Provide access to the connection error reason

[andrejleitner]

I was looking into a way to detect connection errors on server side (e.g. for logging purposes). The only way it can be done seems to be attaching custom request listener to the underlying http server. Check for response status code and in the case of 400 rediscover the reason (bad transport, bad method, unknown session ID) manually. It would be nice to have it accessible programmatically somehow in the process running a socket.io server.

[darrachequesne]

The Engine.IO server could indeed emit an event when such errors occur.

The error codes can be found here: https://github.com/socketio/engine.io/blob/master/lib/server.js#L108

Would you have time to implement it?

[andrejleitner]

Closed by release of v4.1.0.