browse: Fix known bugs (#770)

* browse: Catch the case of a directory disappearing before having been read

* browse: Revert to old pass-through behaviour

PROPFIND is a request for an alternate view on a directory's contents, which
response is indeed not implemented but ideally allowed to ask for.
OPTIONS would ideally return (at least) what methods the requestor could use,
which is an allowed request method, too.

This addresses #767.

middleware/browse/browse.go

@@ -234,12 +234,11 @@ func (b Browse) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 	for i := range b.Configs {
 		if middleware.Path(r.URL.Path).Matches(b.Configs[i].PathScope) {
 			bc = &b.Configs[i]
-			break
+			goto inScope
 		}
 	}
-	if bc == nil {
 	return b.Next.ServeHTTP(w, r)
-	}
+inScope:
 
 	// Browse works on existing directories; delegate everything else
 	requestedFilepath := filepath.Join(b.Root, r.URL.Path)
@@ -261,8 +260,11 @@ func (b Browse) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 	// Do not reply to anything else because it might be nonsensical
 	switch r.Method {
 	case http.MethodGet, http.MethodHead:
+		// proceed, noop
+	case "PROPFIND", http.MethodOptions:
+		return http.StatusNotImplemented, nil
 	default:
-		return http.StatusMethodNotAllowed, nil
+		return b.Next.ServeHTTP(w, r)
 	}
 
 	// Browsing navigation gets messed up if browsing a directory
@@ -275,20 +277,28 @@ func (b Browse) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 	// Load directory contents
 	file, err := os.Open(requestedFilepath)
 	if err != nil {
-		if os.IsPermission(err) {
+		switch {
+		case os.IsPermission(err):
 			return http.StatusForbidden, err
-		}
+		case os.IsExist(err):
+			return http.StatusGone, err
+		default:
 			return http.StatusInternalServerError, err
 		}
+	}
 	defer file.Close()
 
 	files, err := file.Readdir(-1)
 	if err != nil {
-		if os.IsPermission(err) {
+		switch {
+		case os.IsPermission(err):
 			return http.StatusForbidden, err
-		}
+		case os.IsExist(err):
+			return http.StatusGone, err
+		default:
 			return http.StatusInternalServerError, err
 		}
+	}
 
 	// Determine if user can browse up another folder
 	var canGoUp bool
@@ -302,7 +312,7 @@ func (b Browse) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 	// Assemble listing of directory contents
 	listing, err := directoryListing(files, r, canGoUp, b.Root, b.IgnoreIndexes, bc.Variables)
 	if err != nil { // directory isn't browsable
-		return http.StatusInternalServerError, err
+		return b.Next.ServeHTTP(w, r)
 	}
 
 	// Copy the query values into the Listing struct

middleware/browse/browse_test.go

@@ -112,8 +112,7 @@ func TestBrowseHTTPMethods(t *testing.T) {
 
 	b := Browse{
 		Next: middleware.HandlerFunc(func(w http.ResponseWriter, r *http.Request) (int, error) {
-			t.Fatalf("Next shouldn't be called")
-			return 0, nil
+			return http.StatusTeapot, nil // not t.Fatalf, or we will not see what other methods yield
 		}),
 		Root: "./testdata",
 		Configs: []Config{
@@ -128,14 +127,8 @@ func TestBrowseHTTPMethods(t *testing.T) {
 	for method, expected := range map[string]int{
 		http.MethodGet:     http.StatusOK,
 		http.MethodHead:    http.StatusOK,
-		http.MethodOptions: http.StatusMethodNotAllowed,
-		http.MethodPost:    http.StatusMethodNotAllowed,
-		http.MethodPut:     http.StatusMethodNotAllowed,
-		http.MethodPatch:   http.StatusMethodNotAllowed,
-		http.MethodDelete:  http.StatusMethodNotAllowed,
-		"COPY":             http.StatusMethodNotAllowed,
-		"MOVE":             http.StatusMethodNotAllowed,
-		"MKCOL":            http.StatusMethodNotAllowed,
+		http.MethodOptions: http.StatusNotImplemented,
+		"PROPFIND":         http.StatusNotImplemented,
 	} {
 		req, err := http.NewRequest(method, "/photos/", nil)
 		if err != nil {