fix(lib): enable multiple consecutive slash support (#1155)

* fix(lib): enable multiple consecutive slash support

Closes #754
Closes #808
Closes #815

Apparently more applications use multiple slashes in a row than I
thought. There is no easy way around this other than to do this hacky
fix to avoid net/http#ServeMux's URL cleaning.

* test(double_slash): add sourceware case

Signed-off-by: Xe Iaso <me@xeiaso.net>

* test(lib): fix tests for double slash fix

Signed-off-by: Xe Iaso <me@xeiaso.net>

---------

Signed-off-by: Xe Iaso <xe.iaso@techaro.lol>
Signed-off-by: Xe Iaso <me@xeiaso.net>

lib/anubis_test.go

@@ -457,7 +457,7 @@ func TestBasePrefix(t *testing.T) {
 	}{
 		{
 			name:       "no prefix",
-			basePrefix: "/",
+			basePrefix: "",
 			path:       "/.within.website/x/cmd/anubis/api/make-challenge",
 			expected:   "/.within.website/x/cmd/anubis/api/make-challenge",
 		},
@@ -499,9 +499,15 @@ func TestBasePrefix(t *testing.T) {
 			}
 
 			q := req.URL.Query()
-			q.Set("redir", tc.basePrefix)
+			redir := tc.basePrefix
+			if tc.basePrefix == "" {
+				redir = "/"
+			}
+			q.Set("redir", redir)
 			req.URL.RawQuery = q.Encode()
 
+			t.Log(req.URL.String())
+
 			// Test API endpoint with prefix
 			resp, err := cli.Do(req)
 			if err != nil {
@@ -513,8 +519,15 @@ func TestBasePrefix(t *testing.T) {
 				t.Errorf("expected status code %d, got: %d", http.StatusOK, resp.StatusCode)
 			}
 
+			data, err := io.ReadAll(resp.Body)
+			if err != nil {
+				t.Fatalf("can't read body: %v", err)
+			}
+
+			t.Log(string(data))
+
 			var chall challengeResp
-			if err := json.NewDecoder(resp.Body).Decode(&chall); err != nil {
+			if err := json.NewDecoder(bytes.NewBuffer(data)).Decode(&chall); err != nil {
 				t.Fatalf("can't read challenge response body: %v", err)
 			}
 
@@ -535,7 +548,7 @@ func TestBasePrefix(t *testing.T) {
 				nonce++
 			}
 			elapsedTime := 420
-			redir := "/"
+			redir = "/"
 
 			cli.CheckRedirect = func(req *http.Request, via []*http.Request) error {
 				return http.ErrUseLastResponse

lib/config.go

@@ -107,7 +107,7 @@ func New(opts Options) (*Server, error) {
 		opts.ED25519PrivateKey = priv
 	}
 
-	anubis.BasePrefix = opts.BasePrefix
+	anubis.BasePrefix = strings.TrimRight(opts.BasePrefix, "/")
 	anubis.PublicUrl = opts.PublicUrl
 
 	result := &Server{

lib/http.go

@@ -279,7 +279,12 @@ func (s *Server) respondWithStatus(w http.ResponseWriter, r *http.Request, msg s
 }
 
 func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	s.mux.ServeHTTP(w, r)
+	if strings.HasPrefix(r.URL.Path, anubis.BasePrefix+anubis.StaticPath) {
+		s.mux.ServeHTTP(w, r)
+		return
+	}
+
+	s.maybeReverseProxyOrPage(w, r)
 }
 
 func (s *Server) stripBasePrefixFromRequest(r *http.Request) *http.Request {