Splitting files and refactoring it all

It's annoying that we keep needing two URLs for everything. One to
server the UI and one to actually do it: edit/save (with page name in
the URL), add/append (that's a sketchy pair), upload/save (save again,
but this time without a trailing slash, ugh).

.gitignore

@@ -0,0 +1,3 @@
+/oddmu
+test.md
+/testdata/

LICENSE

@@ -1,27 +1,667 @@
-Copyright (c) 2012 The Go Authors. All rights reserved.
+This software is Copyright (c) 2015–2023 by Alex Schroeder.
 
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
+This is free software, licensed under:
 
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
+  The GNU Affero General Public License, Version 3, November 2007
 
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+                    GNU AFFERO GENERAL PUBLIC LICENSE
+                       Version 3, 19 November 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU Affero General Public License is a free, copyleft license for
+software and other kinds of works, specifically designed to ensure
+cooperation with the community in the case of network server software.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+our General Public Licenses are intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  Developers that use our General Public Licenses protect your rights
+with two steps: (1) assert copyright on the software, and (2) offer
+you this License which gives you legal permission to copy, distribute
+and/or modify the software.
+
+  A secondary benefit of defending all users' freedom is that
+improvements made in alternate versions of the program, if they
+receive widespread use, become available for other developers to
+incorporate.  Many developers of free software are heartened and
+encouraged by the resulting cooperation.  However, in the case of
+software used on network servers, this result may fail to come about.
+The GNU General Public License permits making a modified version and
+letting the public access it on a server without ever releasing its
+source code to the public.
+
+  The GNU Affero General Public License is designed specifically to
+ensure that, in such cases, the modified source code becomes available
+to the community.  It requires the operator of a network server to
+provide the source code of the modified version running there to the
+users of that server.  Therefore, public use of a modified version, on
+a publicly accessible server, gives the public access to the source
+code of the modified version.
+
+  An older license, called the Affero General Public License and
+published by Affero, was designed to accomplish similar goals.  This is
+a different license, not a version of the Affero GPL, but Affero has
+released a new version of the Affero GPL which permits relicensing under
+this license.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                       TERMS AND CONDITIONS
+
+  0. Definitions.
+
+  "This License" refers to version 3 of the GNU Affero General Public License.
+
+  "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+  "The Program" refers to any copyrightable work licensed under this
+License.  Each licensee is addressed as "you".  "Licensees" and
+"recipients" may be individuals or organizations.
+
+  To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy.  The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+  A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+  To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy.  Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+  To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies.  Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+  An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License.  If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+  1. Source Code.
+
+  The "source code" for a work means the preferred form of the work
+for making modifications to it.  "Object code" means any non-source
+form of a work.
+
+  A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+  The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form.  A
+"Major Component", in this context, means a major essential component
+(kernel, window system, and so on) of the specific operating system
+(if any) on which the executable work runs, or a compiler used to
+produce the work, or an object code interpreter used to run it.
+
+  The "Corresponding Source" for a work in object code form means all
+the source code needed to generate, install, and (for an executable
+work) run the object code and to modify the work, including scripts to
+control those activities.  However, it does not include the work's
+System Libraries, or general-purpose tools or generally available free
+programs which are used unmodified in performing those activities but
+which are not part of the work.  For example, Corresponding Source
+includes interface definition files associated with source files for
+the work, and the source code for shared libraries and dynamically
+linked subprograms that the work is specifically designed to require,
+such as by intimate data communication or control flow between those
+subprograms and other parts of the work.
+
+  The Corresponding Source need not include anything that users
+can regenerate automatically from other parts of the Corresponding
+Source.
+
+  The Corresponding Source for a work in source code form is that
+same work.
+
+  2. Basic Permissions.
+
+  All rights granted under this License are granted for the term of
+copyright on the Program, and are irrevocable provided the stated
+conditions are met.  This License explicitly affirms your unlimited
+permission to run the unmodified Program.  The output from running a
+covered work is covered by this License only if the output, given its
+content, constitutes a covered work.  This License acknowledges your
+rights of fair use or other equivalent, as provided by copyright law.
+
+  You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force.  You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
+with facilities for running those works, provided that you comply with
+the terms of this License in conveying all material for which you do
+not control copyright.  Those thus making or running the covered works
+for you must do so exclusively on your behalf, under your direction
+and control, on terms that prohibit them from making any copies of
+your copyrighted material outside their relationship with you.
+
+  Conveying under any other circumstances is permitted solely under
+the conditions stated below.  Sublicensing is not allowed; section 10
+makes it unnecessary.
+
+  3. Protecting Users' Legal Rights From Anti-Circumvention Law.
+
+  No covered work shall be deemed part of an effective technological
+measure under any applicable law fulfilling obligations under article
+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+  When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
+is effected by exercising rights under this License with respect to
+the covered work, and you disclaim any intention to limit operation or
+modification of the work as a means of enforcing, against the work's
+users, your or third parties' legal rights to forbid circumvention of
+technological measures.
+
+  4. Conveying Verbatim Copies.
+
+  You may convey verbatim copies of the Program's source code as you
+receive it, in any medium, provided that you conspicuously and
+appropriately publish on each copy an appropriate copyright notice;
+keep intact all notices stating that this License and any
+non-permissive terms added in accord with section 7 apply to the code;
+keep intact all notices of the absence of any warranty; and give all
+recipients a copy of this License along with the Program.
+
+  You may charge any price or no price for each copy that you convey,
+and you may offer support or warranty protection for a fee.
+
+  5. Conveying Modified Source Versions.
+
+  You may convey a work based on the Program, or the modifications to
+produce it from the Program, in the form of source code under the
+terms of section 4, provided that you also meet all of these conditions:
+
+    a) The work must carry prominent notices stating that you modified
+    it, and giving a relevant date.
+
+    b) The work must carry prominent notices stating that it is
+    released under this License and any conditions added under section
+    7.  This requirement modifies the requirement in section 4 to
+    "keep intact all notices".
+
+    c) You must license the entire work, as a whole, under this
+    License to anyone who comes into possession of a copy.  This
+    License will therefore apply, along with any applicable section 7
+    additional terms, to the whole of the work, and all its parts,
+    regardless of how they are packaged.  This License gives no
+    permission to license the work in any other way, but it does not
+    invalidate such permission if you have separately received it.
+
+    d) If the work has interactive user interfaces, each must display
+    Appropriate Legal Notices; however, if the Program has interactive
+    interfaces that do not display Appropriate Legal Notices, your
+    work need not make them do so.
+
+  A compilation of a covered work with other separate and independent
+works, which are not by their nature extensions of the covered work,
+and which are not combined with it such as to form a larger program,
+in or on a volume of a storage or distribution medium, is called an
+"aggregate" if the compilation and its resulting copyright are not
+used to limit the access or legal rights of the compilation's users
+beyond what the individual works permit.  Inclusion of a covered work
+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
+
+  6. Conveying Non-Source Forms.
+
+  You may convey a covered work in object code form under the terms
+of sections 4 and 5, provided that you also convey the
+machine-readable Corresponding Source under the terms of this License,
+in one of these ways:
+
+    a) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by the
+    Corresponding Source fixed on a durable physical medium
+    customarily used for software interchange.
+
+    b) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by a
+    written offer, valid for at least three years and valid for as
+    long as you offer spare parts or customer support for that product
+    model, to give anyone who possesses the object code either (1) a
+    copy of the Corresponding Source for all the software in the
+    product that is covered by this License, on a durable physical
+    medium customarily used for software interchange, for a price no
+    more than your reasonable cost of physically performing this
+    conveying of source, or (2) access to copy the
+    Corresponding Source from a network server at no charge.
+
+    c) Convey individual copies of the object code with a copy of the
+    written offer to provide the Corresponding Source.  This
+    alternative is allowed only occasionally and noncommercially, and
+    only if you received the object code with such an offer, in accord
+    with subsection 6b.
+
+    d) Convey the object code by offering access from a designated
+    place (gratis or for a charge), and offer equivalent access to the
+    Corresponding Source in the same way through the same place at no
+    further charge.  You need not require recipients to copy the
+    Corresponding Source along with the object code.  If the place to
+    copy the object code is a network server, the Corresponding Source
+    may be on a different server (operated by you or a third party)
+    that supports equivalent copying facilities, provided you maintain
+    clear directions next to the object code saying where to find the
+    Corresponding Source.  Regardless of what server hosts the
+    Corresponding Source, you remain obligated to ensure that it is
+    available for as long as needed to satisfy these requirements.
+
+    e) Convey the object code using peer-to-peer transmission, provided
+    you inform other peers where the object code and Corresponding
+    Source of the work are being offered to the general public at no
+    charge under subsection 6d.
+
+  A separable portion of the object code, whose source code is excluded
+from the Corresponding Source as a System Library, need not be
+included in conveying the object code work.
+
+  A "User Product" is either (1) a "consumer product", which means any
+tangible personal property which is normally used for personal, family,
+or household purposes, or (2) anything designed or sold for incorporation
+into a dwelling.  In determining whether a product is a consumer product,
+doubtful cases shall be resolved in favor of coverage.  For a particular
+product received by a particular user, "normally used" refers to a
+typical or common use of that class of product, regardless of the status
+of the particular user or of the way in which the particular user
+actually uses, or expects or is expected to use, the product.  A product
+is a consumer product regardless of whether the product has substantial
+commercial, industrial or non-consumer uses, unless such uses represent
+the only significant mode of use of the product.
+
+  "Installation Information" for a User Product means any methods,
+procedures, authorization keys, or other information required to install
+and execute modified versions of a covered work in that User Product from
+a modified version of its Corresponding Source.  The information must
+suffice to ensure that the continued functioning of the modified object
+code is in no case prevented or interfered with solely because
+modification has been made.
+
+  If you convey an object code work under this section in, or with, or
+specifically for use in, a User Product, and the conveying occurs as
+part of a transaction in which the right of possession and use of the
+User Product is transferred to the recipient in perpetuity or for a
+fixed term (regardless of how the transaction is characterized), the
+Corresponding Source conveyed under this section must be accompanied
+by the Installation Information.  But this requirement does not apply
+if neither you nor any third party retains the ability to install
+modified object code on the User Product (for example, the work has
+been installed in ROM).
+
+  The requirement to provide Installation Information does not include a
+requirement to continue to provide support service, warranty, or updates
+for a work that has been modified or installed by the recipient, or for
+the User Product in which it has been modified or installed.  Access to a
+network may be denied when the modification itself materially and
+adversely affects the operation of the network or violates the rules and
+protocols for communication across the network.
+
+  Corresponding Source conveyed, and Installation Information provided,
+in accord with this section must be in a format that is publicly
+documented (and with an implementation available to the public in
+source code form), and must require no special password or key for
+unpacking, reading or copying.
+
+  7. Additional Terms.
+
+  "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law.  If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+  When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
+it.  (Additional permissions may be written to require their own
+removal in certain cases when you modify the work.)  You may place
+additional permissions on material, added by you to a covered work,
+for which you have or can give appropriate copyright permission.
+
+  Notwithstanding any other provision of this License, for material you
+add to a covered work, you may (if authorized by the copyright holders of
+that material) supplement the terms of this License with terms:
+
+    a) Disclaiming warranty or limiting liability differently from the
+    terms of sections 15 and 16 of this License; or
+
+    b) Requiring preservation of specified reasonable legal notices or
+    author attributions in that material or in the Appropriate Legal
+    Notices displayed by works containing it; or
+
+    c) Prohibiting misrepresentation of the origin of that material, or
+    requiring that modified versions of such material be marked in
+    reasonable ways as different from the original version; or
+
+    d) Limiting the use for publicity purposes of names of licensors or
+    authors of the material; or
+
+    e) Declining to grant rights under trademark law for use of some
+    trade names, trademarks, or service marks; or
+
+    f) Requiring indemnification of licensors and authors of that
+    material by anyone who conveys the material (or modified versions of
+    it) with contractual assumptions of liability to the recipient, for
+    any liability that these contractual assumptions directly impose on
+    those licensors and authors.
+
+  All other non-permissive additional terms are considered "further
+restrictions" within the meaning of section 10.  If the Program as you
+received it, or any part of it, contains a notice stating that it is
+governed by this License along with a term that is a further
+restriction, you may remove that term.  If a license document contains
+a further restriction but permits relicensing or conveying under this
+License, you may add to a covered work material governed by the terms
+of that license document, provided that the further restriction does
+not survive such relicensing or conveying.
+
+  If you add terms to a covered work in accord with this section, you
+must place, in the relevant source files, a statement of the
+additional terms that apply to those files, or a notice indicating
+where to find the applicable terms.
+
+  Additional terms, permissive or non-permissive, may be stated in the
+form of a separately written license, or stated as exceptions;
+the above requirements apply either way.
+
+  8. Termination.
+
+  You may not propagate or modify a covered work except as expressly
+provided under this License.  Any attempt otherwise to propagate or
+modify it is void, and will automatically terminate your rights under
+this License (including any patent licenses granted under the third
+paragraph of section 11).
+
+  However, if you cease all violation of this License, then your
+license from a particular copyright holder is reinstated (a)
+provisionally, unless and until the copyright holder explicitly and
+finally terminates your license, and (b) permanently, if the copyright
+holder fails to notify you of the violation by some reasonable means
+prior to 60 days after the cessation.
+
+  Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+  Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License.  If your rights have been terminated and not permanently
+reinstated, you do not qualify to receive new licenses for the same
+material under section 10.
+
+  9. Acceptance Not Required for Having Copies.
+
+  You are not required to accept this License in order to receive or
+run a copy of the Program.  Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance.  However,
+nothing other than this License grants you permission to propagate or
+modify any covered work.  These actions infringe copyright if you do
+not accept this License.  Therefore, by modifying or propagating a
+covered work, you indicate your acceptance of this License to do so.
+
+  10. Automatic Licensing of Downstream Recipients.
+
+  Each time you convey a covered work, the recipient automatically
+receives a license from the original licensors, to run, modify and
+propagate that work, subject to this License.  You are not responsible
+for enforcing compliance by third parties with this License.
+
+  An "entity transaction" is a transaction transferring control of an
+organization, or substantially all assets of one, or subdividing an
+organization, or merging organizations.  If propagation of a covered
+work results from an entity transaction, each party to that
+transaction who receives a copy of the work also receives whatever
+licenses to the work the party's predecessor in interest had or could
+give under the previous paragraph, plus a right to possession of the
+Corresponding Source of the work from the predecessor in interest, if
+the predecessor has it or can get it with reasonable efforts.
+
+  You may not impose any further restrictions on the exercise of the
+rights granted or affirmed under this License.  For example, you may
+not impose a license fee, royalty, or other charge for exercise of
+rights granted under this License, and you may not initiate litigation
+(including a cross-claim or counterclaim in a lawsuit) alleging that
+any patent claim is infringed by making, using, selling, offering for
+sale, or importing the Program or any portion of it.
+
+  11. Patents.
+
+  A "contributor" is a copyright holder who authorizes use under this
+License of the Program or a work on which the Program is based.  The
+work thus licensed is called the contributor's "contributor version".
+
+  A contributor's "essential patent claims" are all patent claims
+owned or controlled by the contributor, whether already acquired or
+hereafter acquired, that would be infringed by some manner, permitted
+by this License, of making, using, or selling its contributor version,
+but do not include claims that would be infringed only as a
+consequence of further modification of the contributor version.  For
+purposes of this definition, "control" includes the right to grant
+patent sublicenses in a manner consistent with the requirements of
+this License.
+
+  Each contributor grants you a non-exclusive, worldwide, royalty-free
+patent license under the contributor's essential patent claims, to
+make, use, sell, offer for sale, import and otherwise run, modify and
+propagate the contents of its contributor version.
+
+  In the following three paragraphs, a "patent license" is any express
+agreement or commitment, however denominated, not to enforce a patent
+(such as an express permission to practice a patent or covenant not to
+sue for patent infringement).  To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+  If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients.  "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+  If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+  A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License.  You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Remote Network Interaction; Use with the GNU General Public License.
+
+  Notwithstanding any other provision of this License, if you modify the
+Program, your modified version must prominently offer all users
+interacting with it remotely through a computer network (if your version
+supports such interaction) an opportunity to receive the Corresponding
+Source of your version by providing access to the Corresponding Source
+from a network server at no charge, through some standard or customary
+means of facilitating copying of software.  This Corresponding Source
+shall include the Corresponding Source for any work covered by version 3
+of the GNU General Public License that is incorporated pursuant to the
+following paragraph.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the work with which it is combined will remain governed by version
+3 of the GNU General Public License.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU Affero General Public License from time to time.  Such new versions
+will be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU Affero General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU Affero General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU Affero General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<http://www.gnu.org/licenses/>.

Makefile

@@ -0,0 +1,28 @@
+SHELL=/bin/bash
+
+help:
+	@echo Help for Oddmu
+	@echo =====================
+	@echo
+	@echo make run
+	@echo "    runs program, offline"
+	@echo
+	@echo make test
+	@echo "    runs the tests"
+	@echo
+	@echo make upload
+	@echo "    this is how I upgrade my server"
+	@echo
+	@echo go build
+	@echo "    just build it"
+
+run:
+	go run .
+
+test:
+	go test
+
+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"

README.md

@@ -1,22 +1,464 @@
-# Oddµ: A Small Wiki Written in Go
+# Oddµ: A minimal wiki
 
-This is a minimal wiki in the spirit of [Shortest Wiki Contest](https://wiki.c2.com/?ShortestWikiContest)
-and [Wiki Principles](https://wiki.c2.com/?WikiPrinciples).
-The article [Writing Web Applications](https://golang.org/doc/articles/wiki/)
-provided the initial code. It's how I learned Go.
+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.
 
-To get started, use `go run .` to compile and run it; then use your browser to visit
-`http://localhost:8080/edit/index`.
+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.
 
-## Some context
+The wiki lists no recent changes. The expectation is that the people
+that care were involved in the discussions beforehand.
 
-Initially, this wiki used [Cajun](https://github.com/m4tty/cajun) to render Wiki Creole
-but I switched it to [Markdown](https://github.com/gomarkdown/markdown).
+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.
 
-At the time, I planned to use [git2go](https://github.com/libgit2/git2go) to implement
-history pages, recent changes, reverting to old versions. None of that ever came about,
-however.
+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.
 
-Many years later I did use it as the basis for [Oddμ](https://alexschroeder.ch/view/oddmu/index),
-however.
+And last but not least: µ is the letter mu, so Oddµ is usually written
+Oddmu. 🙃
 
+## Markdown
+
+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 Markdown processor comes with a few extensions, some of which are
+enable by default:
+
+* 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)
+
+A table with footers and a columnspan:
+
+```text
+Name    | Age
+--------|------
+Bob     ||
+Alice   | 23
+========|======
+Total   | 23
+```
+
+A definition list:
+
+```text
+Cat
+: Fluffy animal everyone likes
+
+Internet
+: Vector of transmission for pictures of cats
+```
+
+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.
+
+```
+# Title
+
+Text
+
+#Tag #Another_Tag
+```
+
+## Templates
+
+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`.
+😄
+
+See [Structuring the web
+with HTML](https://developer.mozilla.org/en-US/docs/Learn/HTML) to
+learn more about HTML.
+
+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".
+
+## Building
+
+```sh
+go build
+```
+
+## Test
+
+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.
+Here's how to start it in the source directory:
+
+```sh
+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.
+
+## Bugs
+
+If you spot any, [contact](https://alexschroeder.ch/wiki/Contact) me.
+
+## 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

@@ -0,0 +1,6 @@
+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.

add.html

@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+  <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; }
+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>
+      <p><input type="submit" value="Add">
+        <a href="/view/{{.Name}}"><button type="button">Cancel</button></a></p>
+    </form>
+  </body>
+</html>

add_append.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"net/http"
+)
+
+// addHandler uses the "add.html" template to present an empty edit
+// page. What you type there is appended to the page using the
+// appendHandler.
+func addHandler(w http.ResponseWriter, r *http.Request, name string) {
+	p, err := loadPage(name)
+	if err != nil {
+		p = &Page{Title: name, Name: name}
+	} else {
+		p.handleTitle(false)
+	}
+	renderTemplate(w, "add", p)
+}
+
+// appendHandler takes the "body" form parameter and appends it. The
+// browser is redirected to the page view.
+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)}
+	} else {
+		p.handleTitle(false)
+		p.Body = append(p.Body, []byte(body)...)
+	}
+	err = p.save()
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	http.Redirect(w, r, "/view/"+name, http.StatusFound)
+}

add_append_test.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"net/url"
+	"os"
+	"regexp"
+	"testing"
+)
+
+// wipes testdata
+func TestAddAppend(t *testing.T) {
+	_ = os.RemoveAll("testdata")
+	index.load()
+	
+	p := &Page{Name: "testdata/fire", Body: []byte(`# Fire
+Orange sky above
+Reflects a distant fire
+It's not `)}
+	p.save()
+
+	data := url.Values{}
+	data.Set("body", "barbecue")
+
+	assert.Regexp(t, regexp.MustCompile("a distant fire"),
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/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")
+	})
+}

commands.go

@@ -0,0 +1,36 @@
+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

@@ -0,0 +1,15 @@
+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))
+}

edit.html

@@ -1,10 +1,23 @@
 <!DOCTYPE html>
 <html>
-<body>
-<h1>Editing {{.Title}}</h1>
-<form action="/save/{{.Title}}" method="POST">
-<div><textarea name="body" rows="20" cols="80">{{printf "%s" .Body}}</textarea></div>
-<div><input type="submit" value="Save"></div>
-</form>
-</body>
+  <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; }
+form, textarea { width: 100%; }
+    </style>
+  </head>
+  <body>
+    <h1>Editing {{.Title}}</h1>
+    <form action="/save/{{.Name}}" method="POST">
+      <textarea name="body" rows="20" cols="80" placeholder="# Title
+
+Text" autofocus>{{printf "%s" .Body}}</textarea>
+      <p><input type="submit" value="Save">
+        <a href="/view/{{.Name}}"><button type="button">Cancel</button></a></p>
+    </form>
+  </body>
 </html>

edit_save.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"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.
+func editHandler(w http.ResponseWriter, r *http.Request, name string) {
+	p, err := loadPage(name)
+	if err != nil {
+		p = &Page{Title: name, Name: name}
+	} else {
+		p.handleTitle(false)
+	}
+	renderTemplate(w, "edit", p)
+}
+
+// saveHandler takes the "body" form parameter and saves it. The
+// browser is redirected to the page view.
+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 {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	http.Redirect(w, r, "/view/"+name, http.StatusFound)
+}

edit_save_test.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"net/url"
+	"os"
+	"regexp"
+	"testing"
+)
+
+// wipes testdata
+func TestEditSave(t *testing.T) {
+	_ = os.RemoveAll("testdata")
+
+	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")
+	})
+}

go.mod

@@ -1,5 +1,23 @@
 module alexschroeder.ch/cgit/oddmu
 
-go 1.22.3
+go 1.21.0
 
-require github.com/gomarkdown/markdown v0.0.0-20250311123330-531bef5e742b // indirect
+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/pemistahl/lingua-go v1.4.0
+	github.com/stretchr/testify v1.8.4
+)
+
+require (
+	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/pmezard/go-difflib v1.0.0 // 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
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -1,4 +1,38 @@
-github.com/gomarkdown/markdown v0.0.0-20250311123330-531bef5e742b h1:EY/KpStFl60qA17CptGXhwfZ+k1sFNJIUNR8DdbcuUk=
-github.com/gomarkdown/markdown v0.0.0-20250311123330-531bef5e742b/go.mod h1:JDGcbDT52eL4fju3sZ4TeHGsQwhG9nbDV21aMyhwPoA=
-github.com/m4tty/cajun v0.0.0-20150303030909-35de273cc87b h1:aY3LtSBlkQahoWaPTytHcIFsDbeXFYMc4noRQ/N5Q+A=
-github.com/m4tty/cajun v0.0.0-20150303030909-35de273cc87b/go.mod h1:zFXkL7I5vIwKg4dxEA9025SLdIHu9qFX/cYTdUcusHc=
+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/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/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/pemistahl/lingua-go v1.4.0 h1:ifYhthrlW7iO4icdubwlduYnmwU37V1sbNrwhKBR4rM=
+github.com/pemistahl/lingua-go v1.4.0/go.mod h1:ECuM1Hp/3hvyh7k8aWSqNCPlTxLemFZsRjocUf3KgME=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/shopspring/decimal v1.3.1 h1:2Usl1nmF/WZucqkFZhnfFYxxxu8LG21F6nPQBE5gKV8=
+github.com/shopspring/decimal v1.3.1/go.mod h1:DKyhrW/HYNuLGql+MJL6WCR6knT2jwCFRcu2hWCYk4o=
+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=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

highlight.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"regexp"
+)
+
+// highlight splits the query string q into terms and highlights them
+// using the bold tag. Return the highlighted string.
+// This assumes that q already has all its meta characters quoted.
+func highlight(q string, re *regexp.Regexp, s string) string {
+	s = re.ReplaceAllString(s, "<b>$1</b>")
+	return s
+}

highlight_test.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestHighlight(t *testing.T) {
+
+	s := `The windows opens
+A wave of car noise hits me
+No birds to be heard.`
+
+	h := `The <b>window</b>s opens
+A wave of car noise hits me
+No birds to be heard.`
+
+	q := "window"
+	re, _ := re(q)
+	r := highlight(q, re, s)
+	if r != h {
+		t.Logf("The highlighting is wrong in ｢%s｣", r)
+		t.Fail()
+	}
+}
+
+func TestOverlap(t *testing.T) {
+
+	s := `Sit with me my love
+Kids shout and so do parents
+I hear the fountain`
+
+	h := `Sit with me my love
+Kids <b>shout</b> and so do parents
+I hear the fountain`
+
+	q := "shout out"
+	re, _ := re(q)
+	r := highlight(q, re, s)
+	if r != h {
+		t.Logf("The highlighting is wrong in ｢%s｣", r)
+		t.Fail()
+	}
+}

index.go

@@ -0,0 +1,112 @@
+package main
+
+import (
+	trigram "github.com/dgryski/go-trigram"
+	"io/fs"
+	"path/filepath"
+	"strings"
+	"sync"
+)
+
+// 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
+
+	// documents is a map, mapping document ids of the index to
+	// page names.
+	documents map[trigram.DocID]string
+}
+
+// idx is the global Index per wiki.
+var index Index
+
+// reset resets the Index. This assumes that the index is locked!
+func (idx *Index) reset() {
+	idx.index = nil
+	idx.documents = nil
+}
+
+// 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
+	}
+	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
+}
+
+// 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)
+	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
+		}
+	}
+	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)
+	}
+}
+
+func searchDocuments(q string) []string {
+		words := strings.Fields(strings.ToLower(q))
+	var trigrams []trigram.T
+	for _, word := range words {
+		trigrams = trigram.Extract(word, trigrams)
+	}
+	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
+}

index.md

@@ -0,0 +1,5 @@
+# Welcome to Oddµ
+
+Hello! 🙃
+
+Check out the [README](README).

index_test.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"strings"
+	"testing"
+)
+
+// TestIndex relies on README.md being indexed
+func TestIndex(t *testing.T) {
+	index.load()
+	q := "Oddµ"
+	pages := search(q)
+	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)
+	}
+}
+
+func TestSearchHashtag(t *testing.T) {
+	index.load()
+	q := "#Another_Tag"
+	pages := search(q)
+	assert.NotZero(t, len(pages))
+}
+
+func TestIndexUpdates(t *testing.T) {
+	name := "test"
+	_ = os.Remove(name + ".md")
+	index.load()
+	p := &Page{Name: name, Body: []byte("This is a test.")}
+	p.save()
+
+	// Find the phrase
+	pages := search("This is a test")
+	found := false
+	for _, p := range pages {
+		if p.Name == name {
+			found = true
+			break
+		}
+	}
+	assert.True(t, found)
+
+	// Find the phrase, case insensitive
+	pages = search("this is a test")
+	found = false
+	for _, p := range pages {
+		if p.Name == name {
+			found = true
+			break
+		}
+	}
+	assert.True(t, found)
+
+	// Find some words
+	pages = search("this test")
+	found = false
+	for _, p := range pages {
+		if p.Name == name {
+			found = true
+			break
+		}
+	}
+	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.save()
+	pages = search("This is a test")
+	found = false
+	for _, p := range pages {
+		if p.Name == name {
+			found = true
+			break
+		}
+	}
+	assert.False(t, found)
+
+	// Find page using a new word
+	pages = search("Guvf")
+	found = false
+	for _, p := range pages {
+		if p.Name == name {
+			found = true
+			break
+		}
+	}
+	assert.True(t, found)
+
+	t.Cleanup(func() {
+		_ = os.Remove(name + ".md")
+	})
+}

languages.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+	"errors"
+	"github.com/pemistahl/lingua-go"
+	"os"
+	"strings"
+)
+
+// getLangauges returns the environment variable ODDMU_LANGUAGES or
+// all languages.
+func getLanguages() ([]lingua.Language, error) {
+	v := os.Getenv("ODDMU_LANGUAGES")
+	if v == "" {
+		return lingua.AllLanguages(), nil
+	}
+	codes := strings.Split(v, ",")
+	if len(codes) == 1 {
+		return nil, errors.New("detection unnecessary")
+	}
+
+	var langs []lingua.Language
+	for _, lang := range codes {
+		langs = append(langs, lingua.GetLanguageFromIsoCode639_1(lingua.GetIsoCode639_1FromValue(lang)))
+	}
+	return langs, nil
+}
+
+// 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.
+func loadLanguages() int {
+	langs, err := getLanguages()
+	if err == nil {
+		detector = lingua.NewLanguageDetectorBuilder().
+			FromLanguages(langs...).
+			WithPreloadedLanguageModels().
+			WithLowAccuracyMode().
+			Build()
+	} else {
+		detector = nil
+	}
+	return len(langs)
+}
+
+// language returns the language used for a string, as a lower case
+// ISO 639-1 string, e.g. "en" or "de".
+func language(s string) string {
+	if detector == nil {
+		return os.Getenv("ODDMU_LANGUAGES")
+	}
+	if language, ok := detector.DetectLanguageOf(s); ok {
+		return strings.ToLower(language.IsoCode639_1().String())
+	}
+	return ""
+}

languages_test.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"testing"
+)
+
+func TestAllLanguage(t *testing.T) {
+	os.Unsetenv("ODDMU_LANGUAGES")
+	loadLanguages()
+	l := language(`
+My back hurts at night
+My shoulders won't budge today
+Winter bones I say`)
+	assert.Equal(t, "en", l)
+}
+
+func TestSomeLanguages(t *testing.T) {
+	os.Setenv("ODDMU_LANGUAGES", "en,de")
+	loadLanguages()
+	l := language(`
+Kühle Morgenluft
+Keine Amsel singt heute
+Mensch im Dämmerlicht
+`)
+	assert.Equal(t, "de", l)
+}
+
+func TestOneLanguages(t *testing.T) {
+	os.Setenv("ODDMU_LANGUAGES", "en")
+	loadLanguages()
+	l := language(`
+Schwer wiegt die Luft hier
+Atme ein, ermahn' ich mich
+Erinnerungen
+`)
+	assert.Equal(t, "en", l)
+}
+
+func TestWrongLanguages(t *testing.T) {
+	os.Setenv("ODDMU_LANGUAGES", "de,fr")
+	loadLanguages()
+	l := language(`
+Something drifts down there
+Head submerged oh god a man
+Drowning as we stare
+`)
+	assert.NotEqual(t, "en", l)
+}

oddmu.service

@@ -0,0 +1,49 @@
+[Unit]
+Description=Oddmu
+After=network.target
+[Install]
+WantedBy=multi-user.target
+[Service]
+Type=simple
+Restart=always
+DynamicUser=true
+MemoryMax=100M
+MemoryHigh=120M
+ExecStart=/home/oddmu/oddmu
+WorkingDirectory=/home/oddmu
+Environment="ODDMU_PORT=8080"
+
+# (man "systemd.exec")
+ReadWritePaths=/home/oddmu
+ProtectHostname=yes
+RestrictSUIDSGID=yes
+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
+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
+# Doc: https://man7.org/linux/man-pages/man7/capabilities.7.html
+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 

page.go

@@ -0,0 +1,178 @@
+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"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// 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"
+// 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.
+type Page struct {
+	Title    string
+	Name     string
+	Language string
+	Body     []byte
+	Html     template.HTML
+	Score    int
+}
+
+// santize uses bluemonday to sanitize the HTML.
+func sanitize(s string) template.HTML {
+	return template.HTML(bluemonday.UGCPolicy().Sanitize(s))
+}
+
+// santizeBytes uses bluemonday to sanitize the HTML.
+func sanitizeBytes(bytes []byte) template.HTML {
+	return template.HTML(bluemonday.UGCPolicy().SanitizeBytes(bytes))
+}
+
+// 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 {
+		parts[i] = url.PathEscape(part)
+	}
+	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.
+func (p *Page) save() error {
+	filename := p.Name + ".md"
+	s := bytes.ReplaceAll(p.Body, []byte{'\r'}, []byte{})
+	if len(s) == 0 {
+		_ = os.Rename(filename, filename + "~")
+		return os.Remove(filename)
+	}
+	p.Body = s
+	p.updateIndex()
+	d := filepath.Dir(filename)
+	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)
+}
+
+// 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)
+	if err != nil {
+		return nil, err
+	}
+	return &Page{Title: name, Name: name, 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.
+func (p *Page) handleTitle(replace bool) {
+	s := string(p.Body)
+	m := titleRegexp.FindStringSubmatch(s)
+	if m != nil {
+		p.Title = m[1]
+		if replace {
+			p.Body = []byte(strings.Replace(s, m[0], "", 1))
+		}
+	}
+}
+
+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) {
+	p.handleTitle(true)
+	p.Score = score(q, string(p.Body)) + score(q, p.Title)
+	t := p.plainText()
+	p.Html = sanitize(snippets(q, t))
+	p.Language = language(t)
+}
+
+func (p *Page) Dir() string {
+	d := filepath.Dir(p.Name)
+	if d == "." {
+		return ""
+	}
+	return d
+}

page_test.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"regexp"
+	"testing"
+)
+
+func TestPageTitle(t *testing.T) {
+	p := &Page{Body: []byte(`# Ache
+My back aches for you
+I sit, stare and type for hours
+But yearn for blue sky`)}
+	p.handleTitle(false)
+	assert.Equal(t, "Ache", p.Title)
+	assert.Regexp(t, regexp.MustCompile("^# Ache"), string(p.Body))
+	p.handleTitle(true)
+	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")
+	index.load()
+	p := &Page{Name: "testdata/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")
+	assert.NoError(t, err, "load page")
+	assert.Equal(t, p.Body, o.Body)
+	assert.FileExists(t, "testdata/moon.md")
+
+	// Saving an empty page deletes it.
+	p = &Page{Name: "testdata/moon", Body: []byte("")}
+	p.save()
+	assert.NoFileExists(t, "testdata/moon.md")
+
+	// But the backup still exists.
+	assert.FileExists(t, "testdata/moon.md~")
+	
+	t.Cleanup(func() {
+		_ = os.RemoveAll("testdata")
+	})
+}

score.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"regexp"
+	"strings"
+)
+
+// score splits the query string q into terms and scores the text
+// based on those terms. This assumes that q already has all its meta
+// characters quoted.
+func score(q string, s string) int {
+	score := 0
+	re, err := regexp.Compile("(?i)" + q)
+	if err == nil {
+		m := re.FindAllString(s, -1)
+		if m != nil {
+			// Score increases for each full match of q.
+			score += len(m)
+		}
+	}
+	for _, v := range strings.Fields(q) {
+		re, err := regexp.Compile(`(?is)(\pL?)(` + v + `)(\pL?)`)
+		if err != nil {
+			continue
+		}
+		for _, m := range re.FindAllStringSubmatch(s, -1) {
+			// Term matched increases the score.
+			score++
+			// Terms matching at the beginning and
+			// end of words and matching entire
+			// words increase the score further.
+			if len(m[1]) == 0 {
+				score++
+			}
+			if len(m[3]) == 0 {
+				score++
+			}
+			if len(m[1]) == 0 && len(m[3]) == 0 {
+				score++
+			}
+		}
+	}
+	return score
+}

score_test.go

@@ -0,0 +1,104 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestScore(t *testing.T) {
+
+	s := `The windows opens
+A wave of car noise hits me
+No birds to be heard.`
+
+	q := "window"
+	// Score:
+	// - q itself
+	// - the single token
+	// - the beginning of a word
+	c := score(q, s)
+	if c != 3 {
+		t.Logf("%s score is %d", q, c)
+		t.Fail()
+	}
+	q = "windows"
+	c = score(q, s)
+	// Score:
+	// - q itself
+	// - the single token
+	// - the beginning of a word
+	// - the end of a word
+	// - the whole word
+	if c != 5 {
+		t.Logf("%s score is %d", q, c)
+		t.Fail()
+	}
+	q = "car noise"
+	c = score(q, s)
+	// Score:
+	// - car noise (+1)
+	// - car, with beginning, end, whole word (+4)
+	// - noise, with beginning, end, whole word (+4)
+	if c != 9 {
+		t.Logf("%s score is %d", q, c)
+		t.Fail()
+	}
+	q = "noise car"
+	c = score(q, s)
+	// Score:
+	// - the car token
+	// - the noise token
+	// - each with beginning, end and whole token (3 each)
+	if c != 8 {
+		t.Logf("%s score is %d", q, c)
+		t.Fail()
+	}
+}
+
+func TestScoreLong(t *testing.T) {
+	s := `We are immersed in a sea of dead people. All the dead that have gone before us, silent now, just staring, gaping. As we move and talk and fret, never once stopping to ask ourselves – or them! – what it was all about. Instead we drown ourselves in noise. Incessantly we babble, surrounded by false friends claiming that all is well. And look at us! Yes, we are well. Patting our backs and expecting a pat – and we do! – we smugly do enjoy.`
+	q := "all is well"
+	c := score(q, s)
+	// Score:
+	// - all is well (1)
+	// - all, beginning, end, whole word (+4 × 3 = 12)
+	// - is, beginning, end, whole word (+4 × 1 = 4), and as a substring (1)
+	// - well, beginning, end, whole word (+4 × 2 = 8)
+	if c != 26 {
+		t.Logf("%s score is %d", q, c)
+		t.Fail()
+	}
+}
+
+func TestScoreSubstring(t *testing.T) {
+	s := `The loneliness of space means that receiving messages means knowledge that other people are out there. Not satellites pinging forever. Not bots searching and probing. Instead, humans. People who care. Curious and cautious.`
+	q := "search probe"
+	c := score(q, s)
+	// Score:
+	// - search, beginning (2)
+	// - probe (0)
+	if c != 2 {
+		t.Logf("%s score is %d", q, c)
+		t.Fail()
+	}
+	q = "ear"
+	c = score(q, s)
+	// Score:
+	// - ear, all (2)
+	if c != 2 {
+		t.Logf("%s score is %d", q, c)
+		t.Fail()
+	}
+}
+
+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)
+	// "wiki" is not visible in the plain text but the score is no affected:
+	// - wiki, all, whole, beginning, end (5)
+	if p.Score != 5 {
+		t.Logf("%s score is %d", q, p.Score)
+		t.Fail()
+	}
+}

search.go

@@ -0,0 +1,88 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"slices"
+	"unicode"
+	"unicode/utf8"
+)
+
+// Search is a struct containing the result of a search. Query is the
+// query string and Items is the array of pages with the result.
+// 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
+}
+
+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
+		}
+	}
+	// 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
+		}
+	}
+	return items
+}
+
+// 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)
+	}
+	names := searchDocuments(q)
+	items := loadAndSummarize(names, q)
+	slices.SortFunc(items, sortItems)
+	return items
+}
+
+// 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)
+}

search.html

@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<html>
+  <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; }
+body { hyphens: auto; }
+header a { margin-right: 1ch; }
+form { display: inline-block; }
+img { max-width: 20%; }
+.result { font-size: larger }
+.score { font-size: smaller; opacity: 0.8; }
+    </style>
+  </head>
+  <body lang="en">
+    <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>
+    </header>
+    <main id="main">
+      <h1>Search for {{.Query}}</h1>
+      {{if .Results}}
+      {{range .Items}}
+      <article lang="{{.Language}}">
+        <p><a class="result" href="/view/{{.Name}}">{{.Title}}</a>
+          <span class="score">{{.Score}}</span></p>
+        <blockquote>{{.Html}}</blockquote>
+      </article>
+      {{end}}
+      {{else}}
+      <p>No results.</p>
+      {{end}}
+    </main>
+  </body>
+</html>

search_test.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+	"net/url"
+)
+
+func TestSearch(t *testing.T) {
+	data := url.Values{}
+	data.Set("q", "oddµ")
+	assert.Contains(t,
+		assert.HTTPBody(searchHandler, "GET", "/search", data), "Welcome")
+}

snippets.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"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
+	}
+	words := re.ReplaceAllString(q, "|")
+	re, err = regexp.Compile(`(?i)(` + words + `)`)
+	if err != nil {
+		return nil, err
+	}
+	return re, nil
+}
+
+func snippets(q string, s string) string {
+	// Look for Snippets
+	snippetlen := 100
+	maxsnippets := 4
+	re, err := re(q)
+	// If the compilation didn't work, truncate and return
+	if err != nil || len(s) <= snippetlen {
+		if len(s) > 400 {
+			s = s[0:400] + " …"
+		}
+		return s
+	}
+	// show a snippet from the beginning of the document
+	j := strings.LastIndex(s[:snippetlen], " ")
+	if j == -1 {
+		// OK, look for a longer word
+		j = strings.Index(s, " ")
+		if j == -1 {
+			// Or just truncate the body.
+			if len(s) > 400 {
+				s = s[0:400] + " …"
+			}
+			return highlight(q, re, s)
+		}
+	}
+	t := s[0:j]
+	res := t + " …"
+	s = s[j:] // avoid rematching
+	jsnippet := 0
+	for jsnippet < maxsnippets {
+		m := re.FindStringSubmatch(s)
+		if m == nil {
+			break
+		}
+		jsnippet++
+		j = strings.Index(s, m[1])
+		wl := len(m[1])
+		if j > -1 {
+			// get the substring containing the start of
+			// the match, ending on word boundaries
+			from := j - snippetlen/2
+			if from < 0 {
+				from = 0
+			}
+			start := strings.Index(s[from:], " ")
+			if start == -1 {
+				start = 0
+			} else {
+				start += from
+			}
+			to := j + wl + snippetlen/2
+			if to > len(s) {
+				to = len(s)
+			}
+			end := strings.LastIndex(s[:to], " ")
+			if end == -1 || end <= j + wl {
+				// OK, look for a longer word
+				end = strings.Index(s[to:], " ")
+				if end == -1 {
+					end = len(s)
+				} else {
+					end += to
+				}
+			}
+			t = s[start:end]
+			res = res + t
+			if len(s) > end {
+				res = res + " …"
+			}
+			// truncate text to avoid rematching the same string.
+			s = s[end:]
+		}
+	}
+	return highlight(q, re, res)
+}

snippets_test.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestSnippets(t *testing.T) {
+	s := `We are immersed in a sea of dead people. All the dead that have gone before us, silent now, just staring, gaping. As we move and talk and fret, never once stopping to ask ourselves – or them! – what it was all about. Instead we drown ourselves in noise. Incessantly we babble, surrounded by false friends claiming that all is well. And look at us! Yes, we are well. Patting our backs and expecting a pat – and we do! – we smugly do enjoy.`
+
+	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"
+	r := snippets(q, s)
+	assert.Equal(t, h, r)
+}
+
+func TestSnippetsLong(t *testing.T) {
+	s := `VWwXetig mty8fORN UNia4NFm SQsfyFHk BLDdgVnc AcvKP2fs q8KxPH1A IaCzFj96 J0S2fqca jp3ElV9f ULIZ1aMX GSUO1pLI p7vuJie8 kPfc0ONq EthfIUjm u74guCZ8 IiJYxlR6 5j5LlapY TGO98fOQ fO2RUb1g W8zaPa0v ps0haNzW OOeFwf1h 1N3td7zk 0OoMX8Ek aTd3Ciea 2T1aK9WH QbYfUojs nP59gqvR tqoEK3vJ zJ7JmRby qKReayLo 9BIwFgID 4Q4Tk3HH 1VLdDzSx q0hKUOKm vWkUXz9S 684uXanc gIaJNRFc gabtBO9A EhIh4VtT gJ3p9LYL jPVFqc65 QmMu8FUT vV0iphek 9Vvye5xS q7rJJyxa yHiIEMHA Ce8KLI1B FdbpdvWY qLk23poI aRoZ5LTu fWNL8rcj RpZyI052 HTxj28Q0 GiOjJ1UN iW7zrxBD QPpkiBVE nvOAkh7p c2prdKB8 9DAYvYo5 BPSN8wmO Q2oNZouQ zfEjm5aC lLMDotic hi585ip4 c7LYN3LZ xGmpN32s lcF83ipK 0IwvvEe1 tQxKHCCa u51OKNIE kdEsXUHG tTpUtwbG T6E4hMYv nVpbxCPH 0aACMPtu Oq945xMi wlPQHJ1e bROJU0e7 wdBjAYPt gjIaTuLu bicVsgYN L3a5NLwf 30zu9OHL qtDs1PJM OmTsSOZc v4eM7s8f MQlppFcY 6HTWrZPZ Raj94J30 kcSQPdTQ zsOhnhCQ sQDQkA3a uBP00Du8 qoq7syqj urFj9bqQ TV1EDcpC 4jKGRY27 vb3KgZQy EJillDeB UN4YYoLI hWgf1kqn o1B5s6Wm 98fQL4W0 PXaQeRc2 E45QBYtr od4CfqUo YsPizANv WFJj0nhM h7maM5WQ HuDYldsX qy1NLYCZ ZkvkuCxI hcD6Hyod sDiFWy4n tElzo9YK NNdt31gx NaeEtqmR MGwCCYWu y80zQlGX OAYoTGVY wYs20iOY j4eZDalG HDcd6eWZ Wvxqh0RI jykQ3bNt qRjxSxt6 4HjBIMK1 AIX5UEPr 1HQKp2ZH Fie3kxjb tzwmAigF QntpzTJO 9jQiDIDE LD0OlrSk 8PfSKmt4 MQBr2cK0 FLUQLq2h JfmjaCYv DqkdKyr8 ZtGnI5rj iqhACPMu UsY6ZIpT NjjgMBPV RW4YRcnZ Gyr9nest 9tIXI0km plugRQRv AlFpi0PJ DLcM8Zoq Auk5RBWs tMpfMMlU p6jGYq3Z rTIBTHVM zGFwFwQi j4O1AY21 BJnaiScY`
+	// match at the very beginning: the first 100 characters or less
+	assert.Equal(t,
+		"<b>VWwXetig</b> mty8fORN UNia4NFm SQsfyFHk BLDdgVnc AcvKP2fs q8KxPH1A IaCzFj96 J0S2fqca jp3ElV9f ULIZ1aMX …",
+		snippets("VWwXetig", s))
+	// the first 100 … the match, at most 50 (50 from the start of the match)
+	assert.Equal(t,
+		"VWwXetig mty8fORN UNia4NFm SQsfyFHk BLDdgVnc AcvKP2fs q8KxPH1A IaCzFj96 J0S2fqca jp3ElV9f ULIZ1aMX … <b>GSUO1pLI</b> p7vuJie8 kPfc0ONq EthfIUjm u74guCZ8 IiJYxlR6 …",
+		snippets("GSUO1pLI", s))
+	// the first 100 … less than 50, the match, at most 50
+	assert.Equal(t,
+		"VWwXetig mty8fORN UNia4NFm SQsfyFHk BLDdgVnc AcvKP2fs q8KxPH1A IaCzFj96 J0S2fqca jp3ElV9f ULIZ1aMX … GSUO1pLI p7vuJie8 <b>kPfc0ONq</b> EthfIUjm u74guCZ8 IiJYxlR6 5j5LlapY TGO98fOQ …",
+		snippets("kPfc0ONq", s))
+	// the first 100 … 50, the match, at most 50
+	assert.Equal(t,
+		"VWwXetig mty8fORN UNia4NFm SQsfyFHk BLDdgVnc AcvKP2fs q8KxPH1A IaCzFj96 J0S2fqca jp3ElV9f ULIZ1aMX … u74guCZ8 IiJYxlR6 5j5LlapY TGO98fOQ fO2RUb1g <b>W8zaPa0v</b> ps0haNzW OOeFwf1h 1N3td7zk 0OoMX8Ek aTd3Ciea …",
+		snippets("W8zaPa0v", s))
+	// match at the very end
+	assert.Equal(t,
+		"VWwXetig mty8fORN UNia4NFm SQsfyFHk BLDdgVnc AcvKP2fs q8KxPH1A IaCzFj96 J0S2fqca jp3ElV9f ULIZ1aMX … tMpfMMlU p6jGYq3Z rTIBTHVM zGFwFwQi j4O1AY21 <b>BJnaiScY</b>",
+		snippets("BJnaiScY", s))
+	// match near the end
+	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))
+	
+}

upload.html

@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <meta name="format-detection" content="telephone=no">
+    <meta name="viewport" content="width=device-width">
+    <title>Upload File</title>
+    <style>
+html { max-width: 70ch; padding: 2ch; margin: auto; color: #111; background: #ffe; }
+form, textarea { width: 100%; }
+    </style>
+  </head>
+  <body>
+    <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>
+      <p><input type="submit" value="Save">
+        <a href="/view/index"><button type="button">Cancel</button></a></p>
+    </form>
+  </body>
+</html>

upload_drop.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"io"
+	"net/http"
+	"os"
+	"path"
+)
+
+// 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)
+}
+
+// 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.
+func dropHandler(w http.ResponseWriter, r *http.Request, dir string) {
+	d := path.Dir(dir)
+	// ensure the directory exists
+	fi, err := os.Stat(d)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	if !fi.IsDir() {
+		http.Error(w, "file exists", http.StatusInternalServerError)
+		return
+	}
+	filename := r.FormValue("name")
+	file, _, err := r.FormFile("file")
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	defer file.Close()
+	// backup an existing file with the same name
+	_, err = os.Stat(filename)
+	if err != nil {
+		os.Rename(filename, filename + "~")
+	}
+	// create the new file
+	dst, err := os.Create(d + "/" + filename)
+	if err != nil {
+            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)
+}
+

upload_drop_test.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"bytes"
+	"github.com/stretchr/testify/assert"
+	"mime/multipart"
+	"os"
+	"regexp"
+	"testing"
+)
+
+// wipes testdata
+func TestUpload(t *testing.T) {
+	_ = os.RemoveAll("testdata")
+	// for uploads, the directory is not created automatically
+	os.MkdirAll("testdata", 0755)
+	assert.HTTPStatusCode(t, makeHandler(uploadHandler, false), "GET", "/upload/", 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"))
+	assert.NoError(t, err)
+	file, err := writer.CreateFormFile("file", "example.txt");
+	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")
+	})
+}

view.go

@@ -0,0 +1,32 @@
+package main
+
+import(
+	"net/http"
+	"os"
+)
+
+// rootHandler just redirects to /view/index.
+func rootHandler(w http.ResponseWriter, r *http.Request) {
+	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)
+	if err == nil {
+		w.Write(body)
+		return
+	}
+	p, err := loadPage(name)
+	if err == nil {
+		p.handleTitle(true)
+		p.renderHtml()
+		renderTemplate(w, "view", p)
+		return
+	}
+	http.Redirect(w, r, "/edit/"+name, http.StatusFound)
+}

view.html

@@ -1,7 +1,39 @@
 <!DOCTYPE html>
 <html>
-<body>
-{{.Html}}
-<nav><hr><a href="/edit/{{.Title}}">edit</a></nav>
-</body>
+  <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; }
+body { hyphens: auto; }
+header a { margin-right: 1ch; }
+form { display: inline-block; }
+footer { border-top: 1px solid #888 }
+img { max-width: 100%; }
+    </style>
+  </head>
+  <body lang="{{.Language}}">
+    <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>
+      </form>
+    </header>
+    <main id="main">
+      <h1>{{.Title}}</h1>
+      {{.Html}}
+    </main>
+    <footer>
+      <address>
+        Comments? Send mail to Alex Schroeder <<a href="mailto:alex@alexschroeder.ch">alex@alexschroeder.ch</a>>
+      </address>
+    </footer>
+  </body>
 </html>

view_test.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"github.com/stretchr/testify/assert"
+	"os"
+	"regexp"
+	"testing"
+)
+
+func TestRootHandler(t *testing.T) {
+	HTTPRedirectTo(t, rootHandler, "GET", "/", nil, "/view/index")
+}
+
+// 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))
+}
+
+// wipes testdata
+func TestPageTitleWithAmp(t *testing.T) {
+	_ = os.RemoveAll("testdata")
+
+	p := &Page{Name: "testdata/Rock & Roll", Body: []byte("Dancing")}
+	p.save()
+
+	assert.Regexp(t, regexp.MustCompile("Rock & Roll"),
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/Rock%20%26%20Roll", nil))
+
+	p = &Page{Name: "testdata/Rock & Roll", Body: []byte("# Sex & Drugs & Rock'n'Roll\nOh no!")}
+	p.save()
+
+	assert.Regexp(t, regexp.MustCompile("Sex & Drugs"),
+		assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/Rock%20%26%20Roll", nil))
+
+	t.Cleanup(func() {
+		_ = os.RemoveAll("testdata")
+	})
+}
+
+func TestPageTitleWithQuestionMark(t *testing.T) {
+	_ = os.RemoveAll("testdata")
+
+	p := &Page{Name: "testdata/How about no?", Body: []byte("No means no")}
+	p.save()
+
+	body := assert.HTTPBody(makeHandler(viewHandler, true), "GET", "/view/testdata/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")
+	})
+}

wiki.go

@@ -1,92 +1,110 @@
 package main
 
 import (
+	"fmt"
 	"html/template"
 	"net/http"
 	"os"
 	"regexp"
-	"github.com/gomarkdown/markdown"
 )
 
-var templates = template.Must(template.ParseFiles("edit.html", "view.html"))
+// Templates are parsed at startup.
+var templates = template.Must(
+	template.ParseFiles("edit.html", "add.html", "view.html",
+		"search.html", "upload.html"))
 
-var validPath = regexp.MustCompile("^/(edit|save|view)/([a-zA-Z0-9]+)$")
+// validPath is a regular expression where the second group matches a
+// page, so when the editHandler is called, a URL path of "/edit/foo"
+// results in the editHandler being called with title "foo". The
+// regular expression doesn't define the handlers (this happens in the
+// main function).
+var validPath = regexp.MustCompile("^/([^/]+)/(.*)$")
 
-type Page struct {
-	Title string
-	Body  []byte
-	Html  template.HTML
-}
+// 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+")
 
-func (p *Page) save() error {
-	filename := p.Title + ".md"
-	return os.WriteFile(filename, p.Body, 0600)
-}
-
-func loadPage(title string) (*Page, error) {
-	filename := title + ".md"
-	body, err := os.ReadFile(filename)
-	if err != nil {
-		return nil, err
-	}
-	return &Page{Title: title, Body: body}, nil
-}
-
-
-func renderTemplate(w http.ResponseWriter, tmpl string, p *Page) {
-	err := templates.ExecuteTemplate(w, tmpl+".html", p)
+// 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)
 	}
 }
 
-
-func viewHandler(w http.ResponseWriter, r *http.Request, title string) {
-	p, err := loadPage(title)
-	if err != nil {
-		http.Redirect(w, r, "/edit/"+title, http.StatusFound)
-		return
-	}
-	html := markdown.ToHTML([]byte(p.Body), nil, nil)
-	p.Html = template.HTML(html);
-	renderTemplate(w, "view", p)
-}
-
-func editHandler(w http.ResponseWriter, r *http.Request, title string) {
-	p, err := loadPage(title)
-	if err != nil {
-		p = &Page{Title: title}
-	}
-	renderTemplate(w, "edit", p)
-}
-
-func saveHandler(w http.ResponseWriter, r *http.Request, title string) {
-	body := r.FormValue("body")
-	p := &Page{Title: title, Body: []byte(body)}
-	err := p.save()
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-	http.Redirect(w, r, "/view/"+title, http.StatusFound)
-}
-
-func makeHandler(fn func (http.ResponseWriter, *http.Request, string)) http.HandlerFunc {
+// 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.
+func makeHandler(fn func(http.ResponseWriter, *http.Request, string), required bool) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		m := validPath.FindStringSubmatch(r.URL.Path)
-		if m == nil {
+		if m != nil && (!required || len(m[2]) > 0) {
+			fn(w, r, m[2])
+		} else {
 			http.NotFound(w, r)
-			return
 		}
-		fn(w, r, m[2])
 	}
 }
 
+// getPort returns the environment variable ODDMU_PORT or the default
+// port, "8080".
+func getPort() string {
+	port := os.Getenv("ODDMU_PORT")
+	if port == "" {
+		port = "8080"
+	}
+	return port
+}
+
+// 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")
+	n, err := index.load()
+	if err == nil {
+		fmt.Printf("Indexed %d pages\n", n)
+	} else {
+		fmt.Println("Indexing failed")
+	}
+}
+
+// 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")
+	n := loadLanguages()
+	fmt.Printf("Loaded %d languages\n", n)
+}
+
+func serve() {
+	http.HandleFunc("/", rootHandler)
+	http.HandleFunc("/view/", makeHandler(viewHandler, 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)
+	go scheduleLoadIndex()
+	go scheduleLoadLanguages()
+	port := getPort()
+	fmt.Printf("Serving a wiki on port %s\n", port)
+	http.ListenAndServe(":"+port, nil)
+}
 
 func main() {
-	http.HandleFunc("/view/", makeHandler(viewHandler))
-	http.HandleFunc("/edit/", makeHandler(editHandler))
-	http.HandleFunc("/save/", makeHandler(saveHandler))
-
-	http.ListenAndServe(":8080", nil)
+	if len(os.Args) == 1 {
+		serve()
+	} else {
+		commands()
+	}
 }

wiki_test.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"bytes"
+	"github.com/stretchr/testify/assert"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+)
+
+// HTTPHeaders is a helper that returns HTTP headers of the response. It returns
+// nil if building a new request fails.
+func HTTPHeaders(handler http.HandlerFunc, method, url string, values url.Values, header string) []string {
+	w := httptest.NewRecorder()
+	req, err := http.NewRequest(method, url+"?"+values.Encode(), nil)
+	if err != nil {
+		return nil
+	}
+	handler(w, req)
+	return w.Result().Header[header]
+}
+
+// HTTPRedirectTo checks that the request results in a redirect and it
+// checks the destination of the redirect. It returns whether the
+// request did in fact result in a redirect. Note: This method assumes
+// that POST requests ignore the query part of the URL.
+func HTTPRedirectTo(t *testing.T, handler http.HandlerFunc, method, url string, values url.Values, destination string) bool {
+	w := httptest.NewRecorder()
+	var req *http.Request
+	var err error
+	if method == http.MethodPost {
+		body := strings.NewReader(values.Encode())
+		req, err = http.NewRequest(method, url, body)
+		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	} else {
+		req, err = http.NewRequest(method, url+"?"+values.Encode(), nil)
+	}
+	assert.NoError(t, err)
+	handler(w, req)
+	code := w.Code
+	isRedirectCode := code >= http.StatusMultipleChoices && code <= http.StatusTemporaryRedirect
+	assert.True(t, isRedirectCode, "Expected HTTP redirect status code for %q but received %d", url+"?"+values.Encode(), code)
+	headers := w.Result().Header["Location"]
+	assert.True(t, len(headers) == 1 && headers[0] == destination,
+		"Expected HTTP redirect location %s for %q but received %v", destination, url+"?"+values.Encode(), headers)
+	return isRedirectCode
+}
+
+// HTTPUploadAndRedirectTo checks that the request results in a redirect and it
+// checks the destination of the redirect. It returns whether the
+// request did in fact result in a redirect.
+func HTTPUploadAndRedirectTo(t *testing.T, handler http.HandlerFunc, url, contentType string, body *bytes.Buffer, destination string) bool {
+	w := httptest.NewRecorder()
+	req, err := http.NewRequest("POST", url, body)
+	req.Header.Set("Content-Type", contentType)
+	assert.NoError(t, err)
+	handler(w, req)
+	code := w.Code
+	isRedirectCode := code >= http.StatusMultipleChoices && code <= http.StatusTemporaryRedirect
+	assert.True(t, isRedirectCode, "Expected HTTP redirect status code for %q but received %d", url, code)
+	headers := w.Result().Header["Location"]
+	assert.True(t, len(headers) == 1 && headers[0] == destination,
+		"Expected HTTP redirect location %s for %q but received %v", destination, url, headers)
+	return isRedirectCode
+}