WebSocket Connections fail with Internal Server Error

[samuel-p]

First of all thanks for this great Traefik plugin. I played around with it for some days and found out that the middleware actually breaks WebSocket connections. I'm not 100% sure why, because I'm really new to developing Traefik plugins and also not an expert with Go, but I would assume that it is because WebSocket connections remain open permanently/significantly longer than normal http requests.

If I try to open a WebSocket connection with websocat I get this error:

$ docker run --rm -ti ghcr.io/vi/websocat wss://domain.com/ws
websocat: WebSocketError: WebSocketError: Received unexpected status code (500 Internal Server Error)
websocat: error running

For me, I found a workaround in just allowing WebSocket requests in general, but I don't think that's the best solution and probably there might be a better solution to achieve this. I also checked the similar project by tomMoulard and also found a similar issue and merge request there. Unfortunately I could not figure out if this issue/merge request is really related or not.

If you are interested in my workaround you can find it here: https://github.com/samuel-p/traefik-plugin-fail2ban/blob/test/fail2ban.go#L178

I could also open a merge request, but as I hope there could be a better solution for that, I decided to open an issue first. So let me know, if you like me to create a merge request.

[ynsta]

same issue for me.