Stomp via websocket using Spring and sockJS message lost

Question

Client side javascript I have

stomp.subscribe("/topic/path", function (message) { console.info("message received"); }); 

And server side

 public class Controller { private final MessageSendingOperations<String> messagingTemplate; ＠Autowired public Controller(MessageSendingOperations<String> messagingTemplate) { this.messagingTemplate = messagingTemplate; } @SubscribeMapping("/topic/path") public void subscribe() { LOGGER.info("before send"); messagingTemplate.convertAndSend(/topic/path, "msg"); } } 

From this setting, I sometimes (approximately once per 30 pages updated) experience a message, which means that I see neither the message “received” on the client side, nor the web feed using the Chrome debugging tool.

"before sending" is always registered on the server side.

It seems that MessageSendingOperations is not ready when I call it in the subscribe () method. (if I set Thread.sleep (50), before calling messagingTemplate.convertAndSend the problem will disappear (or will be reproduced much less often))

I wonder if someone has experienced the same thing before, and if there is an event that can tell me that MessageSendingOperations is ready or not.

Answer 1

The problem you are facing by default is clientInboundChannel , which is ExecutorSubscribableChannel by default.

It has 3 subscribers :

 0 = { SimpleBrokerMessageHandler@5276 } "SimpleBroker[DefaultSubscriptionRegistry[cache[0 destination(s)], registry[0 sessions]]]" 1 = { UserDestinationMessageHandler@5277 } "UserDestinationMessageHandler[DefaultUserDestinationResolver[prefix=/user/]]" 2 = { SimpAnnotationMethodMessageHandler@5278 } "SimpAnnotationMethodMessageHandler[prefixes=[/app/]]" 

which are called inside taskExecutor , therefore, asynchronously.

The first one here ( SimpleBrokerMessageHandler (or StompBrokerRelayMessageHandler ), if you use broker-relay ), is responsible for registering the subscription for topic .

Your operation messagingTemplate.convertAndSend(/topic/path, "msg") can be performed before registering a subscription for this WebSocket session, as they are executed in separate threads. Therefore, the broker handler does not know how to send a message to the session.

@SubscribeMapping can be configured using the return method, where the result of this method will be sent as a response to this subscription function on the client.

NTN

Answer 2

A little late, but I thought I'd add my solution. I had the same problem when the subscription was not registered before I sent the data through the messaging template. This question was rare and unpredictable due to a race with DefaultSubscriptionRegistry .

Unfortunately, I could not just use the return @SubscriptionMapping method because we used a custom object @SubscriptionMapping that dynamically changed depending on the type of user (essentially filtering attributes).

I searched Spring code and found that SubscriptionMethodReturnValueHandler was responsible for sending the return value of the signatures and had a different messagingTemplate file than the autowired SimpMessagingTemplate my asynchronous controller !!

So, the solution was autwiring MessageChannel clientOutboundChannel in my asynchronous controller and used this to create a SimpMessagingTemplate . (You cannot directly connect it, because you just get a template for the broker).

In the subscription methods, I then used the direct template, while in other methods I used the template that went to the broker.