Files
oddmu/diff.go
Alex Schroeder 098fc1ba19 Unescape the page name for diff
Diff needs to read the files after renderHtml has already escaped the
page name. Perhaps a different solution would be better: two
attributes for Page and changing all the templates to use the new
EscapedName attribute?
2023-10-28 00:56:32 +02:00

67 lines
1.7 KiB
Go

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