respond to close frame with custom close code in jetty-10 websocket

[lachlan-roberts]

Jetty version
10.0.x

Description
Cannot send frames or use the Session from Jetty WebSocket onWebSocketClose event or the java.websocket onClose event. In these events you should be able to do things like send back an alternate close code to the one received.

This is currently working in jetty-9.4.x but not jetty-10.0.x. It was assumed that the onClose events are equivalent of the websocket-core FrameHandler.onClosed. Core has the capability of receiving a close frame in onFrame and responding to it with a custom close code, but this is difficult with the jetty API and not possible with our javax websocket implementation.

[lachlan-roberts]

@sbordet the jetty ws API does have the WebSocketFrameListener interface which will allow you to handle a close frame how you would like.