rewrite diff endpoint to nice URL

WikiServer.go

@@ -6,6 +6,7 @@ import (
 	"html/template"
 	"net/http"
 	"net/url"
+	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -16,6 +17,7 @@ type WikiServer struct {
 	opts    *ServerOptions
 	pageTmp *template.Template
 	loc     *time.Location
+	rxDiff  *regexp.Regexp
 }
 
 func NewWikiServer(opts *ServerOptions) (*WikiServer, error) {
@@ -39,6 +41,7 @@ func NewWikiServer(opts *ServerOptions) (*WikiServer, error) {
 		opts:    opts,
 		pageTmp: tmpl,
 		loc:     loc,
+		rxDiff:  regexp.MustCompile(`diff/(\d+)/(\d+)`),
 	}
 	return &ws, nil
 }
@@ -50,6 +53,11 @@ func (this *WikiServer) Close() {
 func (this *WikiServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Server", "YATWiki3")
 
+	if !strings.HasPrefix(r.URL.Path, this.opts.ExpectBaseURL) {
+		http.Error(w, "Bad request", 400)
+		return
+	}
+
 	if r.Method == "GET" {
 		if r.URL.Path == this.opts.ExpectBaseURL+"wiki.css" {
 			w.Header().Set("Content-Type", "text/css")
@@ -140,14 +148,18 @@ func (this *WikiServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			return
 
 		} else if r.URL.Path == this.opts.ExpectBaseURL+"diff" {
+			this.serveRedirect(w, this.opts.ExpectBaseURL+`diff/`+r.URL.Query().Get("f")+`/`+r.URL.Query().Get("t"))
+			return
 
-			fromRev, err := strconv.Atoi(r.URL.Query().Get("f"))
+		} else if match := this.rxDiff.FindStringSubmatch(r.URL.Path[len(this.opts.ExpectBaseURL):]); len(match) == 3 {
+
+			fromRev, err := strconv.Atoi(match[1])
 			if err != nil {
 				this.serveErrorMessage(w, err)
 				return
 			}
 
-			toRev, err := strconv.Atoi(r.URL.Query().Get("t"))
+			toRev, err := strconv.Atoi(match[2])
 			if err != nil {
 				this.serveErrorMessage(w, err)
 				return