Open the HTTP body to hint clients that all headers have been sent

dunglas · Mar 21, 2019 · 99cb809 · 99cb809
1 parent d3283bc
commit 99cb809
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Showing 3 changed files with 12 additions and 8 deletions.
diff --git a/hub/server_test.go b/hub/server_test.go
@@ -95,7 +95,7 @@ func TestServe(t *testing.T) {
 		defer resp.Body.Close()
 		body, _ := ioutil.ReadAll(resp.Body)
 
-		assert.Equal(t, []byte("id: first\ndata: hello\n\n"), body)
+		assert.Equal(t, []byte(":\nid: first\ndata: hello\n\n"), body)
 	}()
 
 	go func() {
@@ -109,7 +109,7 @@ func TestServe(t *testing.T) {
 		defer resp.Body.Close()
 		body, _ := ioutil.ReadAll(resp.Body)
 
-		assert.Equal(t, []byte("id: first\ndata: hello\n\n"), body)
+		assert.Equal(t, []byte(":\nid: first\ndata: hello\n\n"), body)
 	}()
 
 	wgConnected.Wait()

diff --git a/hub/subscribe.go b/hub/subscribe.go
@@ -120,6 +120,10 @@ func sendHeaders(w http.ResponseWriter) {
 
 	// NGINX support https://www.nginx.com/resources/wiki/start/topics/examples/x-accel/#x-accel-buffering
 	w.Header().Set("X-Accel-Buffering", "no")
+
+	// Write a comment in the body
+	// Go currently doesn't provide a better way to flush the headers
+	fmt.Fprint(w, ":\n")
 	w.(http.Flusher).Flush()
 }
 

diff --git a/hub/subscribe_test.go b/hub/subscribe_test.go
@@ -160,7 +160,7 @@ func TestSubscribe(t *testing.T) {
 
 	resp := w.Result()
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
-	assert.Equal(t, "id: b\ndata: Hello World\n\nid: c\ndata: Great\n\n", w.Body.String())
+	assert.Equal(t, ":\nid: b\ndata: Hello World\n\nid: c\ndata: Great\n\n", w.Body.String())
 }
 
 func TestUnsubscribe(t *testing.T) {
@@ -234,7 +234,7 @@ func TestSubscribeTarget(t *testing.T) {
 
 	resp := w.Result()
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
-	assert.Equal(t, "event: test\nid: b\ndata: Hello World\n\nretry: 1\nid: c\ndata: Great\n\n", w.Body.String())
+	assert.Equal(t, ":\nevent: test\nid: b\ndata: Hello World\n\nretry: 1\nid: c\ndata: Great\n\n", w.Body.String())
 }
 
 func TestSubscribeAllTargets(t *testing.T) {
@@ -274,7 +274,7 @@ func TestSubscribeAllTargets(t *testing.T) {
 
 	resp := w.Result()
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
-	assert.Equal(t, "id: a\ndata: Foo\n\nevent: test\nid: b\ndata: Hello World\n\n", w.Body.String())
+	assert.Equal(t, ":\nid: a\ndata: Foo\n\nevent: test\nid: b\ndata: Hello World\n\n", w.Body.String())
 }
 
 func TestSendMissedEvents(t *testing.T) {
@@ -309,7 +309,7 @@ func TestSendMissedEvents(t *testing.T) {
 		defer w.Done()
 		req := httptest.NewRequest("GET", "http://example.com/hub?topic=http://example.com/foos/{id}&Last-Event-ID=a", nil)
 		hub.SubscribeHandler(wr1, req)
-		assert.Equal(t, "id: b\ndata: d2\n\n", wr1.Body.String())
+		assert.Equal(t, ":\nid: b\ndata: d2\n\n", wr1.Body.String())
 	}(&wg)
 
 	wr2 := newCloseNotifyingRecorder()
@@ -318,7 +318,7 @@ func TestSendMissedEvents(t *testing.T) {
 		req := httptest.NewRequest("GET", "http://example.com/hub?topic=http://example.com/foos/{id}", nil)
 		req.Header.Add("Last-Event-ID", "a")
 		hub.SubscribeHandler(wr2, req)
-		assert.Equal(t, "id: b\ndata: d2\n\n", wr2.Body.String())
+		assert.Equal(t, ":\nid: b\ndata: d2\n\n", wr2.Body.String())
 	}(&wg)
 
 	for {
@@ -368,7 +368,7 @@ func TestSubscribeHeartbeat(t *testing.T) {
 
 	resp := w.Result()
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
-	assert.Equal(t, "id: b\ndata: Hello World\n\n:\n", w.Body.String())
+	assert.Equal(t, ":\nid: b\ndata: Hello World\n\n:\n", w.Body.String())
 }
 
 // From https://github.com/go-martini/martini/blob/master/response_writer_test.go