err)
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// addLinkWithDate adds the link to a page, with date header for today. If a match already exists, it is removed. If
+// this leaves a date header without any links, it is removed as well. If a list is found, the link is added at the top
+// of the list. Lists must use the asterisk, not the minus character.
+func addLinkWithDate(name, link string, re *regexp.Regexp) error {
+	date := time.Now().Format(time.DateOnly)
+	org := ""
+	p, err := loadPage(name)
+	if err != nil {
+		// create a new page
+		p = &Page{Name: name, Body: []byte("# Changes\n\n## " + date + "\n" + link)}
+	} else {
+		org = string(p.Body)
+		// remove the old match, if one exists
+		loc := re.FindIndex(p.Body)
+		if loc != nil {
+			r := p.Body[:loc[0]]
+			if loc[1] < len(p.Body) {
+				r = append(r, p.Body[loc[1]:]...)
+			}
+			p.Body = r
+			if loc[0] >= 14 && len(p.Body) >= loc[0]+15 {
+				// remove the preceding date if there are now two dates following each other
+				re := regexp.MustCompile(`(?m)^## (\d\d\d\d-\d\d-\d\d)\n\n## (\d\d\d\d-\d\d-\d\d)\n`)
+				if re.Match(p.Body[loc[0]-14 : loc[0]+15]) {
+					p.Body = append(p.Body[0:loc[0]-14], p.Body[loc[0]+1:]...)
+				}
+			} else if len(p.Body) == loc[0] {
+				// remove a trailing date
+				re := regexp.MustCompile(`## (\d\d\d\d-\d\d-\d\d)\n`)
+				if re.Match(p.Body[loc[0]-14 : loc[0]]) {
+					p.Body = p.Body[0 : loc[0]-14]
+				}
+			}
+		}
+		// locate the beginning of the list to insert the line
+		re := regexp.MustCompile(`(?m)^\* \[[^\]]+\]\([^\)]+\)\n`)
+		loc = re.FindIndex(p.Body)
+		if loc == nil {
+			// if no list was found, use the end of the page
+			loc = []int{len(p.Body)}
+		}
+		// start with new page content
+		r := []byte("")
+		// check if there is a date right before the insertion point
+		addDate := true
+		if loc[0] >= 14 {
+			re := regexp.MustCompile(`(?m)^## (\d\d\d\d-\d\d-\d\d)\n`)
+			m := re.Find(p.Body[loc[0]-14 : loc[0]])
+			if m == nil {
+				// not a date: insert date, don't move insertion point
+			} else if string(p.Body[loc[0]-11:loc[0]-1]) == date {
+				// if the date is our date, don't add it, don't move insertion point
+				addDate = false
+			} else {
+				// if the date is not out date, move the insertion point
+				loc[0] -= 14
+			}
+		}
+		// append up to the insertion point
+		r = append(r, p.Body[:loc[0]]...)
+		// append date, if necessary
+		if addDate {
+			// ensure paragraph break
+			if len(r) > 0 && r[len(r)-1] != '\n' {
+				r = append(r, '\n')
+			}
+			if len(r) > 1 && r[len(r)-2] != '\n' {
+				r = append(r, '\n')
+			}
+			r = append(r, []byte("## ")...)
+			r = append(r, []byte(date)...)
+			r = append(r, '\n')
+		}
+		// append link
+		r = append(r, []byte(link)...)
+		// if we just added a date, add an empty line after the single-element list
+		if len(p.Body) > loc[0] && p.Body[loc[0]] != '*' {
+			r = append(r, '\n')
+		}
+		// append the rest
+		r = append(r, p.Body[loc[0]:]...)
+		p.Body = r
+	}
+	// only save if something changed
+	if string(p.Body) != org {
+		return p.save()
+	}
+	return nil
+}
+
+// addLink adds a link to a named page, if the page exists and doesn't contain the link. If the link exists but with a
+// different title, the title is fixed.
+func addLink(name string, mandatory bool, link string, re *regexp.Regexp) error {
+	p, err := loadPage(name)
+	if err != nil {
+		if mandatory {
+			p = &Page{Name: name, Body: []byte(link)}
+			return p.save()
+		} else {
+			// Skip non-existing files: no error
+			return nil
+		}
+	}
+	org := string(p.Body)
+	// if a link exists, that's the place to insert the new link (in which case loc[0] and loc[1] differ)
+	loc := re.FindIndex(p.Body)
+	// if no link exists, find a good place to insert it
+	if loc == nil {
+		// locate the beginning of the list to insert the line
+		re = regexp.MustCompile(`(?m)^\* \[[^\]]+\]\([^\)]+\)\n`)
+		loc = re.FindIndex(p.Body)
+		if loc == nil {
+			// if no list was found, use the end of the page
+			m := len(p.Body)
+			loc = []int{m, m}
+		} else {
+			// if a list item was found, use just the beginning as insertion point
+			loc[1] = loc[0]
+		}
+	}
+	// start with new page content
+	r := []byte("")
+	// append up to the insertion point
+	r = append(r, p.Body[:loc[0]]...)
+	// append link
+	r = append(r, []byte(link)...)
+	// append the rest
+	r = append(r, p.Body[loc[1]:]...)
+	p.Body = r
+	// only save if something changed
+	if string(p.Body) != org {
+		return p.save()
+	}
+	return nil
+}

changes_test.go

@@ -0,0 +1,206 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"testing"
+	"time"
+)
+
+// Note TestEditSaveChanges and TestAddAppendChanges.
+
+func TestChanges(t *testing.T) {
+	cleanup(t, "testdata/washing")
+	today := time.Now().Format(time.DateOnly)
+	p := &Page{Name: "testdata/washing/" + today + "-machine",
+		Body: []byte(`# Washing machine
+Churning growling thing
+Water spraying in a box 
+Out of sight and dark`)}
+	p.notify()
+	// Link added to changes.md file
+	s, err := os.ReadFile("testdata/washing/changes.md")
+	assert.NoError(t, err)
+	assert.Contains(t, string(s), "[Washing machine]("+today+"-machine)")
+	// Link added to index.md file
+	s, err = os.ReadFile("testdata/washing/index.md")
+	assert.NoError(t, err)
+	// New index contains just the link
+	assert.Equal(t, string(s), "* [Washing machine]("+today+"-machine)\n")
+}
+
+func TestChangesWithHashtag(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	intro := "# Haiku\n"
+	line := "* [Hotel room](2023-10-27-hotel)\n"
+	h := &Page{Name: "testdata/changes/Haiku", Body: []byte(intro)}
+	h.save()
+	p := &Page{Name: "testdata/changes/2023-10-27-hotel",
+		Body: []byte(`# Hotel room
+White linen and white light
+Wooden floor and painted walls
+Home away from home
+
+#Haiku #Poetry`)}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	assert.Contains(t, string(s), line)
+	s, err = os.ReadFile("testdata/changes/Haiku.md")
+	assert.NoError(t, err)
+	assert.Equal(t, intro+line, string(s))
+	assert.NoFileExists(t, "testdata/changes/Poetry.md")
+}
+
+func TestChangesWithList(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	intro := "# Changes\n\nThis is a paragraph.\n\n"
+	d := "## " + time.Now().Format(time.DateOnly) + "\n"
+	line := "* [a change](change)\n"
+	assert.NoError(t, os.MkdirAll("testdata/changes", 0755))
+	assert.NoError(t, os.WriteFile("testdata/changes/changes.md", []byte(intro+d+line), 0644))
+	p := &Page{Name: "testdata/changes/alex", Body: []byte(`Hallo!`)}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	new_line := "* [testdata/changes/alex](alex)\n"
+	// new line was added at the beginning of the list
+	assert.Equal(t, intro+d+new_line+line, string(s))
+}
+
+func TestChangesWithOldList(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	intro := "# Changes\n\nThis is a paragraph.\n\n"
+	line := "* [a change](change)\n"
+	y := "## " + time.Now().Add(-24*time.Hour).Format(time.DateOnly) + "\n"
+	d := "## " + time.Now().Format(time.DateOnly) + "\n"
+	assert.NoError(t, os.MkdirAll("testdata/changes", 0755))
+	assert.NoError(t, os.WriteFile("testdata/changes/changes.md", []byte(intro+y+line), 0644))
+	p := &Page{Name: "testdata/changes/alex", Body: []byte(`Hallo!`)}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	new_line := "* [testdata/changes/alex](alex)\n"
+	// new line was added at the beginning of the list
+	assert.Equal(t, intro+d+new_line+"\n"+y+line, string(s))
+}
+
+func TestChangesWithOldDisappearingListAtTheEnd(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	intro := "# Changes\n\nThis is a paragraph.\n\n"
+	line := "* [a change](alex)\n"
+	y := "## " + time.Now().Add(-24*time.Hour).Format(time.DateOnly) + "\n"
+	d := "## " + time.Now().Format(time.DateOnly) + "\n"
+	assert.NoError(t, os.MkdirAll("testdata/changes", 0755))
+	assert.NoError(t, os.WriteFile("testdata/changes/changes.md", []byte(intro+y+line), 0644))
+	p := &Page{Name: "testdata/changes/alex", Body: []byte(`Hallo!`)}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	new_line := "* [testdata/changes/alex](alex)\n"
+	// new line was added at the beginning of the list, with the new date, and the old date disappeared
+	assert.Equal(t, intro+d+new_line, string(s))
+}
+
+func TestChangesWithOldDisappearingListInTheMiddle(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	intro := "# Changes\n\nThis is a paragraph.\n\n"
+	line := "* [a change](alex)\n"
+	other := "* [other change](whatever)\n"
+	yy := "## " + time.Now().Add(-48*time.Hour).Format(time.DateOnly) + "\n"
+	y := "## " + time.Now().Add(-24*time.Hour).Format(time.DateOnly) + "\n"
+	d := "## " + time.Now().Format(time.DateOnly) + "\n"
+	assert.NoError(t, os.MkdirAll("testdata/changes", 0755))
+	assert.NoError(t, os.WriteFile("testdata/changes/changes.md", []byte(intro+y+line+"\n"+yy+other), 0644))
+	p := &Page{Name: "testdata/changes/alex", Body: []byte(`Hallo!`)}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	new_line := "* [testdata/changes/alex](alex)\n"
+	// new line was added at the beginning of the list, with the new date, and the old date disappeared
+	assert.Equal(t, intro+d+new_line+"\n"+yy+other, string(s))
+}
+
+func TestChangesWithListAtTheTop(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	line := "* [a change](change)\n"
+	d := "## " + time.Now().Format(time.DateOnly) + "\n"
+	assert.NoError(t, os.MkdirAll("testdata/changes", 0755))
+	assert.NoError(t, os.WriteFile("testdata/changes/changes.md", []byte(line), 0644))
+	p := &Page{Name: "testdata/changes/alex", Body: []byte(`Hallo!`)}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	new_line := "* [testdata/changes/alex](alex)\n"
+	// new line was added at the top, no error due to missing introduction
+	assert.Equal(t, d+new_line+line, string(s))
+}
+
+func TestChangesWithNoList(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	intro := "# Changes\n\nThis is a paragraph."
+	d := "## " + time.Now().Format(time.DateOnly) + "\n"
+	assert.NoError(t, os.MkdirAll("testdata/changes", 0755))
+	assert.NoError(t, os.WriteFile("testdata/changes/changes.md", []byte(intro), 0644))
+	p := &Page{Name: "testdata/changes/alex", Body: []byte(`Hallo!`)}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	new_line := "* [testdata/changes/alex](alex)\n"
+	// into is still there and a new list was started
+	assert.Equal(t, intro+"\n\n"+d+new_line, string(s))
+}
+
+func TestChangesWithUpdate(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	intro := "# Changes\n\nThis is a paragraph.\n\n"
+	other := "* [other change](whatever)\n"
+	d := "## " + time.Now().Format(time.DateOnly) + "\n"
+	line := "* [a change](alex)\n"
+	assert.NoError(t, os.MkdirAll("testdata/changes", 0755))
+	assert.NoError(t, os.WriteFile("testdata/changes/changes.md", []byte(intro+d+other+line), 0644))
+	p := &Page{Name: "testdata/changes/alex", Body: []byte(`Hallo!`)}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	new_line := "* [testdata/changes/alex](alex)\n"
+	// the change was already listed, but now it moved up and has a new title
+	assert.Equal(t, intro+d+new_line+other, string(s))
+}
+
+func TestChangesWithNoChangeToTheOrder(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	intro := "# Changes\n\nThis is a paragraph.\n\n"
+	d := "## " + time.Now().Format(time.DateOnly) + "\n"
+	line := "* [a change](alex)\n"
+	other := "* [other change](whatever)\n"
+	assert.NoError(t, os.MkdirAll("testdata/changes", 0755))
+	assert.NoError(t, os.WriteFile("testdata/changes/changes.md", []byte(intro+d+line+other), 0644))
+	p := &Page{Name: "testdata/changes/alex", Body: []byte(`Hallo!`)}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	new_line := "* [testdata/changes/alex](alex)\n"
+	// the change was already listed at the top, so just use the new title
+	assert.Equal(t, intro+d+new_line+other, string(s))
+	// since the file has changed, a backup was necessary
+	assert.FileExists(t, "testdata/changes/changes.md~")
+}
+
+func TestChangesWithNoChanges(t *testing.T) {
+	cleanup(t, "testdata/changes")
+	intro := "# Changes\n\nThis is a paragraph.\n\n"
+	d := "## " + time.Now().Format(time.DateOnly) + "\n"
+	line := "* [a change](alex)\n"
+	other := "* [other change](whatever)\n"
+	assert.NoError(t, os.MkdirAll("testdata/changes", 0755))
+	assert.NoError(t, os.WriteFile("testdata/changes/changes.md", []byte(intro+d+line+other), 0644))
+	p := &Page{Name: "testdata/changes/alex", Body: []byte("# a change\nHallo!")}
+	p.notify()
+	s, err := os.ReadFile("testdata/changes/changes.md")
+	assert.NoError(t, err)
+	// the change was already listed at the top, so no change was necessary
+	assert.Equal(t, intro+d+line+other, string(s))
+	// since the file hasn't changed, no backup was necessary
+	assert.NoFileExists(t, "testdata/changes/changes.md~")
+}

commands.go

@@ -1,36 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"os"
-)
-
-func commands() {
-	if len(os.Args) == 3 && os.Args[1] == "html" {
-		p, err := loadPage(os.Args[2]);
-		if err != nil {
-			fmt.Println(err);
-		} else {
-			p.renderHtml();
-			fmt.Println(p.Html);
-		}
-	} else if len(os.Args) > 2 && os.Args[1] == "search" {
-		index.load()
-		for _, q := range os.Args[2:] {
-			items := search(q)
-			fmt.Printf("Search %s: %d results\n", q, len(items))
-			for _, p := range items {
-				fmt.Printf("* %s (%d)\n", p.Title, p.Score)
-			}
-		}
-	} else {
-		fmt.Printf("Unknown command: %v\n", os.Args[1:])
-		fmt.Print("Without any arguments, serves a wiki.\n")
-		fmt.Print("  Environment variable ODDMUSE_PORT controls the port.\n")
-		fmt.Print("  Environment variable ODDMUSE_LANGAUGES controls the languages detected.\n")
-		fmt.Print("html PAGENAME\n")
-		fmt.Print("  Print the HTML of the page.\n")
-		fmt.Print("search TERMS\n")
-		fmt.Print("  Print the titles of the page with score.\n")
-	}
-}

concurrency_test.go

@@ -1,15 +0,0 @@
-package main
-
-import (
-	"github.com/stretchr/testify/assert"
-	"testing"
-)
-
-// Use go test -race to see whether this is a race condition.
-func TestLoadAndSearch(t *testing.T) {
-	index.reset()
-	go index.load()
-	q := "Oddµ"
-	pages := search(q)
-	assert.Zero(t, len(pages))
-}

diff.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"bytes"
+	"github.com/sergi/go-diff/diffmatchpatch"
+	"html"
+	"html/template"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func diffHandler(w http.ResponseWriter, r *http.Request, name string) {
+	p, err := loadPage(name)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	p.handleTitle(true)
+	p.renderHtml()
+	renderTemplate(w, p.Dir(), "diff", p)
+}
+
+// Diff computes the diff for a page. At this point, renderHtml has already been called so the Name is escaped.
+func (p *Page) Diff() template.HTML {
+	path, err := url.PathUnescape(p.Name)
+	if err != nil {
+		return template.HTML("Cannot unescape " + p.Name)
+	}
+	fp := filepath.FromSlash(path)
+	a := fp + ".md~"
+	t1, err := os.ReadFile(a)
+	if err != nil {
+		return template.HTML("Cannot read " + a + ", so the page is new.")
+	}
+	b := fp + ".md"
+	t2, err := os.ReadFile(b)
+	if err != nil {
+		return template.HTML("Cannot read " + b + ", so the page was deleted.")
+	}
+	dmp := diffmatchpatch.New()
+	diffs := dmp.DiffMain(string(t1), string(t2), false)
+	return template.HTML(diff2html(dmp.DiffCleanupSemantic(diffs)))
+}
+
+func diff2html(diffs []diffmatchpatch.Diff) string {
+	var buff bytes.Buffer
+	for _, item := range diffs {
+		text := strings.ReplaceAll(html.EscapeString(item.Text), "\n", "<br>")
+		switch item.Type {
+		case diffmatchpatch.DiffInsert:
+			_, _ = buff.WriteString("<ins>")
+			_, _ = buff.WriteString(text)
+			_, _ = buff.WriteString("</ins>")
+		case diffmatchpatch.DiffDelete:
+			_, _ = buff.WriteString("<del>")
+			_, _ = buff.WriteString(text)
+			_, _ = buff.WriteString("</del>")
+		case diffmatchpatch.DiffEqual:
+			_, _ = buff.WriteString("<span>")
+			_, _ = buff.WriteString(text)
+			_, _ = buff.WriteString("</span>")
+		}
+	}
+	return buff.String()
+}

diff.html

@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html lang="{{.Language}}">
+  <head>
+    <meta charset="utf-8">
+    <meta name="format-detection" content="telephone=no">
+    <meta name="viewport" content="width=device-width">
+    <title>{{.Title}}</title>
+    <style>
+html { max-width: 70ch; padding: 1ch; margin: auto; color: #111; background-color: #ffe; }
+body { hyphens: auto; }
+del  { background-color: #fab }
+ins  { background-color: #af8 }
+pre { white-space: normal; background-color: white; border: 1px solid #eee; padding: 1ch }
+    </style>
+  </head>
+  <body>
+    <header>
+      <a href="/view/{{.Name}}">Back</a>
+    </header>
+    <main id="main">
+      <h1>{{.Title}}</h1>
+      <p>This is the diff between <a href="/view/{{.Name}}.md~">the backup</a> and <a href="/view/{{.Name}}.md">the current copy</a>.</p>
+      <pre>
+{{.Diff}}
+      </pre>
+    </main>
+  </body>
+</html>

diff_test.go

@@ -0,0 +1,96 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestDiff(t *testing.T) {
+	cleanup(t, "testdata/diff")
+	index.load()
+	s := `# Bread
+
+The oven breathes
+Fills us with the thought of bread
+Oh so fresh, so warm.`
+	r := `# Bread
+
+The oven whispers
+Fills us with the thought of bread
+Oh so fresh, so warm.`
+	p := &Page{Name: "testdata/diff/bread", Body: []byte(s)}
+	p.save()
+	p.Body = []byte(r)
+	p.save()
+	body := assert.HTTPBody(makeHandler(diffHandler, true),
+		"GET", "/diff/testdata/diff/bread", nil)
+	assert.Contains(t, body, `<del>breathe</del>`)
+	assert.Contains(t, body, `<ins>whisper</ins>`)
+}
+
+func TestDiffPercentEncoded(t *testing.T) {
+	cleanup(t, "testdata/diff")
+	index.load()
+	s := `# Coup de Gras
+
+Playing D&D
+We talk about a killing
+Mispronouncing words`
+	r := `# Coup de Grace
+
+Playing D&D
+We talk about a killing
+Mispronouncing words`
+	p := &Page{Name: "testdata/diff/coup de grace", Body: []byte(s)}
+	p.save()
+	p.Body = []byte(r)
+	p.save()
+	body := assert.HTTPBody(makeHandler(diffHandler, true),
+		"GET", "/diff/testdata/diff/coup%20de%20grace", nil)
+	assert.Contains(t, body, `<del>s</del>`)
+	assert.Contains(t, body, `<ins>ce</ins>`)
+}
+
+func TestDiffBackup(t *testing.T) {
+	cleanup(t, "testdata/backup")
+	s := `# Cold Rooms
+
+I shiver at home
+the monitor glares and moans
+fear or cold, who knows?`
+	r := `# Cold Rooms
+
+I shiver at home
+the monitor glares and moans
+I hate the machine!`
+	u := `# Cold Rooms
+
+I shiver at home
+the monitor glares and moans
+my grey heart grows cold`
+	p := &Page{Name: "testdata/backup/cold", Body: []byte(s)}
+	p.save()
+	p = &Page{Name: "testdata/backup/cold", Body: []byte(r)}
+	p.save()
+	body := string(p.Diff())
+	// diff from s to r:
+	assert.Contains(t, body, `<del>fear or cold, who knows?</del>`)
+	assert.Contains(t, body, `<ins>I hate the machine!</ins>`)
+	p = &Page{Name: "testdata/backup/cold", Body: []byte(u)}
+	p.save()
+	body = string(p.Diff())
+	// diff from s to u since r was not 60 min or older
+	assert.Contains(t, body, `<del>fear or cold, who knows?</del>`)
+	assert.Contains(t, body, `<ins>my grey heart grows cold</ins>`)
+	// set timestamp 2h in the past
+	ts := time.Now().Add(-2 * time.Hour)
+	assert.NoError(t, os.Chtimes("testdata/backup/cold.md~", ts, ts))
+	p = &Page{Name: "testdata/backup/cold", Body: []byte(r)}
+	p.save()
+	body = string(p.Diff())
+	// diff from u to r:
+	assert.Contains(t, body, `<del>my grey heart grows cold</del>`)
+	assert.Contains(t, body, `<ins>I hate the machine!</ins>`)
+}

edit.html

@@ -1,12 +1,12 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
   <head>
     <meta charset="utf-8">
     <meta name="format-detection" content="telephone=no">
     <meta name="viewport" content="width=device-width">
     <title>Editing {{.Title}}</title>
     <style>
-html { max-width: 70ch; padding: 2ch; margin: auto; color: #111; background: #ffe; }
+html { max-width: 70ch; padding: 2ch; margin: auto; color: #111; background-color: #ffe; }
 form, textarea { width: 100%; }
     </style>
   </head>
@@ -15,7 +15,8 @@ form, textarea { width: 100%; }
     <form action="/save/{{.Name}}" method="POST">
       <textarea name="body" rows="20" cols="80" placeholder="# Title
 
-Text" autofocus>{{printf "%s" .Body}}</textarea>
+Text" lang="" autofocus>{{printf "%s" .Body}}</textarea>
+      <p><label><input type="checkbox" name="notify" checked> Add link to <a href="changes">the list of changes</a>.</label></p>
       <p><input type="submit" value="Save">
         <a href="/view/{{.Name}}"><button type="button">Cancel</button></a></p>
     </form>

edit_save.go

@@ -1,13 +1,12 @@
 package main
 
 import (
+	"log"
 	"net/http"
 )
 
-// editHandler uses the "edit.html" template to present an edit page.
-// When editing, the page title is not overriden by a title in the
-// text. Instead, the page name is used. The edit is saved using the
-// saveHandler.
+// editHandler uses the "edit.html" template to present an edit page. When editing, the page title is not overriden by a
+// title in the text. Instead, the page name is used. The edit is saved using the saveHandler.
 func editHandler(w http.ResponseWriter, r *http.Request, name string) {
 	p, err := loadPage(name)
 	if err != nil {
@@ -15,18 +14,32 @@ func editHandler(w http.ResponseWriter, r *http.Request, name string) {
 	} else {
 		p.handleTitle(false)
 	}
-	renderTemplate(w, "edit", p)
+	renderTemplate(w, p.Dir(), "edit", p)
 }
 
-// saveHandler takes the "body" form parameter and saves it. The
-// browser is redirected to the page view.
+// saveHandler takes the "body" form parameter and saves it. The browser is redirected to the page view. This is similar
+// to the appendHandler.
 func saveHandler(w http.ResponseWriter, r *http.Request, name string) {
 	body := r.FormValue("body")
 	p := &Page{Name: name, Body: []byte(body)}
 	err := p.save()
 	if err != nil {
+		log.Println(err)
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
+	username, _, ok := r.BasicAuth()
+	if ok {
+		log.Println("Save", name, "by", username)
+	} else {
+		log.Println("Save", name)
+	}
+	if r.FormValue("notify") == "on" {
+		err = p.notify() // errors have already been logged, so no logging here
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	}
 	http.Redirect(w, r, "/view/"+name, http.StatusFound)
 }

edit_save_test.go

@@ -4,24 +4,73 @@ import (
 	"github.com/stretchr/testify/assert"
 	"net/url"
 	"os"
-	"regexp"
 	"testing"
+	"time"
 )
 
-// wipes testdata
 func TestEditSave(t *testing.T) {
-	_ = os.RemoveAll("testdata")
+	cleanup(t, "testdata/save")
 
 	data := url.Values{}
 	data.Set("body", "Hallo!")
 
-	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata/alex", nil, "/edit/testdata/alex")
-	assert.HTTPStatusCode(t, makeHandler(editHandler, true), "GET", "/edit/testdata/alex", nil, 200)
-	HTTPRedirectTo(t, makeHandler(saveHandler, true), "POST", "/save/testdata/alex", data, "/view/testdata/alex")
-	assert.Regexp(t, regexp.MustCompile("Hallo!"),
-		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/alex", nil))
-
-	t.Cleanup(func() {
-		_ = os.RemoveAll("testdata")
-	})
+	// View of the non-existing page redirects to the edit page
+	HTTPRedirectTo(t, makeHandler(viewHandler, true),
+		"GET", "/view/testdata/save/alex", nil, "/edit/testdata/save/alex")
+	// Edit page can be fetched
+	assert.HTTPStatusCode(t, makeHandler(editHandler, true),
+		"GET", "/edit/testdata/save/alex", nil, 200)
+	// Posting to the save URL saves a page
+	HTTPRedirectTo(t, makeHandler(saveHandler, true),
+		"POST", "/save/testdata/save/alex", data, "/view/testdata/save/alex")
+	// Page now contains the text
+	assert.Contains(t, assert.HTTPBody(makeHandler(viewHandler, true),
+		"GET", "/view/testdata/save/alex", nil),
+		"Hallo!")
+	// Delete the page and you're sent to the empty page
+	data.Set("body", "")
+	HTTPRedirectTo(t, makeHandler(saveHandler, true),
+		"POST", "/save/testdata/save/alex", data, "/view/testdata/save/alex")
+	// Viewing the non-existing page redirects to the edit page (like in the beginning)
+	HTTPRedirectTo(t, makeHandler(viewHandler, true),
+		"GET", "/view/testdata/save/alex", nil, "/edit/testdata/save/alex")
+}
+
+func TestEditSaveChanges(t *testing.T) {
+	cleanup(t, "testdata/notification")
+	data := url.Values{}
+	data.Set("body", "Hallo!")
+	data.Add("notify", "on")
+	today := time.Now().Format("2006-01-02")
+	// Posting to the save URL saves a page
+	HTTPRedirectTo(t, makeHandler(saveHandler, true),
+		"POST", "/save/testdata/notification/"+today,
+		data, "/view/testdata/notification/"+today)
+	// The changes.md file was created
+	s, err := os.ReadFile("testdata/notification/changes.md")
+	assert.NoError(t, err)
+	d := time.Now().Format(time.DateOnly)
+	assert.Equal(t, "# Changes\n\n## "+d+
+		"\n* [testdata/notification/"+today+"]("+today+")\n",
+		string(s))
+	// Link added to index.md file
+	s, err = os.ReadFile("testdata/notification/index.md")
+	assert.NoError(t, err)
+	// New index contains just the link
+	assert.Equal(t, string(s), "* [testdata/notification/"+today+"]("+today+")\n")
+}
+
+// Test the following view.html:
+// <form action="/edit/" method="GET">
+//
+//	<label for="id">New page:</label>
+//	<input id="id" type="text" spellcheck="false" name="id" accesskey="g" value="{{.Dir}}/{{.Today}}" required>
+//	<button>Edit</button>
+//
+// </form>
+func TestEditId(t *testing.T) {
+	cleanup(t, "testdata/id")
+	assert.Contains(t, assert.HTTPBody(makeHandler(editHandler, true),
+		"GET", "/edit/?id=testdata/id/alex", nil),
+		"Editing testdata/id/alex")
 }

feed.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"bytes"
+	"github.com/gomarkdown/markdown"
+	"github.com/gomarkdown/markdown/ast"
+	"html/template"
+	"os"
+	"path"
+	"path/filepath"
+	"time"
+)
+
+type Item struct {
+	Page
+	Date string
+}
+
+type Feed struct {
+	Item
+	Items []Item
+}
+
+func feed(p *Page, ti time.Time) *Feed {
+	feed := new(Feed)
+	feed.Name = p.Name
+	feed.Title = p.Title
+	feed.Date = ti.Format(time.RFC1123Z)
+	parser, _ := wikiParser()
+	doc := markdown.Parse(p.Body, parser)
+	items := make([]Item, 0)
+	inListItem := false
+	ast.WalkFunc(doc, func(node ast.Node, entering bool) ast.WalkStatus {
+		// set the flag if we're in a list item
+		listItem, ok := node.(*ast.ListItem)
+		if ok && listItem.BulletChar == '*' {
+			inListItem = entering
+			return ast.GoToNext
+		}
+		// if we're not in a list item, continue
+		if !inListItem || !entering {
+			return ast.GoToNext
+		}
+		// if we're in a link and it's local
+		link, ok := node.(*ast.Link)
+		if !ok || bytes.Contains(link.Destination, []byte("//")) {
+			return ast.GoToNext
+		}
+		name := path.Join(path.Dir(p.Name), string(link.Destination))
+		fi, err := os.Stat(filepath.FromSlash(name) + ".md")
+		if err != nil {
+			return ast.GoToNext
+		}
+		p2, err := loadPage(name)
+		if err != nil {
+			return ast.GoToNext
+		}
+		p2.handleTitle(false)
+		p2.renderHtml()
+		it := Item{Date: fi.ModTime().Format(time.RFC1123Z)}
+		it.Title = p2.Title
+		it.Name = p2.Name
+		it.Html = template.HTML(template.HTMLEscaper(p2.Html))
+		it.Hashtags = p2.Hashtags
+		items = append(items, it)
+		if len(items) >= 10 {
+			return ast.Terminate
+		}
+		return ast.GoToNext
+	})
+	feed.Items = items
+	return feed
+}

feed.html

@@ -0,0 +1,28 @@
+<rss xmlns:atom="http://www.w3.org/2005/Atom" version="2.0">
+  <channel>
+    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
+    <title>{{.Title}}</title>
+    <link>https://example.org/</link>
+    <managingEditor>you@example.org (Your Name)</managingEditor>
+    <webMaster>you@example.org (Your Name)</webMaster>
+    <atom:link href="https://example.org/view/{{.Name}}.rss" rel="self" type="application/rss+xml"/>
+    <description>This is the digital garden of Your Name.</description>
+    <image>
+      <url>https://example.org/view/logo.jpg</url>
+      <title>{{.Title}}</title>
+      <link>https://example.org/</link>
+    </image>
+    {{range .Items}}
+    <item>
+      <title>{{.Title}}</title>
+      <link>https://example.org/view/{{.Name}}</link>
+      <guid>https://example.org/view/{{.Name}}</guid>
+      <description>{{.Html}}</description>
+      <pubDate>{{.Date}}</pubDate>
+      {{range .Hashtags}}
+      <category>{{.}}</category>
+      {{end}}
+    </item>
+    {{end}}
+  </channel>
+</rss>

feed_test.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestFeed(t *testing.T) {
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/index.rss", nil),
+		"Welcome to Oddµ")
+}
+
+func TestFeedItems(t *testing.T) {
+	cleanup(t, "testdata/feed")
+	index.load()
+
+	p1 := &Page{Name: "testdata/feed/cactus", Body: []byte(`# Cactus
+Green head and white hair
+A bench in the evening sun
+Unmoved by the news
+
+#Succulent`)}
+	p1.save()
+
+	p2 := &Page{Name: "testdata/feed/dragon", Body: []byte(`# Dragon
+My palm tree grows straight
+Up and up to touch the sky
+Ignoring the roof
+
+#Palmtree`)}
+	p2.save()
+
+	p3 := &Page{Name: "testdata/feed/plants", Body: []byte(`# Plants
+Writing poems about plants.
+
+* [My Cactus](cactus)
+* [My Dragon Tree](dragon)`)}
+	p3.save()
+
+	body := assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/feed/plants.rss", nil)
+	assert.Contains(t, body, "<title>Plants</title>")
+	assert.Contains(t, body, "<title>Cactus</title>")
+	assert.Contains(t, body, "<title>Dragon</title>")
+	assert.Contains(t, body, "&lt;h1&gt;Cactus&lt;/h1&gt;")
+	assert.Contains(t, body, "&lt;h1&gt;Dragon&lt;/h1&gt;")
+	assert.Contains(t, body, "<category>Succulent</category>")
+	assert.Contains(t, body, "<category>Palmtree</category>")
+}

go.mod

@@ -3,21 +3,37 @@ module alexschroeder.ch/cgit/oddmu
 go 1.21.0
 
 require (
-	github.com/dgryski/go-trigram v0.0.0-20160407183937-79ec494e1ad0
-	github.com/gomarkdown/markdown v0.0.0-20230912175223-14b07df9d538
-	github.com/microcosm-cc/bluemonday v1.0.25
+	github.com/anthonynsimon/bild v0.13.0
+	github.com/bashdrew/goheif v0.0.0-20230406184952-7a08ca9c9bdd
+	github.com/charmbracelet/lipgloss v0.9.1
+	github.com/gomarkdown/markdown v0.0.0-20231222211730-1d6d20845b47
+	github.com/google/subcommands v1.2.0
+	github.com/hexops/gotextdiff v1.0.3
+	github.com/microcosm-cc/bluemonday v1.0.26
 	github.com/pemistahl/lingua-go v1.4.0
+	github.com/sergi/go-diff v1.3.1
 	github.com/stretchr/testify v1.8.4
+	golang.org/x/exp v0.0.0-20240119083558-1b970713d09a
 )
 
 require (
+	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/aymerick/douceur v0.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/gorilla/css v1.0.0 // indirect
+	github.com/fsnotify/fsnotify v1.7.0 // indirect
+	github.com/gorilla/css v1.0.1 // indirect
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mattn/go-runewidth v0.0.15 // indirect
+	github.com/muesli/reflow v0.3.0 // indirect
+	github.com/muesli/termenv v0.15.2 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/rivo/uniseg v0.4.6 // indirect
+	github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd // indirect
 	github.com/shopspring/decimal v1.3.1 // indirect
-	golang.org/x/exp v0.0.0-20221106115401-f9659909a136 // indirect
-	golang.org/x/net v0.12.0 // indirect
-	google.golang.org/protobuf v1.31.0 // indirect
+	golang.org/x/image v0.15.0 // indirect
+	golang.org/x/net v0.20.0 // indirect
+	golang.org/x/sys v0.16.0 // indirect
+	google.golang.org/protobuf v1.32.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,38 +1,106 @@
+github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/anthonynsimon/bild v0.13.0 h1:mN3tMaNds1wBWi1BrJq0ipDBhpkooYfu7ZFSMhXt1C8=
+github.com/anthonynsimon/bild v0.13.0/go.mod h1:tpzzp0aYkAsMi1zmfhimaDyX1xjn2OUc1AJZK/TF0AE=
+github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
+github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
+github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
 github.com/aymerick/douceur v0.2.0 h1:Mv+mAeH1Q+n9Fr+oyamOlAkUNPWPlA8PPGR0QAaYuPk=
 github.com/aymerick/douceur v0.2.0/go.mod h1:wlT5vV2O3h55X9m7iVYN0TBM0NH/MmbLnd30/FjWUq4=
+github.com/bashdrew/goheif v0.0.0-20230406184952-7a08ca9c9bdd h1:SxkQeH4jjXT0zMgiRgkiIQjIvWfe9vXuTAmE3cfcQrU=
+github.com/bashdrew/goheif v0.0.0-20230406184952-7a08ca9c9bdd/go.mod h1:p1sbxRy+MY71fEWHcfRmerC8WUYXDFCExF9A7aXwp98=
+github.com/charmbracelet/lipgloss v0.9.1 h1:PNyd3jvaJbg4jRHKWXnCj1akQm4rh8dbEzN1p/u1KWg=
+github.com/charmbracelet/lipgloss v0.9.1/go.mod h1:1mPmG4cxScwUQALAAnacHaigiiHB9Pmr+v1VEawJl6I=
+github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
+github.com/coreos/go-etcd v2.0.0+incompatible/go.mod h1:Jez6KQU2B/sWsbdaef3ED8NzMklzPG4d5KIOhIy30Tk=
+github.com/coreos/go-semver v0.2.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3EedlOD2RNk=
+github.com/cpuguy83/go-md2man v1.0.10/go.mod h1:SmD6nW6nTyfqj6ABTjUi3V3JVMnlJmwcJI5acqYI6dE=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/dgryski/go-trigram v0.0.0-20160407183937-79ec494e1ad0 h1:b+7JSiBM+hnLQjP/lXztks5hnLt1PS46hktG9VOJgzo=
-github.com/dgryski/go-trigram v0.0.0-20160407183937-79ec494e1ad0/go.mod h1:qzKC/DpcxK67zaSHdCmIv3L9WJViHVinYXN2S7l3RM8=
-github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
-github.com/gomarkdown/markdown v0.0.0-20230716120725-531d2d74bc12 h1:uK3X/2mt4tbSGoHvbLBHUny7CKiuwUip3MArtukol4E=
-github.com/gomarkdown/markdown v0.0.0-20230716120725-531d2d74bc12/go.mod h1:JDGcbDT52eL4fju3sZ4TeHGsQwhG9nbDV21aMyhwPoA=
-github.com/gomarkdown/markdown v0.0.0-20230912175223-14b07df9d538 h1:ePDpFu7l0QUV46/9A7icfL2wvIOzTJLCWh4RO2NECzE=
-github.com/gomarkdown/markdown v0.0.0-20230912175223-14b07df9d538/go.mod h1:JDGcbDT52eL4fju3sZ4TeHGsQwhG9nbDV21aMyhwPoA=
-github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
+github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
+github.com/gomarkdown/markdown v0.0.0-20231222211730-1d6d20845b47 h1:k4Tw0nt6lwro3Uin8eqoET7MDA4JnT8YgbCjc/g5E3k=
+github.com/gomarkdown/markdown v0.0.0-20231222211730-1d6d20845b47/go.mod h1:JDGcbDT52eL4fju3sZ4TeHGsQwhG9nbDV21aMyhwPoA=
 github.com/google/go-cmp v0.5.8 h1:e6P7q2lk1O+qJJb4BtCQXlK8vWEO8V1ZeuEdJNOqZyg=
 github.com/google/go-cmp v0.5.8/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/gorilla/css v1.0.0 h1:BQqNyPTi50JCFMTw/b67hByjMVXZRwGha6wxVGkeihY=
-github.com/gorilla/css v1.0.0/go.mod h1:Dn721qIggHpt4+EFCcTLTU/vk5ySda2ReITrtgBl60c=
-github.com/microcosm-cc/bluemonday v1.0.25 h1:4NEwSfiJ+Wva0VxN5B8OwMicaJvD8r9tlJWm9rtloEg=
-github.com/microcosm-cc/bluemonday v1.0.25/go.mod h1:ZIOjCQp1OrzBBPIJmfX4qDYFuhU02nx4bn030ixfHLE=
+github.com/google/subcommands v1.2.0 h1:vWQspBTo2nEqTUFita5/KeEWlUL8kQObDFbub/EN9oE=
+github.com/google/subcommands v1.2.0/go.mod h1:ZjhPrFU+Olkh9WazFPsl27BQ4UPiG37m3yTrtFlrHVk=
+github.com/gorilla/css v1.0.1 h1:ntNaBIghp6JmvWnxbZKANoLyuXTPZ4cAMlo6RyhlbO8=
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+github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
+github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
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+github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
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 github.com/shopspring/decimal v1.3.1/go.mod h1:DKyhrW/HYNuLGql+MJL6WCR6knT2jwCFRcu2hWCYk4o=
+github.com/spf13/afero v1.1.2/go.mod h1:j4pytiNVoe2o6bmDsKpLACNPDBIoEAkihy7loJ1B0CQ=
+github.com/spf13/cast v1.3.0/go.mod h1:Qx5cxh0v+4UWYiBimWS+eyWzqEqokIECu5etghLkUJE=
+github.com/spf13/cobra v0.0.5/go.mod h1:3K3wKZymM7VvHMDS9+Akkh4K60UwM26emMESw8tLCHU=
+github.com/spf13/jwalterweatherman v1.0.0/go.mod h1:cQK4TGJAtQXfYWX+Ddv3mKDzgVb68N+wFjFa4jdeBTo=
+github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
+github.com/spf13/viper v1.3.2/go.mod h1:ZiWeW+zYFKm7srdB9IoDzzZXaJaI5eL9QjNiN/DMA2s=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
-golang.org/x/exp v0.0.0-20221106115401-f9659909a136 h1:Fq7F/w7MAa1KJ5bt2aJ62ihqp9HDcRuyILskkpIAurw=
-golang.org/x/exp v0.0.0-20221106115401-f9659909a136/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
-golang.org/x/net v0.12.0 h1:cfawfvKITfUsFCeJIHJrbSxpeu/E81khclypR0GVT50=
-golang.org/x/net v0.12.0/go.mod h1:zEVYFnQC7m/vmpQFELhcD1EWkZlX69l4oqgmer6hfKA=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
-google.golang.org/protobuf v1.31.0 h1:g0LDEJHgrBl9N9r17Ru3sqWhkIx2NB67okBHPwC7hs8=
-google.golang.org/protobuf v1.31.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+github.com/ugorji/go/codec v0.0.0-20181204163529-d75b2dcb6bc8/go.mod h1:VFNgLljTbGfSG7qAOspJ7OScBnGdDN/yBr0sguwnwf0=
+github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77/go.mod h1:aYKd//L2LvnjZzWKhF00oedf4jCCReLcmhLdhm1A27Q=
+golang.org/x/crypto v0.0.0-20181203042331-505ab145d0a9/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
+golang.org/x/exp v0.0.0-20240119083558-1b970713d09a h1:Q8/wZp0KX97QFTc2ywcOE0YRjZPVIx+MXInMzdvQqcA=
+golang.org/x/exp v0.0.0-20240119083558-1b970713d09a/go.mod h1:idGWGoKP1toJGkd5/ig9ZLuPcZBC3ewk7SzmH0uou08=
+golang.org/x/image v0.0.0-20190703141733-d6a02ce849c9/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
+golang.org/x/image v0.15.0 h1:kOELfmgrmJlw4Cdb7g/QGuB3CvDrXbqEIww/pNtNBm8=
+golang.org/x/image v0.15.0/go.mod h1:HUYqC05R2ZcZ3ejNQsIHQDQiwWM4JBqmm6MKANTp4LE=
+golang.org/x/net v0.20.0 h1:aCL9BSgETF1k+blQaYUBx9hJ9LOGP3gAVemcZlf1Kpo=
+golang.org/x/net v0.20.0/go.mod h1:z8BVo6PvndSri0LbOE3hAn0apkU+1YvI6E70E9jsnvY=
+golang.org/x/sys v0.0.0-20181205085412-a5c9d58dba9a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
+golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+google.golang.org/protobuf v1.32.0 h1:pPC6BG5ex8PDFnkbrGU3EixyhKcQ2aDuBS36lqK/C7I=
+google.golang.org/protobuf v1.32.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
+gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

html_cmd.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"github.com/google/subcommands"
+	"io"
+	"os"
+)
+
+type htmlCmd struct {
+	useTemplate bool
+}
+
+func (*htmlCmd) Name() string     { return "html" }
+func (*htmlCmd) Synopsis() string { return "render a page as HTML" }
+func (*htmlCmd) Usage() string {
+	return `html [-view] <page name> ...:
+  Render one or more pages as HTML.
+`
+}
+
+func (cmd *htmlCmd) SetFlags(f *flag.FlagSet) {
+	f.BoolVar(&cmd.useTemplate, "view", false, "use the 'view.html' template.")
+}
+
+func (cmd *htmlCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	return htmlCli(os.Stdout, cmd.useTemplate, f.Args())
+}
+
+func htmlCli(w io.Writer, useTemplate bool, args []string) subcommands.ExitStatus {
+	for _, arg := range args {
+		p, err := loadPage(arg)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Cannot load %s: %s\n", arg, err)
+			return subcommands.ExitFailure
+		}
+		if useTemplate {
+			p.handleTitle(true)
+			p.renderHtml()
+			t := "view.html"
+			loadTemplates()
+			err := templates.template[t].Execute(w, p)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Cannot execute %s template for %s: %s\n", t, arg, err)
+				return subcommands.ExitFailure
+			}
+		} else {
+			// do not handle title
+			p.renderHtml()
+			fmt.Fprintln(w, p.Html)
+		}
+	}
+	return subcommands.ExitSuccess
+}

html_cmd_test.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+	"bytes"
+	"github.com/google/subcommands"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestHtmlCmd(t *testing.T) {
+	b := new(bytes.Buffer)
+	s := htmlCli(b, false, []string{"index"})
+	assert.Equal(t, subcommands.ExitSuccess, s)
+	r := `<h1>Welcome to Oddµ</h1>
+
+<p>Hello! 🙃</p>
+
+<p>Check out the <a href="README">README</a>.</p>
+
+<p>Or <a href="test">create a new page</a>.</p>
+
+`
+	assert.Equal(t, r, b.String())
+}

index.go

@@ -1,112 +1,234 @@
+// Read Artem Krylysov's blog post on full text search as an
+// introduction.
+// https://artem.krylysov.com/blog/2020/07/28/lets-build-a-full-text-search-engine/
+
 package main
 
 import (
-	trigram "github.com/dgryski/go-trigram"
+	"golang.org/x/exp/constraints"
 	"io/fs"
+	"log"
 	"path/filepath"
+	"sort"
 	"strings"
 	"sync"
 )
 
+type docid uint
+
 // Index contains the two maps used for search. Make sure to lock and
 // unlock as appropriate.
 type Index struct {
 	sync.RWMutex
 
-	// index is a struct containing the trigram index for search.
-	// It is generated at startup and updated after every page
-	// edit. The index is case-insensitive.
-	index trigram.Index
+	// next_id is the number of the next document added to the index
+	next_id docid
 
-	// documents is a map, mapping document ids of the index to
-	// page names.
-	documents map[trigram.DocID]string
+	// index is an inverted index mapping tokens to document ids.
+	token map[string][]docid
+
+	// documents is a map, mapping document ids to page names.
+	documents map[docid]string
+
+	// titles is a map, mapping page names to titles.
+	titles map[string]string
 }
 
-// idx is the global Index per wiki.
 var index Index
 
-// reset resets the Index. This assumes that the index is locked!
+func init() {
+	index.reset()
+}
+
+// reset the index. This assumes that the index is locked. It's useful for tests.
 func (idx *Index) reset() {
-	idx.index = nil
-	idx.documents = nil
+	idx.next_id = 0
+	idx.token = make(map[string][]docid)
+	idx.documents = make(map[docid]string)
+	idx.titles = make(map[string]string)
 }
 
-// add reads a file and adds it to the index. This must happen while
-// the idx is locked, which is true when called from loadIndex.
-func (idx *Index) add(path string, info fs.FileInfo, err error) error {
-	if err != nil {
-		return err
+// addDocument adds the text as a new document. This assumes that the index is locked!
+func (idx *Index) addDocument(text []byte) docid {
+	id := idx.next_id
+	idx.next_id++
+	for _, token := range hashtags(text) {
+		ids := idx.token[token]
+		// Don't add same ID more than once. Checking the last
+		// position of the []docid works because the id is
+		// always a new one, i.e. the last one, if at all.
+		if len(ids) > 0 && ids[len(ids)-1] == id {
+			continue
+		}
+		idx.token[token] = append(ids, id)
 	}
-	filename := path
-	if info.IsDir() || strings.HasPrefix(filename, ".") || !strings.HasSuffix(filename, ".md") {
-		return nil
-	}
-	name := strings.TrimSuffix(filename, ".md")
-	p, err := loadPage(name)
-	if err != nil {
-		return err
-	}
-	id := idx.index.Add(strings.ToLower(string(p.Body)))
-	idx.documents[id] = p.Name
-	return nil
+	return id
 }
 
-// load loads all the pages and indexes them. This takes a while.
-// It returns the number of pages indexed.
+// deleteDocument deletes all references to the id. The id can no longer be used. This assumes that the index is locked.
+func (idx *Index) deleteDocument(id docid) {
+	// Looping through all tokens makes sense if there are few tokens (like hashtags). It doesn't make sense if the
+	// number of tokens is large (like for full-text search or a trigram index).
+	for token, ids := range idx.token {
+		// If the token appears only in this document, remove the whole entry.
+		if len(ids) == 1 && ids[0] == id {
+			delete(idx.token, token)
+			continue
+		}
+		// Otherwise, remove the token from the index.
+		i := sort.Search(len(ids), func(i int) bool { return ids[i] >= id })
+		if i != -1 && i < len(ids) && ids[i] == id {
+			copy(ids[i:], ids[i+1:])
+			idx.token[token] = ids[:len(ids)-1]
+			continue
+		}
+	}
+}
+
+// deletePageName determines the document id based on the page name and calls deleteDocument to delete all references.
+// This assumes that the index is unlocked.
+func (idx *Index) deletePageName(name string) {
+	idx.Lock()
+	defer idx.Unlock()
+	var id docid
+	// Reverse lookup! At least it's in memory.
+	for key, value := range idx.documents {
+		if value == name {
+			id = key
+			break
+		}
+	}
+	if id != 0 {
+		idx.deleteDocument(id)
+		delete(idx.documents, id)
+	}
+	delete(idx.titles, name)
+}
+
+// remove the page from the index. Do this when deleting a page. This assumes that the index is unlocked.
+func (idx *Index) remove(p *Page) {
+	idx.deletePageName(p.Name)
+}
+
+// load loads all the pages and indexes them. This takes a while. It returns the number of pages indexed.
 func (idx *Index) load() (int, error) {
 	idx.Lock()
 	defer idx.Unlock()
-	idx.index = make(trigram.Index)
-	idx.documents = make(map[trigram.DocID]string)
-	err := filepath.Walk(".", idx.add)
+	err := filepath.Walk(".", idx.walk)
 	if err != nil {
-		idx.reset()
 		return 0, err
 	}
 	n := len(idx.documents)
 	return n, nil
 }
 
-// updateIndex updates the index for a single page. The old text is
-// loaded from the disk and removed from the index first, if it
-// exists.
-func (p *Page) updateIndex() {
-	index.Lock()
-	defer index.Unlock()
-	var id trigram.DocID
-	// This function does not rely on files actually existing, so
-	// let's quickly find the document id.
-	for docId, name := range index.documents {
-		if name == p.Name {
-			id = docId
-			break
+// walk reads a file and adds it to the index. This assumes that the index is locked.
+func (idx *Index) walk(path string, info fs.FileInfo, err error) error {
+	if err != nil {
+		return err
+	}
+	// skip hidden directories and files
+	if path != "." && strings.HasPrefix(filepath.Base(path), ".") {
+		if info.IsDir() {
+			return filepath.SkipDir
+		} else {
+			return nil
 		}
 	}
-	if id == 0 {
-		id = index.index.Add(strings.ToLower(string(p.Body)))
-		index.documents[id] = p.Name
-	} else {
-		o, err := loadPage(p.Name)
-		if err == nil {
-			index.index.Delete(strings.ToLower(string(o.Body)), id)
-		}
-		index.index.Insert(strings.ToLower(string(p.Body)), id)
+	// skipp all but page files
+	if !strings.HasSuffix(path, ".md") {
+		return nil
+	}
+	p, err := loadPage(strings.TrimSuffix(path, ".md"))
+	if err != nil {
+		return err
+	}
+	p.handleTitle(false)
+	idx.addPage(p)
+	return nil
+}
+
+// addPage adds a page to the index. This assumes that the index is locked.
+func (idx *Index) addPage(p *Page) {
+	id := idx.addDocument(p.Body)
+	idx.documents[id] = p.Name
+	p.handleTitle(false)
+	idx.titles[p.Name] = p.Title
+}
+
+// add a page to the index. This assumes that the index is unlocked.
+func (idx *Index) add(p *Page) {
+	idx.Lock()
+	defer idx.Unlock()
+	idx.addPage(p)
+}
+
+// dump prints the index to the log for debugging.
+func (idx *Index) dump() {
+	idx.RLock()
+	defer idx.RUnlock()
+	for token, ids := range idx.token {
+		log.Printf("%s: %v", token, ids)
 	}
 }
 
-func searchDocuments(q string) []string {
-		words := strings.Fields(strings.ToLower(q))
-	var trigrams []trigram.T
-	for _, word := range words {
-		trigrams = trigram.Extract(word, trigrams)
+// updateIndex updates the index for a single page.
+func (idx *Index) update(p *Page) {
+	idx.remove(p)
+	idx.add(p)
+}
+
+// search searches the index for a query string and returns page
+// names.
+func (idx *Index) search(q string) []string {
+	idx.RLock()
+	defer idx.RUnlock()
+	names := make([]string, 0)
+	hashtags := hashtags([]byte(q))
+	if len(hashtags) > 0 {
+		var r []docid
+		for _, token := range hashtags {
+			if ids, ok := idx.token[token]; ok {
+				if r == nil {
+					r = ids
+				} else {
+					r = intersection(r, ids)
+				}
+			} else {
+				// Token doesn't exist therefore abort search.
+				return nil
+			}
+		}
+		for _, id := range r {
+			names = append(names, idx.documents[id])
+		}
+	} else {
+		for _, name := range idx.documents {
+			names = append(names, name)
+		}
 	}
-	index.RLock()
-	ids := index.index.QueryTrigrams(trigrams)
-	names := make([]string, len(ids))
-	for i, id := range ids {
-		names[i] = index.documents[id]
-	}
-	index.RUnlock()
 	return names
 }
+
+// intersection returns the set intersection between a and b.
+// a and b have to be sorted in ascending order and contain no duplicates.
+func intersection[T constraints.Ordered](a []T, b []T) []T {
+	maxLen := len(a)
+	if len(b) > maxLen {
+		maxLen = len(b)
+	}
+	r := make([]T, 0, maxLen)
+	var i, j int
+	for i < len(a) && j < len(b) {
+		if a[i] < b[j] {
+			i++
+		} else if a[i] > b[j] {
+			j++
+		} else {
+			r = append(r, a[i])
+			i++
+			j++
+		}
+	}
+	return r
+}

index.md

@@ -2,4 +2,6 @@
 
 Hello! 🙃
 
-Check out the [README](README).
+Check out the [[README]].
+
+Or [create a new page](test).

index_test.go

@@ -2,40 +2,51 @@ package main
 
 import (
 	"github.com/stretchr/testify/assert"
-	"os"
 	"strings"
 	"testing"
 )
 
+func TestIndexAdd(t *testing.T) {
+	idx := &Index{}
+	idx.reset()
+	idx.Lock()
+	defer idx.Unlock()
+	tag := "#hello"
+	id := idx.addDocument([]byte("oh hi " + tag))
+	assert.Contains(t, idx.token, tag)
+	idx.deleteDocument(id)
+	assert.NotContains(t, idx.token, tag)
+}
+
 // TestIndex relies on README.md being indexed
 func TestIndex(t *testing.T) {
 	index.load()
 	q := "Oddµ"
-	pages := search(q)
+	pages, _ := search(q, "", "", 1, false)
 	assert.NotZero(t, len(pages))
 	for _, p := range pages {
 		assert.NotContains(t, p.Title, "<b>")
 		assert.True(t, strings.Contains(string(p.Body), q) || strings.Contains(string(p.Title), q))
-		assert.NotZero(t, p.Score)
+		assert.NotZero(t, p.Score, "Score %d for %s", p.Score, p.Name)
 	}
 }
 
 func TestSearchHashtag(t *testing.T) {
 	index.load()
-	q := "#Another_Tag"
-	pages := search(q)
+	q := "#like_this"
+	pages, _ := search(q, "", "", 1, false)
 	assert.NotZero(t, len(pages))
 }
 
 func TestIndexUpdates(t *testing.T) {
-	name := "test"
-	_ = os.Remove(name + ".md")
+	cleanup(t, "testdata/update")
+	name := "testdata/update/test"
 	index.load()
-	p := &Page{Name: name, Body: []byte("This is a test.")}
+	p := &Page{Name: name, Body: []byte("#Old Name\nThis is a test.")}
 	p.save()
 
 	// Find the phrase
-	pages := search("This is a test")
+	pages, _ := search("This is a test", "", "", 1, false)
 	found := false
 	for _, p := range pages {
 		if p.Name == name {
@@ -46,7 +57,7 @@ func TestIndexUpdates(t *testing.T) {
 	assert.True(t, found)
 
 	// Find the phrase, case insensitive
-	pages = search("this is a test")
+	pages, _ = search("this is a test", "", "", 1, false)
 	found = false
 	for _, p := range pages {
 		if p.Name == name {
@@ -57,7 +68,7 @@ func TestIndexUpdates(t *testing.T) {
 	assert.True(t, found)
 
 	// Find some words
-	pages = search("this test")
+	pages, _ = search("this test", "", "", 1, false)
 	found = false
 	for _, p := range pages {
 		if p.Name == name {
@@ -68,9 +79,9 @@ func TestIndexUpdates(t *testing.T) {
 	assert.True(t, found)
 
 	// Update the page and no longer find it with the old phrase
-	p = &Page{Name: name, Body: []byte("Guvf vf n grfg.")}
+	p = &Page{Name: name, Body: []byte("# New page\nGuvf vf n grfg.")}
 	p.save()
-	pages = search("This is a test")
+	pages, _ = search("This is a test", "", "", 1, false)
 	found = false
 	for _, p := range pages {
 		if p.Name == name {
@@ -81,7 +92,7 @@ func TestIndexUpdates(t *testing.T) {
 	assert.False(t, found)
 
 	// Find page using a new word
-	pages = search("Guvf")
+	pages, _ = search("Guvf", "", "", 1, false)
 	found = false
 	for _, p := range pages {
 		if p.Name == name {
@@ -91,7 +102,8 @@ func TestIndexUpdates(t *testing.T) {
 	}
 	assert.True(t, found)
 
-	t.Cleanup(func() {
-		_ = os.Remove(name + ".md")
-	})
+	// Make sure the title was updated
+	index.RLock()
+	defer index.RUnlock()
+	assert.Equal(t, "New page", index.titles[name])
 }

languages.go

@@ -7,8 +7,7 @@ import (
 	"strings"
 )
 
-// getLangauges returns the environment variable ODDMU_LANGUAGES or
-// all languages.
+// getLanguages returns the environment variable ODDMU_LANGUAGES or all languages.
 func getLanguages() ([]lingua.Language, error) {
 	v := os.Getenv("ODDMU_LANGUAGES")
 	if v == "" {
@@ -29,8 +28,9 @@ func getLanguages() ([]lingua.Language, error) {
 // detector is the LanguageDetector initialized at startup by loadLanguages.
 var detector lingua.LanguageDetector
 
-// loadLanguages initializes the detector using the languages returned
-// by getLanguages and returns the number of languages loaded.
+// loadLanguages initializes the detector using the languages returned by getLanguages and returns the number of
+// languages loaded. If this is skipped, no language detection happens and the templates cannot use {{.Language}} to use
+// this. Usually this is used for correct hyphenation by the browser.
 func loadLanguages() int {
 	langs, err := getLanguages()
 	if err == nil {

list_cmd.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"github.com/google/subcommands"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type listCmd struct {
+	dir string
+}
+
+func (cmd *listCmd) SetFlags(f *flag.FlagSet) {
+	f.StringVar(&cmd.dir, "dir", "", "list only pages within this sub-directory")
+}
+
+func (*listCmd) Name() string     { return "list" }
+func (*listCmd) Synopsis() string { return "List pages with name and title." }
+func (*listCmd) Usage() string {
+	return `list [-dir string]:
+  List all pages with name and title, separated by a tabulator.
+`
+}
+
+func (cmd *listCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	return listCli(os.Stdout, cmd.dir, f.Args())
+}
+
+// listCli runs the list command on the command line. It is used
+// here with an io.Writer for easy testing.
+func listCli(w io.Writer, dir string, args []string) subcommands.ExitStatus {
+	dir, err := checkDir(dir)
+	if err != nil {
+		return subcommands.ExitFailure
+	}
+	index.load()
+	index.RLock()
+	defer index.RUnlock()
+	for name, title := range index.titles {
+		if strings.HasPrefix(name, dir) {
+			name = strings.Replace(name, dir, "", 1)
+			fmt.Fprintf(w, "%s\t%s\n", name, title)
+		}
+	}
+	return subcommands.ExitSuccess
+}
+
+// checkDir returns an error if the directory doesn't exist. If if exists, it returns a copy ending in a slash suiteable
+// for substring matching of page names.
+func checkDir(dir string) (string, error) {
+	if dir != "" {
+		fi, err := os.Stat(filepath.FromSlash(dir))
+		if err != nil {
+			fmt.Println(err)
+			return "", err
+		}
+		if !fi.IsDir() {
+			fmt.Println("This is not a sub-directory:", dir)
+			return "", err
+		}
+		if !strings.HasSuffix(dir, "/") {
+			dir += "/"
+		}
+	}
+	return dir, nil
+}

list_cmd_test.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"bytes"
+	"github.com/google/subcommands"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestListCmd(t *testing.T) {
+	b := new(bytes.Buffer)
+	s := listCli(b, "", nil)
+	assert.Equal(t, subcommands.ExitSuccess, s)
+	x := b.String()
+	assert.Contains(t, x, "README\tOddµ: A minimal wiki\n")
+	assert.Contains(t, x, "index\tWelcome to Oddµ\n")
+}
+
+func TestListSubdirCmd(t *testing.T) {
+	cleanup(t, "testdata/list")
+	p := &Page{Name: "testdata/list/red", Body: []byte(`# Red
+Shifting darkness waits
+I open my eyes in fear
+And see the red dot`)}
+	p.save()
+	b := new(bytes.Buffer)
+	s := listCli(b, "testdata/list", nil)
+	assert.Equal(t, subcommands.ExitSuccess, s)
+	x := b.String()
+	assert.Contains(t, x, "red\tRed\n")
+}

man/.gitignore

@@ -0,0 +1 @@
+*.md

man/Makefile

@@ -0,0 +1,31 @@
+TEXT=$(wildcard *.txt)
+MAN=$(patsubst %.txt,%,${TEXT})
+HTML=$(patsubst %.txt,%.html,${TEXT})
+MD=$(patsubst %.txt,%.md,${TEXT})
+
+man: ${MAN}
+
+%: %.txt
+	scdoc < $< > $@
+
+html: ${HTML}
+
+%.html: %
+	groff -mandoc -Dutf8 -Thtml $< | sed 's/<style type="text\/css">/<style type="text\/css">\n       body {font-family: mono; max-width: 80ch }/' > $@
+
+md: ${MD}
+
+%.md: %.txt
+	sed --regexp-extended \
+	  -e 's/\*([^*]+)\*/**\1**/g' \
+	  -e 's/_(oddmu[a-z.-]*)_\(([1-9])\)/[\1(\2)](\1.\2)/g' \
+	  -e 's/_([^_]+)_/*\1*/g' \
+	  -e 's/^#/##/' \
+	  -e 's/^([A-Z.-]*\([1-9]\))( ".*")?$$/# \1/' \
+	  < $< > $@
+
+upload: ${MD}
+	rsync --itemize-changes --archive *.md sibirocobombus:alexschroeder.ch/wiki/oddmu/
+
+clean:
+	rm --force ${HTML} ${MD}

man/oddmu-apache.5

@@ -0,0 +1,386 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-APACHE" "5" "2024-02-13"
+.PP
+.SH NAME
+.PP
+oddmu-apache - how to setup Apache as a reverse proxy for Oddmu
+.PP
+.SS DESCRIPTION
+.PP
+The oddmu program serves the current working directory as a wiki on port 8080.\&
+This is an unpriviledged port so an ordinary user account can do this.\&
+Alternatively, you can reverse proxy HTTP over a Unix-domain socket,
+as shown later.\&
+.PP
+The best way to protect the wiki against vandalism and spam is to use a regular
+web server as reverse proxy.\& This page explains how to setup Apache on Debian to
+do this.\&
+.PP
+.SS CONFIGURATION
+.PP
+HTTPS is not part of Oddmu.\& You probably want to configure this in your
+webserver.\& I guess you could use stunnel, too.\& If you'\&re using Apache, you can
+use "mod_md" to manage your domain.\&
+.PP
+The examples below use the domain "transjovian.\&org" and the Apache installation
+is the one that comes with Debian.\&
+.PP
+The site itself is configured in a file called
+"/etc/apache2/sites-available/transjovian.\&conf" and a link points there from
+"/etc/apache2/sites-enabled".\& Create this link using \fIa2ensite\fR(1).\&
+.PP
+.nf
+.RS 4
+MDomain transjovian\&.org
+MDCertificateAgreement accepted
+ServerAdmin alex@alexschroeder\&.ch
+
+<VirtualHost *:80>
+  ServerName transjovian\&.org
+  Redirect "/" "https://transjovian\&.org/"
+</VirtualHost>
+<VirtualHost *:443>
+  ServerName transjovian\&.org
+  SSLEngine on
+  ProxyPassMatch "^/((view|diff|edit|save|add|append|upload|drop|search)/(\&.*))?$" 
+                 "http://localhost:8080/$1"
+</VirtualHost>
+.fi
+.RE
+.PP
+First, it manages the domain, getting the necessary certificates.\& It redirects
+regular HTTP traffic from port 80 to port 443.\& It turns on the SSL engine for
+port 443.\& It proxies the requests for Oddmu to port 8080.\& Importantly, it
+doesn'\&t send \fIall\fR the requests to Oddmu.\& This allows us to still host static
+files using the web server (see \fBServe static files\fR).\&
+.PP
+This is what happens:
+.PP
+.PD 0
+.IP \(bu 4
+The user tells the browser to visit "transjovian.\&org"
+.IP \(bu 4
+The browser sends a request for "http://transjovian.\&org" (on port 80)
+.IP \(bu 4
+Apache redirects this to "https://transjovian.\&org/" by default (now on port 443)
+.IP \(bu 4
+This is proxied to "http://transjovian.\&org:8080/" (now on port 8080)
+.PD
+.PP
+Restart the server, gracefully:
+.PP
+.nf
+.RS 4
+apachectl graceful
+.fi
+.RE
+.PP
+.SS Allow HTTP for viewing
+.PP
+When looking at pages, you might want to allow HTTP since no password is
+required.\& Therefore, proxy the read-only requests from the virtual host on port
+80 to the wiki instead of redirecting them to port 443.\&
+.PP
+.nf
+.RS 4
+MDomain transjovian\&.org
+MDCertificateAgreement accepted
+ServerAdmin alex@alexschroeder\&.ch
+
+<VirtualHost *:80>
+  ServerName transjovian\&.org
+  ProxyPassMatch "^/((view|diff|search)/(\&.*))?$" 
+                 "http://localhost:8080/$1"
+  RedirectMatch  "^/((edit|save|add|append|upload|drop)/(\&.*))?$" 
+                 "https://transjovian\&.org/$1"
+</VirtualHost>
+<VirtualHost *:443>
+  ServerName transjovian\&.org
+  SSLEngine on
+  ProxyPassMatch "^/((view|diff|edit|save|add|append|upload|drop|search)/(\&.*))?$" 
+                 "http://localhost:8080/$1"
+</VirtualHost>
+.fi
+.RE
+.PP
+.SS Using a Unix-domain Socket
+.PP
+Instead of having Oddmu listen on a TCP port, you can have it listen on a
+Unix-domain socket.\& This requires socket activation.\& An example of configuring
+the service is given in \fIoddmu.\&service(5)\fR.\&
+.PP
+To test just the unix domain socket, use \fIncat(1)\fR:
+.PP
+.nf
+.RS 4
+echo -e "GET /view/index HTTP/1\&.1rnHost: localhostrnrn" 
+  | ncat --unixsock /run/oddmu/oddmu\&.sock
+.fi
+.RE
+.PP
+On the Apache side, you can proxy to the socket directly.\& This sends all
+requests to the socket:
+.PP
+.nf
+.RS 4
+ProxyPass "/" "unix:/run/oddmu/oddmu\&.sock|http://localhost/"
+.fi
+.RE
+.PP
+Now, all traffic between the web server and the wiki goes over the socket at
+"/run/oddmu/oddmu.\&sock".\&
+.PP
+To test it on the command-line, use a tool like \fIcurl(1)\fR.\& Make sure to provide
+the correct servername!\&
+.PP
+.nf
+.RS 4
+curl http://transjovian\&.org/view/index
+.fi
+.RE
+.PP
+You probably want to serve some static files as well (see \fBServe static files\fR).\&
+In that case, you need to use the ProxyPassMatch directive.\&
+.PP
+.nf
+.RS 4
+ProxyPassMatch "^/((view|diff|edit|save|add|append|upload|drop|search)/(\&.*))?$" 
+               "unix:/run/oddmu/oddmu\&.sock|http://localhost/$1"
+.fi
+.RE
+.PP
+There'\&s a curious problem with this expression, however.\& If you use \fIcurl(1)\fR to
+get the root path, Apache hangs:
+.PP
+.nf
+.RS 4
+curl http://transjovian\&.org/
+.fi
+.RE
+.PP
+A workaround is to add the redirect manually and drop the question-mark:
+.PP
+.nf
+.RS 4
+RedirectMatch "^/$" "/view/index"
+ProxyPassMatch "^/((view|diff|edit|save|add|append|upload|drop|search)/(\&.*))$" 
+               "unix:/run/oddmu/oddmu\&.sock|http://localhost/$1"
+.fi
+.RE
+.PP
+If you know why this is happening, let me know.\&
+.PP
+.SS Access
+.PP
+Access control is not part of Oddmu.\& By default, the wiki is editable by all.\&
+This is most likely not what you want unless you'\&re running it stand-alone,
+unconnected to the Internet – a personal memex on your laptop, for example.\&
+.PP
+The following instructions create user accounts with passwords just for Oddmu.\&
+These users are not real users on the web server and don'\&t have access to a
+shell, mail, or any other service.\&
+.PP
+Create a new password file called ".\&htpasswd" and add the user "alex".\& The "-c"
+flag creates the file.\&
+.PP
+.nf
+.RS 4
+cd /home/oddmu
+htpasswd -c \&.htpasswd alex
+.fi
+.RE
+.PP
+To add more users, don'\&t use the "-c" option or you will overwrite the existing
+file.\& To add another user, use no option at all.\&
+.PP
+.nf
+.RS 4
+htpasswd \&.htpasswd berta
+.fi
+.RE
+.PP
+To remove a user, use the "-D" option.\&
+.PP
+.nf
+.RS 4
+htpasswd -D \&.htpasswd berta
+.fi
+.RE
+.PP
+Modify your site configuration and protect the "/edit/", "/save/", "/add/",
+"/append/", "/upload/" and "/drop/" URLs with a password by adding the following
+to your "<VirtualHost *:443>" section:
+.PP
+.nf
+.RS 4
+<LocationMatch "^/(edit|save|add|append|upload|drop)/">
+  AuthType Basic
+  AuthName "Password Required"
+  AuthUserFile /home/oddmu/\&.htpasswd
+  Require valid-user
+</LocationMatch>
+.fi
+.RE
+.PP
+The way Oddmu handles subdirectories is that all files and directories are
+visible, except for "hidden" files and directories (whose name starts with a
+period).\& Specifically, do not rely on Apache to hide locations in subdirectories
+from public view.\& Search reveals the existence of these pages and produces an
+extract, even if users cannot follow the links.\& Archive links pack all the
+subdirectories, including locations you may have hidden from view using Apache.\&
+.PP
+If you want private subdirectories, you need to set the environment variable
+ODDMU_FILTER to a regular expression matching the private directories.\& If search
+starts in a directory matching the regular expression, the directory and its
+subdirectories are searched.\& If search starts in a directory that doesn'\&t match
+the regular expression, all directories matching the regular expression are
+excluded.\&
+.PP
+In the following example, ODDMU_FILTER is set to "^secret/".\&
+.PP
+http://transjovian.\&org/search/index?\&q=something does not search the "secret"
+directory and its subdirectories are excluded.\&
+.PP
+http://transjovian.\&org/search/secret/index?\&q=something searches just the
+"secret" directory and its subdirectories.\&
+.PP
+Now you need to ensure that the "secret" directory are not public.\&
+.PP
+.nf
+.RS 4
+<LocationMatch "^/(edit|save|add|append|upload|drop|view/secret|search/secret)/">
+  AuthType Basic
+  AuthName "Password Required"
+  AuthUserFile /home/oddmu/\&.htpasswd
+  Require valid-user
+</LocationMatch>
+.fi
+.RE
+.PP
+.SS Serve static files
+.PP
+If you want to serve static files as well, add a document root to your webserver
+configuration.\& In this case, the document root is the directory where all the
+data files are.\& Apache does not serve files such as ".\&htpasswd".\&
+.PP
+.nf
+.RS 4
+DocumentRoot /home/oddmu
+<Directory /home/oddmu>
+  Require all granted
+</Directory>
+.fi
+.RE
+.PP
+Make sure that none of the subdirectories look like the wiki paths "/view/",
+"/diff/", "/edit/", "/save/", "/add/", "/append/", "/upload/", "/drop/" or
+"/search/".\& For example, create a file called "robots.\&txt" containing the
+following, telling all robots that they'\&re not welcome.\&
+.PP
+.nf
+.RS 4
+User-agent: *
+Disallow: /
+.fi
+.RE
+.PP
+Your site now serves "/robots.\&txt" without interfering with the wiki, and
+without needing a wiki page.\&
+.PP
+Another option would be to create a CSS file and use it with a <link> element in
+all the templates instead of relying on the <style> element.\&
+.PP
+The "view.\&html" template would start as follows:
+.PP
+.nf
+.RS 4
+<!DOCTYPE html>
+<html lang="{{\&.Language}}">
+  <head>
+    <meta charset="utf-8">
+    <meta name="format-detection" content="telephone=no">
+    <meta name="viewport" content="width=device-width">
+    <title>{{\&.Title}}</title>
+    <link href="/css/oddmu-2023\&.css" rel="stylesheet" />
+    <link rel="alternate" type="application/rss+xml" title="Alex Schroeder: {{\&.Title}}" href="/view/{{\&.Name}}\&.rss" />
+  </head>
+…
+.fi
+.RE
+.PP
+In this case, "/css/oddmu-2023.\&css" would be the name of your stylesheet.\& If
+your document root is "/home/oddmu", then the filename of your stylesheet would
+have to be "/home/oddmu/css/oddmu-2023.\&css" for this to work.\&
+.PP
+.SS Different logins for different access rights
+.PP
+What if you have a site with various subdirectories and each subdirectory is for
+a different group of friends?\& You can set this up using your webserver.\& One way
+to do this is to require specific usernames (which must have a password in the
+password file mentioned above.\&
+.PP
+This requires a valid login by the user "alex" or "berta":
+.PP
+.nf
+.RS 4
+<LocationMatch "^/(edit|save|add|append|upload|drop)/intetebi/">
+  Require user alex berta
+</LocationMatch>
+.fi
+.RE
+.PP
+.SS Private wikis
+.PP
+Based on the above, you can prevent people from \fIreading\fR the wiki.\& The
+"LocationMatch" must cover all the URLs in order to protect everything.\&
+.PP
+.nf
+.RS 4
+<Location />
+  AuthType Basic
+  AuthName "Password Required"
+  AuthUserFile /home/oddmu/\&.htpasswd
+  Require valid-user
+</Location>
+.fi
+.RE
+.PP
+.SS Virtual hosting
+.PP
+Virtual hosting in this context means that the program serves two different
+sites for two different domains from the same machine.\& Oddmu doesn'\&t support
+that, but your webserver does.\& Therefore, start an Oddmu instance for every
+domain name, each listening on a different port.\& Then set up your web server
+such that ever domain acts as a reverse proxy to a different Oddmu instance.\&
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1)
+.PP
+"Apache Core Features".\&
+https://httpd.\&apache.\&org/docs/current/mod/core.\&html
+.PP
+"Apache: Authentication and Authorization".\&
+https://httpd.\&apache.\&org/docs/current/howto/auth.\&html
+.PP
+"Apache Module mod_proxy".\&
+https://httpd.\&apache.\&org/docs/current/mod/mod_proxy.\&html
+.PP
+"Robot exclusion standard" on Wikipedia.\&
+https://en.\&wikipedia.\&org/wiki/Robot_exclusion_standard
+.PP
+"<style>: The Style Information element"
+https://developer.\&mozilla.\&org/en-US/docs/Web/HTML/Element/style
+.PP
+"<link>: The External Resource Link element"
+https://developer.\&mozilla.\&org/en-US/docs/Web/HTML/Element/link
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-apache.5.txt

@@ -0,0 +1,335 @@
+ODDMU-APACHE(5)
+
+# NAME
+
+oddmu-apache - how to setup Apache as a reverse proxy for Oddmu
+
+## DESCRIPTION
+
+The oddmu program serves the current working directory as a wiki on port 8080.
+This is an unpriviledged port so an ordinary user account can do this.
+Alternatively, you can reverse proxy HTTP over a Unix-domain socket,
+as shown later.
+
+The best way to protect the wiki against vandalism and spam is to use a regular
+web server as reverse proxy. This page explains how to setup Apache on Debian to
+do this.
+
+## CONFIGURATION
+
+HTTPS is not part of Oddmu. You probably want to configure this in your
+webserver. I guess you could use stunnel, too. If you're using Apache, you can
+use "mod_md" to manage your domain.
+
+The examples below use the domain "transjovian.org" and the Apache installation
+is the one that comes with Debian.
+
+The site itself is configured in a file called
+"/etc/apache2/sites-available/transjovian.conf" and a link points there from
+"/etc/apache2/sites-enabled". Create this link using _a2ensite_(1).
+
+```
+MDomain transjovian.org
+MDCertificateAgreement accepted
+ServerAdmin alex@alexschroeder.ch
+
+<VirtualHost *:80>
+  ServerName transjovian.org
+  Redirect "/" "https://transjovian.org/"
+</VirtualHost>
+<VirtualHost *:443>
+  ServerName transjovian.org
+  SSLEngine on
+  ProxyPassMatch "^/((view|diff|edit|save|add|append|upload|drop|search)/(.*))?$" \
+                 "http://localhost:8080/$1"
+</VirtualHost>
+```
+
+First, it manages the domain, getting the necessary certificates. It redirects
+regular HTTP traffic from port 80 to port 443. It turns on the SSL engine for
+port 443. It proxies the requests for Oddmu to port 8080. Importantly, it
+doesn't send _all_ the requests to Oddmu. This allows us to still host static
+files using the web server (see *Serve static files*).
+
+This is what happens:
+
+- The user tells the browser to visit "transjovian.org"
+- The browser sends a request for "http://transjovian.org" (on port 80)
+- Apache redirects this to "https://transjovian.org/" by default (now on port 443)
+- This is proxied to "http://transjovian.org:8080/" (now on port 8080)
+
+Restart the server, gracefully:
+
+```
+apachectl graceful
+```
+
+## Allow HTTP for viewing
+
+When looking at pages, you might want to allow HTTP since no password is
+required. Therefore, proxy the read-only requests from the virtual host on port
+80 to the wiki instead of redirecting them to port 443.
+
+```
+MDomain transjovian.org
+MDCertificateAgreement accepted
+ServerAdmin alex@alexschroeder.ch
+
+<VirtualHost *:80>
+  ServerName transjovian.org
+  ProxyPassMatch "^/((view|diff|search)/(.*))?$" \
+                 "http://localhost:8080/$1"
+  RedirectMatch  "^/((edit|save|add|append|upload|drop)/(.*))?$" \
+                 "https://transjovian.org/$1"
+</VirtualHost>
+<VirtualHost *:443>
+  ServerName transjovian.org
+  SSLEngine on
+  ProxyPassMatch "^/((view|diff|edit|save|add|append|upload|drop|search)/(.*))?$" \
+                 "http://localhost:8080/$1"
+</VirtualHost>
+```
+
+## Using a Unix-domain Socket
+
+Instead of having Oddmu listen on a TCP port, you can have it listen on a
+Unix-domain socket. This requires socket activation. An example of configuring
+the service is given in _oddmu.service(5)_.
+
+To test just the unix domain socket, use _ncat(1)_:
+
+```
+echo -e "GET /view/index HTTP/1.1\r\nHost: localhost\r\n\r\n" \
+  | ncat --unixsock /run/oddmu/oddmu.sock
+```
+
+On the Apache side, you can proxy to the socket directly. This sends all
+requests to the socket:
+
+```
+ProxyPass "/" "unix:/run/oddmu/oddmu.sock|http://localhost/"
+```
+
+Now, all traffic between the web server and the wiki goes over the socket at
+"/run/oddmu/oddmu.sock".
+
+To test it on the command-line, use a tool like _curl(1)_. Make sure to provide
+the correct servername!
+
+```
+curl http://transjovian.org/view/index
+```
+
+You probably want to serve some static files as well (see *Serve static files*).
+In that case, you need to use the ProxyPassMatch directive.
+
+```
+ProxyPassMatch "^/((view|diff|edit|save|add|append|upload|drop|search)/(.*))?$" \
+               "unix:/run/oddmu/oddmu.sock|http://localhost/$1"
+```
+
+There's a curious problem with this expression, however. If you use _curl(1)_ to
+get the root path, Apache hangs:
+
+```
+curl http://transjovian.org/
+```
+
+A workaround is to add the redirect manually and drop the question-mark:
+
+```
+RedirectMatch "^/$" "/view/index"
+ProxyPassMatch "^/((view|diff|edit|save|add|append|upload|drop|search)/(.*))$" \
+               "unix:/run/oddmu/oddmu.sock|http://localhost/$1"
+```
+
+If you know why this is happening, let me know.
+
+## Access
+
+Access control is not part of Oddmu. By default, the wiki is editable by all.
+This is most likely not what you want unless you're running it stand-alone,
+unconnected to the Internet – a personal memex on your laptop, for example.
+
+The following instructions create user accounts with passwords just for Oddmu.
+These users are not real users on the web server and don't have access to a
+shell, mail, or any other service.
+
+Create a new password file called ".htpasswd" and add the user "alex". The "-c"
+flag creates the file.
+
+```
+cd /home/oddmu
+htpasswd -c .htpasswd alex
+```
+
+To add more users, don't use the "-c" option or you will overwrite the existing
+file. To add another user, use no option at all.
+
+```
+htpasswd .htpasswd berta
+```
+
+To remove a user, use the "-D" option.
+
+```
+htpasswd -D .htpasswd berta
+```
+
+Modify your site configuration and protect the "/edit/", "/save/", "/add/",
+"/append/", "/upload/" and "/drop/" URLs with a password by adding the following
+to your "<VirtualHost \*:443>" section:
+
+```
+<LocationMatch "^/(edit|save|add|append|upload|drop)/">
+  AuthType Basic
+  AuthName "Password Required"
+  AuthUserFile /home/oddmu/.htpasswd
+  Require valid-user
+</LocationMatch>
+```
+
+The way Oddmu handles subdirectories is that all files and directories are
+visible, except for "hidden" files and directories (whose name starts with a
+period). Specifically, do not rely on Apache to hide locations in subdirectories
+from public view. Search reveals the existence of these pages and produces an
+extract, even if users cannot follow the links. Archive links pack all the
+subdirectories, including locations you may have hidden from view using Apache.
+
+If you want private subdirectories, you need to set the environment variable
+ODDMU_FILTER to a regular expression matching the private directories. If search
+starts in a directory matching the regular expression, the directory and its
+subdirectories are searched. If search starts in a directory that doesn't match
+the regular expression, all directories matching the regular expression are
+excluded.
+
+In the following example, ODDMU_FILTER is set to "^secret/".
+
+http://transjovian.org/search/index?q=something does not search the "secret"
+directory and its subdirectories are excluded.
+
+http://transjovian.org/search/secret/index?q=something searches just the
+"secret" directory and its subdirectories.
+
+Now you need to ensure that the "secret" directory are not public.
+
+```
+<LocationMatch "^/(edit|save|add|append|upload|drop|view/secret|search/secret)/">
+  AuthType Basic
+  AuthName "Password Required"
+  AuthUserFile /home/oddmu/.htpasswd
+  Require valid-user
+</LocationMatch>
+```
+
+## Serve static files
+
+If you want to serve static files as well, add a document root to your webserver
+configuration. In this case, the document root is the directory where all the
+data files are. Apache does not serve files such as ".htpasswd".
+
+```
+DocumentRoot /home/oddmu
+<Directory /home/oddmu>
+  Require all granted
+</Directory>
+```
+
+Make sure that none of the subdirectories look like the wiki paths "/view/",
+"/diff/", "/edit/", "/save/", "/add/", "/append/", "/upload/", "/drop/" or
+"/search/". For example, create a file called "robots.txt" containing the
+following, telling all robots that they're not welcome.
+
+```
+User-agent: *
+Disallow: /
+```
+
+Your site now serves "/robots.txt" without interfering with the wiki, and
+without needing a wiki page.
+
+Another option would be to create a CSS file and use it with a <link> element in
+all the templates instead of relying on the <style> element.
+
+The "view.html" template would start as follows:
+
+```
+<!DOCTYPE html>
+<html lang="{{.Language}}">
+  <head>
+    <meta charset="utf-8">
+    <meta name="format-detection" content="telephone=no">
+    <meta name="viewport" content="width=device-width">
+    <title>{{.Title}}</title>
+    <link href="/css/oddmu-2023.css" rel="stylesheet" />
+    <link rel="alternate" type="application/rss+xml" title="Alex Schroeder: {{.Title}}" href="/view/{{.Name}}.rss" />
+  </head>
+…
+```
+
+In this case, "/css/oddmu-2023.css" would be the name of your stylesheet. If
+your document root is "/home/oddmu", then the filename of your stylesheet would
+have to be "/home/oddmu/css/oddmu-2023.css" for this to work.
+
+## Different logins for different access rights
+
+What if you have a site with various subdirectories and each subdirectory is for
+a different group of friends? You can set this up using your webserver. One way
+to do this is to require specific usernames (which must have a password in the
+password file mentioned above.
+
+This requires a valid login by the user "alex" or "berta":
+
+```
+<LocationMatch "^/(edit|save|add|append|upload|drop)/intetebi/">
+  Require user alex berta
+</LocationMatch>
+```
+
+## Private wikis
+
+Based on the above, you can prevent people from _reading_ the wiki. The
+"LocationMatch" must cover all the URLs in order to protect everything.
+
+```
+<Location />
+  AuthType Basic
+  AuthName "Password Required"
+  AuthUserFile /home/oddmu/.htpasswd
+  Require valid-user
+</Location>
+```
+
+## Virtual hosting
+
+Virtual hosting in this context means that the program serves two different
+sites for two different domains from the same machine. Oddmu doesn't support
+that, but your webserver does. Therefore, start an Oddmu instance for every
+domain name, each listening on a different port. Then set up your web server
+such that ever domain acts as a reverse proxy to a different Oddmu instance.
+
+# SEE ALSO
+
+_oddmu_(1)
+
+"Apache Core Features".
+https://httpd.apache.org/docs/current/mod/core.html
+
+"Apache: Authentication and Authorization".
+https://httpd.apache.org/docs/current/howto/auth.html
+
+"Apache Module mod_proxy".
+https://httpd.apache.org/docs/current/mod/mod_proxy.html
+
+"Robot exclusion standard" on Wikipedia.
+https://en.wikipedia.org/wiki/Robot_exclusion_standard
+
+"<style>: The Style Information element"
+https://developer.mozilla.org/en-US/docs/Web/HTML/Element/style
+
+"<link>: The External Resource Link element"
+https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-html.1

@@ -0,0 +1,53 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-HTML" "1" "2023-10-09"
+.PP
+.SH NAME
+.PP
+oddmu-html - render Oddmu page HTML from the command-line
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu html\fR [-view] \fIpage-name\fR
+.PP
+.SH DESCRIPTION
+.PP
+The "html" subcommand opens the Markdown file for the given page name (appending
+the ".\&md" extension) and prints the HTML to STDOUT without invoking the
+"view.\&html" template.\&
+.PP
+.SH OPTIONS
+.PP
+\fB-view\fR
+.RS 4
+Use the "view.\&html" template to render the page.\& Without this, the HTML
+lacks html and body tags.\&
+.PP
+.RE
+.SH EXAMPLE
+.PP
+Generate the HTML for "README.\&md":
+.PP
+.nf
+.RS 4
+oddmu html README
+.fi
+.RE
+.PP
+.SH ENVIRONMENT
+.PP
+The ODDMU_WEBFINGER environment variable has no effect in this situation.\&
+Fediverse accounts are not linked to their profile pages.\&
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-html.1.txt

@@ -0,0 +1,42 @@
+ODDMU-HTML(1)
+
+# NAME
+
+oddmu-html - render Oddmu page HTML from the command-line
+
+# SYNOPSIS
+
+*oddmu html* [-view] _page-name_
+
+# DESCRIPTION
+
+The "html" subcommand opens the Markdown file for the given page name (appending
+the ".md" extension) and prints the HTML to STDOUT without invoking the
+"view.html" template.
+
+# OPTIONS
+
+*-view*
+	Use the "view.html" template to render the page. Without this, the HTML
+	lacks html and body tags.
+
+# EXAMPLE
+
+Generate the HTML for "README.md":
+
+```
+oddmu html README
+```
+
+# ENVIRONMENT
+
+The ODDMU_WEBFINGER environment variable has no effect in this situation.
+Fediverse accounts are not linked to their profile pages.
+
+# SEE ALSO
+
+_oddmu_(1)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-list.1

@@ -0,0 +1,56 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-LIST" "1" "2023-12-20"
+.PP
+.SH NAME
+.PP
+oddmu-list - list page names and titles from the command-line
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu list\fR [-dir string]
+.PP
+.SH DESCRIPTION
+.PP
+The "list" subcommand lists page names and their titles, separated by a TAB
+character.\& This saves you from opening and parsing all the files yourself if you
+need the page titles.\&
+.PP
+If a directory is provided, only files from the tree starting at that
+subdirectory are listed, and the directory is stripped from the page name.\&
+.PP
+.SH OPTIONS
+.PP
+\fB-dir\fR \fIstring\fR
+.RS 4
+Limit the list to a particular directory.\&
+.PP
+.RE
+.SH EXAMPLE
+.PP
+Create list of links to pages in the "dad" directory, filter it for date pages
+(starting with "2"), format it as a list of links and sort in reverse order.\&
+This is a list of links you could append to "dad/index.\&md" if it doesn'\&t already
+have a list of links.\&
+.PP
+.nf
+.RS 4
+oddmu list -dir dad 
+| grep \&'^2\&' 
+| awk -F "t" -e \&'{ print "* [" $2 "](" $1 ")" }\&' 
+| sort -r
+.fi
+.RE
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1), \fIoddmu-search\fR(1)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-list.1.txt

@@ -0,0 +1,45 @@
+ODDMU-LIST(1)
+
+# NAME
+
+oddmu-list - list page names and titles from the command-line
+
+# SYNOPSIS
+
+*oddmu list* [-dir string]
+
+# DESCRIPTION
+
+The "list" subcommand lists page names and their titles, separated by a TAB
+character. This saves you from opening and parsing all the files yourself if you
+need the page titles.
+
+If a directory is provided, only files from the tree starting at that
+subdirectory are listed, and the directory is stripped from the page name.
+
+# OPTIONS
+
+*-dir* _string_
+	Limit the list to a particular directory.
+
+# EXAMPLE
+
+Create list of links to pages in the "dad" directory, filter it for date pages
+(starting with "2"), format it as a list of links and sort in reverse order.
+This is a list of links you could append to "dad/index.md" if it doesn't already
+have a list of links.
+
+```
+oddmu list -dir dad \
+| grep '^2' \
+| awk -F "\t" -e '{ print "* [" $2 "](" $1 ")" }' \
+| sort -r
+```
+
+# SEE ALSO
+
+_oddmu_(1), _oddmu-search_(1)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-missing.1

@@ -0,0 +1,57 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-MISSING" "1" "2023-11-05"
+.PP
+.SH NAME
+.PP
+oddmu-missing - list missing pages from the command-line
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu missing\fR
+.PP
+.SH DESCRIPTION
+.PP
+The "missing" subcommand lists pages and their local links that are missing.\&
+.PP
+Any links that seem like they might point outside the wiki are ignored: links
+that start with a slash "/" and links that start with a known URL schema
+(currently: "http:", "https:", "ftp:", "mailto:", "gopher:", "gemini:",
+"finger:").\&
+.PP
+Notably, links that start with ".\&.\&/" are reported as missing.\&
+.PP
+.SH EXAMPLE
+.PP
+Looking for broken links:
+.PP
+.nf
+.RS 4
+oddmu missing
+.fi
+.RE
+.PP
+Result:
+.PP
+.nf
+.RS 4
+Page	Missing
+README	github\&.com/pemistahl/lingua-go
+.fi
+.RE
+.PP
+This shows how the README file had a link where the URL was missing the scheme
+"https://".\&
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1), \fIoddmu-replace\fR(1), \fIoddmu-missing\fR(7)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-missing.1.txt

@@ -0,0 +1,46 @@
+ODDMU-MISSING(1)
+
+# NAME
+
+oddmu-missing - list missing pages from the command-line
+
+# SYNOPSIS
+
+*oddmu missing*
+
+# DESCRIPTION
+
+The "missing" subcommand lists pages and their local links that are missing.
+
+Any links that seem like they might point outside the wiki are ignored: links
+that start with a slash "/" and links that start with a known URL schema
+(currently: "http:", "https:", "ftp:", "mailto:", "gopher:", "gemini:",
+"finger:").
+
+Notably, links that start with "../" are reported as missing.
+
+# EXAMPLE
+
+Looking for broken links:
+
+```
+oddmu missing
+```
+
+Result:
+
+```
+Page	Missing
+README	github.com/pemistahl/lingua-go
+```
+
+This shows how the README file had a link where the URL was missing the scheme
+"https://".
+
+# SEE ALSO
+
+_oddmu_(1), _oddmu-replace_(1), _oddmu-missing_(7)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-notify.1

@@ -0,0 +1,108 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-NOTIFY" "1" "2024-01-17"
+.PP
+.SH NAME
+.PP
+oddmu-notify - add links to changes.\&md, index.\&md, and hashtag pages
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu notify\fR \fIpage names.\&.\&.\&\fR 
+.PP
+.SH DESCRIPTION
+.PP
+The "notify" subcommand takes all the page names provided (without the ".\&md"
+extension) and adds links to it from other pages.\&
+.PP
+A new link is added to the \fBchanges\fR page in the current directory if it doesn'\&t
+exist.\& The current date of the machine Oddmu is running on is used as the
+heading.\& If the requested link already exists on the changes page, it is moved
+up to the current date.\& If that leaves an old date without any links, that date
+heading is removed.\&
+.PP
+A page whose name starts with an ISO date (YYYY-MM-DD, e.\&g.\& "2023-10-28") is
+called a \fBblog\fR page.\&
+.PP
+A link is created from the \fBindex\fR page in the current directory to blog pages
+if and only if the blog pages are from the current year.\& The idea is that the
+front page contains a lot of links to blog posts but eventually the blog post
+links are moved onto archive pages (one per year, for example), or simply
+deleted.\& As when editing older pages, links to those pages should not get added
+to the index as if those older pages were new again.\& A link on the changes page
+is enough.\&
+.PP
+For every \fBhashtag\fR used on the pages named, another link might be created.\& If a
+page named like the hashtag exists, a backlink is added to it.\& A hashtag
+consists of a number sign ('\&#'\&) followed by Unicode letters, numbers or the
+underscore ('\&_'\&).\& Thus, a hashtag ends with punctuation or whitespace.\&
+.PP
+If a link already exists but it'\&s title is no longer correct, it is updated.\&
+.PP
+New links added for blog pages are added at the top of the first unnumbered list
+using the asterisk ('\&*'\&).\& If no such list exists, a new one is started at the
+bottom of the page.\& This allows you to have a different unnumbered list further
+up on the page, as long as it uses the minus for items ('\&-'\&).\&
+.PP
+.SH EXAMPLE
+.PP
+After writing the file "2023-11-05-climate.\&md" containing the hashtag
+"#Climate", add links to it from "index.\&md", "changes.\&md", and "Climate.\&md" (if
+it exists):
+.PP
+.nf
+.RS 4
+oddmu notify 2023-11-05-climate
+.fi
+.RE
+.PP
+The changes file might look as follows:
+.PP
+.nf
+.RS 4
+# Changes
+
+This page lists all the changes made to the wiki\&.
+
+## 2023-11-05
+
+* [Global warming](2023-11-05-climate)
+.fi
+.RE
+.PP
+The index file might look as follows:
+.PP
+.nf
+.RS 4
+# Blog
+
+This page links to all the blog posts\&.
+
+* [Global warming](2023-11-05-climate)
+.fi
+.RE
+.PP
+The hashtag file might look as follows:
+.PP
+.nf
+.RS 4
+# Climate
+
+This page links to all the blog posts tagged #Climate\&.
+
+* [Global warming](2023-11-05-climate)
+.fi
+.RE
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-notify.1.txt

@@ -0,0 +1,93 @@
+ODDMU-NOTIFY(1)
+
+# NAME
+
+oddmu-notify - add links to changes.md, index.md, and hashtag pages
+
+# SYNOPSIS
+
+*oddmu notify* _page names..._ 
+
+# DESCRIPTION
+
+The "notify" subcommand takes all the page names provided (without the ".md"
+extension) and adds links to it from other pages.
+
+A new link is added to the *changes* page in the current directory if it doesn't
+exist. The current date of the machine Oddmu is running on is used as the
+heading. If the requested link already exists on the changes page, it is moved
+up to the current date. If that leaves an old date without any links, that date
+heading is removed.
+
+A page whose name starts with an ISO date (YYYY-MM-DD, e.g. "2023-10-28") is
+called a *blog* page.
+
+A link is created from the *index* page in the current directory to blog pages
+if and only if the blog pages are from the current year. The idea is that the
+front page contains a lot of links to blog posts but eventually the blog post
+links are moved onto archive pages (one per year, for example), or simply
+deleted. As when editing older pages, links to those pages should not get added
+to the index as if those older pages were new again. A link on the changes page
+is enough.
+
+For every *hashtag* used on the pages named, another link might be created. If a
+page named like the hashtag exists, a backlink is added to it. A hashtag
+consists of a number sign ('#') followed by Unicode letters, numbers or the
+underscore ('\_'). Thus, a hashtag ends with punctuation or whitespace.
+
+If a link already exists but it's title is no longer correct, it is updated.
+
+New links added for blog pages are added at the top of the first unnumbered list
+using the asterisk ('\*'). If no such list exists, a new one is started at the
+bottom of the page. This allows you to have a different unnumbered list further
+up on the page, as long as it uses the minus for items ('-').
+
+# EXAMPLE
+
+After writing the file "2023-11-05-climate.md" containing the hashtag
+"#Climate", add links to it from "index.md", "changes.md", and "Climate.md" (if
+it exists):
+
+```
+oddmu notify 2023-11-05-climate
+```
+
+The changes file might look as follows:
+
+```
+# Changes
+
+This page lists all the changes made to the wiki.
+
+## 2023-11-05
+
+* [Global warming](2023-11-05-climate)
+```
+
+The index file might look as follows:
+
+```
+# Blog
+
+This page links to all the blog posts.
+
+* [Global warming](2023-11-05-climate)
+```
+
+The hashtag file might look as follows:
+
+```
+# Climate
+
+This page links to all the blog posts tagged #Climate.
+
+* [Global warming](2023-11-05-climate)
+```
+
+# SEE ALSO
+
+_oddmu_(1)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-replace.1

@@ -0,0 +1,105 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-REPLACE" "1" "2023-11-24"
+.PP
+.SH NAME
+.PP
+oddmu-replace - replace text in Oddmu pages from the command-line
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu replace\fR [-confirm] [-regexp] \fIterm\fR \fIreplacement\fR
+.PP
+.SH DESCRIPTION
+.PP
+The "replace" subcommand does a search and replace on all the Markdown files in
+the current directory and its subdirectories.\&
+.PP
+.SH OPTIONS
+.PP
+\fB-confirm\fR
+.RS 4
+By default, the replacement doesn'\&t save the changes made.\& Instead, a
+unified diff is produced and printed.\& Given this option, the changed
+Markdown files are saved to disk.\&
+.PP
+.RE
+\fB-regexp\fR
+.RS 4
+By default, the term to be replaced is just a string.\& With this flag,
+the term is a regular expression and the replacement can contain
+backreferences ($1, $2, $3, etc.\&) to capture groups.\&
+.PP
+.RE
+.SH EXAMPLE
+.PP
+Replace "Oddmu" in the Markdown files of the current directory:
+.PP
+.nf
+.RS 4
+oddmu replace Oddmu Oddµ
+.fi
+.RE
+.PP
+Result:
+.PP
+.nf
+.RS 4
+--- README\&.md~
++++ README\&.md
+
+(diff omitted)
+
+1 file would be changed\&.
+This is a dry run\&. Use -confirm to make it happen\&.
+.fi
+.RE
+.PP
+.SH NOTES
+.PP
+This is the equivalent of using \fIsed\fR(1) with the --quiet, --regexp-extended,
+--in-place=~ and --expression command with the s command
+"s/regexp/replacement/g" except that it prints a unified diff per default
+instead of making any changes and the regexp rules differ slightly.\&
+.PP
+The search is case-sensitive.\& To make it case-insensitive, search for a regular
+expression that sets the case-insensitive flag, e.\&g.\& "(?\&i)oddmu".\&
+.PP
+.SH SECURITY
+.PP
+Consider creating a backup before doing replacements!\&
+.PP
+The following Bash script creates a copy of the current directory using hard
+links.\& If you'\&re in a directory called "wiki", it creates a sibling directory
+called "wiki-2023-11-24" (using the current date) full of links.\& This takes
+little space and time.\& It works as a backup as long as you don'\&t use an
+application that edits files in place.\& Most programs overwrite old files by
+creating new files with the same name, so you should be safe.\&
+.PP
+.nf
+.RS 4
+#!/usr/bin/bash
+d=$(basename $(pwd))
+t=$(date --iso-8601)
+echo Creating a snapshot of $d in \&.\&./$d-$t
+rsync --link-dest "\&.\&./$d" --archive \&. "\&.\&./$d-$t/"
+.fi
+.RE
+.PP
+The above wouldn'\&t work for database files, for example.\& There, the database
+changes the file in place thus the file is changed in the backup directory as
+well.\& For Oddmu and the usual text editors, it works.\& If you use Emacs, don'\&t
+set \fIbackup-by-copying\fR, \fIbackup-by-copying-when-linked\fR and related variables.\&
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1), \fIoddmu-search\fR(7)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-replace.1.txt

@@ -0,0 +1,88 @@
+ODDMU-REPLACE(1)
+
+# NAME
+
+oddmu-replace - replace text in Oddmu pages from the command-line
+
+# SYNOPSIS
+
+*oddmu replace* [-confirm] [-regexp] _term_ _replacement_
+
+# DESCRIPTION
+
+The "replace" subcommand does a search and replace on all the Markdown files in
+the current directory and its subdirectories.
+
+# OPTIONS
+
+*-confirm*
+	By default, the replacement doesn't save the changes made. Instead, a
+	unified diff is produced and printed. Given this option, the changed
+	Markdown files are saved to disk.
+
+*-regexp*
+	By default, the term to be replaced is just a string. With this flag,
+	the term is a regular expression and the replacement can contain
+	backreferences ($1, $2, $3, etc.) to capture groups.
+
+# EXAMPLE
+
+Replace "Oddmu" in the Markdown files of the current directory:
+
+```
+oddmu replace Oddmu Oddµ
+```
+
+Result:
+
+```
+--- README.md~
++++ README.md
+
+(diff omitted)
+
+1 file would be changed.
+This is a dry run. Use -confirm to make it happen.
+```
+
+# NOTES
+
+This is the equivalent of using _sed_(1) with the --quiet, --regexp-extended,
+\--in-place=~ and --expression command with the s command
+"s/regexp/replacement/g" except that it prints a unified diff per default
+instead of making any changes and the regexp rules differ slightly.
+
+The search is case-sensitive. To make it case-insensitive, search for a regular
+expression that sets the case-insensitive flag, e.g. "(?i)oddmu".
+
+# SECURITY
+
+Consider creating a backup before doing replacements!
+
+The following Bash script creates a copy of the current directory using hard
+links. If you're in a directory called "wiki", it creates a sibling directory
+called "wiki-2023-11-24" (using the current date) full of links. This takes
+little space and time. It works as a backup as long as you don't use an
+application that edits files in place. Most programs overwrite old files by
+creating new files with the same name, so you should be safe.
+
+```
+#!/usr/bin/bash
+d=$(basename $(pwd))
+t=$(date --iso-8601)
+echo Creating a snapshot of $d in ../$d-$t
+rsync --link-dest "../$d" --archive . "../$d-$t/"
+```
+
+The above wouldn't work for database files, for example. There, the database
+changes the file in place thus the file is changed in the backup directory as
+well. For Oddmu and the usual text editors, it works. If you use Emacs, don't
+set _backup-by-copying_, _backup-by-copying-when-linked_ and related variables.
+
+# SEE ALSO
+
+_oddmu_(1), _oddmu-search_(7)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-search.1

@@ -0,0 +1,77 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-SEARCH" "1" "2023-12-20"
+.PP
+.SH NAME
+.PP
+oddmu-search - search the Oddmu pages from the command-line
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu search\fR [-extract] [-page \fIn\fR] \fIterms.\&.\&.\&\fR
+.PP
+.SH DESCRIPTION
+.PP
+The "search" subcommand searches the Markdown files in the current
+directory.\&
+.PP
+Be default, this returns a Markdown-formatted list suitable for pasting into
+Oddmu pages.\&
+.PP
+If a directory is provided, only files from the tree starting at that
+subdirectory are listed, and the directory is stripped from the page name.\&
+.PP
+See \fIoddmu-search\fR(7) for more information of how pages are searched, sorted and
+scored.\&
+.PP
+.SH OPTIONS
+.PP
+\fB-dir\fR \fIstring\fR
+.RS 4
+Limit search to a particular directory.\&
+.RE
+\fB-extract\fR
+.RS 4
+Print search extracts for interactive use from the command-line.\&
+.RE
+\fB-page\fR \fIn\fR
+.RS 4
+Search results are paginated and by default only the first page is
+shown.\& This option allows you to view other pages.\&
+.RE
+\fB-all\fR
+.RS 4
+Ignore pagination and just print a long list of results.\&
+.PP
+.RE
+.SH EXAMPLE
+.PP
+Search for "oddmu" in the Markdown files of the current directory:
+.PP
+.nf
+.RS 4
+oddmu search oddmu
+.fi
+.RE
+.PP
+Result:
+.PP
+.nf
+.RS 4
+Search oddmu: 1 result
+* [Oddµ: A minimal wiki](README) (5)
+.fi
+.RE
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1), \fIoddmu-replace\fR(1), \fIoddmu-search\fR(7)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-search.1.txt

@@ -0,0 +1,58 @@
+ODDMU-SEARCH(1)
+
+# NAME
+
+oddmu-search - search the Oddmu pages from the command-line
+
+# SYNOPSIS
+
+*oddmu search* [-extract] [-page _n_] _terms..._
+
+# DESCRIPTION
+
+The "search" subcommand searches the Markdown files in the current
+directory.
+
+Be default, this returns a Markdown-formatted list suitable for pasting into
+Oddmu pages.
+
+If a directory is provided, only files from the tree starting at that
+subdirectory are listed, and the directory is stripped from the page name.
+
+See _oddmu-search_(7) for more information of how pages are searched, sorted and
+scored.
+
+# OPTIONS
+
+*-dir* _string_
+	Limit search to a particular directory.
+*-extract*
+	Print search extracts for interactive use from the command-line.
+*-page* _n_
+	Search results are paginated and by default only the first page is
+	shown. This option allows you to view other pages.
+*-all*
+	Ignore pagination and just print a long list of results.
+
+# EXAMPLE
+
+Search for "oddmu" in the Markdown files of the current directory:
+
+```
+oddmu search oddmu
+```
+
+Result:
+
+```
+Search oddmu: 1 result
+* [Oddµ: A minimal wiki](README) (5)
+```
+
+# SEE ALSO
+
+_oddmu_(1), _oddmu-replace_(1), _oddmu-search_(7)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-search.7

@@ -0,0 +1,98 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-SEARCH" "7" "2023-10-28"
+.PP
+.SH NAME
+.PP
+oddmu-search - understanding the Oddmu search engine
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu search\fR \fIterms\fR.\&.\&.\&
+.PP
+.SH DESCRIPTION
+.PP
+The wiki keeps an index of all the hash tags and page titles in memory.\& Using
+hashtags and predicates in your queries speeds them up because fewer files are
+opened.\&
+.PP
+A hashtag starts with a number sign ('\&#'\&) and contains numbers, letters, and the
+underscore ('\&_'\&).\&
+.PP
+Example: #old_school random encounter
+.PP
+The title predicate filters for pages where the term is contained in the page
+title.\&
+.PP
+Example: title:geo title:cache zürich
+.PP
+The blog predicate filters for pages where the page name begins with an ISO date
+like "2023-09-26" if true, or doesn'\&t begin with an ISO date if false.\&
+.PP
+Example: blog:false fountain
+.PP
+The sorting of all the pages does not depend on the number of matches or any
+kind of score because computing the score is expensive as this requires the page
+to be loaded from disk.\& Therefore, results are sorted by title:
+.PP
+.PD 0
+.IP \(bu 4
+If a page title matches the query string exactly, it gets sorted first.\&
+.IP \(bu 4
+If the page title contains the query string, it gets sorted next.\&
+.IP \(bu 4
+If the page name starts with a number, it is sorted descending.\&
+.IP \(bu 4
+All other pages follow, sorted ascending.\&
+.PD
+.PP
+The effect is that first, the pages with matches in the page title are shown,
+and then all the others.\& Within these two groups, the most recent blog posts are
+shown first.\& This assumes that blog pages start with an ISO date like
+"2023-09-16".\&
+.PP
+When searching for a hashtag, a page name (not the title!\&) matching the hashtag
+exactly (without the leading '\&#'\&) is listed first, even if it doesn'\&t contain
+the hashtag.\& It is assumed that this page offers some kind of introduction to
+people searching for the hashtag.\&
+.PP
+Example: When people click on the hashtag "#Oddµ" and a page named "Oddµ" exists
+(in other words, the file "Oddµ.\&md" exists), it is prepended to the results even
+if it doesn'\&t have the hashtag "#Oddµ" and even if it has a title of "Oddµ, a
+minimal wiki" (which wouldn'\&t be an exact match).\&
+.PP
+The score and highlighting of snippets is used to help visitors decide which
+links to click.\&
+.PP
+Each document found is scored.\& Each of the following increases the score by one
+point:
+.PP
+.PD 0
+.IP \(bu 4
+the entire phrase matches
+.IP \(bu 4
+a word matches
+.IP \(bu 4
+a word matches at the beginning of a word
+.IP \(bu 4
+a word matches at the end of a word
+.IP \(bu 4
+a word matches as a whole word
+.PD
+.PP
+A document with content "This is a test" when searched with the phrase "this
+test" therefore gets a score of 8: the entire phrase does not match but each
+word gets four points.\&
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1), \fIoddmu-search\fR(1)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-search.7.txt

@@ -0,0 +1,78 @@
+ODDMU-SEARCH(7)
+
+# NAME
+
+oddmu-search - understanding the Oddmu search engine
+
+# SYNOPSIS
+
+*oddmu search* _terms_...
+
+# DESCRIPTION
+
+The wiki keeps an index of all the hash tags and page titles in memory. Using
+hashtags and predicates in your queries speeds them up because fewer files are
+opened.
+
+A hashtag starts with a number sign ('#') and contains numbers, letters, and the
+underscore ('\_').
+
+Example: #old_school random encounter
+
+The title predicate filters for pages where the term is contained in the page
+title.
+
+Example: title:geo title:cache zürich
+
+The blog predicate filters for pages where the page name begins with an ISO date
+like "2023-09-26" if true, or doesn't begin with an ISO date if false.
+
+Example: blog:false fountain
+
+The sorting of all the pages does not depend on the number of matches or any
+kind of score because computing the score is expensive as this requires the page
+to be loaded from disk. Therefore, results are sorted by title:
+
+- If a page title matches the query string exactly, it gets sorted first.
+- If the page title contains the query string, it gets sorted next.
+- If the page name starts with a number, it is sorted descending.
+- All other pages follow, sorted ascending.
+
+The effect is that first, the pages with matches in the page title are shown,
+and then all the others. Within these two groups, the most recent blog posts are
+shown first. This assumes that blog pages start with an ISO date like
+"2023-09-16".
+
+When searching for a hashtag, a page name (not the title!) matching the hashtag
+exactly (without the leading '#') is listed first, even if it doesn't contain
+the hashtag. It is assumed that this page offers some kind of introduction to
+people searching for the hashtag.
+
+Example: When people click on the hashtag "#Oddµ" and a page named "Oddµ" exists
+(in other words, the file "Oddµ.md" exists), it is prepended to the results even
+if it doesn't have the hashtag "#Oddµ" and even if it has a title of "Oddµ, a
+minimal wiki" (which wouldn't be an exact match).
+
+The score and highlighting of snippets is used to help visitors decide which
+links to click.
+
+Each document found is scored. Each of the following increases the score by one
+point:
+
+- the entire phrase matches
+- a word matches
+- a word matches at the beginning of a word
+- a word matches at the end of a word
+- a word matches as a whole word
+
+A document with content "This is a test" when searched with the phrase "this
+test" therefore gets a score of 8: the entire phrase does not match but each
+word gets four points.
+
+# SEE ALSO
+
+_oddmu_(1), _oddmu-search_(1)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-static.1

@@ -0,0 +1,85 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-STATIC" "1" "2024-02-09"
+.PP
+.SH NAME
+.PP
+oddmu-static - create a static copy of the site
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu static\fR \fIdir-name\fR
+.PP
+.SH DESCRIPTION
+.PP
+The "static" subcommand generates a static copy of the pages in the current
+directory and saves them in the given destination directory.\& The destination
+directory must not exist.\&
+.PP
+All pages (files with the ".\&md" extension) are turned into HTML files (with the
+".\&html" extension) using the "static.\&html" template.\& Links pointing to existing
+pages get ".\&html" appended.\&
+.PP
+Hidden files and directories (starting with a ".\&") and backup files (ending with
+a "~") are skipped.\&
+.PP
+All other files are \fIhard linked\fR.\& This is done to save space: on a typical blog
+the images take a lot more space than the text.\& On my blog in 2023 I had 2.\&62
+GiB of JPG files and 0.\&02 GiB of Markdown files.\& There is no point in copying
+all those images, most of the time.\&
+.PP
+Note, however: Hard links cannot span filesystems.\& A hard link is just an extra
+name for the same file.\& This is why the destination directory for the static
+site has to be on same filesystem as the current directory, if it contains any
+other files besides Markdown files.\&
+.PP
+Furthermore, in-place editing changes the file for all names.\& Avoid editing the
+hard-linked files (anything that'\&s not a HTML file) in the destination
+directory, just to be on the safe side.\& Usually you should be fine, as an editor
+moves the file that'\&s being edited to a backup file and creates a new file.\& But
+then again, who knows.\& A SQLite file, for example, would change in-place, and
+therefore making changes to it in the destination directory would change the
+original, too.\&
+.PP
+.SH EXAMPLE
+.PP
+Generate a static copy of the site:
+.PP
+.nf
+.RS 4
+oddmu static \&.\&./archive
+.fi
+.RE
+.PP
+.SH LIMITATIONS
+.PP
+Links from files to pages do not get ".\&html" appended.\& This affects existing
+HTML or XML files including SVG files.\&
+.PP
+Links to absolute URLs (starting with "/") are not changed at all.\& It is up to
+you to migrate static folders and applications.\&
+.PP
+.SH ENVIRONMENT
+.PP
+The ODDMU_WEBFINGER environment variable has no effect in this situation.\&
+Fediverse accounts are not linked to their profile pages.\& Since the data isn'\&t
+cached, every run of this command would trigger a webfinger request for every
+fediverse account mentioned.\&
+.PP
+If the site is large, determining the language of a page slows things down.\& Set
+the ODDMU_LANGUAGES environment variable to a comma-separated list of ISO 639-1
+codes, e.\&g.\& "en" or "en,de,fr,pt" to limit the languages loaded and thereby
+speed language determination up.\&
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1), \fIoddmu-templates\fR(5)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-static.1.txt

@@ -0,0 +1,76 @@
+ODDMU-STATIC(1)
+
+# NAME
+
+oddmu-static - create a static copy of the site
+
+# SYNOPSIS
+
+*oddmu static* _dir-name_
+
+# DESCRIPTION
+
+The "static" subcommand generates a static copy of the pages in the current
+directory and saves them in the given destination directory. The destination
+directory must not exist.
+
+All pages (files with the ".md" extension) are turned into HTML files (with the
+".html" extension) using the "static.html" template. Links pointing to existing
+pages get ".html" appended.
+
+Hidden files and directories (starting with a ".") and backup files (ending with
+a "~") are skipped.
+
+All other files are _hard linked_. This is done to save space: on a typical blog
+the images take a lot more space than the text. On my blog in 2023 I had 2.62
+GiB of JPG files and 0.02 GiB of Markdown files. There is no point in copying
+all those images, most of the time.
+
+Note, however: Hard links cannot span filesystems. A hard link is just an extra
+name for the same file. This is why the destination directory for the static
+site has to be on same filesystem as the current directory, if it contains any
+other files besides Markdown files.
+
+Furthermore, in-place editing changes the file for all names. Avoid editing the
+hard-linked files (anything that's not a HTML file) in the destination
+directory, just to be on the safe side. Usually you should be fine, as an editor
+moves the file that's being edited to a backup file and creates a new file. But
+then again, who knows. A SQLite file, for example, would change in-place, and
+therefore making changes to it in the destination directory would change the
+original, too.
+
+# EXAMPLE
+
+Generate a static copy of the site:
+
+```
+oddmu static ../archive
+```
+
+# LIMITATIONS
+
+Links from files to pages do not get ".html" appended. This affects existing
+HTML or XML files including SVG files.
+
+Links to absolute URLs (starting with "/") are not changed at all. It is up to
+you to migrate static folders and applications.
+
+# ENVIRONMENT
+
+The ODDMU_WEBFINGER environment variable has no effect in this situation.
+Fediverse accounts are not linked to their profile pages. Since the data isn't
+cached, every run of this command would trigger a webfinger request for every
+fediverse account mentioned.
+
+If the site is large, determining the language of a page slows things down. Set
+the ODDMU_LANGUAGES environment variable to a comma-separated list of ISO 639-1
+codes, e.g. "en" or "en,de,fr,pt" to limit the languages loaded and thereby
+speed language determination up.
+
+# SEE ALSO
+
+_oddmu_(1), _oddmu-templates_(5)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-templates.5

@@ -0,0 +1,219 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-TEMPLATES" "5" "2024-02-06" "File Formats Manual"
+.PP
+.SH NAME
+.PP
+oddmu-templates - how to write the templates
+.PP
+.SH SYNOPSIS
+.PP
+These files act as HTML templates: add.\&html, diff.\&html, edit.\&html, feed.\&html,
+search.\&html, static.\&html, upload.\&html and view.\&html.\& They contain special
+placeholders in double bracers {{like this}}.\&
+.PP
+.SH SYNTAX
+.PP
+The templates can refer to the following properties of a page:
+.PP
+\fI{{.\&Title}}\fR is the page title.\& If the page doesn'\&t provide its own title, the
+page name is used.\&
+.PP
+\fI{{.\&Name}}\fR is the page name, escaped for use in URLs.\& More specifically, it is
+percent-escaped except for the slashes.\& The page name doesn'\&t include the \fI.\&md\fR
+extension.\&
+.PP
+\fI{{.\&Dir}}\fR is the page directory, percent-escaped except for the slashes.\&
+.PP
+\fI{{.\&Base}}\fR is the basename of the current file (without the directory and
+without the \fI.\&md\fR extension), escaped for use in URLs.\&
+.PP
+\fI{{.\&Today}}\fR is the current date, in ISO format.\& This is useful for "new page"
+like links or forms (see \fBEXAMPLE\fR below).\&
+.PP
+For the \fIview.\&html\fR and \fIstatic.\&html\fR template:
+.PP
+\fI{{.\&Html}}\fR is the rendered Markdown, as HTML.\&
+.PP
+\fI{{.\&Hashtags}}\fR is an array of strings.\&
+.PP
+For the \fIdiff.\&html\fR template:
+.PP
+\fI{{.\&Diff}}\fR is the diff for this page.\& This is only computed on demand so it can
+be used in other templates, too.\& It probably doesn'\&t make much sense to do so,
+however.\&
+.PP
+For the \fIedit.\&html\fR template:
+.PP
+\fI{{printf "%s" .\&Body}}\fR is the Markdown, as a string (the data itself is a byte
+array and that'\&s why we need to call \fIprintf\fR).\&
+.PP
+For the \fIsearch.\&html\fR template only:
+.PP
+\fI{{.\&Previous}}\fR, \fI{{.\&Page}}\fR and \fI{{.\&Next}}\fR are the previous, current and next
+page number in the results since doing arithmetics in templates is hard.\& The
+first page number is 1.\& The last page is expensive to dermine and so that isn'\&t
+done.\&
+.PP
+\fI{{.\&More}}\fR indicates if there are any more search results.\&
+.PP
+\fI{{.\&Results}}\fR indicates if there were any search results at all.\&
+.PP
+\fI{{.\&Items}}\fR is an array of pages, each containing a search result.\& A search
+result is a page (with the properties seen above).\& Thus, to refer to them, you
+need to use a \fI{{range .\&Items}}\fR … \fI{{end}}\fR construct.\&
+.PP
+For items in the search result:
+.PP
+\fI{{.\&Html}}\fR is the rendered Markdown of a page summary, as HTML.\&
+.PP
+\fI{{.\&Score}}\fR is a numerical score for search results.\&
+.PP
+For the \fIfeed.\&html\fR template:
+.PP
+\fI{{.\&Name}}\fR is the page name, escaped for use in URLs.\&
+.PP
+\fI{{.\&Title}}\fR is the title of the underlying main page.\&
+.PP
+\fI{{.\&Date}}\fR is the date of the last update to the underlying main page, in RFC
+822 format.\&
+.PP
+\fI{{.\&Items}}\fR is an array of feed items.\&
+.PP
+For items in the feed:
+.PP
+\fI{{.\&Name}}\fR is the page name, escaped for use in URLs.\&
+.PP
+\fI{{.\&Title}}\fR is the title of the page.\&
+.PP
+\fI{{.\&Html}}\fR is the rendered Markdown, as escaped (!\&) HTML.\&
+.PP
+\fI{{.\&Hashtags}}\fR is an array of strings.\&
+.PP
+\fI{{.\&Date}}\fR, the date of the last update to this page, in RFC 822 format.\&
+.PP
+The \fIupload.\&html\fR template cannot refer to anything.\&
+.PP
+When calling the \fIsave\fR and \fIappend\fR action, the page name is taken from the URL
+path and the page content is taken from the \fIbody\fR form parameter.\& To
+illustrate, here'\&s how to edit the "welcome" page using \fIcurl\fR:
+.PP
+.nf
+.RS 4
+curl --form body="Did you bring a towel?" 
+  http://localhost:8080/save/welcome
+.fi
+.RE
+.PP
+When calling the \fIsearch\fR action, the query is taken from the query parameter \fIq\fR.\&
+.PP
+.nf
+.RS 4
+curl \&'http://localhost:8080/search/?q=towel\&'
+.fi
+.RE
+.PP
+The page name to act upon is optionally taken from the query parameter \fIid\fR.\& In
+this case, the directory must also be part of the query parameter and not of the
+URL path.\&
+.PP
+.nf
+.RS 4
+curl \&'http://localhost:8080/view/?id=man/oddmu\&.1\&.txt\&'
+.fi
+.RE
+.PP
+.SS Non-English hyphenation
+.PP
+Automatic hyphenation by the browser requires two things: The style sheet must
+indicate "hyphen: auto" for an HTML element such as "body", and that element
+must have a "lang" set (usually a two letter language code such as "de" for
+German).\&
+.PP
+Oddmu attempts to detect the correct language for each page.\& It assumes that
+languages are not mixed on the same page.\& If you know that you'\&re only going to
+use a small number of languages – or just a single language!\& – you can set the
+environment variable ODDMU_LANGUAGES to a comma-separated list of ISO 639-1
+codes, e.\&g.\& "en" or "en,de,fr,pt".\&
+.PP
+"view.\&html" is used the template to render a single page and so the language
+detected is added to the "html" element.\&
+.PP
+"search.\&html" is the template used to render search results and so "en" is used
+for the "html" element and the language detected for every page in the search
+result is added to the "article" element for each snippet.\&
+.PP
+"edit.\&html" and "add.\&html" are the templates used to edit a page and at that
+point, the language isn'\&t known, so "en" is used for the "html" element and no
+language is used for the "textarea" element.\&
+.PP
+.SH EXAMPLE
+.PP
+The following link in a template takes people to today'\&s page.\& If no such page
+exists, they are redirected to the edit form where it can be created.\&
+.PP
+.nf
+.RS 4
+<a href="/view/{{\&.Today}}" accesskey="t">Today</a>
+.fi
+.RE
+.PP
+The following form allows people to edit the suggested page name.\&
+.PP
+.nf
+.RS 4
+<form role="new" action="/edit/{{\&.Dir}}" method="GET">
+  <label for="id">New page:</label>
+  <input id="id" type="text" spellcheck="false" name="id"
+	  accesskey="g" value="{{\&.Today}}" required>
+  <button>Edit</button>
+</form>
+.fi
+.RE
+.PP
+.SH NOTES
+.PP
+The templates are always used as-is, irrespective of the current directory.\&
+Therefore, a link to a specific page must be \fIabsolute\fR or it'\&ll point to a
+different page depending on the current directory.\&
+.PP
+Consider the link to "/view/index".\& No matter what page a visitor is looking,
+this takes visitors to the top "index" page.\& If the link points to "index"
+instead, it takes a visitor to the "index" page of the current directory.\& In
+this case, a visitor looking at "/view/projects/wiki" following a link to
+"index" ends up on "/view/projects/index", not on "/view/index".\&
+.PP
+It'\&s up to you to decide what'\&s best for your site, of course.\&
+.PP
+Templates can be changed by uploading new copies of the template files.\&
+.PP
+Subdirectories can have their own copies of template files.\& One example use for
+this is that they can point to a different CSS file.\&
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1)
+.PP
+"Structuring the web with HTML"
+https://developer.\&mozilla.\&org/en-US/docs/Learn/HTML
+.PP
+"Learn to style HTML using CSS"
+https://developer.\&mozilla.\&org/en-US/docs/Learn/CSS
+.PP
+The "text/template" library explains how to write templates from a programmer
+perspective.\& https://pkg.\&go.\&dev/text/template
+.PP
+The "html/template" library explains how the templates are made more secure in a
+HTML context.\& https://pkg.\&go.\&dev/html/template
+.PP
+"Lingua" is the library used to detect languages.\&
+https://github.\&com/pemistahl/lingua-go
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-templates.5.txt

@@ -0,0 +1,202 @@
+ODDMU-TEMPLATES(5) "File Formats Manual"
+
+# NAME
+
+oddmu-templates - how to write the templates
+
+# SYNOPSIS
+
+These files act as HTML templates: add.html, diff.html, edit.html, feed.html,
+search.html, static.html, upload.html and view.html. They contain special
+placeholders in double bracers {{like this}}.
+
+# SYNTAX
+
+The templates can refer to the following properties of a page:
+
+_{{.Title}}_ is the page title. If the page doesn't provide its own title, the
+page name is used.
+
+_{{.Name}}_ is the page name, escaped for use in URLs. More specifically, it is
+percent-escaped except for the slashes. The page name doesn't include the _.md_
+extension.
+
+_{{.Dir}}_ is the page directory, percent-escaped except for the slashes.
+
+_{{.Base}}_ is the basename of the current file (without the directory and
+without the _.md_ extension), escaped for use in URLs.
+
+_{{.Today}}_ is the current date, in ISO format. This is useful for "new page"
+like links or forms (see *EXAMPLE* below).
+
+For the _view.html_ and _static.html_ template:
+
+_{{.Html}}_ is the rendered Markdown, as HTML.
+
+_{{.Hashtags}}_ is an array of strings.
+
+For the _diff.html_ template:
+
+_{{.Diff}}_ is the diff for this page. This is only computed on demand so it can
+be used in other templates, too. It probably doesn't make much sense to do so,
+however.
+
+For the _edit.html_ template:
+
+_{{printf "%s" .Body}}_ is the Markdown, as a string (the data itself is a byte
+array and that's why we need to call _printf_).
+
+For the _search.html_ template only:
+
+_{{.Previous}}_, _{{.Page}}_ and _{{.Next}}_ are the previous, current and next
+page number in the results since doing arithmetics in templates is hard. The
+first page number is 1. The last page is expensive to dermine and so that isn't
+done.
+
+_{{.More}}_ indicates if there are any more search results.
+
+_{{.Results}}_ indicates if there were any search results at all.
+
+_{{.Items}}_ is an array of pages, each containing a search result. A search
+result is a page (with the properties seen above). Thus, to refer to them, you
+need to use a _{{range .Items}}_ … _{{end}}_ construct.
+
+For items in the search result:
+
+_{{.Html}}_ is the rendered Markdown of a page summary, as HTML.
+
+_{{.Score}}_ is a numerical score for search results.
+
+For the _feed.html_ template:
+
+_{{.Name}}_ is the page name, escaped for use in URLs.
+
+_{{.Title}}_ is the title of the underlying main page.
+
+_{{.Date}}_ is the date of the last update to the underlying main page, in RFC
+822 format.
+
+_{{.Items}}_ is an array of feed items.
+
+For items in the feed:
+
+_{{.Name}}_ is the page name, escaped for use in URLs.
+
+_{{.Title}}_ is the title of the page.
+
+_{{.Html}}_ is the rendered Markdown, as escaped (!) HTML.
+
+_{{.Hashtags}}_ is an array of strings.
+
+_{{.Date}}_, the date of the last update to this page, in RFC 822 format.
+
+The _upload.html_ template cannot refer to anything.
+
+When calling the _save_ and _append_ action, the page name is taken from the URL
+path and the page content is taken from the _body_ form parameter. To
+illustrate, here's how to edit the "welcome" page using _curl_:
+
+```
+curl --form body="Did you bring a towel?" \
+  http://localhost:8080/save/welcome
+```
+
+When calling the _search_ action, the query is taken from the query parameter _q_.
+
+```
+curl 'http://localhost:8080/search/?q=towel'
+```
+
+The page name to act upon is optionally taken from the query parameter _id_. In
+this case, the directory must also be part of the query parameter and not of the
+URL path.
+
+```
+curl 'http://localhost:8080/view/?id=man/oddmu.1.txt'
+```
+
+## Non-English hyphenation
+
+Automatic hyphenation by the browser requires two things: The style sheet must
+indicate "hyphen: auto" for an HTML element such as "body", and that element
+must have a "lang" set (usually a two letter language code such as "de" for
+German).
+
+Oddmu attempts to detect the correct language for each page. It assumes that
+languages are not mixed on the same page. If you know that you're only going to
+use a small number of languages – or just a single language! – you can set the
+environment variable ODDMU_LANGUAGES to a comma-separated list of ISO 639-1
+codes, e.g. "en" or "en,de,fr,pt".
+
+"view.html" is used the template to render a single page and so the language
+detected is added to the "html" element.
+
+"search.html" is the template used to render search results and so "en" is used
+for the "html" element and the language detected for every page in the search
+result is added to the "article" element for each snippet.
+
+"edit.html" and "add.html" are the templates used to edit a page and at that
+point, the language isn't known, so "en" is used for the "html" element and no
+language is used for the "textarea" element.
+
+# EXAMPLE
+
+The following link in a template takes people to today's page. If no such page
+exists, they are redirected to the edit form where it can be created.
+
+```
+<a href="/view/{{.Today}}" accesskey="t">Today</a>
+```
+
+The following form allows people to edit the suggested page name.
+
+```
+<form role="new" action="/edit/{{.Dir}}" method="GET">
+  <label for="id">New page:</label>
+  <input id="id" type="text" spellcheck="false" name="id"
+	  accesskey="g" value="{{.Today}}" required>
+  <button>Edit</button>
+</form>
+```
+
+# NOTES
+
+The templates are always used as-is, irrespective of the current directory.
+Therefore, a link to a specific page must be _absolute_ or it'll point to a
+different page depending on the current directory.
+
+Consider the link to "/view/index". No matter what page a visitor is looking,
+this takes visitors to the top "index" page. If the link points to "index"
+instead, it takes a visitor to the "index" page of the current directory. In
+this case, a visitor looking at "/view/projects/wiki" following a link to
+"index" ends up on "/view/projects/index", not on "/view/index".
+
+It's up to you to decide what's best for your site, of course.
+
+Templates can be changed by uploading new copies of the template files.
+
+Subdirectories can have their own copies of template files. One example use for
+this is that they can point to a different CSS file.
+
+# SEE ALSO
+
+_oddmu_(1)
+
+"Structuring the web with HTML"
+https://developer.mozilla.org/en-US/docs/Learn/HTML
+
+"Learn to style HTML using CSS"
+https://developer.mozilla.org/en-US/docs/Learn/CSS
+
+The "text/template" library explains how to write templates from a programmer
+perspective. https://pkg.go.dev/text/template
+
+The "html/template" library explains how the templates are made more secure in a
+HTML context. https://pkg.go.dev/html/template
+
+"Lingua" is the library used to detect languages.
+https://github.com/pemistahl/lingua-go
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu-version.1

@@ -0,0 +1,38 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU-VERSION" "1" "2024-02-13"
+.PP
+.SH NAME
+.PP
+oddmu-version - print build info on the command-line
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu version\fR
+.PP
+.SH DESCRIPTION
+.PP
+The "version" subcommand prints a lot of stuff used to build the binary,
+including the git revision, git repository, versions of dependencies used and
+more.\&
+.PP
+It'\&s the equivalent of running this:
+.PP
+.nf
+.RS 4
+go version -m oddmu
+.fi
+.RE
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu-version.1.txt

@@ -0,0 +1,29 @@
+ODDMU-VERSION(1)
+
+# NAME
+
+oddmu-version - print build info on the command-line
+
+# SYNOPSIS
+
+*oddmu version*
+
+# DESCRIPTION
+
+The "version" subcommand prints a lot of stuff used to build the binary,
+including the git revision, git repository, versions of dependencies used and
+more.
+
+It's the equivalent of running this:
+
+```
+go version -m oddmu
+```
+
+# SEE ALSO
+
+_oddmu_(1)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu.1

@@ -0,0 +1,267 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU" "1" "2024-02-13"
+.PP
+.SH NAME
+.PP
+oddmu - a wiki server
+.PP
+Oddmu is sometimes written Oddµ because µ is the letter mu.\&
+.PP
+.SH SYNOPSIS
+.PP
+\fBoddmu\fR
+.PP
+.SH DESCRIPTION
+.PP
+The oddmu program serves the current working directory as a wiki on port 8080.\&
+Point your browser to http://localhost:8080/ to get started.\& This is equivalent
+to http://localhost:8080/view/index – the first page you'\&ll create, most likely.\&
+.PP
+If you request a page that doesn'\&t exist, oddmu tries to find a matching
+Markdown file by appending the extension ".\&md" to the page name.\& In the example
+above, the page name requested is "index" and the file name oddmu tries to read
+is "index.\&md".\& If no such file exists, oddmu offers you to create the page.\&
+.PP
+If your files don'\&t provide their own title ("# title"), the file name (without
+".\&md") is used for the page title.\&
+.PP
+Every file can be viewed as feed by using the extension ".\&rss".\& The
+feed items are based on links in bullet lists using the asterix
+("*").\&
+.PP
+Subdirectories are created as necessary.\&
+.PP
+See \fIoddmu\fR(5) for details about the page formatting.\&
+.PP
+.SH CONFIGURATION
+.PP
+The template files are the HTML files in the working directory:
+"add.\&html", "diff.\&html", "edit.\&html", "search.\&html", "upload.\&html" and
+"view.\&html".\& Please change them!\&
+.PP
+The first change you should make is to replace the name and email
+address in the footer of "view.\&html".\& Look for "Your Name" and
+"example.\&org".\&
+.PP
+The second change you should make is to replace the name, email
+address and domain name in "feed.\&html".\& Look for "Your Name" and
+"example.\&org".\& This second template is used to generate the RSS feeds
+(despite its ".\&html" extension).\&
+.PP
+See \fIoddmu-templates\fR(5) for more.\&
+.PP
+.SH ENVIRONMENT
+.PP
+You can change the port served by setting the ODDMU_PORT environment variable.\&
+.PP
+You can change the address served by setting the ODDMU_ADDRESS environment
+variable to either an IPv4 address or an IPv6 address.\& If ODDMU_ADDRESS is
+unset, then the program listens on all available unicast addresses, both IPv4
+and IPv6.\& Here are a few example addresses:
+.PP
+ODDMU_ADDRESS=127.\&0.\&0.\&1 # The loopback IPv4 address.\&
+ODDMU_ADDRESS=2001:db8::3:1 # An IPv6 address.\&
+.PP
+See the Socket Activation section for an alternative method of listening which
+supports Unix-domain sockets.\&
+.PP
+In order to limit language-detection to the languages you actually use, set the
+environment variable ODDMU_LANGUAGES to a comma-separated list of ISO 639-1
+codes, e.\&g.\& "en" or "en,de,fr,pt".\&
+.PP
+You can enable webfinger to link fediverse accounts to their correct profile
+pages by setting ODDMU_WEBFINGER to "1".\& See \fIoddmu\fR(5).\&
+.PP
+If you use secret subdirectories, you cannot rely on the web server to hide
+those pages because search includes subdirectories.\& In order to protect those
+pages from search, you need to use the ODDMU_FILTER to a regular exression such
+as "^secret/".\& See \fIoddmu-apache\fR(5).\&
+.PP
+.SH Socket Activation
+.PP
+Instead of specifying ODDMU_ADDRESS or ODDMU_PORT, you can start the service
+through socket activation.\& The advantage of this method is that you can use a
+Unix-domain socket instead of a TCP socket, and the permissions and ownership of
+the socket are set before the program starts.\& See \fIoddmu.\&service\fR(5) and
+\fIoddmu-apache\fR(5) for an example of how to use socket activation with a
+Unix-domain socket under systemd and Apache.\&
+.PP
+.SH SECURITY
+.PP
+If the machine you are running Oddmu on is accessible from the Internet, you
+must secure your installation.\& The best way to do this is use a regular web
+server as a reverse proxy.\&
+.PP
+See \fIoddmu-apache\fR(5) for an example.\&
+.PP
+Oddmu assumes that all the users that can edit pages or upload files are trusted
+users and therefore their content is trusted.\& Therefore, Oddmu doesn'\&t perform
+HTML sanitization!\&
+.PP
+For an extra dose of security, consider using a Unix-domain socket.\&
+.PP
+.SH OPTIONS
+.PP
+The oddmu program can be run on the command-line using various subcommands.\&
+.PP
+.PD 0
+.IP \(bu 4
+to generate the HTML for a single page, see \fIoddmu-html\fR(1)
+.IP \(bu 4
+to generate the HTML for the entire site, using Oddmu as a static site
+generator, see \fIoddmu-static\fR(1)
+.IP \(bu 4
+to search a regular expression and replace it across all files, see
+\fIoddmu-replace\fR(1)
+.IP \(bu 4
+to emulate a search of the files, see \fIoddmu-search\fR(1); to understand how the
+search engine indexes pages and how it sorts and scores results, see
+\fIoddmu-search\fR(7)
+.IP \(bu 4
+to find missing pages (local links that go nowhere), see \fIoddmu-missing\fR(1)
+.IP \(bu 4
+to add links to changes, index and hashtag pages to pages you created locally,
+see \fIoddmu-notify\fR(1)
+.PD
+.PP
+.SH EXAMPLE
+.PP
+When saving a page, the page name is take from the URL and the page content is
+taken from the "body" form parameter.\& To illustrate, here'\&s how to edit a page
+using \fIcurl\fR(1):
+.PP
+.nf
+.RS 4
+curl --form body="Did you bring a towel?" 
+  http://localhost:8080/save/welcome
+.fi
+.RE
+.PP
+.SH DESIGN
+.PP
+This is a minimal wiki.\& There is no version history.\& It'\&s well suited as a
+\fIsecondary\fR medium: collaboration and conversation happens elsewhere, in chat,
+on social media.\& The wiki serves as the text repository that results from these
+discussions.\&
+.PP
+The idea is that the webserver handles as many tasks as possible.\& It logs
+requests, does rate limiting, handles encryption, gets the certificates, and so
+on.\& The web server acts as a reverse proxy and the wiki ends up being a content
+management system with almost no structure – or endless malleability, depending
+on your point of view.\& See \fIoddmu-apache\fR(5).\&
+.PP
+.SH NOTES
+.PP
+Page names are filenames with ".\&md" appended.\& If your filesystem cannot handle
+it, it can'\&t be a page name.\& Filenames can contain slashes and oddmu creates
+subdirectories as necessary.\&
+.PP
+Files may not end with a tilde ('\&~'\&) – these are backup files.\& When saving pages
+and file uploads, the old file renamed to the backup file unless the backup file
+is less than an hour old, thus collapsing all edits made in an hour into a
+single diff when comparing backup and current version.\&
+.PP
+The \fBindex\fR page is the default page.\& People visiting the "root" of the site are
+redirected to "/view/index".\&
+.PP
+The \fBchanges\fR page is where links to new and changed files are added.\& As an
+author, you can prevent this from happening by deselecting the checkbox "Add
+link to the list of changes.\&" The changes page can be edited like every other
+page, so it'\&s easy to undo mistakes.\&
+.PP
+Links on the changes page are grouped by date.\& When new links are added, the
+current date of the machine Oddmu is running on is used.\& If a link already
+exists on the changes page, it is moved up to the current date.\& If that leaves
+an old date without any links, that date heading is removed.\&
+.PP
+If you want to link to the changes page, you need to do this yourself.\& Add a
+link from the index, for example.\& The "view.\&html" template currently doesn'\&t do
+it.\& See \fIoddmu-templates\fR(5) if you want to add the link to the template.\&
+.PP
+A page whose name starts with an ISO date (YYYY-MM-DD, e.\&g.\& "2023-10-28") is
+called a \fBblog\fR page.\& When creating or editing blog pages, links to it are added
+from other pages.\&
+.PP
+If the blog page name starts with the current year, a link is created from the
+index page back to the blog page being created or edited.\& Again, you can prevent
+this from happening by deselecting the checkbox "Add link to the list of
+changes.\&" The index page can be edited like every other page, so it'\&s easy to
+undo mistakes.\&
+.PP
+For every \fBhashtag\fR used, another link might be created.\& If a page named like
+the hashtag exists, a backlink is added to it, linking to the new or edited blog
+page.\&
+.PP
+If a link to the new or edited blog page already exists but it'\&s title is no
+longer correct, it is updated.\&
+.PP
+New links added for blog pages are added at the top of the first unnumbered list
+using the asterisk ('\&*'\&).\& If no such list exists, a new one is started at the
+bottom of the page.\& This allows you to have a different unnumbered list further
+up on the page, as long as it uses the minus for items ('\&-'\&).\&
+.PP
+Changes made locally do not create any links on the changes page, the index page
+or on any hashtag pages.\& See \fIoddmu-notify\fR(1) for a way to add the necessary
+links to the changes page and possibly to the index and hashtag pages.\&
+.PP
+A hashtag consists of a number sign ('\&#'\&) followed by Unicode letters, numbers
+or the underscore ('\&_'\&).\& Thus, a hashtag ends with punctuation or whitespace.\&
+.PP
+The page names, titles and hashtags are loaded into memory when the server
+starts.\& If you have a lot of pages, this takes a lot of memory.\&
+.PP
+Oddmu watches the working directory and any subdirectories for changes made
+directly.\& Thus, in theory, it'\&s not necessary to restart it after making such
+changes.\&
+.PP
+You cannot edit uploaded files.\& If you upload a file called "hello.\&txt" and
+attempt to edit it by using "/edit/hello.\&txt" you create a page with the name
+"hello.\&txt.\&md" instead.\&
+.PP
+In order to delete uploaded files via the web, create an empty file and upload
+it.\& In order to delete a wiki page, save an empty page.\&
+.PP
+Note that some HTML file names are special: they act as templates.\& See
+\fIoddmu-templates\fR(5) for their names and their use.\&
+.PP
+.SH SEE ALSO
+.PP
+.PD 0
+.IP \(bu 4
+\fIoddmu\fR(5), about the markup syntax and how feeds are generated based on link lists
+.IP \(bu 4
+\fIoddmu.\&service\fR(5), on how to run the service under systemd
+.IP \(bu 4
+\fIoddmu-apache\fR(5), on how to set up a web server such as Apache
+.IP \(bu 4
+\fIoddmu-html\fR(1), on how to render a page from the command-line
+.IP \(bu 4
+\fIoddmu-list\fR(1), on how to list pages and titles from the command-line
+.IP \(bu 4
+\fIoddmu-missing\fR(1), on how to find broken local links from the command-line
+.IP \(bu 4
+\fIoddmu-replace\fR(1), on how to search and replace text from the command-line
+.IP \(bu 4
+\fIoddmu-search\fR(1), on how to run a search from the command-line
+.IP \(bu 4
+\fIoddmu-search\fR(7), on how search works
+.IP \(bu 4
+\fIoddmu-static\fR(1), on generating a static site from the command-line
+.IP \(bu 4
+\fIoddmu-notify\fR(1), on updating index, changes and hashtag pages from the
+command-line
+.IP \(bu 4
+\fIoddmu-templates\fR(5), on how to write the HTML templates
+.IP \(bu 4
+\fIoddmu-version\fR(1), on how to get all the build information from the binary
+.PD
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu.1.txt

@@ -0,0 +1,235 @@
+ODDMU(1)
+
+# NAME
+
+oddmu - a wiki server
+
+Oddmu is sometimes written Oddµ because µ is the letter mu.
+
+# SYNOPSIS
+
+*oddmu*
+
+# DESCRIPTION
+
+The oddmu program serves the current working directory as a wiki on port 8080.
+Point your browser to http://localhost:8080/ to get started. This is equivalent
+to http://localhost:8080/view/index – the first page you'll create, most likely.
+
+If you request a page that doesn't exist, oddmu tries to find a matching
+Markdown file by appending the extension ".md" to the page name. In the example
+above, the page name requested is "index" and the file name oddmu tries to read
+is "index.md". If no such file exists, oddmu offers you to create the page.
+
+If your files don't provide their own title ("# title"), the file name (without
+".md") is used for the page title.
+
+Every file can be viewed as feed by using the extension ".rss". The
+feed items are based on links in bullet lists using the asterix
+("\*").
+
+Subdirectories are created as necessary.
+
+See _oddmu_(5) for details about the page formatting.
+
+# CONFIGURATION
+
+The template files are the HTML files in the working directory:
+"add.html", "diff.html", "edit.html", "search.html", "upload.html" and
+"view.html". Please change them!
+
+The first change you should make is to replace the name and email
+address in the footer of "view.html". Look for "Your Name" and
+"example.org".
+
+The second change you should make is to replace the name, email
+address and domain name in "feed.html". Look for "Your Name" and
+"example.org". This second template is used to generate the RSS feeds
+(despite its ".html" extension).
+
+See _oddmu-templates_(5) for more.
+
+# ENVIRONMENT
+
+You can change the port served by setting the ODDMU_PORT environment variable.
+
+You can change the address served by setting the ODDMU_ADDRESS environment
+variable to either an IPv4 address or an IPv6 address. If ODDMU_ADDRESS is
+unset, then the program listens on all available unicast addresses, both IPv4
+and IPv6. Here are a few example addresses:
+
+ODDMU_ADDRESS=127.0.0.1 # The loopback IPv4 address.
+ODDMU_ADDRESS=2001:db8::3:1 # An IPv6 address.
+
+See the Socket Activation section for an alternative method of listening which
+supports Unix-domain sockets.
+
+In order to limit language-detection to the languages you actually use, set the
+environment variable ODDMU_LANGUAGES to a comma-separated list of ISO 639-1
+codes, e.g. "en" or "en,de,fr,pt".
+
+You can enable webfinger to link fediverse accounts to their correct profile
+pages by setting ODDMU_WEBFINGER to "1". See _oddmu_(5).
+
+If you use secret subdirectories, you cannot rely on the web server to hide
+those pages because search includes subdirectories. In order to protect those
+pages from search, you need to use the ODDMU_FILTER to a regular exression such
+as "^secret/". See _oddmu-apache_(5).
+
+# Socket Activation
+
+Instead of specifying ODDMU_ADDRESS or ODDMU_PORT, you can start the service
+through socket activation. The advantage of this method is that you can use a
+Unix-domain socket instead of a TCP socket, and the permissions and ownership of
+the socket are set before the program starts. See _oddmu.service_(5) and
+_oddmu-apache_(5) for an example of how to use socket activation with a
+Unix-domain socket under systemd and Apache.
+
+# SECURITY
+
+If the machine you are running Oddmu on is accessible from the Internet, you
+must secure your installation. The best way to do this is use a regular web
+server as a reverse proxy.
+
+See _oddmu-apache_(5) for an example.
+
+Oddmu assumes that all the users that can edit pages or upload files are trusted
+users and therefore their content is trusted. Therefore, Oddmu doesn't perform
+HTML sanitization!
+
+For an extra dose of security, consider using a Unix-domain socket.
+
+# OPTIONS
+
+The oddmu program can be run on the command-line using various subcommands.
+
+- to generate the HTML for a single page, see _oddmu-html_(1)
+- to generate the HTML for the entire site, using Oddmu as a static site
+  generator, see _oddmu-static_(1)
+- to search a regular expression and replace it across all files, see
+  _oddmu-replace_(1)
+- to emulate a search of the files, see _oddmu-search_(1); to understand how the
+  search engine indexes pages and how it sorts and scores results, see
+  _oddmu-search_(7)
+- to find missing pages (local links that go nowhere), see _oddmu-missing_(1)
+- to add links to changes, index and hashtag pages to pages you created locally,
+  see _oddmu-notify_(1)
+
+# EXAMPLE
+
+When saving a page, the page name is take from the URL and the page content is
+taken from the "body" form parameter. To illustrate, here's how to edit a page
+using _curl_(1):
+
+```
+curl --form body="Did you bring a towel?" \
+  http://localhost:8080/save/welcome
+```
+
+# DESIGN
+
+This is a minimal wiki. There is no version history. It's well suited as a
+_secondary_ medium: collaboration and conversation happens elsewhere, in chat,
+on social media. The wiki serves as the text repository that results from these
+discussions.
+
+The idea is that the webserver handles as many tasks as possible. It logs
+requests, does rate limiting, handles encryption, gets the certificates, and so
+on. The web server acts as a reverse proxy and the wiki ends up being a content
+management system with almost no structure – or endless malleability, depending
+on your point of view. See _oddmu-apache_(5).
+
+# NOTES
+
+Page names are filenames with ".md" appended. If your filesystem cannot handle
+it, it can't be a page name. Filenames can contain slashes and oddmu creates
+subdirectories as necessary.
+
+Files may not end with a tilde ('~') – these are backup files. When saving pages
+and file uploads, the old file renamed to the backup file unless the backup file
+is less than an hour old, thus collapsing all edits made in an hour into a
+single diff when comparing backup and current version.
+
+The *index* page is the default page. People visiting the "root" of the site are
+redirected to "/view/index".
+
+The *changes* page is where links to new and changed files are added. As an
+author, you can prevent this from happening by deselecting the checkbox "Add
+link to the list of changes." The changes page can be edited like every other
+page, so it's easy to undo mistakes.
+
+Links on the changes page are grouped by date. When new links are added, the
+current date of the machine Oddmu is running on is used. If a link already
+exists on the changes page, it is moved up to the current date. If that leaves
+an old date without any links, that date heading is removed.
+
+If you want to link to the changes page, you need to do this yourself. Add a
+link from the index, for example. The "view.html" template currently doesn't do
+it. See _oddmu-templates_(5) if you want to add the link to the template.
+
+A page whose name starts with an ISO date (YYYY-MM-DD, e.g. "2023-10-28") is
+called a *blog* page. When creating or editing blog pages, links to it are added
+from other pages.
+
+If the blog page name starts with the current year, a link is created from the
+index page back to the blog page being created or edited. Again, you can prevent
+this from happening by deselecting the checkbox "Add link to the list of
+changes." The index page can be edited like every other page, so it's easy to
+undo mistakes.
+
+For every *hashtag* used, another link might be created. If a page named like
+the hashtag exists, a backlink is added to it, linking to the new or edited blog
+page.
+
+If a link to the new or edited blog page already exists but it's title is no
+longer correct, it is updated.
+
+New links added for blog pages are added at the top of the first unnumbered list
+using the asterisk ('\*'). If no such list exists, a new one is started at the
+bottom of the page. This allows you to have a different unnumbered list further
+up on the page, as long as it uses the minus for items ('-').
+
+Changes made locally do not create any links on the changes page, the index page
+or on any hashtag pages. See _oddmu-notify_(1) for a way to add the necessary
+links to the changes page and possibly to the index and hashtag pages.
+
+A hashtag consists of a number sign ('#') followed by Unicode letters, numbers
+or the underscore ('\_'). Thus, a hashtag ends with punctuation or whitespace.
+
+The page names, titles and hashtags are loaded into memory when the server
+starts. If you have a lot of pages, this takes a lot of memory.
+
+Oddmu watches the working directory and any subdirectories for changes made
+directly. Thus, in theory, it's not necessary to restart it after making such
+changes.
+
+You cannot edit uploaded files. If you upload a file called "hello.txt" and
+attempt to edit it by using "/edit/hello.txt" you create a page with the name
+"hello.txt.md" instead.
+
+In order to delete uploaded files via the web, create an empty file and upload
+it. In order to delete a wiki page, save an empty page.
+
+Note that some HTML file names are special: they act as templates. See
+_oddmu-templates_(5) for their names and their use.
+
+# SEE ALSO
+
+- _oddmu_(5), about the markup syntax and how feeds are generated based on link lists
+- _oddmu.service_(5), on how to run the service under systemd
+- _oddmu-apache_(5), on how to set up a web server such as Apache
+- _oddmu-html_(1), on how to render a page from the command-line
+- _oddmu-list_(1), on how to list pages and titles from the command-line
+- _oddmu-missing_(1), on how to find broken local links from the command-line
+- _oddmu-replace_(1), on how to search and replace text from the command-line
+- _oddmu-search_(1), on how to run a search from the command-line
+- _oddmu-search_(7), on how search works
+- _oddmu-static_(1), on generating a static site from the command-line
+- _oddmu-notify_(1), on updating index, changes and hashtag pages from the
+  command-line
+- _oddmu-templates_(5), on how to write the HTML templates
+- _oddmu-version_(1), on how to get all the build information from the binary
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu.5

@@ -0,0 +1,211 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU" "5" "2023-11-12" "File Formats Manual"
+.PP
+.SH NAME
+.PP
+oddmu - text formatting of wiki pages
+.PP
+.SH SYNTAX
+.PP
+The wiki pages are UTF-8 encoded Markdown files (with the ".\&md" extension).\&
+Oddmu links are regular Markdown links to page names (without the ".\&md"
+extension):
+.PP
+.nf
+.RS 4
+[link text](page-name)
+.fi
+.RE
+.PP
+The page name has to be percent-encoded.\& See the section "Percent Encoding".\&
+.PP
+If you link to the actual Markdown file (with the ".\&md" extension), then Oddmu
+serves the Markdown file!\&
+.PP
+There are three Oddµ-specific extensions: local links, hashtags and fediverse
+account links.\& The Markdown library used features some additional extensions,
+most importantly tables and definition lists.\&
+.PP
+.SS Local links
+.PP
+Local links use double square brackets [[like this]].\& Oddmu does not treat
+underscores like spaces, so [[like this]] and [[like_this]] link to different
+destinations and are served by different files: "like this.\&md" and
+"like_this.\&md".\&
+.PP
+.SS Hashtags
+.PP
+Hashtags are single word links to searches for themselves.\& Use the underscore to
+use hashtags consisting of multiple words.\& Hashtags are distinguished from page
+titles because there is no space after the hash.\&
+.PP
+.nf
+.RS 4
+# Example
+
+Text
+
+#Tag #Another_Tag
+.fi
+.RE
+.PP
+When a page containing hashtags is saved, a link to that page is added to every
+page with the same name as the hashtag, if it exists.\& In the example above, if
+the file "Tag.\&md" or the file "Another_Tag.\&md" exists, a link to the Example
+page is added.\&
+.PP
+.SS Tables
+.PP
+A table with footers and a columnspan:
+.PP
+.nf
+.RS 4
+Name    | Age
+--------|------
+Bob     ||
+Alice   | 23
+========|======
+Total   | 23
+.fi
+.RE
+.PP
+.SS Definition lists:
+.PP
+.nf
+.RS 4
+Cat
+: Fluffy animal everyone likes
+
+Internet
+: Vector of transmission for pictures of cats
+.fi
+.RE
+.PP
+.SS Fediverse account links
+.PP
+Fediverse accounts look a bit like an at sign followed by an email address, e.\&g.\&
+@alex@alexschroeder.\&ch.\& When rendering a page, these turn into a username linked
+to a profile page.\& In this case, "@alex" would be linked to
+"https://alexschroeder.\&ch/users/alex".\&
+.PP
+In many cases, this works as is.\& In reality, however, the link to the profile
+page needs to be retrieved via webfinger.\& Oddµ does that in the background, and
+as soon as the information is available, the actual profile link is used when
+pages are rendered.\& In the example above, the result would be
+"https://social.\&alexschroeder.\&ch/@alex".\&
+.PP
+As this sort of packground network activity is surprising, it is not enabled by
+default.\& Set the environment variable ODDMU_WEBFINGER to "1" in order to enable
+this.\&
+.PP
+.SS Other extensions
+.PP
+The Markdown processor comes with a few extensions:
+.PP
+.PD 0
+.IP \(bu 4
+emphasis markers inside words are ignored
+.IP \(bu 4
+fenced code blocks are supported
+.IP \(bu 4
+autolinking of "naked" URLs are supported
+.IP \(bu 4
+strikethrough using two tildes is supported (~~like this~~)
+.IP \(bu 4
+it is strict about prefix heading rules
+.IP \(bu 4
+you can specify an id for headings ({#id})
+.IP \(bu 4
+trailing backslashes turn into line breaks
+.PD
+.PP
+.SH FEEDS
+.PP
+Every file can be viewed as feed by using the extension ".\&rss".\& The feed items
+are based on links in bullet lists using the asterix ("*").\& The items must
+point to local pages.\& This is why the link may not contain two forward slashes
+("//").\&
+.PP
+Assume this is the index page.\& The feed would be "/view/index.\&rss".\& It would
+contain the pages "Arianism", "Donatism" and "Monophysitism" but it would not
+contain the pages "Feed" and "About" since the list items don'\&t start with an
+asterix.\&
+.PP
+.nf
+.RS 4
+# Main Page
+
+Hello and welcome! Here are some important links:
+
+- [Feed](index\&.rss)
+- [About](about)
+
+Recent posts:
+
+* [Arianism](arianism)
+* [Donatism](donatism)
+* [Monophysitism](monophysitism)
+.fi
+.RE
+.PP
+The feed contains at most 10 items, starting at the top.\&
+.PP
+.SH PERCENT ENCODING
+.PP
+If you use Markdown links to local pages, you must percent-encode the link
+target.\& Any character that is not an "unreserved character" according to RFC
+3986 might need to be encoded.\& The unreserved characters are a-z, A-Z, 0-9, as
+well as the four characters '\&-'\&, '\&_'\&, '\&.\&'\& and '\&~'\&.\&
+.PP
+Percent-encoding means that each character is converted into one or more bytes,
+and each byte is represented as a percent character followed by a hexadecimal
+representation.\&
+.PP
+Realistically, what probably works best is to use a browser.\& If you type
+"http://example.\&org/Alex Schröder" into the address bar, you'\&ll get sent to the
+example domain.\& If you now copy the address and paste it back into a text
+editor, you'\&ll get "http://example.\&org/Alex%20Schr%C3%B6der" and that'\&s how
+you'\&ll learn that the Space is encoded by %20 and that the character '\&ö'\& is
+encoded by %C3%B6.\& To link to the page "Alex Schröder" you would write something
+like this: "[Alex](Alex%20Schr%C3%B6der)".\&
+.PP
+Another thing that'\&s common is that your page name contains a colon.\&
+This is legal.\& The URL parser might still reject it.\& If you run the
+"missing" subcommand, you'\&ll get to see error: "first path segment in
+URL cannot contain colon".\& The solution is to prepend ".\&/"!\&
+.PP
+Example:
+.PP
+.nf
+.RS 4
+[2021-10-15 Re: Mark It Down](2021-10-15_Re:_Mark_It_Down)
+.fi
+.RE
+.PP
+Fixed:
+.PP
+.nf
+.RS 4
+[2021-10-15 Re: Mark It Down](\&./2021-10-15_Re:_Mark_It_Down)
+.fi
+.RE
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1), \fIoddmu-missing\fR(1)
+.PP
+This wiki uses the Go Markdown library.\&
+https://github.\&com/gomarkdown/markdown
+.PP
+For more about percent-encoding, see Wikipedia.\&
+https://en.\&wikipedia.\&org/wiki/Percent-encoding
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu.5.txt

@@ -0,0 +1,181 @@
+ODDMU(5) "File Formats Manual"
+
+# NAME
+
+oddmu - text formatting of wiki pages
+
+# SYNTAX
+
+The wiki pages are UTF-8 encoded Markdown files (with the ".md" extension).
+Oddmu links are regular Markdown links to page names (without the ".md"
+extension):
+
+```
+[link text](page-name)
+```
+
+The page name has to be percent-encoded. See the section "Percent Encoding".
+
+If you link to the actual Markdown file (with the ".md" extension), then Oddmu
+serves the Markdown file!
+
+There are three Oddµ-specific extensions: local links, hashtags and fediverse
+account links. The Markdown library used features some additional extensions,
+most importantly tables and definition lists.
+
+## Local links
+
+Local links use double square brackets [[like this]]. Oddmu does not treat
+underscores like spaces, so [[like this]] and [[like_this]] link to different
+destinations and are served by different files: "like this.md" and
+"like_this.md".
+
+## Hashtags
+
+Hashtags are single word links to searches for themselves. Use the underscore to
+use hashtags consisting of multiple words. Hashtags are distinguished from page
+titles because there is no space after the hash.
+
+```
+# Example
+
+Text
+
+#Tag #Another_Tag
+```
+
+When a page containing hashtags is saved, a link to that page is added to every
+page with the same name as the hashtag, if it exists. In the example above, if
+the file "Tag.md" or the file "Another_Tag.md" exists, a link to the Example
+page is added.
+
+## Tables
+
+A table with footers and a columnspan:
+
+```
+Name    | Age
+--------|------
+Bob     ||
+Alice   | 23
+========|======
+Total   | 23
+```
+
+## Definition lists:
+
+```
+Cat
+: Fluffy animal everyone likes
+
+Internet
+: Vector of transmission for pictures of cats
+```
+
+## Fediverse account links
+
+Fediverse accounts look a bit like an at sign followed by an email address, e.g.
+@alex@alexschroeder.ch. When rendering a page, these turn into a username linked
+to a profile page. In this case, "@alex" would be linked to
+"https://alexschroeder.ch/users/alex".
+
+In many cases, this works as is. In reality, however, the link to the profile
+page needs to be retrieved via webfinger. Oddµ does that in the background, and
+as soon as the information is available, the actual profile link is used when
+pages are rendered. In the example above, the result would be
+"https://social.alexschroeder.ch/@alex".
+
+As this sort of packground network activity is surprising, it is not enabled by
+default. Set the environment variable ODDMU_WEBFINGER to "1" in order to enable
+this.
+
+## Other extensions
+
+The Markdown processor comes with a few extensions:
+
+- emphasis markers inside words are ignored
+- fenced code blocks are supported
+- autolinking of "naked" URLs are supported
+- strikethrough using two tildes is supported (~~like this~~)
+- it is strict about prefix heading rules
+- you can specify an id for headings ({#id})
+- trailing backslashes turn into line breaks
+
+# FEEDS
+
+Every file can be viewed as feed by using the extension ".rss". The feed items
+are based on links in bullet lists using the asterix ("\*"). The items must
+point to local pages. This is why the link may not contain two forward slashes
+("//").
+
+Assume this is the index page. The feed would be "/view/index.rss". It would
+contain the pages "Arianism", "Donatism" and "Monophysitism" but it would not
+contain the pages "Feed" and "About" since the list items don't start with an
+asterix.
+
+```
+# Main Page
+
+Hello and welcome! Here are some important links:
+
+- [Feed](index.rss)
+- [About](about)
+
+Recent posts:
+
+* [Arianism](arianism)
+* [Donatism](donatism)
+* [Monophysitism](monophysitism)
+```
+
+The feed contains at most 10 items, starting at the top.
+
+# PERCENT ENCODING
+
+If you use Markdown links to local pages, you must percent-encode the link
+target. Any character that is not an "unreserved character" according to RFC
+3986 might need to be encoded. The unreserved characters are a-z, A-Z, 0-9, as
+well as the four characters '-', '\_', '.' and '~'.
+
+Percent-encoding means that each character is converted into one or more bytes,
+and each byte is represented as a percent character followed by a hexadecimal
+representation.
+
+Realistically, what probably works best is to use a browser. If you type
+"http://example.org/Alex Schröder" into the address bar, you'll get sent to the
+example domain. If you now copy the address and paste it back into a text
+editor, you'll get "http://example.org/Alex%20Schr%C3%B6der" and that's how
+you'll learn that the Space is encoded by %20 and that the character 'ö' is
+encoded by %C3%B6. To link to the page "Alex Schröder" you would write something
+like this: "[Alex](Alex%20Schr%C3%B6der)".
+
+Another thing that's common is that your page name contains a colon.
+This is legal. The URL parser might still reject it. If you run the
+"missing" subcommand, you'll get to see error: "first path segment in
+URL cannot contain colon". The solution is to prepend "./"!
+
+Example:
+
+```
+[2021-10-15 Re: Mark It Down](2021-10-15_Re:_Mark_It_Down)
+```
+
+Fixed:
+
+```
+[2021-10-15 Re: Mark It Down](./2021-10-15_Re:_Mark_It_Down)
+```
+
+# SEE ALSO
+
+_oddmu_(1), _oddmu-missing_(1)
+
+This wiki uses the Go Markdown library.
+https://github.com/gomarkdown/markdown
+
+For more about percent-encoding, see Wikipedia.
+https://en.wikipedia.org/wiki/Percent-encoding
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

man/oddmu.service.5

@@ -0,0 +1,110 @@
+.\" Generated by scdoc 1.11.2
+.\" Complete documentation for this program is not available as a GNU info page
+.ie \n(.g .ds Aq \(aq
+.el       .ds Aq '
+.nh
+.ad l
+.\" Begin generated content:
+.TH "ODDMU.SERVICE" "5" "2024-01-17"
+.PP
+.SH NAME
+.PP
+oddmu.\&service - how to setup Oddmu using systemd
+.PP
+.SS DESCRIPTION
+.PP
+Here'\&s how to setup a wiki using systemd such that it starts automatically when
+the system boots and gets restarted automatically when it crashes.\&
+.PP
+First, create a new user called "oddmu" with it'\&s own home directory but without
+a login.\&
+.PP
+.nf
+.RS 4
+adduser --system --home /home/oddmu oddmu
+.fi
+.RE
+.PP
+The directory "/home/oddmu" contains the templates and all the data files.\& Copy
+all the templates files ending in ".\&html" from the source distribution to
+"/home/oddmu".\&
+.PP
+If you want to keep everything in one place, copy the binary "oddmu" and the
+service file "oddmu.\&service" to "/home/oddmu", too.\&
+.PP
+Edit the `oddmu.\&service` file.\& These are the lines you most likely have to take
+care of:
+.PP
+.nf
+.RS 4
+ExecStart=/home/oddmu/oddmu
+WorkingDirectory=/home/oddmu
+Environment="ODDMU_PORT=8080"
+Environment="ODDMU_WEBFINGER=1"
+.fi
+.RE
+.PP
+Install the service file and enable it:
+.PP
+.nf
+.RS 4
+ln -s /home/oddmu/oddmu\&.service /etc/systemd/system/
+systemctl enable --now oddmu
+.fi
+.RE
+.PP
+You should be able to visit the wiki at http://localhost:8080/.\&
+.PP
+Check the log:
+.PP
+.nf
+.RS 4
+journalctl --unit oddmu
+.fi
+.RE
+.PP
+Follow the log:
+.PP
+.nf
+.RS 4
+journalctl --follow --unit oddmu
+.fi
+.RE
+.PP
+For it to restart when the server reboots:
+.PP
+.nf
+.RS 4
+sudo ln -sf /home/oddmu/oddmu\&.service 
+  /etc/systemd/system/multi-user\&.target\&.wants/
+.fi
+.RE
+.PP
+.SH Socket Activation
+.PP
+Alternatively, you can let systemd handle the creation of the listening socket,
+passing it to Oddmu.\& See "oddmu-unix-domain.\&service" and
+"oddmu-unix-domain.\&socket" for a fully worked example of how to do this with a
+Unix domain socket.\& Take note of "Accept=no" in the .\&socket file and
+"StandardInput=socket" in the .\&service file.\& The option "StandardInput=socket"
+tells systemd to pass the socket to the service as its standard input.\&
+"Accept=no" tells systemd to pass a listening socket, rather than to try calling
+Oddmu for each connection.\&
+.PP
+The instructions for starting and enabling the systemd service are almost
+exactly the same as those in the previous section, with "oddmu.\&service" replaced
+by "oddmu-unix-domain.\&service".\& You'\&ll also need to run the following:
+.PP
+.nf
+.RS 4
+ln -s /home/oddmu/oddmu-unix-domain\&.socket /etc/systemd/system
+.fi
+.RE
+.PP
+.SH SEE ALSO
+.PP
+\fIoddmu\fR(1), \fIsystemd.\&exec\fR(5), \fIsystemd.\&socket(5), \fRcapabilities_(7)
+.PP
+.SH AUTHORS
+.PP
+Maintained by Alex Schroeder <alex@gnu.\&org>.\&

man/oddmu.service.5.txt

@@ -0,0 +1,89 @@
+ODDMU.SERVICE(5)
+
+# NAME
+
+oddmu.service - how to setup Oddmu using systemd
+
+## DESCRIPTION
+
+Here's how to setup a wiki using systemd such that it starts automatically when
+the system boots and gets restarted automatically when it crashes.
+
+First, create a new user called "oddmu" with it's own home directory but without
+a login.
+
+```
+adduser --system --home /home/oddmu oddmu
+```
+
+The directory "/home/oddmu" contains the templates and all the data files. Copy
+all the templates files ending in ".html" from the source distribution to
+"/home/oddmu".
+
+If you want to keep everything in one place, copy the binary "oddmu" and the
+service file "oddmu.service" to "/home/oddmu", too.
+
+Edit the `oddmu.service` file. These are the lines you most likely have to take
+care of:
+
+```
+ExecStart=/home/oddmu/oddmu
+WorkingDirectory=/home/oddmu
+Environment="ODDMU_PORT=8080"
+Environment="ODDMU_WEBFINGER=1"
+```
+
+Install the service file and enable it:
+
+```
+ln -s /home/oddmu/oddmu.service /etc/systemd/system/
+systemctl enable --now oddmu
+```
+
+You should be able to visit the wiki at http://localhost:8080/.
+
+Check the log:
+
+```
+journalctl --unit oddmu
+```
+
+Follow the log:
+
+```
+journalctl --follow --unit oddmu
+```
+
+For it to restart when the server reboots:
+
+```
+sudo ln -sf /home/oddmu/oddmu.service \
+  /etc/systemd/system/multi-user.target.wants/
+```
+
+# Socket Activation
+
+Alternatively, you can let systemd handle the creation of the listening socket,
+passing it to Oddmu. See "oddmu-unix-domain.service" and
+"oddmu-unix-domain.socket" for a fully worked example of how to do this with a
+Unix domain socket. Take note of "Accept=no" in the .socket file and
+"StandardInput=socket" in the .service file. The option "StandardInput=socket"
+tells systemd to pass the socket to the service as its standard input.
+"Accept=no" tells systemd to pass a listening socket, rather than to try calling
+Oddmu for each connection.
+
+The instructions for starting and enabling the systemd service are almost
+exactly the same as those in the previous section, with "oddmu.service" replaced
+by "oddmu-unix-domain.service". You'll also need to run the following:
+
+```
+ln -s /home/oddmu/oddmu-unix-domain.socket /etc/systemd/system
+```
+
+# SEE ALSO
+
+_oddmu_(1), _systemd.exec_(5), _systemd.socket(5), _capabilities_(7)
+
+# AUTHORS
+
+Maintained by Alex Schroeder <alex@gnu.org>.

missing_cmd.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"github.com/gomarkdown/markdown"
+	"github.com/gomarkdown/markdown/ast"
+	"github.com/google/subcommands"
+	"io"
+	"io/fs"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type missingCmd struct {
+}
+
+func (*missingCmd) Name() string     { return "missing" }
+func (*missingCmd) Synopsis() string { return "list missing pages" }
+func (*missingCmd) Usage() string {
+	return `missing:
+  Listing pages with links to missing pages.
+`
+}
+
+func (cmd *missingCmd) SetFlags(f *flag.FlagSet) {
+}
+
+func (cmd *missingCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	return missingCli(os.Stdout, f.Args())
+}
+
+func missingCli(w io.Writer, args []string) subcommands.ExitStatus {
+	names := make(map[string]bool)
+	err := filepath.Walk(".", func(path string, info fs.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		// skip hidden directories and files
+		if path != "." && strings.HasPrefix(filepath.Base(path), ".") {
+			if info.IsDir() {
+				return filepath.SkipDir
+			} else {
+				return nil
+			}
+		}
+		if strings.HasSuffix(path, ".md") {
+			name := filepath.ToSlash(strings.TrimSuffix(path, ".md"))
+			names[name] = true
+		} else {
+			names[path] = false
+		}
+		return nil
+	})
+	if err != nil {
+		fmt.Fprintln(w, err)
+		return subcommands.ExitFailure
+	}
+	found := false
+	for name, isPage := range names {
+		if !isPage {
+			continue
+		}
+		p, err := loadPage(name)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Loading %s: %s\n", p.Name, err)
+			return subcommands.ExitFailure
+		}
+		for _, link := range p.links() {
+			u, err := url.Parse(link)
+			if err != nil {
+				fmt.Fprintln(os.Stderr, p.Name, err)
+				return subcommands.ExitFailure
+			}
+			if u.Scheme == "" && u.Path != "" && !strings.HasPrefix(u.Path, "/") {
+				// feeds can work if the matching page works
+				u.Path = strings.TrimSuffix(u.Path, ".rss")
+				// links to the source file can work
+				u.Path = strings.TrimSuffix(u.Path, ".md")
+				// pages containing a colon need the ./ prefix
+				u.Path = strings.TrimPrefix(u.Path, "./")
+				// check whether the destinatino is a known page
+				destination, err := url.PathUnescape(u.Path)
+				if err != nil {
+					fmt.Fprintf(os.Stderr, "Cannot decode %s: %s\n", link, err)
+					return subcommands.ExitFailure
+				}
+				_, ok := names[destination]
+				if !ok {
+					if !found {
+						fmt.Fprintln(w, "Page\tMissing")
+						found = true
+					}
+					fmt.Fprintf(w, "%s\t%s\n", p.Name, link)
+				}
+			}
+		}
+	}
+	if !found {
+		fmt.Fprintln(w, "No missing pages found.")
+	}
+	return subcommands.ExitSuccess
+}
+
+// links parses the page content and returns an array of link destinations.
+func (p *Page) links() []string {
+	var links []string
+	parser, _ := wikiParser()
+	doc := markdown.Parse(p.Body, parser)
+	ast.WalkFunc(doc, func(node ast.Node, entering bool) ast.WalkStatus {
+		if entering {
+			switch v := node.(type) {
+			case *ast.Link:
+				links = append(links, string(v.Destination))
+			}
+		}
+		return ast.GoToNext
+	})
+	return links
+}

missing_cmd_test.go

@@ -0,0 +1,18 @@
+package main
+
+import (
+	"bytes"
+	"github.com/google/subcommands"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestMissingCmd(t *testing.T) {
+	b := new(bytes.Buffer)
+	s := missingCli(b, nil)
+	assert.Equal(t, subcommands.ExitSuccess, s)
+	r := `Page	Missing
+index	test
+`
+	assert.Equal(t, r, b.String())
+}

notify_cmd.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"github.com/google/subcommands"
+	"io"
+	"os"
+)
+
+type notifyCmd struct {
+}
+
+func (*notifyCmd) Name() string     { return "notify" }
+func (*notifyCmd) Synopsis() string { return "add links to changes.md, index.md, and hashtag pages" }
+func (*notifyCmd) Usage() string {
+	return `notify <page name> ...:
+  For each page, add entries to changes.md, index.md, and hashtag pages.
+  This is useful when writing pages offline and replicates the behaviour
+  triggered by the "Add link to the list of changes" checkbox, online.
+`
+}
+
+func (cmd *notifyCmd) SetFlags(f *flag.FlagSet) {
+}
+
+func (cmd *notifyCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	return notifyCli(os.Stdout, f.Args())
+}
+
+func notifyCli(w io.Writer, args []string) subcommands.ExitStatus {
+	index.load()
+	for _, name := range args {
+		p, err := loadPage(name)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Loading %s: %s\n", name, err)
+			return subcommands.ExitFailure
+		}
+		err = p.notify()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s: %s\n", name, err)
+			return subcommands.ExitFailure
+		}
+	}
+	return subcommands.ExitSuccess
+}

oddmu-unix-domain.service

@@ -0,0 +1,53 @@
+[Unit]
+Description=Oddmu
+After=network.target
+Requires=oddmu-unix-domain.socket
+[Install]
+WantedBy=multi-user.target
+[Service]
+Type=simple
+Restart=always
+StandardInput=socket
+StandardOutput=journal
+StandardError=journal
+DynamicUser=true
+MemoryMax=256M
+MemoryHigh=128M
+ExecStart=/home/oddmu/oddmu
+WorkingDirectory=/home/oddmu
+Environment="ODDMU_PORT=8080"
+Environment="ODDMU_WEBFINGER=1"
+
+# (man "systemd.exec")
+ReadWritePaths=/home/oddmu
+ProtectHostname=yes
+RestrictSUIDSGID=yes
+RemoveIPC=yes
+MemoryDenyWriteExecute=yes
+
+# Sandboxing options to harden security
+NoNewPrivileges=yes
+PrivateTmp=yes
+PrivateDevices=yes
+RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6
+RestrictNamespaces=yes
+RestrictRealtime=yes
+DevicePolicy=closed
+ProtectSystem=full
+ProtectControlGroups=yes
+ProtectKernelModules=yes
+ProtectKernelTunables=yes
+LockPersonality=yes
+SystemCallFilter=~@clock @debug @module @mount @obsolete @reboot @setuid @swap
+
+# Denying access to capabilities that should not be relevant
+# (man "capabilities")
+CapabilityBoundingSet=~CAP_RAWIO CAP_MKNOD
+CapabilityBoundingSet=~CAP_AUDIT_CONTROL CAP_AUDIT_READ CAP_AUDIT_WRITE
+CapabilityBoundingSet=~CAP_SYS_BOOT CAP_SYS_TIME CAP_SYS_MODULE CAP_SYS_PACCT
+CapabilityBoundingSet=~CAP_LEASE CAP_LINUX_IMMUTABLE CAP_IPC_LOCK
+CapabilityBoundingSet=~CAP_BLOCK_SUSPEND CAP_WAKE_ALARM
+CapabilityBoundingSet=~CAP_SYS_TTY_CONFIG
+CapabilityBoundingSet=~CAP_MAC_ADMIN CAP_MAC_OVERRIDE
+CapabilityBoundingSet=~CAP_NET_ADMIN CAP_NET_BROADCAST CAP_NET_RAW
+CapabilityBoundingSet=~CAP_SYS_ADMIN CAP_SYS_PTRACE CAP_SYSLOG

oddmu-unix-domain.socket

@@ -0,0 +1,14 @@
+[Unit]
+Description=Oddmu server socket
+
+[Socket]
+ListenStream=/run/oddmu/oddmu.sock
+SocketGroup=www-data
+# Systemd manages the socket, so may as well let it be owned by root.
+SocketUser=root
+# But it needs to be readable and writable by the web server.
+SocketMode=0660
+Accept=no
+
+[Install]
+WantedBy=sockets.target

oddmu.service

@@ -12,6 +12,7 @@ MemoryHigh=120M
 ExecStart=/home/oddmu/oddmu
 WorkingDirectory=/home/oddmu
 Environment="ODDMU_PORT=8080"
+Environment="ODDMU_WEBFINGER=1"
 
 # (man "systemd.exec")
 ReadWritePaths=/home/oddmu
@@ -21,7 +22,6 @@ RemoveIPC=yes
 MemoryDenyWriteExecute=yes
 
 # Sandboxing options to harden security
-# Details for these options: https://www.freedesktop.org/software/systemd/man/systemd.exec.html
 NoNewPrivileges=yes
 PrivateTmp=yes
 PrivateDevices=yes
@@ -37,7 +37,7 @@ LockPersonality=yes
 SystemCallFilter=~@clock @debug @module @mount @obsolete @reboot @setuid @swap
 
 # Denying access to capabilities that should not be relevant
-# Doc: https://man7.org/linux/man-pages/man7/capabilities.7.html
+# (man "capabilities")
 CapabilityBoundingSet=~CAP_RAWIO CAP_MKNOD
 CapabilityBoundingSet=~CAP_AUDIT_CONTROL CAP_AUDIT_READ CAP_AUDIT_WRITE
 CapabilityBoundingSet=~CAP_SYS_BOOT CAP_SYS_TIME CAP_SYS_MODULE CAP_SYS_PACCT

page.go

@@ -2,21 +2,21 @@ package main
 
 import (
 	"bytes"
-	"fmt"
-	"github.com/gomarkdown/markdown"
-	"github.com/gomarkdown/markdown/ast"
-	"github.com/gomarkdown/markdown/parser"
 	"github.com/microcosm-cc/bluemonday"
 	"html/template"
+	"log"
 	"net/url"
 	"os"
+	"path"
 	"path/filepath"
+	"regexp"
 	"strings"
+	"time"
 )
 
 // Page is a struct containing information about a single page. Title
 // is the title extracted from the page content using titleRegexp.
-// Name is the filename without extension (so a filename of "foo.md"
+// Name is the path without extension (so a path of "foo.md"
 // results in the Name "foo"). Body is the Markdown content of the
 // page and Html is the rendered HTML for that Markdown. Score is a
 // number indicating how well the page matched for a search query.
@@ -27,20 +27,27 @@ type Page struct {
 	Body     []byte
 	Html     template.HTML
 	Score    int
+	Hashtags []string
 }
 
-// santize uses bluemonday to sanitize the HTML.
-func sanitize(s string) template.HTML {
-	return template.HTML(bluemonday.UGCPolicy().Sanitize(s))
+var blogRe = regexp.MustCompile(`^\d\d\d\d-\d\d-\d\d`)
+
+// santizeStrict uses bluemonday to sanitize the HTML away. No elements are allowed except for the b tag because this is
+// used for snippets.
+func sanitizeStrict(s string) template.HTML {
+	policy := bluemonday.StrictPolicy()
+	policy.AllowElements("b")
+	return template.HTML(policy.Sanitize(s))
 }
 
-// santizeBytes uses bluemonday to sanitize the HTML.
-func sanitizeBytes(bytes []byte) template.HTML {
-	return template.HTML(bluemonday.UGCPolicy().SanitizeBytes(bytes))
+// unsafeBytes does not use bluemonday to sanitize the HTML used for pages. This is where you make changes if you want
+// to be more lenient. If you look at the git repository, there are older versions containing the function sanitizeBytes
+// which would do elaborate checking.
+func unsafeBytes(bytes []byte) template.HTML {
+	return template.HTML(bytes)
 }
 
-// nameEscape returns the page name safe for use in URLs. That is,
-// percent escaping is used except for the slashes.
+// nameEscape returns the page name safe for use in URLs. That is, percent escaping is used except for the slashes.
 func nameEscape(s string) string {
 	parts := strings.Split(s, "/")
 	for i, part := range parts {
@@ -49,50 +56,65 @@ func nameEscape(s string) string {
 	return strings.Join(parts, "/")
 }
 
-// save saves a Page. The filename is based on the Page.Name and gets
-// the ".md" extension. Page.Body is saved, without any carriage
-// return characters ("\r"). Page.Title and Page.Html are not saved.
-// There is no caching. Before removing or writing a file, the old
-// copy is renamed to a backup, appending "~". There is no error
-// checking for this.
+// save saves a Page. The path is based on the Page.Name and gets the ".md" extension. Page.Body is saved, without any
+// carriage return characters ("\r"). Page.Title and Page.Html are not saved. There is no caching. Before removing or
+// writing a file, the old copy is renamed to a backup, appending "~". Errors are not logged but returned.
 func (p *Page) save() error {
-	filename := p.Name + ".md"
+	fp := filepath.FromSlash(p.Name + ".md")
+	watches.ignore(fp)
 	s := bytes.ReplaceAll(p.Body, []byte{'\r'}, []byte{})
 	if len(s) == 0 {
-		_ = os.Rename(filename, filename + "~")
-		return os.Remove(filename)
+		log.Println("Delete", p.Name)
+		index.remove(p)
+		return os.Rename(fp, fp+"~")
 	}
 	p.Body = s
-	p.updateIndex()
-	d := filepath.Dir(filename)
+	index.update(p)
+	d := filepath.Dir(fp)
 	if d != "." {
 		err := os.MkdirAll(d, 0755)
 		if err != nil {
-			fmt.Printf("Creating directory %s failed", d)
 			return err
 		}
 	}
-	_ = os.Rename(filename, filename + "~")
-	return os.WriteFile(filename, s, 0644)
+	err := backup(fp)
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(fp, s, 0644)
 }
 
-// loadPage loads a Page given a name. The filename loaded is that
-// Page.Name with the ".md" extension. The Page.Title is set to the
-// Page.Name (and possibly changed, later). The Page.Body is set to
-// the file content. The Page.Html remains undefined (there is no
-// caching).
-func loadPage(name string) (*Page, error) {
-	filename := name + ".md"
-	body, err := os.ReadFile(filename)
+// backup a file by renaming (!) it unless the existing backup is less than an hour old. A backup gets a tilde appended
+// to it ("~"). This is true even if the file refers to a binary file like "image.png" and most applications don't know
+// what to do with a file called "image.png~". This expects a file path. Use filepath.FromSlash(path) if necessary.
+func backup(fp string) error {
+	_, err := os.Stat(fp)		
+	if err != nil {
+		return nil
+	}
+	bp := fp + "~"
+	fi, err := os.Stat(bp)
+	if err != nil || time.Since(fi.ModTime()).Minutes() >= 60 {
+		return os.Rename(fp, bp)
+	}
+	return nil
+}
+
+// loadPage loads a Page given a name. The path loaded is that Page.Name with the ".md" extension. The Page.Title is set
+// to the Page.Name (and possibly changed, later). The Page.Body is set to the file content. The Page.Html remains
+// undefined (there is no caching).
+func loadPage(path string) (*Page, error) {
+	path = strings.TrimPrefix(path, "./") // result of a filepath.TreeWalk starting with "."
+	body, err := os.ReadFile(filepath.FromSlash(path+".md"))
 	if err != nil {
 		return nil, err
 	}
-	return &Page{Title: name, Name: name, Body: body, Language: ""}, nil
+	return &Page{Title: path, Name: path, Body: body, Language: ""}, nil
 }
 
-// handleTitle extracts the title from a Page and sets Page.Title, if
-// any. If replace is true, the page title is also removed from
-// Page.Body. Make sure not to save this! This is only for rendering.
+// handleTitle extracts the title from a Page and sets Page.Title, if any. If replace is true, the page title is also
+// removed from Page.Body. Make sure not to save this! This is only for rendering. In a template, the title is a
+// separate attribute and is not repeated in the HTML.
 func (p *Page) handleTitle(replace bool) {
 	s := string(p.Body)
 	m := titleRegexp.FindStringSubmatch(s)
@@ -104,75 +126,47 @@ func (p *Page) handleTitle(replace bool) {
 	}
 }
 
-func hashtag(p *parser.Parser, data []byte, offset int) (int, ast.Node) {
-	data = data[offset:]
-	i := 0
-	n := len(data)
-	for i < n && !parser.IsSpace(data[i]) {
-		i++
-	}
-	if i == 0 {
-		return 0, nil
-	}
-	link := &ast.Link{
-		Destination: append([]byte("/search?q=%23"), data[1:i]...),
-		Title:       data[0:i],
-	}
-	text := bytes.ReplaceAll(data[0:i], []byte("_"), []byte(" "))
-	ast.AppendChild(link, &ast.Text{Leaf: ast.Leaf{Literal: text}})
-	return i, link
-}
-
-// renderHtml renders the Page.Body to HTML and sets Page.Html.
-func (p *Page) renderHtml() {
-	parser := parser.New()
-	parser.RegisterInline('#', hashtag)
-	maybeUnsafeHTML := markdown.ToHTML(p.Body, parser, nil)
-	p.Name = nameEscape(p.Name)
-	p.Html = sanitizeBytes(maybeUnsafeHTML)
-	p.Language = language(p.plainText())
-}
-
-// plainText renders the Page.Body to plain text and returns it,
-// ignoring all the Markdown and all the newlines. The result is one
-// long single line of text.
-func (p *Page) plainText() string {
-	parser := parser.New()
-	doc := markdown.Parse(p.Body, parser)
-	text := []byte("")
-	ast.WalkFunc(doc, func(node ast.Node, entering bool) ast.WalkStatus {
-		if entering && node.AsLeaf() != nil {
-			text = append(text, node.AsLeaf().Literal...)
-			text = append(text, []byte(" ")...)
-		}
-		return ast.GoToNext
-	})
-	// Some Markdown still contains newlines
-	for i, c := range text {
-		if c == '\n' {
-			text[i] = ' '
-		}
-	}
-	// Remove trailing space
-	for len(text) > 0 && text[len(text)-1] == ' ' {
-		text = text[0 : len(text)-1]
-	}
-	return string(text)
-}
-
-// summarize for query string q sets Page.Html to an extract.
-func (p *Page) summarize(q string) {
+// score sets Page.Title and computes Page.Score.
+func (p *Page) score(q string) {
 	p.handleTitle(true)
 	p.Score = score(q, string(p.Body)) + score(q, p.Title)
+}
+
+// summarize sets Page.Html to an extract and sets Page.Language.
+func (p *Page) summarize(q string) {
 	t := p.plainText()
-	p.Html = sanitize(snippets(q, t))
+	p.Name = nameEscape(p.Name)
+	p.Html = sanitizeStrict(snippets(q, t))
 	p.Language = language(t)
 }
 
+// isBlog returns true if the page name starts with an ISO date
+func (p *Page) isBlog() bool {
+	name := path.Base(p.Name)
+	return blogRe.MatchString(name)
+}
+
+// Dir returns the directory the page is in. It's either the empty string if the page is in the Oddmu working directory,
+// or it ends in a slash. This is used to create the upload link in "view.html", for example.
 func (p *Page) Dir() string {
 	d := filepath.Dir(p.Name)
 	if d == "." {
 		return ""
 	}
-	return d
+	return d + "/"
+}
+
+// Base returns the basename of the page name: no directory and no extension. This is used to create the upload link
+// in "view.html", for example.
+func (p *Page) Base() string {
+	n := filepath.Base(p.Name)
+	if n == "." {
+		return ""
+	}
+	return n
+}
+
+// Today returns the date, as a string, for use in templates.
+func (p *Page) Today() string {
+	return time.Now().Format(time.DateOnly)
 }

page_test.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"github.com/stretchr/testify/assert"
-	"os"
 	"regexp"
 	"testing"
 )
@@ -19,73 +18,25 @@ But yearn for blue sky`)}
 	assert.Regexp(t, regexp.MustCompile("^My back"), string(p.Body))
 }
 
-func TestPagePlainText(t *testing.T) {
-	p := &Page{Body: []byte(`# Water
-The air will not come
-To inhale is an effort
-The summer heat kills`)}
-	r := "Water The air will not come To inhale is an effort The summer heat kills"
-	assert.Equal(t, r, p.plainText())
-}
-
-func TestPageHtml(t *testing.T) {
-	p := &Page{Body: []byte(`# Sun
-Silver leaves shine bright
-They droop, boneless, weak and sad
-A cruel sun stares down`)}
-	p.renderHtml()
-	r := `<h1>Sun</h1>
-
-<p>Silver leaves shine bright
-They droop, boneless, weak and sad
-A cruel sun stares down</p>
-`
-	assert.Equal(t, r, string(p.Html))
-}
-
-func TestPageHtmlHashtag(t *testing.T) {
-	p := &Page{Body: []byte(`# Comet
-Stars flicker above
-Too faint to focus, so far
-I am cold, alone
-
-#Haiku #Cold_Poets`)}
-	p.renderHtml()
-	r := `<h1>Comet</h1>
-
-<p>Stars flicker above
-Too faint to focus, so far
-I am cold, alone</p>
-
-<p><a href="/search?q=%23Haiku" rel="nofollow">#Haiku</a> <a href="/search?q=%23Cold_Poets" rel="nofollow">#Cold Poets</a></p>
-`
-	assert.Equal(t, r, string(p.Html))
-}
-
-// wipes testdata
 func TestPageDir(t *testing.T) {
-	_ = os.RemoveAll("testdata")
+	cleanup(t, "testdata/dir")
 	index.load()
-	p := &Page{Name: "testdata/moon", Body: []byte(`# Moon
+	p := &Page{Name: "testdata/dir/moon", Body: []byte(`# Moon
 From bed to bathroom
 A slow shuffle in the dark
 Moonlight floods the aisle`)}
 	p.save()
-	
-	o, err := loadPage("testdata/moon")
+
+	o, err := loadPage("testdata/dir/moon")
 	assert.NoError(t, err, "load page")
 	assert.Equal(t, p.Body, o.Body)
-	assert.FileExists(t, "testdata/moon.md")
+	assert.FileExists(t, "testdata/dir/moon.md")
 
 	// Saving an empty page deletes it.
-	p = &Page{Name: "testdata/moon", Body: []byte("")}
+	p = &Page{Name: "testdata/dir/moon", Body: []byte("")}
 	p.save()
-	assert.NoFileExists(t, "testdata/moon.md")
+	assert.NoFileExists(t, "testdata/dir/moon.md")
 
 	// But the backup still exists.
-	assert.FileExists(t, "testdata/moon.md~")
-	
-	t.Cleanup(func() {
-		_ = os.RemoveAll("testdata")
-	})
+	assert.FileExists(t, "testdata/dir/moon.md~")
 }

parser.go

@@ -0,0 +1,122 @@
+package main
+
+import (
+	"bytes"
+	"github.com/gomarkdown/markdown"
+	"github.com/gomarkdown/markdown/ast"
+	"github.com/gomarkdown/markdown/html"
+	"github.com/gomarkdown/markdown/parser"
+	"net/url"
+)
+
+// wikiLink returns an inline parser function. This indirection is
+// required because we want to call the previous definition in case
+// this is not a wikiLink.
+func wikiLink(p *parser.Parser, fn func(p *parser.Parser, data []byte, offset int) (int, ast.Node)) func(p *parser.Parser, data []byte, offset int) (int, ast.Node) {
+	return func(p *parser.Parser, original []byte, offset int) (int, ast.Node) {
+		data := original[offset:]
+		n := len(data)
+		// minimum: [[X]]
+		if n < 5 || data[1] != '[' {
+			return fn(p, original, offset)
+		}
+		i := 2
+		for i+1 < n && data[i] != ']' && data[i+1] != ']' {
+			i++
+		}
+		text := data[2 : i+1]
+		link := &ast.Link{
+			Destination: []byte(url.PathEscape(string(text))),
+		}
+		ast.AppendChild(link, &ast.Text{Leaf: ast.Leaf{Literal: text}})
+		return i + 3, link
+	}
+}
+
+// hashtag returns an inline parser function. This indirection is
+// required because we want to receive an array of hashtags found.
+func hashtag() (func(p *parser.Parser, data []byte, offset int) (int, ast.Node), *[]string) {
+	hashtags := make([]string, 0)
+	return func(p *parser.Parser, data []byte, offset int) (int, ast.Node) {
+		data = data[offset:]
+		i := 0
+		n := len(data)
+		for i < n && !parser.IsSpace(data[i]) {
+			i++
+		}
+		if i == 0 {
+			return 0, nil
+		}
+		hashtags = append(hashtags, string(data[1:i]))
+		link := &ast.Link{
+			AdditionalAttributes: []string{`class="tag"`},
+			Destination:          append([]byte("/search/?q=%23"), data[1:i]...),
+		}
+		text := bytes.ReplaceAll(data[0:i], []byte("_"), []byte(" "))
+		ast.AppendChild(link, &ast.Text{Leaf: ast.Leaf{Literal: text}})
+		return i, link
+	}, &hashtags
+}
+
+// wikiParser returns a parser with the Oddmu specific changes. Specifically: [[wiki links]], #hash_tags,
+// @webfinger@accounts. It also uses the CommonExtensions and Block Attributes, and no MathJax ($).
+func wikiParser() (*parser.Parser, *[]string) {
+	extensions := (parser.CommonExtensions | parser.Attributes) & ^parser.MathJax
+	parser := parser.NewWithExtensions(extensions)
+	prev := parser.RegisterInline('[', nil)
+	parser.RegisterInline('[', wikiLink(parser, prev))
+	fn, hashtags := hashtag()
+	parser.RegisterInline('#', fn)
+	if useWebfinger {
+		parser.RegisterInline('@', account)
+	}
+	return parser, hashtags
+}
+
+// wikiRenderer is a Renderer for Markdown that adds lazy loading of images. This in turn requires an exception for the
+// sanitization policy!
+func wikiRenderer() *html.Renderer {
+	htmlFlags := html.CommonFlags | html.LazyLoadImages
+	opts := html.RendererOptions{Flags: htmlFlags}
+	renderer := html.NewRenderer(opts)
+	return renderer
+}
+
+// renderHtml renders the Page.Body to HTML and sets Page.Html, Page.Language, Page.Hashtags, and escapes Page.Name.
+// Note: If the rendered HTML doesn't contain the attributes or elements you expect it to contain, check sanitizeBytes!
+func (p *Page) renderHtml() {
+	parser, hashtags := wikiParser()
+	renderer := wikiRenderer()
+	maybeUnsafeHTML := markdown.ToHTML(p.Body, parser, renderer)
+	p.Name = nameEscape(p.Name)
+	p.Html = unsafeBytes(maybeUnsafeHTML)
+	p.Language = language(p.plainText())
+	p.Hashtags = *hashtags
+}
+
+// plainText renders the Page.Body to plain text and returns it,
+// ignoring all the Markdown and all the newlines. The result is one
+// long single line of text.
+func (p *Page) plainText() string {
+	parser := parser.New()
+	doc := markdown.Parse(p.Body, parser)
+	text := []byte("")
+	ast.WalkFunc(doc, func(node ast.Node, entering bool) ast.WalkStatus {
+		if entering && node.AsLeaf() != nil {
+			text = append(text, node.AsLeaf().Literal...)
+			text = append(text, []byte(" ")...)
+		}
+		return ast.GoToNext
+	})
+	// Some Markdown still contains newlines
+	for i, c := range text {
+		if c == '\n' {
+			text[i] = ' '
+		}
+	}
+	// Remove trailing space
+	for len(text) > 0 && text[len(text)-1] == ' ' {
+		text = text[0 : len(text)-1]
+	}
+	return string(text)
+}

parser_test.go

@@ -0,0 +1,85 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestPagePlainText(t *testing.T) {
+	p := &Page{Body: []byte(`# Water
+The air will not come
+To inhale is an effort
+The summer heat kills`)}
+	r := "Water The air will not come To inhale is an effort The summer heat kills"
+	assert.Equal(t, r, p.plainText())
+}
+
+func TestPageHtml(t *testing.T) {
+	p := &Page{Body: []byte(`# Sun
+Silver leaves shine bright
+They droop, boneless, weak and sad
+A cruel sun stares down`)}
+	p.renderHtml()
+	r := `<h1>Sun</h1>
+
+<p>Silver leaves shine bright
+They droop, boneless, weak and sad
+A cruel sun stares down</p>
+`
+	assert.Equal(t, r, string(p.Html))
+}
+
+func TestPageHtmlHashtag(t *testing.T) {
+	p := &Page{Body: []byte(`# Comet
+Stars flicker above
+Too faint to focus, so far
+I am cold, alone
+
+#Haiku #Cold_Poets`)}
+	p.renderHtml()
+	r := `<h1>Comet</h1>
+
+<p>Stars flicker above
+Too faint to focus, so far
+I am cold, alone</p>
+
+<p><a class="tag" href="/search/?q=%23Haiku">#Haiku</a> <a class="tag" href="/search/?q=%23Cold_Poets">#Cold Poets</a></p>
+`
+	assert.Equal(t, r, string(p.Html))
+}
+
+func TestPageHtmlWikiLink(t *testing.T) {
+	p := &Page{Body: []byte(`# Photos and Books
+Blue and green and black
+Sky and grass and [ragged cliffs](cliffs)
+Our [[time together]]`)}
+	p.renderHtml()
+	r := `<h1>Photos and Books</h1>
+
+<p>Blue and green and black
+Sky and grass and <a href="cliffs">ragged cliffs</a>
+Our <a href="time%20together">time together</a></p>
+`
+	assert.Equal(t, r, string(p.Html))
+}
+
+func TestPageHtmlDollar(t *testing.T) {
+	p := &Page{Body: []byte(`# No $dollar$ can buy this
+Dragonfly hovers
+darts chases turns lands and rests
+A mighty jewel`)}
+	p.renderHtml()
+	r := `<h1>No $dollar$ can buy this</h1>
+
+<p>Dragonfly hovers
+darts chases turns lands and rests
+A mighty jewel</p>
+`
+	assert.Equal(t, r, string(p.Html))
+}
+
+func TestLazyLoadImages(t *testing.T) {
+	p := &Page{Body: []byte(`![](test.jpg)`)}
+	p.renderHtml()
+	assert.Contains(t, string(p.Html), "lazy")
+}

replace_cmd.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"github.com/google/subcommands"
+	"github.com/hexops/gotextdiff"
+	"github.com/hexops/gotextdiff/myers"
+	"github.com/hexops/gotextdiff/span"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"regexp"
+	"slices"
+	"strings"
+)
+
+type replaceCmd struct {
+	confirm bool
+	regexp  bool
+}
+
+func (cmd *replaceCmd) SetFlags(f *flag.FlagSet) {
+	f.BoolVar(&cmd.confirm, "confirm", false, "do the replacement instead of just doing a dry run")
+	f.BoolVar(&cmd.regexp, "regexp", false, "the search string is a regular expression")
+}
+
+func (*replaceCmd) Name() string     { return "replace" }
+func (*replaceCmd) Synopsis() string { return "search and replace in all the pages" }
+func (*replaceCmd) Usage() string {
+	return `replace [-confirm] [-regexp] <term> <replacement>:
+  Search a string or a regular expression and replace it. By default,
+  this is a dry run and nothing is saved. If this is a regular
+  expression, the replacement can use $1, $2, etc. to refer to capture
+  groups in the regular expression.
+`
+}
+
+func (cmd *replaceCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	return replaceCli(os.Stdout, cmd.confirm, cmd.regexp, f.Args())
+}
+
+func replaceCli(w io.Writer, isConfirmed bool, isRegexp bool, args []string) subcommands.ExitStatus {
+	if len(args) != 2 {
+		fmt.Fprintln(os.Stderr, "Replace takes exactly two arguments.")
+		return subcommands.ExitFailure
+	}
+	var re *regexp.Regexp
+	if isRegexp {
+		re = regexp.MustCompile(args[0])
+	} else {
+		re = regexp.MustCompile(regexp.QuoteMeta(args[0]))
+	}
+	repl := []byte(args[1])
+	changes := 0
+	err := filepath.Walk(".", func(path string, info fs.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		// skip hidden directories and files
+		if path != "." && strings.HasPrefix(filepath.Base(path), ".") {
+			if info.IsDir() {
+				return filepath.SkipDir
+			} else {
+				return nil
+			}
+		}
+		// skipp all but page files
+		if !strings.HasSuffix(path, ".md") {
+			return nil
+		}
+		body, err := os.ReadFile(path)
+		if err != nil {
+			return err
+		}
+		result := re.ReplaceAll(body, repl)
+		if !slices.Equal(result, body) {
+			changes++
+			if isConfirmed {
+				fmt.Fprintln(w, path)
+				_ = os.Rename(path, path+"~")
+				err = os.WriteFile(path, result, 0644)
+				if err != nil {
+					return err
+				}
+			} else {
+				edits := myers.ComputeEdits(span.URIFromPath(path+"~"), string(body), string(result))
+				diff := fmt.Sprint(gotextdiff.ToUnified(path+"~", path, string(body), edits))
+				fmt.Fprintln(w, diff)
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		return subcommands.ExitFailure
+	}
+	if changes == 1 {
+		if isConfirmed {
+			fmt.Fprintln(w, "1 file was changed.")
+		} else {
+			fmt.Fprintln(w, "1 file would be changed.")
+		}
+	} else {
+		if isConfirmed {
+			fmt.Fprintf(w, "%d files were changed.\n", changes)
+		} else {
+			fmt.Fprintf(w, "%d files would be changed.\n", changes)
+		}
+	}
+	if !isConfirmed && changes > 0 {
+		fmt.Fprintln(w, "This is a dry run. Use -confirm to make it happen.")
+	}
+	return subcommands.ExitSuccess
+}

replace_cmd_test.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"bytes"
+	"github.com/google/subcommands"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestReplaceCmd(t *testing.T) {
+	cleanup(t, "testdata/replace")
+	index.load()
+	p := &Page{Name: "testdata/replace/pluto", Body: []byte(`# Pluto
+Out there is a rock
+And more rocks uncountable
+You are no planet`)}
+	p.save()
+
+	r := `--- testdata/replace/pluto.md~
++++ testdata/replace/pluto.md
+@@ -1,4 +1,4 @@
+ # Pluto
+ Out there is a rock
+ And more rocks uncountable
+-You are no planet
+\ No newline at end of file
++You are planetoid
+\ No newline at end of file
+
+1 file would be changed.
+This is a dry run. Use -confirm to make it happen.
+`
+
+	b := new(bytes.Buffer)
+	s := replaceCli(b, false, true, []string{`\bno planet`, `planetoid`})
+	assert.Equal(t, subcommands.ExitSuccess, s)
+	assert.Equal(t, r, b.String())
+}

score.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"regexp"
-	"strings"
 )
 
 // score splits the query string q into terms and scores the text
@@ -10,7 +9,7 @@ import (
 // characters quoted.
 func score(q string, s string) int {
 	score := 0
-	re, err := regexp.Compile("(?i)" + q)
+	re, err := regexp.Compile("(?i)" + regexp.QuoteMeta(q))
 	if err == nil {
 		m := re.FindAllString(s, -1)
 		if m != nil {
@@ -18,8 +17,8 @@ func score(q string, s string) int {
 			score += len(m)
 		}
 	}
-	for _, v := range strings.Fields(q) {
-		re, err := regexp.Compile(`(?is)(\pL?)(` + v + `)(\pL?)`)
+	for _, token := range highlightTokens(q) {
+		re, err := regexp.Compile(`(?is)(\pL?)(` + regexp.QuoteMeta(token) + `)(\pL?)`)
 		if err != nil {
 			continue
 		}

score_test.go

@@ -94,7 +94,7 @@ func TestScorePageAndMarkup(t *testing.T) {
 	s := `The Transjovian Council accepts new members. If you think we'd be a good fit, apply for an account. Contact [Alex Schroeder](https://alexschroeder.ch/wiki/Contact). Mail is best. Encrypted mail is best. [Delta Chat](https://delta.chat/de/) is a messenger app that uses encrypted mail. It's the bestest best.`
 	p := &Page{Title: "Test", Name: "Test", Body: []byte(s)}
 	q := "wiki"
-	p.summarize(q)
+	p.score(q)
 	// "wiki" is not visible in the plain text but the score is no affected:
 	// - wiki, all, whole, beginning, end (5)
 	if p.Score != 5 {

search.go

@@ -1,9 +1,14 @@
 package main
 
 import (
-	"fmt"
+	"log"
 	"net/http"
+	"os"
+	"path"
+	"regexp"
 	"slices"
+	"strconv"
+	"strings"
 	"unicode"
 	"unicode/utf8"
 )
@@ -13,76 +18,242 @@ import (
 // Currently there is no pagination of results! When a page is part of
 // a search result, Body and Html are simple extracts.
 type Search struct {
-	Query   string
-	Items   []Page
-	Results bool
+	Query    string
+	Dir      string
+	Items    []*Page
+	Previous int
+	Page     int
+	Next     int
+	More     bool
+	Results  bool
 }
 
-func sortItems(a, b Page) int {
-	// Sort by score
-	if a.Score < b.Score {
-		return 1
-	} else if a.Score > b.Score {
-		return -1
-	}
-	// If the score is the same and both page names start
-	// with a number (like an ISO date), sort descending.
-	ra, _ := utf8.DecodeRuneInString(a.Title)
-	rb, _ := utf8.DecodeRuneInString(b.Title)
-	if unicode.IsNumber(ra) && unicode.IsNumber(rb) {
-		if a.Title < b.Title {
-			return 1
-		} else if a.Title > b.Title {
-			return -1
-		} else {
-			return 0
+// sortNames returns a sort function that sorts in three stages: 1.
+// whether the query string matches the page title; 2. descending if
+// the page titles start with a digit; 3. otherwise ascending.
+// Access to the index requires a read lock!
+func sortNames(tokens []string) func(a, b string) int {
+	return func(a, b string) int {
+		// If only one page contains the query string, it
+		// takes precedence.
+		ia := false
+		ib := false
+		for _, token := range tokens {
+			if !ia && strings.Contains(index.titles[a], token) {
+				ia = true
+			}
+			if !ib && strings.Contains(index.titles[b], token) {
+				ib = true
+			}
+		}
+		if ia && !ib {
+			return -1
+		} else if !ia && ib {
+			return 1
+		}
+		// Page names starting with a number come first. If
+		// both page names start with a number (like an ISO
+		// date), sort by page name, descending.
+		ra, _ := utf8.DecodeRuneInString(a)
+		na := unicode.IsNumber(ra)
+		rb, _ := utf8.DecodeRuneInString(b)
+		nb := unicode.IsNumber(rb)
+		if na && !nb {
+			return -1
+		} else if !na && nb {
+			return 1
+		} else if na && nb {
+			if a < b {
+				return 1
+			} else if a > b {
+				return -1
+			}
+		}
+		// Otherwise sort by title, ascending.
+		if index.titles[a] < index.titles[b] {
+			return -1
+		} else if index.titles[a] > index.titles[b] {
+			return 1
+		}
+		// Either the titles are equal or the index isn't
+		// initialized.
+		if a < b {
+			return -1
+		} else if a > b {
+			return 1
 		}
-	}
-	// Otherwise sort ascending.
-	if a.Title < b.Title {
-		return -1
-	} else if a.Title > b.Title {
-		return 1
-	} else {
 		return 0
 	}
 }
 
-// loadAndSummarize loads the pages named and summarizes them for the
-// query give.
-func loadAndSummarize(names []string, q string) []Page {
-	// Load and summarize the items.
-	items := make([]Page, len(names))
-	for i, name := range names {
-		p, err := loadPage(name)
-		if err != nil {
-			fmt.Printf("Error loading %s\n", name)
-		} else {
-			p.summarize(q)
-			items[i] = *p
+// itemsPerPage says how many items to print on a page of search
+// results.
+const itemsPerPage = 20
+
+// search returns a sorted []Page where each page contains an extract of the actual Page.Body in its Page.Html. Page
+// size is 20. Specify either the page number to return, or that all the results should be returned. Only ask for all
+// results if runtime is not an issue, like on the command line. The boolean return value indicates whether there are
+// more results.
+func search(q, dir, filter string, page int, all bool) ([]*Page, bool) {
+	if len(q) == 0 {
+		return make([]*Page, 0), false
+	}
+	names := index.search(q) // hashtags or all names
+	names = filterPath(names, dir, filter)
+	predicates, terms := predicatesAndTokens(q)
+	names = filterNames(names, predicates)
+	index.RLock()
+	slices.SortFunc(names, sortNames(terms))
+	index.RUnlock()
+	names, keepFirst := prependQueryPage(names, dir, q)
+	from := itemsPerPage * (page - 1)
+	to := from + itemsPerPage - 1
+	items, more := grep(terms, names, from, to, all, keepFirst)
+	for _, p := range items {
+		p.score(q)
+		p.summarize(q)
+	}
+	return items, more
+}
+
+// filterPath filters the names by prefix and by a regular expression. A prefix of "." means that all the names are
+// returned, since this is what path.Dir returns for "no directory".
+//
+// The regular expression can be used to ensure that search does not descend into subdirectories unless the search
+// already starts there. Given the pages a, public/b and secret/c and ODDMU_FILTER=^secret/ then if search starts in the
+// root directory /, search does not enter secret/, but if search starts in secret/, search does search the pages in
+// secret/ – it us up to the web server to ensure access to secret/ is limited. More specifically: If the current
+// directory matches the regular expression, the page names must match; if the regular expression does not match the
+// current directory, the page name must not match the filter either. If the filter is empty, all prefixes and all page
+// names match, so no problem.
+func filterPath(names []string, prefix, filter string) []string {
+	re, err := regexp.Compile(filter)
+	if err != nil {
+		log.Println("ODDMU_FILTER does not compile:", filter, err)
+		return []string{}
+	}
+	mustMatch := re.MatchString(prefix)
+	r := make([]string, 0)
+	for _, name := range names {
+		if strings.HasPrefix(name, prefix) &&
+			(mustMatch && re.MatchString(name) ||
+				!mustMatch && !re.MatchString(name)) {
+			r = append(r, name)
 		}
 	}
-	return items
+	return r
 }
 
-// search returns a sorted []Page where each page contains an extract
-// of the actual Page.Body in its Page.Html.
-func search(q string) []Page {
-	if len(q) == 0 {
-		return make([]Page, 0)
+// filterNames filters the names by all the predicats such as
+// "title:foo" or "blog:true".
+func filterNames(names, predicates []string) []string {
+	if len(predicates) == 0 {
+		return names
 	}
-	names := searchDocuments(q)
-	items := loadAndSummarize(names, q)
-	slices.SortFunc(items, sortItems)
-	return items
+	// the intersection requires sorted lists
+	slices.Sort(names)
+	index.RLock()
+	defer index.RUnlock()
+	for _, predicate := range predicates {
+		r := make([]string, 0)
+		if strings.HasPrefix(predicate, "title:") {
+			token := predicate[6:]
+			for _, name := range names {
+				if strings.Contains(strings.ToLower(index.titles[name]), token) {
+					r = append(r, name)
+				}
+			}
+		} else if predicate == "blog:true" || predicate == "blog:false" {
+			blog := predicate == "blog:true"
+			re := regexp.MustCompile(`(^|/)\d\d\d\d-\d\d-\d\d`)
+			for _, name := range names {
+				match := re.MatchString(name)
+				if blog && match || !blog && !match {
+					r = append(r, name)
+				}
+			}
+		} else {
+			log.Printf("Unsupported predicate: %s", predicate)
+		}
+		names = intersection(names, r)
+	}
+	return names
 }
 
-// searchHandler presents a search result. It uses the query string in
-// the form parameter "q" and the template "search.html". For each
-// page found, the HTML is just an extract of the actual body.
-func searchHandler(w http.ResponseWriter, r *http.Request) {
-	q := r.FormValue("q")
-	items := search(q)
-	s := &Search{Query: q, Items: items, Results: len(items) > 0}
-	renderTemplate(w, "search", s)
+// grep searches the files for matches to all the tokens. It returns just a single page of results based [from:to-1] and
+// returns if there are more results. The all parameter ignores pagination (the from and to parameters). The keepFirst
+// parameter keeps the first page in the list, even if there is no match. This is used for hashtag pages.
+func grep(tokens, names []string, from, to int, all, keepFirst bool) ([]*Page, bool) {
+	pages := make([]*Page, 0)
+	i := 0
+NameLoop:
+	for n, name := range names {
+		p, err := loadPage(name)
+		if err != nil {
+			log.Printf("grep: cannot load %s: %s", name, err)
+			continue NameLoop
+		}
+		if n != 0 || !keepFirst {
+			body := strings.ToLower(string(p.Body))
+			for _, token := range tokens {
+				if !strings.Contains(body, token) {
+					continue NameLoop
+				}
+			}
+		}
+		i++
+		if all || i > from {
+			pages = append(pages, p)
+		}
+		if !all && i > to {
+			return pages, true
+		}
+	}
+	return pages, false
+}
+
+// prependQueryPage prepends the query itself, if a matching page name exists. This helps if people remember the name
+// exactly, or if searching for a hashtag. This function assumes that q is not the empty string. Return wether a page
+// was prepended or not.
+func prependQueryPage(names []string, dir, q string) ([]string, bool) {
+	index.RLock()
+	defer index.RUnlock()
+	if q[0] == '#' && !strings.Contains(q[1:], "#") {
+		q = q[1:]
+	}
+	q = path.Join(dir, q)
+	// if q exists in names, move it to the front
+	i := slices.Index(names, q)
+	if i == 0 {
+		return names, false
+	} else if i != -1 {
+		r := []string{q}
+		r = append(r, names[0:i]...)
+		r = append(r, names[i+1:]...)
+		return r, false
+	}
+	// otherwise, if q is a known page name, prepend it
+	_, ok := index.titles[q]
+	if ok {
+		return append([]string{q}, names...), true
+	}
+	return names, false
+}
+
+// searchHandler presents a search result. It uses the query string in the form parameter "q" and the template
+// "search.html". For each page found, the HTML is just an extract of the actual body. Search is limited to a directory
+// and its subdirectories.
+//
+// A filter can be defined using the environment variable ODDMU_FILTER. It is passed on to search.
+func searchHandler(w http.ResponseWriter, r *http.Request, dir string) {
+	q := r.FormValue("q")
+	page, err := strconv.Atoi(r.FormValue("page"))
+	if err != nil {
+		page = 1
+	}
+	filter := os.Getenv("ODDMU_FILTER")
+	items, more := search(q, dir, filter, page, false)
+	s := &Search{Query: q, Dir: dir, Items: items, Previous: page - 1, Page: page, Next: page + 1,
+		Results: len(items) > 0, More: more}
+	renderTemplate(w, dir, "search", s)
 }

search.html

@@ -1,32 +1,40 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
   <head>
     <meta charset="utf-8">
     <meta name="format-detection" content="telephone=no">
     <meta name="viewport" content="width=device-width">
     <title>Search for {{.Query}}</title>
     <style>
-html { max-width: 65ch; padding: 2ch; margin: auto; color: #111; background: #ffe; }
+html { max-width: 70ch; padding: 2ch; margin: auto; color: #111; background-color: #ffe; }
 body { hyphens: auto; }
 header a { margin-right: 1ch; }
 form { display: inline-block; }
+input#search { width: 20ch; }
+button { background-color: #eee; color: inherit; border-radius: 4px; border-width: 1px; }
 img { max-width: 20%; }
 .result { font-size: larger }
 .score { font-size: smaller; opacity: 0.8; }
     </style>
   </head>
-  <body lang="en">
+  <body>
     <header>
       <a href="#main">Skip navigation</a>
       <a href="/view/index">Home</a>
-      <form role="search" action="/search" method="GET">
-        <input type="text" value="{{.Query}}" spellcheck="false" name="q" required>
-        <button>Search</button>
+      <form role="search" action="/search/{{.Dir}}" method="GET">
+        <label for="search">Search:</label>
+        <input id="search" type="text" value="{{.Query}}" spellcheck="false" name="q" accesskey="f" placeholder="term #tag title:term blog:true" required>
+        <button>Go</button>
       </form>
     </header>
     <main id="main">
       <h1>Search for {{.Query}}</h1>
       {{if .Results}}
+      <p>
+        {{if gt .Page 2}}<a href="/search/{{.Dir}}?q={{.Query}}&page=1">First</a>{{end}}
+        {{if gt .Page 1}}<a href="/search/{{.Dir}}?q={{.Query}}&page={{.Previous}}">Previous</a>{{end}}
+        Page {{.Page}}
+        {{if .More}}<a href="/search/{{.Dir}}?q={{.Query}}&page={{.Next}}">Next</a>{{end}}
       {{range .Items}}
       <article lang="{{.Language}}">
         <p><a class="result" href="/view/{{.Name}}">{{.Title}}</a>
@@ -34,6 +42,11 @@ img { max-width: 20%; }
         <blockquote>{{.Html}}</blockquote>
       </article>
       {{end}}
+      <p>
+        {{if gt .Page 2}}<a href="/search/{{.Dir}}?q={{.Query}}&page=1">First</a>{{end}}
+        {{if gt .Page 1}}<a href="/search/{{.Dir}}?q={{.Query}}&page={{.Previous}}">Previous</a>{{end}}
+        Page {{.Page}}
+        {{if .More}}<a href="/search/{{.Dir}}?q={{.Query}}&page={{.Next}}">Next</a>{{end}}
       {{else}}
       <p>No results.</p>
       {{end}}

search_cmd.go

@@ -0,0 +1,98 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"github.com/charmbracelet/lipgloss"
+	"github.com/google/subcommands"
+	"io"
+	"os"
+	"regexp"
+	"strings"
+)
+
+type searchCmd struct {
+	dir     string
+	page    int
+	all     bool
+	extract bool
+}
+
+func (cmd *searchCmd) SetFlags(f *flag.FlagSet) {
+	f.StringVar(&cmd.dir, "dir", "", "search only pages within this sub-directory")
+	f.IntVar(&cmd.page, "page", 1, "the page in the search result set, default 1")
+	f.BoolVar(&cmd.all, "all", false, "show all the pages and ignore -page")
+	f.BoolVar(&cmd.extract, "extract", false, "print page extract instead of link list")
+}
+
+func (*searchCmd) Name() string     { return "search" }
+func (*searchCmd) Synopsis() string { return "Search pages and print a list of links." }
+func (*searchCmd) Usage() string {
+	return `search [-dir string] [-page <n>|-all] [-extract] <terms>:
+  Search for pages matching terms and print the result set as a
+  Markdown list. Before searching, all the pages are indexed. Thus,
+  startup is slow. The benefit is that the page order is exactly as
+  when the wiki runs.
+`
+}
+
+func (cmd *searchCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	return searchCli(os.Stdout, cmd.dir, cmd.page, cmd.all, cmd.extract, false, f.Args())
+}
+
+// searchCli runs the search command on the command line. It is used
+// here with an io.Writer for easy testing.
+func searchCli(w io.Writer, dir string, n int, all, extract bool, quiet bool, args []string) subcommands.ExitStatus {
+	dir, err := checkDir(dir)
+	if err != nil {
+		return subcommands.ExitFailure
+	}
+	index.reset()
+	index.load()
+	q := strings.Join(args, " ")
+	items, more := search(q, dir, "", n, true)
+	if !quiet {
+		fmt.Fprint(os.Stderr, "Search for ", q)
+		if !all {
+			fmt.Fprint(os.Stderr, ", page ", n)
+		}
+		fmt.Fprint(os.Stderr, ": ", len(items))
+		if len(items) == 1 {
+			fmt.Fprint(os.Stderr, " result\n")
+		} else {
+			fmt.Fprint(os.Stderr, " results\n")
+		}
+	}
+	if extract {
+		searchExtract(w, items)
+	} else {
+		for _, p := range items {
+			name := p.Name
+			if strings.HasPrefix(name, dir) {
+				name = strings.Replace(name, dir, "", 1)
+			}
+			fmt.Fprintf(w, "* [%s](%s)\n", p.Title, name)
+		}
+	}
+	if more {
+		fmt.Fprintf(os.Stderr, "There are more results\n")
+	}
+	return subcommands.ExitSuccess
+}
+
+// searchExtract prints the search extracts to stdout with highlighting for a terminal.
+func searchExtract(w io.Writer, items []*Page) {
+	heading := lipgloss.NewStyle().Bold(true).Underline(true)
+	quote := lipgloss.NewStyle().PaddingLeft(4).Width(78)
+	match := lipgloss.NewStyle().Bold(true)
+	re := regexp.MustCompile(`<b>(.*?)</b>`)
+	for _, p := range items {
+		s := re.ReplaceAllString(string(p.Html), match.Render(`$1`))
+		fmt.Fprintln(w, heading.Render(p.Title))
+		if p.Name != p.Title {
+			fmt.Fprintln(w, p.Name)
+		}
+		fmt.Fprintln(w, quote.Render(s))
+	}
+}

search_cmd_test.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"bytes"
+	"github.com/google/subcommands"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestSearchCmd(t *testing.T) {
+	b := new(bytes.Buffer)
+	s := searchCli(b, "", 1, false, false, true, []string{"oddµ"})
+	assert.Equal(t, subcommands.ExitSuccess, s)
+	r := `* [Oddµ: A minimal wiki](README)
+* [Welcome to Oddµ](index)
+`
+	assert.Equal(t, r, b.String())
+}
+
+func TestSearchSubdirCmd(t *testing.T) {
+	cleanup(t, "testdata/search")
+	p := &Page{Name: "testdata/search/wait", Body: []byte(`# Wait
+We should make it so
+that before we type and speak
+we hear that moment`)}
+	p.save()
+	b := new(bytes.Buffer)
+	s := searchCli(b, "testdata/search", 1, false, false, true, []string{"speak"})
+	assert.Equal(t, subcommands.ExitSuccess, s)
+	r := `* [Wait](wait)
+`
+	assert.Equal(t, r, b.String())
+}

search_test.go

@@ -1,14 +1,272 @@
 package main
 
 import (
+	"fmt"
 	"github.com/stretchr/testify/assert"
-	"testing"
 	"net/url"
+	"slices"
+	"testing"
 )
 
+func TestSortNames(t *testing.T) {
+	index.Lock()
+	defer index.Unlock()
+	for _, s := range []string{"Alex", "Berta", "Chris", "2015-06-14", "2023-09-26"} {
+		index.titles[s] = s
+	}
+	terms := []string{"Z"}
+	fn := sortNames(terms)
+	assert.Equal(t, 1, fn("Berta", "Alex"), "B is after A")
+	assert.Equal(t, -1, fn("Alex", "Berta"), "A is before B")
+	assert.Equal(t, 0, fn("Berta", "Berta"), "B and B are equal")
+	assert.Equal(t, -1, fn("2023-09-26", "Alex"), "numbers before letters")
+	assert.Equal(t, 1, fn("Alex", "2023-09-26"), "numbers after letters")
+	assert.Equal(t, -1, fn("2023-09-26", "2015-06-14"), "higher numbers before lower numbers")
+	assert.Equal(t, 1, fn("2015-06-14", "2023-09-26"), "lower numbers after higher numbers")
+
+	names := []string{"Berta", "Chris", "Alex"}
+	slices.SortFunc(names, sortNames(terms))
+	assert.True(t, slices.IsSorted(names), fmt.Sprintf("Sorted: %v", names))
+}
+
+func TestPrependMatches(t *testing.T) {
+	index.Lock()
+	for _, s := range []string{"Alex", "Berta", "Chris"} {
+		index.titles[s] = s
+	}
+	index.Unlock()
+	r := []string{"Berta", "Chris"}         // does not prepend
+	u := []string{"Alex", "Berta", "Chris"} // does prepend
+	v, _ := prependQueryPage(r, "", "Alex")
+	assert.Equal(t, u, v, "prepend q")
+	v, _ = prependQueryPage(r, "", "lex")
+	assert.Equal(t, r, v, "exact matches only")
+	v, _ = prependQueryPage(r, "", "#Alex")
+	assert.Equal(t, u, v, "prepend hashtag")
+	v, _ = prependQueryPage(r, "", "#Alex #Berta")
+	assert.Equal(t, r, v, "do not prepend two hashtags")
+	v, _ = prependQueryPage(r, "", "#alex")
+	assert.Equal(t, r, v, "do not ignore case")
+	v, _ = prependQueryPage(u, "", "Alex")
+	assert.Equal(t, u, v, "do not prepend q twice")
+	v, _ = prependQueryPage([]string{"Berta", "Alex", "Chris"}, "", "Alex")
+	assert.Equal(t, u, v, "sort q to the front")
+	v, _ = prependQueryPage([]string{"Berta", "Chris", "Alex"}, "", "Alex")
+	assert.Equal(t, u, v, "sort q to the front")
+}
+
 func TestSearch(t *testing.T) {
+	// working in the main directory
+	index.reset()
+	index.load()
+
 	data := url.Values{}
 	data.Set("q", "oddµ")
-	assert.Contains(t,
-		assert.HTTPBody(searchHandler, "GET", "/search", data), "Welcome")
+
+	body := assert.HTTPBody(makeHandler(searchHandler, false), "GET", "/search/", data)
+	assert.Contains(t, body, "Welcome")
+	assert.Contains(t, body, `<span class="score">5</span>`)
+
+	body = assert.HTTPBody(makeHandler(searchHandler, false), "GET", "/search/testdata", data)
+	assert.NotContains(t, body, "Welcome")
+}
+
+func TestSearchFilter(t *testing.T) {
+	names := []string{"a", "public/b", "secret/c"}
+
+	f := filterPath(names, "", "")
+	assert.Equal(t, names, f)
+
+	f = filterPath(names, "public/", "")
+	assert.Equal(t, []string{"public/b"}, f)
+
+	f = filterPath(names, "secret/", "")
+	assert.Equal(t, []string{"secret/c"}, f)
+
+	// critically, this no longer returns c
+	f = filterPath(names, "", "^secret/")
+	assert.Equal(t, []string{"a", "public/b"}, f)
+
+	// unchanged
+	f = filterPath(names, "public/", "^secret/")
+	assert.Equal(t, []string{"public/b"}, f)
+
+	// unchanged
+	f = filterPath(names, "secret/", "^secret/")
+	assert.Equal(t, []string{"secret/c"}, f)
+
+}
+
+func TestSearchFilterLong(t *testing.T) {
+	cleanup(t, "testdata/filter")
+	p := &Page{Name: "testdata/filter/one", Body: []byte(`# One
+
+One day, I heard you say
+Just one more day and I'd know
+But that was last spring`)}
+	p.save()
+	p = &Page{Name: "testdata/filter/public/two", Body: []byte(`# Two
+Oh, the two of us
+Have often seen this forest
+But this bird is new`)}
+	p.save()
+	p = &Page{Name: "testdata/filter/secret/three", Body: []byte(`# Three
+Three years have gone by
+And we're good, we live, we breathe
+But we don't say it`)}
+	p.save()
+
+	// normal search works
+	items, _ := search("spring", "testdata/", "", 1, false)
+	assert.Equal(t, len(items), 1)
+	assert.Equal(t, "One", items[0].Title)
+
+	// not found because it's in /secret and we start at /
+	items, _ = search("year", "testdata/", "^testdata/filter/secret/", 1, false)
+	assert.Equal(t, 0, len(items))
+
+	// only found two because the third one is in /secret and we start at /
+	items, _ = search("but", "testdata/", "^testdata/filter/secret/", 1, false)
+	assert.Equal(t, 2, len(items))
+	assert.Equal(t, "One", items[0].Title)
+	assert.Equal(t, "Two", items[1].Title)
+
+	// starting in the public/ directory, we find only one page
+	items, _ = search("but", "testdata/filter/public/", "^testdata/filter/secret/", 1, false)
+	assert.Equal(t, 1, len(items))
+	assert.Equal(t, "Two", items[0].Title)
+
+	// starting in the secret/ directory, we find only one page
+	items, _ = search("but", "testdata/filter/secret/", "^testdata/filter/secret/", 1, false)
+	assert.Equal(t, 1, len(items))
+	assert.Contains(t, "Three", items[0].Title)
+}
+
+func TestSearchDir(t *testing.T) {
+	cleanup(t, "testdata/dir")
+	p := &Page{Name: "testdata/dir/dice", Body: []byte(`# Dice
+
+A tiny drum roll
+Dice rolling bouncing stopping
+Where is lady luck?`)}
+	p.save()
+
+	data := url.Values{}
+	data.Set("q", "luck")
+
+	body := assert.HTTPBody(makeHandler(searchHandler, false), "GET", "/search/", data)
+	assert.Contains(t, body, "luck")
+
+	body = assert.HTTPBody(makeHandler(searchHandler, false), "GET", "/search/testdata", data)
+	assert.Contains(t, body, "luck")
+
+	body = assert.HTTPBody(makeHandler(searchHandler, false), "GET", "/search/testdata/dir", data)
+	assert.Contains(t, body, "luck")
+
+	body = assert.HTTPBody(makeHandler(searchHandler, false), "GET", "/search/testdata/other", data)
+	assert.Contains(t, body, "No results")
+}
+
+func TestTitleSearch(t *testing.T) {
+	// working in the main directory
+	index.reset()
+	index.load()
+
+	items, more := search("title:readme", "", "", 1, false)
+	assert.Equal(t, 0, len(items), "no page found")
+	assert.False(t, more)
+
+	items, more = search("title:wel", "", "", 1, false) // README also contains "wel"
+	assert.Equal(t, 1, len(items), "one page found")
+	assert.Equal(t, "index", items[0].Name, "Welcome to Oddµ")
+	assert.Greater(t, items[0].Score, 0, "matches result in a score")
+	assert.False(t, more)
+
+	items, more = search("wel", "", "", 1, false)
+	assert.Greater(t, len(items), 1, "two pages found")
+	assert.False(t, more)
+}
+
+func TestBlogSearch(t *testing.T) {
+	cleanup(t, "testdata/grep")
+	p := &Page{Name: "testdata/grep/2023-09-25", Body: []byte(`# Back then
+
+I check the git log
+Was it 2015
+We met in the park?`)}
+	p.save()
+
+	items, _ := search("blog:false", "", "", 1, false)
+	for _, item := range items {
+		assert.NotEqual(t, "Back then", item.Title, item.Name)
+	}
+
+	items, _ = search("blog:true", "", "", 1, false)
+	assert.Equal(t, 1, len(items), "one blog page found")
+	assert.Equal(t, "Back then", items[0].Title, items[0].Name)
+}
+
+func TestHashtagSearch(t *testing.T) {
+	cleanup(t, "testdata/hashtag")
+
+	p := &Page{Name: "testdata/hashtag/Haiku", Body: []byte("# Haikus\n")}
+	p.save()
+
+	p = &Page{Name: "testdata/hashtag/2023-10-28", Body: []byte(`# Tea
+
+My tongue is on fire
+It looked so calm and peaceful
+A quick sip too quick
+
+#Haiku`)}
+	p.save()
+
+	items, _ := search("#Haiku", "testdata/hashtag", "", 1, false)
+	assert.Equal(t, 2, len(items), "two pages found")
+	assert.Equal(t, "Haikus", items[0].Title, items[0].Name)
+	assert.Equal(t, "Tea", items[1].Title, items[1].Name)
+}
+
+func TestSearchQuestionmark(t *testing.T) {
+	cleanup(t, "testdata/question")
+	p := &Page{Name: "testdata/question/Odd?", Body: []byte(`# Even?
+
+We look at the plants.
+They need water. We need us.
+The silence streches.`)}
+	p.save()
+	data := url.Values{}
+	data.Set("q", "look")
+	body := assert.HTTPBody(makeHandler(searchHandler, false), "GET", "/search/", data)
+	assert.Contains(t, body, "We <b>look</b>")
+	assert.NotContains(t, body, "Odd?")
+	assert.Contains(t, body, "Even?")
+}
+
+func TestSearchPagination(t *testing.T) {
+	cleanup(t, "testdata/pagination")
+	index.load()
+	alphabet := "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	for _, r := range alphabet {
+		s := fmt.Sprintf("secret%c secretX", r)
+		p := &Page{Name: "testdata/pagination/" + string(r), Body: []byte(s)}
+		p.save()
+	}
+
+	items, more := search("secretA", "", "", 1, false)
+	assert.Equal(t, 1, len(items), "one page found, %v", items)
+	assert.Equal(t, "testdata/pagination/A", items[0].Name)
+	assert.False(t, more)
+
+	items, more = search("secretX", "", "", 1, false)
+	assert.Equal(t, itemsPerPage, len(items))
+	assert.Equal(t, "testdata/pagination/A", items[0].Name)
+	assert.Equal(t, "testdata/pagination/T", items[itemsPerPage-1].Name)
+	assert.True(t, more)
+
+	items, more = search("secretX", "", "", 2, false)
+	assert.Equal(t, 6, len(items))
+	assert.Equal(t, "testdata/pagination/U", items[0].Name)
+	assert.Equal(t, "testdata/pagination/Z", items[5].Name)
+	assert.False(t, more)
 }

snippets.go

@@ -1,20 +1,21 @@
 package main
 
 import (
+	"log"
 	"regexp"
 	"strings"
 )
 
 // re returns a regular expression matching any word in q.
 func re(q string) (*regexp.Regexp, error) {
-	q = regexp.QuoteMeta(q)
-	re, err := regexp.Compile(`\s+`)
-	if err != nil {
-		return nil, err
+	fields := highlightTokens(q)
+	quoted := make([]string, len(fields))
+	for i, w := range fields {
+		quoted[i] = regexp.QuoteMeta(w)
 	}
-	words := re.ReplaceAllString(q, "|")
-	re, err = regexp.Compile(`(?i)(` + words + `)`)
+	re, err := regexp.Compile(`(?i)(` + strings.Join(quoted, "|") + `)`)
 	if err != nil {
+		log.Printf("Cannot compile %s %v: %s", q, quoted, err)
 		return nil, err
 	}
 	return re, nil
@@ -26,12 +27,16 @@ func snippets(q string, s string) string {
 	maxsnippets := 4
 	re, err := re(q)
 	// If the compilation didn't work, truncate and return
-	if err != nil || len(s) <= snippetlen {
+	if err != nil {
 		if len(s) > 400 {
 			s = s[0:400] + " …"
 		}
 		return s
 	}
+	// Short cut for short pages
+	if len(s) <= snippetlen {
+		return highlight(q, re, s)
+	}
 	// show a snippet from the beginning of the document
 	j := strings.LastIndex(s[:snippetlen], " ")
 	if j == -1 {
@@ -75,7 +80,7 @@ func snippets(q string, s string) string {
 				to = len(s)
 			}
 			end := strings.LastIndex(s[:to], " ")
-			if end == -1 || end <= j + wl {
+			if end == -1 || end <= j+wl {
 				// OK, look for a longer word
 				end = strings.Index(s[to:], " ")
 				if end == -1 {

snippets_test.go

@@ -10,7 +10,7 @@ func TestSnippets(t *testing.T) {
 
 	h := `We are immersed in a sea of dead people. <b>All</b> the dead that have gone before us, silent now, just … to ask ourselves – or them! – what it was <b>all</b> about. Instead we drown ourselves in no<b>is</b>e. … surrounded by false friends claiming that <b>all</b> <b>is</b> <b>well</b>. And look at us! Yes, we are <b>well</b>. …`
 
-	q := "all is well"
+	q := "title:all is well"
 	r := snippets(q, s)
 	assert.Equal(t, h, r)
 }
@@ -41,5 +41,5 @@ func TestSnippetsLong(t *testing.T) {
 	assert.Equal(t,
 		"VWwXetig mty8fORN UNia4NFm SQsfyFHk BLDdgVnc AcvKP2fs q8KxPH1A IaCzFj96 J0S2fqca jp3ElV9f ULIZ1aMX … Auk5RBWs tMpfMMlU p6jGYq3Z rTIBTHVM zGFwFwQi <b>j4O1AY21</b> BJnaiScY",
 		snippets("j4O1AY21", s))
-	
+
 }

static.html

@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html lang="{{.Language}}">
+  <head>
+    <meta charset="utf-8">
+    <meta name="format-detection" content="telephone=no">
+    <meta name="viewport" content="width=device-width">
+    <title>{{.Title}}</title>
+    <style>
+html { max-width: 65ch; padding: 1ch; margin: auto; color: #111; background-color: #ffe; }
+body { hyphens: auto; }
+header a { margin-right: 1ch; }
+form { display: inline-block; }
+input#search { width: 12ch; }
+button { background-color: #eee; color: inherit; border-radius: 4px; border-width: 1px; }
+footer { border-top: 1px solid #888 }
+img { max-width: 100%; }
+    </style>
+  </head>
+  <body>
+    <main id="main">
+      <h1>{{.Title}}</h1>
+      {{.Html}}
+    </main>
+    <footer>
+      <address>
+        Comments? Send mail to Your Name <<a href="mailto:you@example.org">you@example.org</a>>
+      </address>
+    </footer>
+  </body>
+</html>

static_cmd.go

@@ -0,0 +1,158 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"flag"
+	"fmt"
+	"github.com/gomarkdown/markdown"
+	"github.com/gomarkdown/markdown/ast"
+	"github.com/gomarkdown/markdown/html"
+	"github.com/google/subcommands"
+	"io/fs"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type staticCmd struct {
+}
+
+func (*staticCmd) Name() string     { return "static" }
+func (*staticCmd) Synopsis() string { return "generate static HTML files for all pages" }
+func (*staticCmd) Usage() string {
+	return `static <dir name>:
+  Create static copies in the given directory.
+`
+}
+
+func (cmd *staticCmd) SetFlags(f *flag.FlagSet) {
+}
+
+func (cmd *staticCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	args := f.Args()
+	if len(args) != 1 {
+		fmt.Println("Exactly one target directory is required")
+		return subcommands.ExitFailure
+	}
+	return staticCli(filepath.Clean(args[0]), false)
+}
+
+// staticCli generates a static site in the designated directory. The quiet flag is used to suppress output when running
+// tests.
+func staticCli(dir string, quiet bool) subcommands.ExitStatus {
+	loadLanguages()
+	loadTemplates()
+	n := 0
+	err := filepath.Walk(".", func(path string, info fs.FileInfo, err error) error {
+		n++
+		if !quiet && (n < 100 || n < 1000 && n%10 == 0 || n%100 == 0) {
+			fmt.Fprintf(os.Stdout, "\r%d", n)
+		}
+		return staticFile(path, dir, info, err)
+	})
+	if !quiet {
+		fmt.Printf("\r%d\n", n)
+	}
+	if err != nil {
+		fmt.Println(err)
+		return subcommands.ExitFailure
+	}
+	return subcommands.ExitSuccess
+}
+
+// staticFile is used to walk the file trees and do the right thing for the destination directory: create
+// subdirectories, link files, render HTML files.
+func staticFile(path, dir string, info fs.FileInfo, err error) error {
+	if err != nil {
+		return err
+	}
+	// skip hidden directories and files
+	if path != "." && strings.HasPrefix(filepath.Base(path), ".") {
+		if info.IsDir() {
+			return filepath.SkipDir
+		} else {
+			return nil
+		}
+	}
+	// skip backup files, avoid recursion
+	if strings.HasSuffix(path, "~") || strings.HasPrefix(path, dir) {
+		return nil
+	}
+	// recreate subdirectories
+	if info.IsDir() {
+		return os.Mkdir(filepath.Join(dir, path), 0755)
+	}
+	// render pages
+	if strings.HasSuffix(path, ".md") {
+		return staticPage(path, dir)
+	}
+	// remaining files are linked
+	return os.Link(path, filepath.Join(dir, path))
+}
+
+// staticPage takes the filename of a page (ending in ".md") and generates a static HTML page.
+func staticPage(path, dir string) error {
+	name := strings.TrimSuffix(path, ".md")
+	p, err := loadPage(filepath.ToSlash(name))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Cannot load %s: %s\n", name, err)
+		return err
+	}
+	p.handleTitle(true)
+	// instead of p.renderHtml() we do it all ourselves, appending ".html" to all the local links
+	parser, hashtags := wikiParser()
+	doc := markdown.Parse(p.Body, parser)
+	ast.WalkFunc(doc, staticLinks)
+	opts := html.RendererOptions{
+		Flags: html.CommonFlags,
+	}
+	renderer := html.NewRenderer(opts)
+	maybeUnsafeHTML := markdown.Render(doc, renderer)
+	p.Name = nameEscape(p.Name)
+	p.Html = unsafeBytes(maybeUnsafeHTML)
+	p.Language = language(p.plainText())
+	p.Hashtags = *hashtags
+	return p.write(filepath.Join(dir, name+".html"))
+}
+
+// staticLinks checks a node and if it is a link to a local page, it appends ".html" to the link destination.
+func staticLinks(node ast.Node, entering bool) ast.WalkStatus {
+	if entering {
+		switch v := node.(type) {
+		case *ast.Link:
+			// not an absolute URL, not a full URL, not a mailto: URI
+			if !bytes.HasPrefix(v.Destination, []byte("/")) &&
+				!bytes.Contains(v.Destination, []byte("://")) &&
+				!bytes.HasPrefix(v.Destination, []byte("mailto:")) {
+				// pointing to a page file (instead of an image file, for example).
+				fn, err := url.PathUnescape(string(v.Destination))
+				if err != nil {
+					return ast.GoToNext
+				}
+				_, err = os.Stat(fn + ".md")
+				if err != nil {
+					return ast.GoToNext
+				}
+				v.Destination = append(v.Destination, []byte(".html")...)
+			}
+		}
+	}
+	return ast.GoToNext
+}
+
+func (p *Page) write(destination string) error {
+	t := "static.html"
+	f, err := os.Create(destination)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Cannot create %s.html: %s\n", destination, err)
+		return err
+	}
+	err = templates.template[t].Execute(f, p)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Cannot execute %s template for %s: %s\n", t, destination, err)
+		return err
+	}
+	return nil
+}

static_cmd_test.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	"github.com/google/subcommands"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestStatusCmd(t *testing.T) {
+	cleanup(t, "testdata/static")
+	s := staticCli("testdata/static", true)
+	assert.Equal(t, subcommands.ExitSuccess, s)
+	// pages
+	assert.FileExists(t, "testdata/static/index.html")
+	assert.FileExists(t, "testdata/static/README.html")
+	// regular files
+	assert.FileExists(t, "testdata/static/static_cmd.go")
+	assert.FileExists(t, "testdata/static/static_cmd_test.go")
+}

templates.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	"html/template"
+	"io/fs"
+	"log"
+	"net/http"
+	"path"
+	"path/filepath"
+	"slices"
+	"strings"
+	"sync"
+)
+
+// templateFiles are the various HTML template files used. These files must exist in the root directory for Oddmu to be
+// able to generate HTML output. This always requires a template.
+var templateFiles = []string{"edit.html", "add.html", "view.html",
+	"diff.html", "search.html", "static.html", "upload.html", "feed.html"}
+
+// templates are the parsed HTML templates used. See renderTemplate and loadTemplates. Subdirectories may contain their
+// own templates which override the templates in the root directory. If so, they are not filepaths. Use
+// filepath.ToSlash() if necessary.
+type Template struct {
+	sync.RWMutex
+	template map[string]*template.Template
+}
+
+var templates Template
+
+// loadTemplates loads the templates. If templates have already been loaded, return immediately.
+func loadTemplates() {
+	if templates.template != nil {
+		return
+	}
+	templates.Lock()
+	defer templates.Unlock()
+	// walk the directory, load templates and add directories
+	templates.template = make(map[string]*template.Template)
+	filepath.Walk(".", loadTemplate)
+	log.Println(len(templates.template), "templates loaded")
+}
+
+// loadTemplate is used to walk the directory. It loads all the template files it finds, including the ones in
+// subdirectories. This is called with templates already locked.
+func loadTemplate(fp string, info fs.FileInfo, err error) error {
+	if err != nil {
+		return err
+	}
+	if strings.HasSuffix(fp, ".html") &&
+		slices.Contains(templateFiles, filepath.Base(fp)) {
+		t, err := template.ParseFiles(fp)
+		if err != nil {
+			log.Println("Cannot parse template:", fp, err)
+			// ignore error
+		} else {
+			// log.Println("Parse template:", path)
+			templates.template[filepath.ToSlash(fp)] = t
+		}
+	}
+	return nil
+}
+
+// updateTemplate checks whether this is a valid template file and if so, reloads it.
+func updateTemplate(fp string) {
+	if strings.HasSuffix(fp, ".html") &&
+		slices.Contains(templateFiles, filepath.Base(fp)) {
+		t, err := template.ParseFiles(fp)
+		if err != nil {
+			log.Println("Template:", fp, err)
+		} else {
+			templates.Lock()
+			defer templates.Unlock()
+			templates.template[filepath.ToSlash(fp)] = t
+			log.Println("Parse template:", fp)
+		}
+	}
+}
+
+// removeTemplate removes a template unless it's a root template because that would result in the site being unusable.
+func removeTemplate(fp string) {
+	if slices.Contains(templateFiles, filepath.Base(fp)) &&
+		filepath.Dir(fp) != "." {
+		templates.Lock()
+		defer templates.Unlock()
+		delete(templates.template, filepath.ToSlash(fp))
+		log.Println("Discard template:", fp)
+	}
+}
+
+// renderTemplate is the helper that is used to render the templates with data.
+// A template in the same directory is preferred, if it exists.
+func renderTemplate(w http.ResponseWriter, dir, tmpl string, data any) {
+	loadTemplates()
+	base := tmpl + ".html"
+	templates.RLock()
+	defer templates.RUnlock()
+	t := templates.template[path.Join(dir, base)]
+	if t == nil {
+		t = templates.template[base]
+	}
+	if t == nil {
+		log.Println("Template not found:", base)
+		http.Error(w, "Template not found", http.StatusInternalServerError)
+		return
+	}
+	err := t.Execute(w, data)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+}

templates_test.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"bytes"
+	"github.com/stretchr/testify/assert"
+	"mime/multipart"
+	"testing"
+)
+
+func TestTemplates(t *testing.T) {
+	cleanup(t, "testdata/templates")
+	// save a file to create the directory
+	p := &Page{Name: "testdata/templates/snow", Body: []byte(`# Snow
+
+A blob on the grass
+Covered in needles and dust
+Memories of cold
+`)}
+	p.save()
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/templates/snow", nil),
+		"Skip navigation")
+	// save a new view handler
+	html := "<body><h1>{{.Title}}</h1>{{.Html}}"
+	form := new(bytes.Buffer)
+	writer := multipart.NewWriter(form)
+	field, err := writer.CreateFormField("name")
+	assert.NoError(t, err)
+	field.Write([]byte("view.html"))
+	file, err := writer.CreateFormFile("file", "test.html")
+	assert.NoError(t, err)
+	n, err := file.Write([]byte(html))
+	assert.NoError(t, err)
+	assert.Equal(t, len(html), n)
+	writer.Close()
+	HTTPUploadLocation(t, makeHandler(dropHandler, false), "/drop/testdata/templates/", writer.FormDataContentType(), form)
+	assert.FileExists(t, "view.html", "original view.html still exists")
+	assert.FileExists(t, "testdata/templates/view.html", "new view.html also exists")
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, false), "GET", "/view/testdata/templates/view.html", nil),
+		html)
+	// verify that it works
+	body := assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/templates/snow", nil)
+	assert.Contains(t, body, "<h1>Snow</h1>")
+	assert.NotContains(t, body, "Skip")
+	// verify that the top level still uses the old template
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/index", nil),
+		"Skip navigation")
+}

tokenizer.go

@@ -0,0 +1,95 @@
+package main
+
+import (
+	"bytes"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+// lowercaseFilter returns a slice of lower case tokens.
+func lowercaseFilter(tokens []string) []string {
+	r := make([]string, len(tokens))
+	for i, token := range tokens {
+		r[i] = strings.ToLower(token)
+	}
+	return r
+}
+
+// tokenizeWithPredicates returns a slice of tokens for the given
+// text, including punctuation. Use this to begin tokenizing the query
+// string.
+func tokenizeOnWhitespace(q string) []string {
+	return strings.Fields(q)
+}
+
+// predicateFilter returns two slices of tokens: the first with
+// predicates, the other without predicates. Use this for query
+// string tokens.
+func predicateFilter(tokens []string) ([]string, []string) {
+	with := make([]string, 0)
+	without := make([]string, 0)
+	for _, token := range tokens {
+		if strings.Contains(token, ":") {
+			with = append(with, token)
+		} else {
+			without = append(without, token)
+		}
+	}
+	return with, without
+}
+
+// predicatesAndTokens returns two slices of tokens: the first with
+// predicates, the other without predicates, all of them lower case.
+// Use this for query strings.
+func predicatesAndTokens(q string) ([]string, []string) {
+	tokens := tokenizeOnWhitespace(q)
+	tokens = lowercaseFilter(tokens)
+	return predicateFilter(tokens)
+}
+
+// noPredicateFilter returns a slice of tokens: the predicates without
+// the predicate, and all the others. That is: "foo:bar baz" is turned
+// into ["bar", "baz"] and the predicate "foo:" is dropped.
+func noPredicateFilter(tokens []string) []string {
+	r := make([]string, 0)
+	for _, token := range tokens {
+		parts := strings.Split(token, ":")
+		r = append(r, parts[len(parts)-1])
+	}
+	return r
+}
+
+// highlightTokens returns the tokens to highlight, including title
+// predicates.
+func highlightTokens(q string) []string {
+	tokens := tokenizeOnWhitespace(q)
+	tokens = lowercaseFilter(tokens)
+	return noPredicateFilter(tokens)
+}
+
+// hashtags returns a slice of hashtags. Use this to extract hashtags
+// from a page body.
+func hashtags(s []byte) []string {
+	hashtags := make([]string, 0)
+	for {
+		i := bytes.IndexRune(s, '#')
+		if i == -1 {
+			return hashtags
+		}
+		from := i
+		i++
+		for {
+			r, n := utf8.DecodeRune(s[i:])
+			if n > 0 && (unicode.IsLetter(r) || unicode.IsNumber(r) || r == '_') {
+				i += n
+			} else {
+				break
+			}
+		}
+		if i > from+1 { // not just "#"
+			hashtags = append(hashtags, string(bytes.ToLower(s[from:i])))
+		}
+		s = s[i:]
+	}
+}

tokenizer_test.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestHashtags(t *testing.T) {
+	assert.EqualValues(t, []string{"#truth"}, hashtags([]byte("This is boring. #Truth")), "hashtags")
+}
+
+func TestTokensAndPredicates(t *testing.T) {
+	predicates, terms := predicatesAndTokens("foo title:bar")
+	assert.EqualValues(t, []string{"foo"}, terms)
+	assert.EqualValues(t, []string{"title:bar"}, predicates)
+}

upload.html

@@ -6,15 +6,40 @@
     <meta name="viewport" content="width=device-width">
     <title>Upload File</title>
     <style>
-html { max-width: 70ch; padding: 2ch; margin: auto; color: #111; background: #ffe; }
+html { max-width: 70ch; padding: 2ch; margin: auto; color: #111; background-color: #ffe; }
+body { hyphens: auto; }
 form, textarea { width: 100%; }
+label { display: inline-block; width: 20ch }
+.last { max-width: 20% }
     </style>
   </head>
-  <body>
+  <body lang="en">
     <h1>Upload File</h1>
-    <form action="/drop/{{.}}" method="POST" enctype="multipart/form-data">
-      <input type="text" name="name" placeholder="image.jpg" autofocus required>
-      <p><input type="file" name="file" required>
+    {{if ne .Last ""}}
+    <p>Previous upload: <a href="/view/{{.Last}}">{{.Last}}</a></p>
+    {{if .Image}}
+    <p><img class="last" src="/view/{{.Last}}"></p>
+    {{end}}
+    {{end}}
+    <form action="/drop/{{.Dir}}" method="POST" enctype="multipart/form-data">
+      <p>When uploading pictures from a phone, its filename is going to be something cryptic like IMG_1234.JPG.
+        Please provide your own filename. End the filename with "-1" to auto-increment.
+      <p><label for="text">Filename to use:</label>
+        <input id="text" name="name" value="{{.Name}}" type="text" placeholder="image-1.jpg" autofocus required>
+      <p>If the uploaded file is a picture from a phone, it is going to be too big for your site.
+        Sadly, resizing only works for JPG and PNG files. Luckily, most pictures from a phone camera are JPG images.
+        Feel free to specify a max width of 1200 pixels, for example.
+      <p><label for="maxwidth">Max width:</label>
+        <input id="maxwidth" name="maxwidth" value="{{.MaxWidth}}" type="number" min="10" placeholder="1200">
+      <p>If the uploaded file is a JPEG-encoded picture, like most pictures from a phone, you can specify a quality.
+        Typically, a quality of 60 is not too bad and a quality of 90 is more than enough.
+      <p><label for="quality">Quality:</label>
+        <input id="quality" name="quality" value="{{.Quality}}" type="number" min="1" max="99" placeholder="75">
+      <p>Finally, pick the file or photo to upload.
+        Picture metadata is only removed if the picture gets resized.
+        Providing a new max width is recommended for all pictures.
+      <p><label for="file">Pick file to upload:</label>
+        <input type="file" name="file" required>
       <p><input type="submit" value="Save">
         <a href="/view/index"><button type="button">Cancel</button></a></p>
     </form>

upload_drop.go

@@ -1,56 +1,195 @@
 package main
 
 import (
+	"github.com/anthonynsimon/bild/imgio"
+	"github.com/anthonynsimon/bild/transform"
+	"github.com/bashdrew/goheif"
+	"image/jpeg"
+	"image/png"
 	"io"
+	"log"
 	"net/http"
+	"net/url"
 	"os"
 	"path"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
 )
 
-// uploadHandler uses the "upload.html" template to enable uploads.
-// The file is saved using the saveUploadHandler.
-func uploadHandler(w http.ResponseWriter, r *http.Request, dir string) {
-	renderTemplate(w, "upload", dir)
+type Upload struct {
+	Dir      string
+	Name     string
+	Last     string
+	Image    bool
+	MaxWidth string
+	Quality  string
 }
 
-// dropHandler takes the "name" form field and the "file" form
-// file and saves the file under the given name. The browser is
-// redirected to the view of that file.
+var lastRe = regexp.MustCompile(`^(.*)([0-9]+)(.*)$`)
+
+// uploadHandler uses the "upload.html" template to enable uploads. The file is saved using the dropHandler. URL
+// parameters are used to copy name, maxwidth and quality from the previous upload. If the previous name contains a
+// number, this is incremented by one.
+func uploadHandler(w http.ResponseWriter, r *http.Request, dir string) {
+	data := &Upload{Dir: dir}
+	maxwidth := r.FormValue("maxwidth")
+	if maxwidth != "" {
+		data.MaxWidth = maxwidth
+	}
+	quality := r.FormValue("quality")
+	if quality != "" {
+		data.Quality = quality
+	}
+	name := r.FormValue("filename")
+	if name != "" {
+		data.Name = name
+	} else if last := r.FormValue("last"); last != "" {
+		ext := strings.ToLower(filepath.Ext(last))
+		switch ext {
+		case ".png", ".jpg", ".jpeg":
+			data.Image = true
+		}
+		data.Last = path.Join(dir, last)
+		m := lastRe.FindStringSubmatch(last)
+		if m != nil {
+			n, err := strconv.Atoi(m[2])
+			if err == nil {
+				data.Name = m[1] + strconv.Itoa(n+1) + m[3]
+			}
+		}
+	}
+	renderTemplate(w, dir, "upload", data)
+}
+
+// dropHandler takes the "name" form field and the "file" form file and saves the file under the given name. The browser
+// is redirected to the view of that file. Some errors are for the users and some are for users and the admins. Those
+// later errors are printed, too.
 func dropHandler(w http.ResponseWriter, r *http.Request, dir string) {
-	d := path.Dir(dir)
+	d := filepath.Dir(filepath.FromSlash(dir))
 	// ensure the directory exists
 	fi, err := os.Stat(d)
 	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
+		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
 	if !fi.IsDir() {
-		http.Error(w, "file exists", http.StatusInternalServerError)
+		http.Error(w, "directory does not exist", http.StatusBadRequest)
+		return
+	}
+	data := url.Values{}
+	name := r.FormValue("name")
+	data.Set("last", name)
+	filename := filepath.Base(name)
+	// no overwriting of hidden files or adding subdirectories
+	if strings.HasPrefix(filename, ".") || filepath.Dir(name) != "." {
+		http.Error(w, "no filename", http.StatusForbidden)
 		return
 	}
-	filename := r.FormValue("name")
 	file, _, err := r.FormFile("file")
 	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
+		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
 	defer file.Close()
-	// backup an existing file with the same name
-	_, err = os.Stat(filename)
+	path := filepath.Join(d, filename)
+	watches.ignore(path)
+	err = backup(path)
 	if err != nil {
-		os.Rename(filename, filename + "~")
+		log.Println(err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
 	}
-	// create the new file
-	dst, err := os.Create(d + "/" + filename)
+	dst, err := os.Create(path)
 	if err != nil {
-            http.Error(w, err.Error(), http.StatusInternalServerError)
-            return
-        }
+		log.Println(err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
 	defer dst.Close()
-	if _, err := io.Copy(dst, file); err != nil {
-            http.Error(w, err.Error(), http.StatusInternalServerError)
-            return
-        }
-	http.Redirect(w, r, "/view/"+filename, http.StatusFound)
+	// if a resize was requested
+	maxwidth := r.FormValue("maxwidth")
+	if len(maxwidth) > 0 {
+		mw, err := strconv.Atoi(maxwidth)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		data.Add("maxwidth", maxwidth)
+		// determine how the file will be written
+		ext := strings.ToLower(filepath.Ext(path))
+		var encoder imgio.Encoder
+		switch ext {
+		case ".png":
+			encoder = imgio.PNGEncoder()
+		case ".jpg", ".jpeg":
+			q := jpeg.DefaultQuality
+			quality := r.FormValue("quality")
+			if len(quality) > 0 {
+				q, err = strconv.Atoi(quality)
+				if err != nil {
+					http.Error(w, err.Error(), http.StatusBadRequest)
+					return
+				}
+				data.Add("quality", quality)
+			}
+			encoder = imgio.JPEGEncoder(q)
+		default:
+			http.Error(w, "Resizing images requires a .png, .jpg or .jpeg extension for the filename", http.StatusBadRequest)
+			return
+		}
+		// try and decode the data in various formats
+		img, err := jpeg.Decode(file)
+		if err != nil {
+			img, err = png.Decode(file)
+		}
+		if err != nil {
+			img, err = goheif.Decode(file)
+		}
+		if err != nil {
+			http.Error(w, "The image could not be decoded (only PNG, JPG and HEIC formats are supported for resizing)", http.StatusBadRequest)
+			return
+		}
+		rect := img.Bounds()
+		width := rect.Max.X - rect.Min.X
+		if width > mw {
+			height := (rect.Max.Y - rect.Min.Y) * mw / width
+			img = transform.Resize(img, mw, height, transform.Linear)
+			if err := imgio.Save(path, img, encoder); err != nil {
+				log.Println(err)
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+		} else {
+			http.Error(w, "The file is too small for this", http.StatusBadRequest)
+			return
+		}
+	} else {
+		// just copy the bytes
+		n, err := io.Copy(dst, file)
+		if err != nil {
+			log.Println(err)
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		// if zero bytes were copied, delete the file instead
+		if n == 0 {
+			err := os.Remove(path)
+			if err != nil {
+				log.Println(err)
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			log.Println("Delete", path)
+		}
+	}
+	username, _, ok := r.BasicAuth()
+	if ok {
+		log.Println("Save", path, "by", username)
+	} else {
+		log.Println("Save", path)
+	}
+	updateTemplate(path)
+	http.Redirect(w, r, "/upload/"+dir+"?"+data.Encode(), http.StatusFound)
 }
-

upload_drop_test.go

@@ -3,34 +3,176 @@ package main
 import (
 	"bytes"
 	"github.com/stretchr/testify/assert"
+	"image"
+	"image/jpeg"
+	"image/png"
 	"mime/multipart"
+	"net/url"
 	"os"
-	"regexp"
 	"testing"
 )
 
-// wipes testdata
 func TestUpload(t *testing.T) {
-	_ = os.RemoveAll("testdata")
+	cleanup(t, "testdata/files")
 	// for uploads, the directory is not created automatically
-	os.MkdirAll("testdata", 0755)
-	assert.HTTPStatusCode(t, makeHandler(uploadHandler, false), "GET", "/upload/", nil, 200)
+	os.MkdirAll("testdata/files", 0755)
+	assert.HTTPStatusCode(t, makeHandler(uploadHandler, false), "GET", "/upload/testdata/files/", nil, 200)
 	form := new(bytes.Buffer)
 	writer := multipart.NewWriter(form)
 	field, err := writer.CreateFormField("name")
 	assert.NoError(t, err)
-	_, err = field.Write([]byte("testdata/ok.txt"))
+	_, err = field.Write([]byte("ok.txt"))
 	assert.NoError(t, err)
-	file, err := writer.CreateFormFile("file", "example.txt");
+	file, err := writer.CreateFormFile("file", "example.txt")
+	assert.NoError(t, err)
+	_, err = file.Write([]byte("Hello!"))
 	assert.NoError(t, err)
-	file.Write([]byte("Hello!"))
 	err = writer.Close()
 	assert.NoError(t, err)
-	HTTPUploadAndRedirectTo(t, makeHandler(dropHandler, false), "/drop/",
-		writer.FormDataContentType(), form, "/view/testdata/ok.txt")
-	assert.Regexp(t, regexp.MustCompile("Hello!"),
-		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/ok.txt", nil))
-	t.Cleanup(func() {
-		_ = os.RemoveAll("testdata")
-	})
+	HTTPUploadAndRedirectTo(t, makeHandler(dropHandler, false), "/drop/testdata/files/",
+		writer.FormDataContentType(), form, "/upload/testdata/files/?last=ok.txt")
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/files/ok.txt", nil),
+		"Hello!")
+}
+
+func TestUploadPng(t *testing.T) {
+	cleanup(t, "testdata/png")
+	// for uploads, the directory is not created automatically
+	os.MkdirAll("testdata/png", 0755)
+	form := new(bytes.Buffer)
+	writer := multipart.NewWriter(form)
+	field, _ := writer.CreateFormField("name")
+	field.Write([]byte("ok.png"))
+	file, _ := writer.CreateFormFile("file", "ok.png")
+	img := image.NewRGBA(image.Rect(0, 0, 20, 20))
+	png.Encode(file, img)
+	writer.Close()
+	HTTPUploadAndRedirectTo(t, makeHandler(dropHandler, false), "/drop/testdata/png/",
+		writer.FormDataContentType(), form, "/upload/testdata/png/?last=ok.png")
+}
+
+func TestUploadJpg(t *testing.T) {
+	cleanup(t, "testdata/jpg")
+	// for uploads, the directory is not created automatically
+	os.MkdirAll("testdata/jpg", 0755)
+	form := new(bytes.Buffer)
+	writer := multipart.NewWriter(form)
+	field, _ := writer.CreateFormField("name")
+	field.Write([]byte("ok.jpg"))
+	file, _ := writer.CreateFormFile("file", "ok.jpg")
+	img := image.NewRGBA(image.Rect(0, 0, 20, 20))
+	jpeg.Encode(file, img, &jpeg.Options{Quality: 90})
+	writer.Close()
+	HTTPUploadAndRedirectTo(t, makeHandler(dropHandler, false), "/drop/testdata/jpg/",
+		writer.FormDataContentType(), form, "/upload/testdata/jpg/?last=ok.jpg")
+}
+
+func TestDeleteFile(t *testing.T) {
+	cleanup(t, "testdata/delete")
+	os.MkdirAll("testdata/delete", 0755)
+	assert.NoError(t, os.WriteFile("testdata/delete/nothing.txt", []byte(`# Nothing
+
+I pause and look up
+Look at the mountains you say
+What happened just now?`), 0644))
+	// check that it worked
+	assert.FileExists(t, "testdata/delete/nothing.txt")
+	// delete it by upload a zero byte file
+	form := new(bytes.Buffer)
+	writer := multipart.NewWriter(form)
+	field, _ := writer.CreateFormField("name")
+	field.Write([]byte("nothing.txt"))
+	file, _ := writer.CreateFormFile("file", "test.txt")
+	file.Write([]byte(""))
+	writer.Close()
+	HTTPUploadAndRedirectTo(t, makeHandler(dropHandler, false), "/drop/testdata/delete/",
+		writer.FormDataContentType(), form, "/upload/testdata/delete/?last=nothing.txt")
+	// check that it worked
+	assert.NoFileExists(t, "testdata/delete/nothing.txt")
+}
+
+func TestUploadMultiple(t *testing.T) {
+	cleanup(t, "testdata/multi")
+	p := &Page{Name: "testdata/multi/culture", Body: []byte(`# Culture
+
+The road has walls
+Iron gates and tree tops
+But here: jasmin dreams`)}
+	p.save()
+
+	// check location for upload
+	body := assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/multi/culture", nil)
+	assert.Contains(t, body, `href="/upload/testdata/multi/?filename=culture-1.jpg"`)
+
+	// check location for drop
+	body = assert.HTTPBody(makeHandler(uploadHandler, false), "GET", "/upload/testdata/multi/", nil)
+	assert.Contains(t, body, `action="/drop/testdata/multi/"`)
+
+	// actually do the upload
+	form := new(bytes.Buffer)
+	writer := multipart.NewWriter(form)
+	field, _ := writer.CreateFormField("name")
+	field.Write([]byte("2023-10-02-hike-1.jpg"))
+	field, _ = writer.CreateFormField("maxwidth")
+	field.Write([]byte("15"))
+	field, _ = writer.CreateFormField("quality")
+	field.Write([]byte("50"))
+	file, _ := writer.CreateFormFile("file", "ok.jpg")
+	img := image.NewRGBA(image.Rect(0, 0, 20, 20))
+	jpeg.Encode(file, img, &jpeg.Options{Quality: 90})
+	writer.Close()
+	location := HTTPUploadLocation(t, makeHandler(dropHandler, false), "/drop/testdata/multi/",
+		writer.FormDataContentType(), form)
+	url, _ := url.Parse(location)
+	assert.Equal(t, "/upload/testdata/multi/", url.Path, "Redirect to upload location")
+	values := url.Query()
+	assert.Equal(t, "2023-10-02-hike-1.jpg", values.Get("last"))
+	assert.Equal(t, "15", values.Get("maxwidth"))
+	assert.Equal(t, "50", values.Get("quality"))
+
+	// check the result page
+	body = assert.HTTPBody(makeHandler(uploadHandler, false), "GET", url.Path, values)
+	assert.Contains(t, body, `value="2023-10-02-hike-2.jpg"`)
+	assert.Contains(t, body, `value="15"`)
+	assert.Contains(t, body, `value="50"`)
+	assert.Contains(t, body, `src="/view/testdata/multi/2023-10-02-hike-1.jpg"`)
+}
+
+func TestUploadDir(t *testing.T) {
+	cleanup(t, "testdata/dir")
+	p := &Page{Name: "testdata/dir/test", Body: []byte(`# Test
+
+Eyes are an abyss
+We stare into each other
+There is no answer`)}
+	p.save()
+
+	// check location for upload
+	body := assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/dir/test", nil)
+	assert.Contains(t, body, `href="/upload/testdata/dir/?filename=test-1.jpg"`)
+
+	// check location for drop
+	body = assert.HTTPBody(makeHandler(uploadHandler, false), "GET", "/upload/testdata/dir/", nil)
+	assert.Contains(t, body, `action="/drop/testdata/dir/"`)
+
+	// actually do the upload
+	form := new(bytes.Buffer)
+	writer := multipart.NewWriter(form)
+	field, _ := writer.CreateFormField("name")
+	field.Write([]byte("test.jpg"))
+	file, _ := writer.CreateFormFile("file", "ok.jpg")
+	img := image.NewRGBA(image.Rect(0, 0, 20, 20))
+	jpeg.Encode(file, img, &jpeg.Options{Quality: 90})
+	writer.Close()
+	location := HTTPUploadLocation(t, makeHandler(dropHandler, false), "/drop/testdata/dir/",
+		writer.FormDataContentType(), form)
+	url, _ := url.Parse(location)
+	assert.Equal(t, "/upload/testdata/dir/", url.Path, "Redirect to upload location")
+	values := url.Query()
+	assert.Equal(t, "test.jpg", values.Get("last"))
+
+	// check the result page
+	body = assert.HTTPBody(makeHandler(uploadHandler, false), "GET", url.Path, values)
+	assert.Contains(t, body, `src="/view/testdata/dir/test.jpg"`)
 }

version_cmd.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"github.com/google/subcommands"
+	"io"
+	"os"
+	"runtime/debug"
+)
+
+type versionCmd struct {
+}
+
+func (cmd *versionCmd) SetFlags(f *flag.FlagSet) {
+}
+
+func (*versionCmd) Name() string     { return "version" }
+func (*versionCmd) Synopsis() string { return "report build information" }
+func (*versionCmd) Usage() string {
+	return `version:
+  Report all the debug information about this build.
+`
+}
+
+func (cmd *versionCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	return versionCli(os.Stdout, f.Args())
+}
+
+func versionCli(w io.Writer, args []string) subcommands.ExitStatus {
+	if len(args) > 0 {
+		fmt.Fprintln(os.Stderr, "Version takes no arguments.")
+		return subcommands.ExitFailure
+	}
+	info, _ := debug.ReadBuildInfo()
+	fmt.Println(info)
+	return subcommands.ExitSuccess
+}

version_cmd_test.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"bytes"
+	"github.com/google/subcommands"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestVersionCmd(t *testing.T) {
+	b := new(bytes.Buffer)
+	s := versionCli(b, nil)
+	assert.Equal(t, subcommands.ExitSuccess, s)
+	assert.Contains(t, "vcs.revision", b.String())
+}

view.go

@@ -1,32 +1,126 @@
 package main
 
-import(
+import (
+	"io"
 	"net/http"
 	"os"
+	urlpath "path"
+	"path/filepath"
+	"strings"
+	"time"
 )
 
-// rootHandler just redirects to /view/index.
+// rootHandler just redirects to /view/index. The root handler handles requests to the root path, and – implicity – all
+// unhandled request. Thus, if the URL path is not "/", return a 404 NOT FOUND response.
 func rootHandler(w http.ResponseWriter, r *http.Request) {
-	http.Redirect(w, r, "/view/index", http.StatusFound)
+	if r.URL.Path != "/" {
+		http.NotFound(w, r)
+	} else {
+		http.Redirect(w, r, "/view/index", http.StatusFound)
+	}
 }
 
-// viewHandler serves existing files (including markdown files with
-// the .md extension). If the requested file does not exist, a page
-// with the same name is loaded. This means adding the .md extension
-// and using the "view.html" template to render the HTML. Both
-// attempts fail, the browser is redirected to an edit page.
-func viewHandler(w http.ResponseWriter, r *http.Request, name string) {
-	body, err := os.ReadFile(name)
+// viewHandler serves pages. If the requested URL ends in ".rss" and the corresponding file ending with ".md" exists, a
+// feed is generated and the "feed.html" template is used (it is used to generate a RSS 2.0 feed, even if the extension
+// is ".html"). If the requested URL maps to a page name, the corresponding file (by appending ".md") is loaded and
+// served using the "view.html" template. If the requested URL maps to an existing file, it is served (you can therefore
+// request the ".md" files directly). If the requested URL maps to a directory, the browser is redirected to the index
+// page. If none of the above, the browser is redirected to an edit page.
+//
+// Uploading files ending in ".rss" does not prevent RSS feed generation.
+//
+// Caching: a 304 NOT MODIFIED is returned if the request has an If-Modified-Since header that matches the file's
+// modification time, truncated to one second. Truncation is required because the file's modtime has sub-second
+// precision and the HTTP timestamp for the Last-Modified header has not.
+func viewHandler(w http.ResponseWriter, r *http.Request, path string) {
+	const (
+		unknown = iota
+		file
+		page
+		rss
+		dir
+	)
+	t := unknown
+	if strings.HasSuffix(path, ".rss") {
+		path = path[:len(path)-4]
+		t = rss
+	}
+	fp := filepath.FromSlash(path)
+	fi, err := os.Stat(fp+".md")
 	if err == nil {
-		w.Write(body)
+		if fi.IsDir() {
+			t = dir // directory ending in ".md"
+		} else if t == unknown {
+			t = page
+		}
+		// otherwise t == rss
+	} else {
+		if fp == "" {
+			fp = "." // make sure Stat works
+		}
+		fi, err = os.Stat(fp)
+		if err == nil {
+			if fi.IsDir() {
+				t = dir
+			} else {
+				t = file
+			}
+		}
+	}
+	// if nothing was found, offer to create it
+	if t == unknown {
+		http.Redirect(w, r, "/edit/"+path, http.StatusFound)
 		return
 	}
-	p, err := loadPage(name)
-	if err == nil {
-		p.handleTitle(true)
-		p.renderHtml()
-		renderTemplate(w, "view", p)
+	// directories are redirected to the index page
+	if t == dir {
+		http.Redirect(w, r, urlpath.Join("/view", path, "index"), http.StatusFound)
 		return
 	}
-	http.Redirect(w, r, "/edit/"+name, http.StatusFound)
+	// if the page has not been modified, return (file, rss or page)
+	h, ok := r.Header["If-Modified-Since"]
+	if ok {
+		ti, err := http.ParseTime(h[0])
+		if err == nil && !fi.ModTime().Truncate(time.Second).After(ti) {
+			w.WriteHeader(http.StatusNotModified)
+			return
+		}
+	}
+	// if only the headers were requested, return
+	w.Header().Set("Last-Modified", fi.ModTime().UTC().Format(http.TimeFormat))
+	if r.Method == http.MethodHead {
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+	if t == file {
+		file, err := os.Open(fp)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		_, err = io.Copy(w, file)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		return
+	}
+	p, err := loadPage(path)
+	if err != nil {
+		if t == rss {
+			http.Error(w, err.Error(), http.StatusNotFound)
+			return
+		}
+		http.Redirect(w, r, "/edit/"+path, http.StatusFound)
+		return
+	}
+	p.handleTitle(true)
+	if t == rss {
+		it := feed(p, fi.ModTime())
+		w.Write([]byte(`<?xml version="1.0" encoding="UTF-8"?>`))
+		renderTemplate(w, p.Dir(), "feed", it)
+		return
+	}
+	p.renderHtml()
+	renderTemplate(w, p.Dir(), "view", p)
 }

view.html

@@ -1,29 +1,33 @@
 <!DOCTYPE html>
-<html>
+<html lang="{{.Language}}">
   <head>
     <meta charset="utf-8">
     <meta name="format-detection" content="telephone=no">
     <meta name="viewport" content="width=device-width">
     <title>{{.Title}}</title>
     <style>
-html { max-width: 65ch; padding: 1ch; margin: auto; color: #111; background: #ffe; }
+html { max-width: 70ch; padding: 1ch; margin: auto; color: #111; background-color: #ffe; }
 body { hyphens: auto; }
 header a { margin-right: 1ch; }
 form { display: inline-block; }
+input#search { width: 12ch; }
+button { background-color: #eee; color: inherit; border-radius: 4px; border-width: 1px; }
 footer { border-top: 1px solid #888 }
 img { max-width: 100%; }
     </style>
   </head>
-  <body lang="{{.Language}}">
+  <body>
     <header>
       <a href="#main">Skip navigation</a>
-      <a href="/view/index">Home</a>
-      <a href="/edit/{{.Name}}">Edit</a>
-      <a href="/add/{{.Name}}">Add</a>
-      <a href="/upload/{{.Dir}}">Upload</a>
-      <form role="search" action="/search" method="GET">
-        <input type="text" spellcheck="false" name="q" required>
-        <button>Search</button>
+      <a href="index">Home</a>
+      <a href="/edit/{{.Name}}" accesskey="e">Edit</a>
+      <a href="/add/{{.Name}}" accesskey="a">Add</a>
+      <a href="/diff/{{.Name}}" accesskey="d">Diff</a>
+      <a href="/upload/{{.Dir}}?filename={{.Base}}-1.jpg" accesskey="u">Upload</a>
+      <form role="search" action="/search/{{.Dir}}" method="GET">
+        <label for="search">Search:</label>
+        <input id="search" type="text" spellcheck="false" name="q" accesskey="f" placeholder="term #tag title:term blog:true" required>
+        <button>Go</button>
       </form>
     </header>
     <main id="main">
@@ -32,7 +36,7 @@ img { max-width: 100%; }
     </main>
     <footer>
       <address>
-        Comments? Send mail to Alex Schroeder <<a href="mailto:alex@alexschroeder.ch">alex@alexschroeder.ch</a>>
+        Comments? Send mail to Your Name <<a href="mailto:you@example.org">you@example.org</a>>
       </address>
     </footer>
   </body>

view_test.go

@@ -2,8 +2,9 @@ package main
 
 import (
 	"github.com/stretchr/testify/assert"
+	"net/http"
+	"net/url"
 	"os"
-	"regexp"
 	"testing"
 )
 
@@ -13,42 +14,129 @@ func TestRootHandler(t *testing.T) {
 
 // relies on index.md in the current directory!
 func TestViewHandler(t *testing.T) {
-	assert.Regexp(t, regexp.MustCompile("Welcome to Oddµ"),
-		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/index", nil))
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/index", nil),
+		"Welcome to Oddµ")
+}
+
+func TestViewHandlerDir(t *testing.T) {
+	cleanup(t, "testdata/dir")
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/", nil, "/view/index")
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata", nil, "/view/testdata/index")
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata/", nil, "/view/testdata/index")
+	assert.NoError(t, os.Mkdir("testdata/dir", 0755))
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata/dir", nil, "/view/testdata/dir/index")
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata/dir/", nil, "/view/testdata/dir/index")
+	assert.NoError(t, os.Mkdir("testdata/dir/dir", 0755))
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata/dir", nil, "/view/testdata/dir/index")
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata/dir/", nil, "/view/testdata/dir/index")
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata/dir/dir", nil, "/view/testdata/dir/dir/index")
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata/dir/dir/", nil, "/view/testdata/dir/dir/index")
+	assert.NoError(t, os.WriteFile("testdata/dir/dir.md", []byte(`# Blackbird
+
+The oven hums and
+the music plays, coffee smells
+blackbirds sing outside
+`), 0644))
+	assert.Contains(t, assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/dir/dir", nil), "<h1>Blackbird</h1>")
+	assert.Contains(t, assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/dir/dir.md", nil), "# Blackbird")
+	HTTPRedirectTo(t, makeHandler(viewHandler, true), "GET", "/view/testdata/dir/dir/", nil, "/view/testdata/dir/dir/index")
+}
+
+// relies on index.md in the current directory!
+func TestViewHandlerWithId(t *testing.T) {
+	data := make(url.Values)
+	data.Set("id", "index")
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/", data),
+		"Welcome to Oddµ")
 }
 
-// wipes testdata
 func TestPageTitleWithAmp(t *testing.T) {
-	_ = os.RemoveAll("testdata")
+	cleanup(t, "testdata/amp")
 
-	p := &Page{Name: "testdata/Rock & Roll", Body: []byte("Dancing")}
+	p := &Page{Name: "testdata/amp/Rock & Roll", Body: []byte("Dancing")}
 	p.save()
 
-	assert.Regexp(t, regexp.MustCompile("Rock &amp; Roll"),
-		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/Rock%20%26%20Roll", nil))
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/amp/Rock%20%26%20Roll", nil),
+		"Rock &amp; Roll")
 
-	p = &Page{Name: "testdata/Rock & Roll", Body: []byte("# Sex & Drugs & Rock'n'Roll\nOh no!")}
+	p = &Page{Name: "testdata/amp/Rock & Roll", Body: []byte("# Sex & Drugs & Rock'n'Roll\nOh no!")}
 	p.save()
 
-	assert.Regexp(t, regexp.MustCompile("Sex &amp; Drugs"),
-		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/Rock%20%26%20Roll", nil))
-
-	t.Cleanup(func() {
-		_ = os.RemoveAll("testdata")
-	})
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/amp/Rock%20%26%20Roll", nil),
+		"Sex &amp; Drugs")
 }
 
 func TestPageTitleWithQuestionMark(t *testing.T) {
-	_ = os.RemoveAll("testdata")
+	cleanup(t, "testdata/q")
 
-	p := &Page{Name: "testdata/How about no?", Body: []byte("No means no")}
+	p := &Page{Name: "testdata/q/How about no?", Body: []byte("No means no")}
 	p.save()
 
-	body := assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/How%20about%20no%3F", nil)
+	body := assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/q/How%20about%20no%3F", nil)
 	assert.Contains(t, body, "No means no")
-	assert.Contains(t, body, "<a href=\"/edit/testdata/How%20about%20no%3F\">Edit</a>")
-
-	t.Cleanup(func() {
-		_ = os.RemoveAll("testdata")
-	})
+	assert.Contains(t, body, "<a href=\"/edit/testdata/q/How%20about%20no%3F\" accesskey=\"e\">Edit</a>")
+}
+
+func TestFileLastModified(t *testing.T) {
+	cleanup(t, "testdata/file-mod")
+	assert.NoError(t, os.Mkdir("testdata/file-mod", 0755))
+	assert.NoError(t, os.WriteFile("testdata/file-mod/now.txt", []byte(`
+A spider sitting
+Unmoving and still
+In the autumn chill
+`), 0644))
+	fi, err := os.Stat("testdata/file-mod/now.txt")
+	assert.NoError(t, err)
+	h := makeHandler(viewHandler, true)
+	assert.Equal(t, []string{fi.ModTime().UTC().Format(http.TimeFormat)},
+		HTTPHeaders(h, "GET", "/view/testdata/file-mod/now.txt", nil, "Last-Modified"))
+	HTTPStatusCodeIfModifiedSince(t, h, "/view/testdata/file-mod/now.txt", fi.ModTime())
+}
+
+func TestForbidden(t *testing.T) {
+	assert.HTTPStatusCode(t, makeHandler(viewHandler, true), "GET", "/view/", nil, http.StatusFound)
+	assert.HTTPStatusCode(t, makeHandler(viewHandler, true), "GET", "/view/.", nil, http.StatusForbidden)
+	assert.HTTPStatusCode(t, makeHandler(viewHandler, true), "GET", "/view/.htaccess", nil, http.StatusForbidden)
+	assert.HTTPStatusCode(t, makeHandler(viewHandler, true), "GET", "/view/.git/description", nil, http.StatusForbidden)
+}
+
+func TestPageLastModified(t *testing.T) {
+	cleanup(t, "testdata/page-mod")
+	p := &Page{Name: "testdata/page-mod/now", Body: []byte(`
+The sky glows softly
+Sadly, the birds are quiet
+I like spring better
+`)}
+	p.save()
+	fi, err := os.Stat("testdata/page-mod/now.md")
+	assert.NoError(t, err)
+	h := makeHandler(viewHandler, true)
+	assert.Equal(t, []string{fi.ModTime().UTC().Format(http.TimeFormat)},
+		HTTPHeaders(h, "GET", "/view/testdata/page-mod/now", nil, "Last-Modified"))
+	HTTPStatusCodeIfModifiedSince(t, h, "/view/testdata/page-mod/now", fi.ModTime())
+}
+
+func TestPageHead(t *testing.T) {
+	cleanup(t, "testdata/head")
+	p := &Page{Name: "testdata/head/peace", Body: []byte(`
+No urgent typing
+No todos, no list, no queue.
+Just me and the birds.
+`)}
+	p.save()
+	fi, err := os.Stat("testdata/head/peace.md")
+	assert.NoError(t, err)
+	h := makeHandler(viewHandler, true)
+	assert.Equal(t, []string(nil),
+		HTTPHeaders(h, "HEAD", "/view/testdata/head/war", nil, "Last-Modified"))
+	assert.Equal(t, []string(nil),
+		HTTPHeaders(h, "GET", "/view/testdata/head/war", nil, "Last-Modified"))
+	assert.Equal(t, []string{fi.ModTime().UTC().Format(http.TimeFormat)},
+		HTTPHeaders(h, "HEAD", "/view/testdata/head/peace", nil, "Last-Modified"))
+	assert.Equal(t, "",
+		assert.HTTPBody(h, "HEAD", "/view/testdata/head/peace", nil))
 }

watch.go

@@ -0,0 +1,206 @@
+package main
+
+import (
+ 	"github.com/fsnotify/fsnotify"
+	"io/fs"
+ 	"log"
+	"os"
+	"path/filepath"
+ 	"slices"
+ 	"strings"
+ 	"sync"
+ 	"time"
+)
+
+// Watches holds a map and a mutex. The map contains the template names that have been requested and the exact time at
+// which they have been requested. Adding the same file multiple times, such as when the watch function sees multiple
+// Write events for the same file, the time keeps getting updated so that when the go routine runs, it only acts on
+// files that haven't been updated in the last second. The go routine is what forces us to use the RWMutex for the map.
+type Watches struct {
+ 	sync.RWMutex
+	ignores map[string]time.Time
+	files map[string]time.Time
+	watcher *fsnotify.Watcher
+}
+
+var watches Watches
+
+func init() {
+	watches.ignores = make(map[string]time.Time)
+	watches.files = make(map[string]time.Time)
+}
+
+// install initializes watches and installs watchers for all directories and subdirectories.
+func (w *Watches) install() (int, error) {
+	// create a watcher for the root directory and never close it
+	var err error
+	w.watcher, err = fsnotify.NewWatcher()
+	if err != nil {
+		log.Println("Creating a watcher for file changes:", err)
+		return 0, err
+	}
+	go w.watch()
+	err = filepath.Walk(".", w.add)
+	if err != nil {
+		return 0, err
+	}
+	return len(w.watcher.WatchList()), nil
+}
+
+// add installs a watch for every directory that isn't hidden. Note that the root directory (".") is not skipped.
+func (w *Watches) add(path string, info fs.FileInfo, err error) error {
+	if err != nil {
+		return err
+	}
+	if info.IsDir() {
+		if path != "." && strings.HasPrefix(filepath.Base(path), ".") {
+			return filepath.SkipDir
+		}
+		err := w.watcher.Add(path)
+		if err != nil {
+			log.Println("Cannot add watch:", path)
+			return err
+		}
+		// log.Println("Watching", path)
+	}
+	return nil
+}
+
+// watch reloads templates that have changed and reindexes fils that have changed. Since there can be multiple writes to
+// a file, there's a 1s delay before a file is actually handled. The reason is that writing a file can cause multiple
+// Write events and we don't want to keep reloading the template while it is being written. Instead, each Write event
+// adds an entry to the files map, or updates the file's time, and starts a go routine. Example: If a file gets three
+// consecutive Write events, the first two go routine invocations won't do anything, since the time kept getting
+// updated. Only the last invocation will act upon the event.
+func (w *Watches) watch() {
+	for {
+		select {
+		case err, ok := <-w.watcher.Errors:
+			if !ok {
+				return
+			}
+			log.Println("Watcher:", err)
+		case e, ok := <-w.watcher.Events:
+			if !ok {
+				return
+			}
+			w.watchHandle(e)
+		}
+	}
+}
+
+// watchHandle is called for every fsnotify.Event. It handles template updates, page updates (both on a 1s timer), and
+// the creation of pages and directories (immediately). Files and directories starting with a dot are skipped.
+// Incidentally, this also prevents rsync updates from generating activity ("stat ./.index.md.tTfPFg: no such file or
+// directory"). Note the painful details: If moving a file into a watched directory, a Create event is received. If a
+// new file is created in a watched directory, a Create event and one or more Write events is received.
+func (w *Watches) watchHandle(e fsnotify.Event) {
+	path := strings.TrimPrefix(e.Name, "./")
+	if strings.HasPrefix(filepath.Base(path), ".") {
+		return;
+	}
+	// log.Println(e)
+	w.Lock()
+	defer w.Unlock()
+	if e.Op.Has(fsnotify.Create | fsnotify.Write) &&
+		(strings.HasSuffix(path, ".html") &&
+			slices.Contains(templateFiles, filepath.Base(path)) ||
+			strings.HasSuffix(path, ".md")) {
+		w.files[path] = time.Now()
+		timer := time.NewTimer(time.Second)
+		go func() {
+			<-timer.C
+			w.Lock()
+			defer w.Unlock()
+			w.watchTimer(path)
+		}()
+	} else if e.Op.Has(fsnotify.Rename | fsnotify.Remove) {
+		w.watchDoRemove(path)
+	} else if e.Op.Has(fsnotify.Create) &&
+		!slices.Contains(w.watcher.WatchList(), path) {
+		fi, err := os.Stat(path)
+		if err != nil {
+			log.Println(err)
+		} else if fi.IsDir() {
+			log.Println("Add watch for", path)
+			w.watcher.Add(path)
+		}
+	}
+}
+
+// watchTimer checks if the file hasn't been updated in 1s and if so, it calls watchDoUpdate. If another write has
+// updated the file, do nothing because another watchTimer will run at the appropriate time and check again.
+func (w *Watches) watchTimer(path string) {
+	t, ok := w.files[path]
+	if ok && t.Add(time.Second).Before(time.Now().Add(time.Nanosecond)) {
+		delete(w.files, path)
+		w.watchDoUpdate(path)
+	}
+}
+
+// Do the right thing right now. For Create events such as directories being created or files being moved into a watched
+// directory, this is the right thing to do. When a file is being written to, watchHandle will have started a timer and
+// will call this function after 1s of no more writes. If, however, the path is in the ignores map, do nothing.
+func (w *Watches) watchDoUpdate(path string) {
+	_, ignored := w.ignores[path]
+	if ignored {
+		return
+	} else if strings.HasSuffix(path, ".html") {
+		updateTemplate(path)
+	} else if strings.HasSuffix(path, ".md") {
+		p, err := loadPage(path[:len(path)-3]) // page name without ".md"
+		if err != nil {
+			log.Println("Cannot load page", path)
+		} else {
+			log.Println("Update index for", path)
+			index.update(p)
+		}
+	} else if !slices.Contains(w.watcher.WatchList(), path) {
+		fi, err := os.Stat(path)
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		if fi.IsDir() {
+			log.Println("Add watch for", path)
+			w.watcher.Add(path)
+		}
+	}
+}
+
+// watchDoRemove removes files from the index or discards templates. If the path in question is in the ignores map, do
+// nothing.
+func (w *Watches) watchDoRemove(path string) {
+	_, ignored := w.ignores[path]
+	if ignored {
+		return
+	} else if strings.HasSuffix(path, ".html") {
+		removeTemplate(path)
+	} else if strings.HasSuffix(path, ".md") {
+		_, err := os.Stat(path)
+		if err == nil {
+			log.Println("Cannot remove existing page from the index", path)
+		} else {
+			log.Println("Deindex", path)
+			index.deletePageName(path[:len(path)-3]) // page name without ".md"
+		}
+	}
+}
+
+// ignore is before code that is known suspected save files and trigger watchHandle eventhough the code already handles
+// this. This is achieved by adding the path to the ignores map for 1s.
+func (w *Watches) ignore(path string) {
+	w.Lock()
+	defer w.Unlock()
+	w.ignores[path] = time.Now()
+	timer := time.NewTimer(time.Second)
+	go func() {
+		<-timer.C
+		w.Lock()
+		defer w.Unlock()
+		t := w.ignores[path]
+		if t.Add(time.Second).Before(time.Now().Add(time.Nanosecond)) {
+			delete(w.ignores, path)
+		}
+	}()
+}

watch_test.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"testing"
+ 	"time"
+)
+
+func TestWatchedPageUpdate(t *testing.T) {
+	dir := "testdata/watched-page"
+	path := dir + "/haiku.md"
+	cleanup(t, dir)
+	index.load()
+	watches.install()
+	assert.NoError(t, os.MkdirAll(dir, 0755))
+	time.Sleep(time.Millisecond)
+	assert.Contains(t, watches.watcher.WatchList(), dir)
+
+	haiku := []byte(`# Pine cones
+
+Soft steps on the trail
+Up and up in single file
+Who ate half a cone?`)
+	assert.NoError(t, os.WriteFile(path, haiku, 0644))
+
+	time.Sleep(time.Millisecond)
+
+	watches.RLock()
+	assert.Contains(t, watches.files, path)
+	watches.RUnlock()
+
+	watches.Lock()
+	watches.files[path] = watches.files[path].Add(-2 * time.Second)
+	watches.Unlock()
+
+	watches.watchTimer(path)
+
+	index.RLock()
+	assert.Contains(t, index.titles, path[:len(path)-3])
+	index.RUnlock()
+}
+
+func TestWatchedTemplateUpdate(t *testing.T) {
+	dir := "testdata/watched-template"
+	name := dir + "/raclette"
+	path := dir + "/view.html"
+	cleanup(t, dir)
+	index.load()
+	watches.install()
+	assert.NoError(t, os.MkdirAll(dir, 0755))
+
+	time.Sleep(time.Millisecond)
+
+	assert.Contains(t, watches.watcher.WatchList(), dir)
+
+	p := &Page{Name: name, Body: []byte(`# Raclette
+
+The heat element
+glows red and the cheese bubbles
+the smell is everywhere
+`)}
+	p.save()
+	assert.Contains(t,
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/watched-template/raclette", nil),
+		"Skip navigation")
+	
+	// save a new view handler directly
+	assert.NoError(t,
+		os.WriteFile(path,
+			[]byte("<body><h1>{{.Title}}</h1>{{.Html}}"),
+			0644))
+
+	time.Sleep(time.Millisecond)
+
+	watches.RLock()
+	assert.Contains(t, watches.files, path)
+	watches.RUnlock()
+
+	watches.Lock()
+	watches.files[path] = watches.files[path].Add(-2 * time.Second)
+	watches.Unlock()
+
+	watches.watchTimer(path)
+	
+	body := assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/" + name, nil)
+	assert.Contains(t, body, "<h1>Raclette</h1>") // page text is still there
+	assert.NotContains(t, body, "Skip") // but the header is not
+}

wiki.go

@@ -1,59 +1,69 @@
 package main
 
 import (
+	"context"
+	"flag"
 	"fmt"
-	"html/template"
+	"github.com/google/subcommands"
+	"io/fs"
+	"log"
+	"net"
 	"net/http"
 	"os"
 	"regexp"
+	"strings"
 )
 
-// Templates are parsed at startup.
-var templates = template.Must(
-	template.ParseFiles("edit.html", "add.html", "view.html",
-		"search.html", "upload.html"))
-
-// validPath is a regular expression where the second group matches a
-// page, so when the editHandler is called, a URL path of "/edit/foo"
-// results in the editHandler being called with title "foo". The
-// regular expression doesn't define the handlers (this happens in the
-// main function).
+// validPath is a regular expression where the second group matches a page, so when the editHandler is called, a URL
+// path of "/edit/foo" results in the editHandler being called with title "foo". The regular expression doesn't define
+// the handlers (this happens in the main function).
 var validPath = regexp.MustCompile("^/([^/]+)/(.*)$")
 
-// titleRegexp is a regular expression matching a level 1 header line
-// in a Markdown document. The first group matches the actual text and
-// is used to provide an title for pages. If no title exists in the
-// document, the page name is used instead.
+// titleRegexp is a regular expression matching a level 1 header line in a Markdown document. The first group matches
+// the actual text and is used to provide an title for pages. If no title exists in the document, the page name is used
+// instead.
 var titleRegexp = regexp.MustCompile("(?m)^#\\s*(.*)\n+")
 
-// renderTemplate is the helper that is used render the templates with
-// data.
-func renderTemplate(w http.ResponseWriter, tmpl string, data any) {
-	err := templates.ExecuteTemplate(w, tmpl+".html", data)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-	}
-}
-
-// makeHandler returns a handler that uses the URL path without the
-// first path element as its argument, e.g. if the URL path is
-// /edit/foo/bar, the editHandler is called with "foo/bar" as its
-// argument. This uses the second group from the validPath regular
-// expression. The boolean argument indicates whether the following
-// path is required. When false, a URL /upload/ is OK.
+// makeHandler returns a handler that uses the URL path without the first path element as its argument, e.g. if the URL
+// path is /edit/foo/bar, the editHandler is called with "foo/bar" as its argument. This uses the second group from the
+// validPath regular expression. The boolean argument indicates whether the following path is required. When false, a
+// URL like /upload/ is OK. The argument can also be provided using a form parameter, i.e. call /edit/?id=foo/bar.
 func makeHandler(fn func(http.ResponseWriter, *http.Request, string), required bool) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
+		// no hidden files or directories
+		for _, segment := range strings.Split(r.URL.Path, "/") {
+			if strings.HasPrefix(segment, ".") {
+				http.Error(w, "can neither confirm nor deny the existence of this resource", http.StatusForbidden)
+				return
+			}
+		}
 		m := validPath.FindStringSubmatch(r.URL.Path)
 		if m != nil && (!required || len(m[2]) > 0) {
 			fn(w, r, m[2])
-		} else {
-			http.NotFound(w, r)
+			return
 		}
+		err := r.ParseForm()
+		if err != nil {
+			http.Error(w, "Cannot parse form", 400)
+			return
+		}
+		id := r.Form.Get("id")
+		// no hidden files or directories
+		for _, segment := range strings.Split(id, "/") {
+			if strings.HasPrefix(segment, ".") {
+				http.Error(w, "can neither confirm nor deny the existence of this resource", http.StatusForbidden)
+				return
+			}
+		}
+		if m != nil {
+			fn(w, r, id)
+			return
+		}
+		http.NotFound(w, r)
 	}
 }
 
-// getPort returns the environment variable ODDMU_PORT or the default
-// port, "8080".
+// getPort returns the environment variable ODDMU_PORT or the default port, "8080".
 func getPort() string {
 	port := os.Getenv("ODDMU_PORT")
 	if port == "" {
@@ -62,43 +72,116 @@ func getPort() string {
 	return port
 }
 
-// scheduleLoadIndex calls index.load and prints some messages before
-// and after. For testing, call index.load directly and skip the
-// messages.
+// When stdin is a socket, getListener returns a listener that listens
+// on the socket passed as stdin.  This allows systemd-style socket
+// activation.
+// Otherwise, getListener returns a net.Listener listening on the address from
+// ODDMU_ADDRESS and the port from ODDMU_PORT.
+// ODDMU_ADDRESS may be either an IPV4 address or an IPv6 address.
+// If ODDMU_ADDRESS is unspecified, then the
+// listener listens on all available unicast addresses, both IPv4 and IPv6.
+func getListener() (net.Listener, error) {
+	address := os.Getenv("ODDMU_ADDRESS")
+	port := getPort()
+
+	stat, err := os.Stdin.Stat()
+	if stat == nil {
+		return nil, err
+	}
+	if stat.Mode().Type() == fs.ModeSocket {
+		// Listening socket passed on stdin, through systemd socket
+		// activation or similar:
+		log.Println("Serving a wiki on a listening socket passed by systemd.")
+		return net.FileListener(os.Stdin)
+	}
+	if strings.ContainsRune(address, ':') {
+		address = fmt.Sprintf("[%s]:%s", address, port)
+	} else {
+		address = fmt.Sprintf("%s:%s", address, port)
+	}
+	log.Printf("Serving a wiki at address %s", address)
+	return net.Listen("tcp", address)
+}
+
+// scheduleLoadIndex calls index.load and prints some messages before and after. For testing, call index.load directly
+// and skip the messages.
 func scheduleLoadIndex() {
-	fmt.Print("Indexing pages\n")
+	log.Print("Indexing pages")
 	n, err := index.load()
 	if err == nil {
-		fmt.Printf("Indexed %d pages\n", n)
+		log.Printf("Indexed %d pages", n)
 	} else {
-		fmt.Println("Indexing failed")
+		log.Printf("Indexing failed: %s", err)
 	}
 }
 
-// scheduleLoadLanguages calls loadLanguages and prints some messages before
-// and after. For testing, call loadLanguages directly and skip the
-// messages.
+// scheduleLoadLanguages calls loadLanguages and prints some messages before and after. For testing, call loadLanguages
+// directly and skip the messages.
 func scheduleLoadLanguages() {
-	fmt.Print("Loading languages\n")
+	log.Print("Loading languages")
 	n := loadLanguages()
-	fmt.Printf("Loaded %d languages\n", n)
+	log.Printf("Loaded %d languages", n)
+}
+
+// scheduleInstallWatcher calls watches.install and prints some messages before and after. For testing, call watch.init
+// directly and skip the messages.
+func scheduleInstallWatcher() {
+	log.Print("Installing watcher")
+	n, err := watches.install()
+	if err == nil {
+		if n == 1 {
+			log.Println("Installed watchers for one directory")
+		} else {
+			log.Printf("Installed watchers for %d directories", n)
+		}
+	} else {
+		log.Printf("Installing watcher failed: %s", err)
+	}
 }
 
 func serve() {
 	http.HandleFunc("/", rootHandler)
 	http.HandleFunc("/view/", makeHandler(viewHandler, true))
+	http.HandleFunc("/diff/", makeHandler(diffHandler, true))
 	http.HandleFunc("/edit/", makeHandler(editHandler, true))
 	http.HandleFunc("/save/", makeHandler(saveHandler, true))
 	http.HandleFunc("/add/", makeHandler(addHandler, true))
 	http.HandleFunc("/append/", makeHandler(appendHandler, true))
 	http.HandleFunc("/upload/", makeHandler(uploadHandler, false))
 	http.HandleFunc("/drop/", makeHandler(dropHandler, false))
-	http.HandleFunc("/search", searchHandler)
+	http.HandleFunc("/search/", makeHandler(searchHandler, false))
 	go scheduleLoadIndex()
 	go scheduleLoadLanguages()
-	port := getPort()
-	fmt.Printf("Serving a wiki on port %s\n", port)
-	http.ListenAndServe(":"+port, nil)
+	go scheduleInstallWatcher()
+	listener, err := getListener()
+	if listener == nil {
+		log.Println(err)
+	} else {
+		err := http.Serve(listener, nil)
+		if err != nil {
+			log.Println(err)
+		}
+	}
+}
+
+// commands does the command line parsing in case Oddmu is called with some arguments. Without any arguments, the wiki
+// server is started. At this point we already know that there is at least one subcommand.
+func commands() {
+	subcommands.Register(subcommands.HelpCommand(), "")
+	subcommands.Register(subcommands.FlagsCommand(), "")
+	subcommands.Register(subcommands.CommandsCommand(), "")
+	subcommands.Register(&htmlCmd{}, "")
+	subcommands.Register(&listCmd{}, "")
+	subcommands.Register(&missingCmd{}, "")
+	subcommands.Register(&notifyCmd{}, "")
+	subcommands.Register(&replaceCmd{}, "")
+	subcommands.Register(&searchCmd{}, "")
+	subcommands.Register(&staticCmd{}, "")
+	subcommands.Register(&versionCmd{}, "")
+
+	flag.Parse()
+	ctx := context.Background()
+	os.Exit(int(subcommands.Execute(ctx)))
 }
 
 func main() {