fix：introduce buffered response writer for webdav, fix status/error return failed. (#2544)

* fix: introduce buffered response writer for webdav, fix webdav status/error return failed.

* fix: bypass buffered writer for GET/HEAD/POST requests

server/webdav/buffered_response_writer.go

@@ -0,0 +1,46 @@
+package webdav
+
+import (
+	"net/http"
+)
+
+type bufferedResponseWriter struct {
+	statusCode int
+	data       []byte
+	header     http.Header
+}
+
+func (w *bufferedResponseWriter) Header() http.Header {
+	if w.header == nil {
+		w.header = make(http.Header)
+	}
+	return w.header
+}
+
+func (w *bufferedResponseWriter) Write(bytes []byte) (int, error) {
+	w.data = append(w.data, bytes...)
+	return len(bytes), nil
+}
+
+func (w *bufferedResponseWriter) WriteHeader(statusCode int) {
+	if w.statusCode == 0 {
+		w.statusCode = statusCode
+	}
+}
+
+func (w *bufferedResponseWriter) WriteToResponse(rw http.ResponseWriter) (int, error) {
+	h := rw.Header()
+	for k, vs := range w.header {
+		for _, v := range vs {
+			h.Add(k, v)
+		}
+	}
+	rw.WriteHeader(w.statusCode)
+	return rw.Write(w.data)
+}
+
+func newBufferedResponseWriter() *bufferedResponseWriter {
+	return &bufferedResponseWriter{
+		statusCode: 0,
+	}
+}

server/webdav/webdav.go

@@ -45,30 +45,33 @@ func (h *Handler) stripPrefix(p string) (string, int, error) {
 
 func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	status, err := http.StatusBadRequest, errUnsupportedMethod
+	brw := newBufferedResponseWriter()
+	useBufferedWriter := true
 	if h.LockSystem == nil {
 		status, err = http.StatusInternalServerError, errNoLockSystem
 	} else {
 		switch r.Method {
 		case "OPTIONS":
-			status, err = h.handleOptions(w, r)
+			status, err = h.handleOptions(brw, r)
 		case "GET", "HEAD", "POST":
+			useBufferedWriter = false
 			status, err = h.handleGetHeadPost(w, r)
 		case "DELETE":
-			status, err = h.handleDelete(w, r)
+			status, err = h.handleDelete(brw, r)
 		case "PUT":
-			status, err = h.handlePut(w, r)
+			status, err = h.handlePut(brw, r)
 		case "MKCOL":
-			status, err = h.handleMkcol(w, r)
+			status, err = h.handleMkcol(brw, r)
 		case "COPY", "MOVE":
-			status, err = h.handleCopyMove(w, r)
+			status, err = h.handleCopyMove(brw, r)
 		case "LOCK":
-			status, err = h.handleLock(w, r)
+			status, err = h.handleLock(brw, r)
 		case "UNLOCK":
-			status, err = h.handleUnlock(w, r)
+			status, err = h.handleUnlock(brw, r)
 		case "PROPFIND":
-			status, err = h.handlePropfind(w, r)
+			status, err = h.handlePropfind(brw, r)
 		case "PROPPATCH":
-			status, err = h.handleProppatch(w, r)
+			status, err = h.handleProppatch(brw, r)
 		}
 	}
 
@@ -77,6 +80,8 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		if status != http.StatusNoContent {
 			w.Write([]byte(StatusText(status)))
 		}
+	} else if useBufferedWriter {
+		brw.WriteToResponse(w)
 	}
 	if h.Logger != nil && err != nil {
 		h.Logger(r, err)