Fix response for empty topic/queue by responding with HTTP 204 No Content instead of 404 Not Found (Fixes #25)

client/client.go

@@ -93,7 +93,8 @@ func (c *Client) Pull(topic string) (msg *msgbus.Message, err error) {
 		return nil, err
 	}
 
-	if res.StatusCode == http.StatusNotFound {
+	// XXX: StatusNotFound is for backwards compatibility only for older clients.
+	if res.StatusCode == http.StatusNoContent || res.StatusCode == http.StatusNotFound {
 		// Empty queue
 		return nil, nil
 	}

go.mod

@@ -1,6 +1,6 @@
 module git.mills.io/prologic/msgbus
 
-go 1.17
+go 1.18
 
 require (
 	github.com/gorilla/websocket v1.5.0

msgbus.go

@@ -567,8 +567,7 @@ func (mb *MessageBus) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		message, ok := mb.Get(t)
 
 		if !ok {
-			msg := fmt.Sprintf("no messages enqueued for topic: %s", topic)
-			http.Error(w, msg, http.StatusNotFound)
+			http.Error(w, "No Messages", http.StatusNoContent)
 			return
 		}
 

msgbus_test.go

@@ -89,7 +89,7 @@ func TestServeHTTPGETEmptyQueue(t *testing.T) {
 	r, _ := http.NewRequest("GET", "/hello", nil)
 
 	mb.ServeHTTP(w, r)
-	assert.Equal(w.Code, http.StatusNotFound)
+	assert.Equal(w.Code, http.StatusNoContent)
 }
 
 func TestServeHTTPPOST(t *testing.T) {