Spring WebSocket @SendToSession: send message to specific session

Question

Is it possible to send a message to specific session?

I have an unauthenticated websocket between clients and a Spring servlet. I need to send an unsolicited message

Answer 1

It is very complicated and in my opinion, isn't worth it. You need to create a subscription for every user (even unauthenticated ones) by their session id.

Let's say that every user subscribes to a unique queue only for him:

stompClient.subscribe('/session/specific' + uuid, handler);

On the server, before the user subscribes you will need to notify and send a message for the specific session and save to a map:

    @MessageMapping("/putAnonymousSession/{sessionId}")
    public void start(@DestinationVariable sessionId) throws Exception {
        anonymousUserSession.put(key, sessionId);
    }

After that, when you want to send message to the user you will need to:

messagingTemplate.convertAndSend("/session/specific" + key); 

But I don't really know what you are trying to do and how you will find the specific session (who is anonymous).