Error pages and header merge

middlewares/errorpages/error_pages.go

@@ -101,12 +101,7 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, req *http.Request, next http.
 
 			h.backendHandler.ServeHTTP(recorderErrorPage, pageReq.WithContext(req.Context()))
 
-			utils.CopyHeaders(w.Header(), recorder.Header())
-			for key := range recorderErrorPage.Header() {
-				w.Header().Del(key)
-			}
 			utils.CopyHeaders(w.Header(), recorderErrorPage.Header())
-
 			w.WriteHeader(recorder.GetCode())
 			w.Write(recorderErrorPage.GetBody().Bytes())
 			return
@@ -174,64 +169,65 @@ type responseRecorderWithCloseNotify struct {
 
 // CloseNotify returns a channel that receives at most a
 // single value (true) when the client connection has gone away.
-func (rw *responseRecorderWithCloseNotify) CloseNotify() <-chan bool {
-	return rw.responseWriter.(http.CloseNotifier).CloseNotify()
+func (r *responseRecorderWithCloseNotify) CloseNotify() <-chan bool {
+	return r.responseWriter.(http.CloseNotifier).CloseNotify()
 }
 
 // Header returns the response headers.
-func (rw *responseRecorderWithoutCloseNotify) Header() http.Header {
-	if rw.HeaderMap == nil {
-		rw.HeaderMap = make(http.Header)
+func (r *responseRecorderWithoutCloseNotify) Header() http.Header {
+	if r.HeaderMap == nil {
+		r.HeaderMap = make(http.Header)
 	}
-	return rw.HeaderMap
+
+	return r.HeaderMap
 }
 
-func (rw *responseRecorderWithoutCloseNotify) GetCode() int {
-	return rw.Code
+func (r *responseRecorderWithoutCloseNotify) GetCode() int {
+	return r.Code
 }
 
-func (rw *responseRecorderWithoutCloseNotify) GetBody() *bytes.Buffer {
-	return rw.Body
+func (r *responseRecorderWithoutCloseNotify) GetBody() *bytes.Buffer {
+	return r.Body
 }
 
-func (rw *responseRecorderWithoutCloseNotify) IsStreamingResponseStarted() bool {
-	return rw.streamingResponseStarted
+func (r *responseRecorderWithoutCloseNotify) IsStreamingResponseStarted() bool {
+	return r.streamingResponseStarted
 }
 
 // Write always succeeds and writes to rw.Body, if not nil.
-func (rw *responseRecorderWithoutCloseNotify) Write(buf []byte) (int, error) {
-	if rw.err != nil {
-		return 0, rw.err
+func (r *responseRecorderWithoutCloseNotify) Write(buf []byte) (int, error) {
+	if r.err != nil {
+		return 0, r.err
 	}
-	return rw.Body.Write(buf)
+	return r.Body.Write(buf)
 }
 
 // WriteHeader sets rw.Code.
-func (rw *responseRecorderWithoutCloseNotify) WriteHeader(code int) {
-	rw.Code = code
+func (r *responseRecorderWithoutCloseNotify) WriteHeader(code int) {
+	r.Code = code
 }
 
 // Hijack hijacks the connection
-func (rw *responseRecorderWithoutCloseNotify) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-	return rw.responseWriter.(http.Hijacker).Hijack()
+func (r *responseRecorderWithoutCloseNotify) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return r.responseWriter.(http.Hijacker).Hijack()
 }
 
 // Flush sends any buffered data to the client.
-func (rw *responseRecorderWithoutCloseNotify) Flush() {
-	if !rw.streamingResponseStarted {
-		utils.CopyHeaders(rw.responseWriter.Header(), rw.Header())
-		rw.responseWriter.WriteHeader(rw.Code)
-		rw.streamingResponseStarted = true
+func (r *responseRecorderWithoutCloseNotify) Flush() {
+	if !r.streamingResponseStarted {
+		utils.CopyHeaders(r.responseWriter.Header(), r.Header())
+		r.responseWriter.WriteHeader(r.Code)
+		r.streamingResponseStarted = true
 	}
 
-	_, err := rw.responseWriter.Write(rw.Body.Bytes())
+	_, err := r.responseWriter.Write(r.Body.Bytes())
 	if err != nil {
-		log.Errorf("Error writing response in responseRecorder: %s", err)
-		rw.err = err
+		log.Errorf("Error writing response in responseRecorder: %v", err)
+		r.err = err
 	}
-	rw.Body.Reset()
+	r.Body.Reset()
 
-	if flusher, ok := rw.responseWriter.(http.Flusher); ok {
+	if flusher, ok := r.responseWriter.(http.Flusher); ok {
 		flusher.Flush()
 	}
 }

middlewares/errorpages/error_pages_test.go

@@ -318,7 +318,6 @@ func TestHandlerOldWayIntegration(t *testing.T) {
 			require.NoError(t, err)
 
 			handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-				w.Header().Set("X-Foo", "bar")
 				w.WriteHeader(test.backendCode)
 				fmt.Fprintln(w, http.StatusText(test.backendCode))
 			})
@@ -331,7 +330,6 @@ func TestHandlerOldWayIntegration(t *testing.T) {
 			n.ServeHTTP(recorder, req)
 
 			test.validate(t, recorder)
-			assert.Equal(t, "bar", recorder.Header().Get("X-Foo"), "missing header")
 		})
 	}
 }