Does Spring @SubscribeMapping really subscribe the client to some topic?

Question

I am using Spring Websocket with STOMP, Simple Message Broker. In my @Controller I use method-level @SubscribeMapping, which should subscribe the clien

Answer 1

So having both:

• Using a topic to handle subscription
• Using @SubscribeMapping on that topic to deliver a connection-response

does not work as you experienced (as well as me).

The way to solve your situation (as I did mine) is:

1. Remove the @SubscribeMapping - it only works with /app prefix
2. Subscribe to the /topic just as you would naturally (w/o /app prefix)

3. Implement an ApplicationListener

   1. If you want to directly reply to a single client use a user destination (see websocket-stomp-user-destination or you could also subscribe to a sub-path e.g. /topic/my-id-42 then you can send a message to this subtopic (I don't know about your exact use case, mine is that I have dedicated subscriptions and I iterate over them if I want to do a broadcast)

   2. Send a message in your onApplicationEvent method of the ApplicationListener as soon as you receive a StompCommand.SUBSCRIBE

Subscription Event Handler:

@Override
  public void onApplicationEvent(SessionSubscribeEvent event) {
      Message message = event.getMessage();
      StompHeaderAccessor accessor = StompHeaderAccessor.wrap(message);
      StompCommand command = accessor.getCommand();
      if (command.equals(StompCommand.SUBSCRIBE)) {
          String sessionId = accessor.getSessionId();
          String stompSubscriptionId = accessor.getSubscriptionId();
          String destination = accessor.getDestination();
          // Handle subscription event here
          // e.g. send welcome message to *destination*
       }
  }