Push down headers from client (#1453)

* Push down headers from client

* Push first, serve later

* After review fixes

caddyhttp/push/handler.go

@@ -21,20 +21,16 @@ func (h Middleware) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, erro
 		return h.Next.ServeHTTP(w, r)
 	}
 
-	// Serve file first
-	code, err := h.Next.ServeHTTP(w, r)
-
-	if flusher, ok := w.(http.Flusher); ok {
-		flusher.Flush()
-	}
+	headers := h.filterProxiedHeaders(r.Header)
 
+	// Push first
 outer:
 	for _, rule := range h.Rules {
 		if httpserver.Path(r.URL.Path).Matches(rule.Path) {
 			for _, resource := range rule.Resources {
 				pushErr := pusher.Push(resource.Path, &http.PushOptions{
 					Method: resource.Method,
-					Header: resource.Header,
+					Header: h.mergeHeaders(headers, resource.Header),
 				})
 				if pushErr != nil {
 					// If we cannot push (either not supported or concurrent streams are full - break)
@@ -44,14 +40,17 @@ outer:
 		}
 	}
 
+	// Serve later
+	code, err := h.Next.ServeHTTP(w, r)
+
 	if links, exists := w.Header()["Link"]; exists {
-		h.pushLinks(pusher, links)
+		h.servePreloadLinks(pusher, headers, links)
 	}
 
 	return code, err
 }
 
-func (h Middleware) pushLinks(pusher http.Pusher, links []string) {
+func (h Middleware) servePreloadLinks(pusher http.Pusher, headers http.Header, links []string) {
 outer:
 	for _, link := range links {
 		parts := strings.Split(link, ";")
@@ -62,9 +61,51 @@ outer:
 
 		target := strings.TrimSuffix(strings.TrimPrefix(parts[0], "<"), ">")
 
-		err := pusher.Push(target, &http.PushOptions{Method: http.MethodGet})
+		err := pusher.Push(target, &http.PushOptions{
+			Method: http.MethodGet,
+			Header: headers,
+		})
+
 		if err != nil {
 			break outer
 		}
 	}
 }
+
+func (h Middleware) mergeHeaders(l, r http.Header) http.Header {
+
+	out := http.Header{}
+
+	for k, v := range l {
+		out[k] = v
+	}
+
+	for k, vv := range r {
+		for _, v := range vv {
+			out.Add(k, v)
+		}
+	}
+
+	return out
+}
+
+func (h Middleware) filterProxiedHeaders(headers http.Header) http.Header {
+
+	filter := http.Header{}
+
+	for _, header := range proxiedHeaders {
+		if val, ok := headers[header]; ok {
+			filter[header] = val
+		}
+	}
+
+	return filter
+}
+
+var proxiedHeaders = []string{
+	"Accept-Encoding",
+	"Accept-Language",
+	"Cache-Control",
+	"Host",
+	"User-Agent",
+}

caddyhttp/push/handler_test.go

@@ -61,7 +61,51 @@ func TestMiddlewareWillPushResources(t *testing.T) {
 
 		"/index2.css": {
 			Method: http.MethodGet,
-			Header: nil,
+			Header: http.Header{},
+		},
+	}
+
+	comparePushedResources(t, expectedPushedResources, pushingWriter.pushed)
+}
+
+func TestMiddlewareWillPushResourcesWithMergedHeaders(t *testing.T) {
+
+	// given
+	request, err := http.NewRequest(http.MethodGet, "/index.html", nil)
+	request.Header = http.Header{"Accept-Encoding": []string{"br"}, "Invalid-Header": []string{"Should be filter out"}}
+	writer := httptest.NewRecorder()
+
+	if err != nil {
+		t.Fatalf("Could not create HTTP request: %v", err)
+	}
+
+	middleware := Middleware{
+		Next: httpserver.HandlerFunc(func(w http.ResponseWriter, r *http.Request) (int, error) {
+			return 0, nil
+		}),
+		Rules: []Rule{
+			{Path: "/index.html", Resources: []Resource{
+				{Path: "/index.css", Method: http.MethodHead, Header: http.Header{"Test": []string{"Value"}}},
+				{Path: "/index2.css", Method: http.MethodGet},
+			}},
+		},
+	}
+
+	pushingWriter := &MockedPusher{ResponseWriter: writer}
+
+	// when
+	middleware.ServeHTTP(pushingWriter, request)
+
+	// then
+	expectedPushedResources := map[string]*http.PushOptions{
+		"/index.css": {
+			Method: http.MethodHead,
+			Header: http.Header{"Test": []string{"Value"}, "Accept-Encoding": []string{"br"}},
+		},
+
+		"/index2.css": {
+			Method: http.MethodGet,
+			Header: http.Header{"Accept-Encoding": []string{"br"}},
 		},
 	}
 
@@ -169,7 +213,7 @@ func TestMiddlewareWillNotPushResources(t *testing.T) {
 
 	// then
 	if err2 != nil {
-		t.Errorf("Should not return error")
+		t.Error("Should not return error")
 	}
 }
 
@@ -201,21 +245,21 @@ func TestMiddlewareShouldInterceptLinkHeader(t *testing.T) {
 
 	// then
 	if err2 != nil {
-		t.Errorf("Should not return error")
+		t.Error("Should not return error")
 	}
 
 	expectedPushedResources := map[string]*http.PushOptions{
 		"/index.css": {
 			Method: http.MethodGet,
-			Header: nil,
+			Header: http.Header{},
 		},
 		"/index2.css": {
 			Method: http.MethodGet,
-			Header: nil,
+			Header: http.Header{},
 		},
 		"/index3.css": {
 			Method: http.MethodGet,
-			Header: nil,
+			Header: http.Header{},
 		},
 	}
 
@@ -224,7 +268,10 @@ func TestMiddlewareShouldInterceptLinkHeader(t *testing.T) {
 
 func TestMiddlewareShouldInterceptLinkHeaderPusherError(t *testing.T) {
 	// given
+	expectedHeaders := http.Header{"Accept-Encoding": []string{"br"}}
 	request, err := http.NewRequest(http.MethodGet, "/index.html", nil)
+	request.Header = http.Header{"Accept-Encoding": []string{"br"}, "Invalid-Header": []string{"Should be filter out"}}
+
 	writer := httptest.NewRecorder()
 
 	if err != nil {
@@ -247,13 +294,13 @@ func TestMiddlewareShouldInterceptLinkHeaderPusherError(t *testing.T) {
 
 	// then
 	if err2 != nil {
-		t.Errorf("Should not return error")
+		t.Error("Should not return error")
 	}
 
 	expectedPushedResources := map[string]*http.PushOptions{
 		"/index.css": {
 			Method: http.MethodGet,
-			Header: nil,
+			Header: expectedHeaders,
 		},
 	}
 
@@ -273,7 +320,7 @@ func comparePushedResources(t *testing.T, expected, actual map[string]*http.Push
 			}
 
 			if !reflect.DeepEqual(expectedTarget.Header, actualTarget.Header) {
-				t.Errorf("Expected %s resource push headers to be %v, actual: %v", target, expectedTarget.Header, actualTarget.Header)
+				t.Errorf("Expected %s resource push headers to be %+v, actual: %+v", target, expectedTarget.Header, actualTarget.Header)
 			}
 		} else {
 			t.Errorf("Expected %s to be pushed", target)