Add ApplicationEvents for WebSocket connection and disconnection [SPR-11578]

[spring-projects-issues]

Sergi Almar opened SPR-11578 and commented

Even if detecting WebSocket connections and disconnections is currently doable with ChannelInterceptor / HandlerDecorator, these require some extra logic and configuration. It would be useful to have a more event driven and decoupled solution with ApplicationEvent s like WebSocketConnectEvent and WebSocketDisconnectEvent

---

Affects: 4.0.2

Referenced from: commits 13da705, a247d5f

[spring-projects-issues]

Rossen Stoyanchev commented

Sergi Almar, is it WebSocket session events you're looking for in which case the connect could have WebSocket session id, principal, and maybe HTTP handshake URL and headers (from the WebSocketSession essentially). The disconnect it may have a close status, error message, or Throwable if available.

Or are you more likely looking for connect and disconnect events on the sub-protocol level? In which case we can provide MessageHeaders with the event that correspond to the SimpMessageType that flow through the clientInbound and clientOutbound channels. Something along the lines of a SessionConnectEvent, SessionConnectedEvent, and SessionDisconnectEvent.

I am more inclined to provide the latter since they can provide all of the above including what we would provide in WebSocket events. Plus it's more on the level at which the client sees things, i.e. connecting through STOMP, providing connect headers, and so on.

[spring-projects-issues]

Sergi Almar commented

I'm also interested to see the later one, I think it makes more sense and as you say, aligned to what the client does.

[spring-projects-issues]

Rossen Stoyanchev commented

Sergi Almar this is now available. If you are able give it a quick look. We are probably releasing some time tomorrow so minor adjustments can still be made.

[spring-projects-issues]

Sergi Almar commented

As discussed in private conversation, exceptions in listeners prevented proper connection / disconnection, should be fixed now with this change.