Can nginx be used as a reverse proxy for a backend websocket server?

Question

We\'re working on a Ruby on Rails app that needs to take advantage of html5 websockets. At the moment, we have two separate \"servers\" so to speak: our main app running on

Answer 1

You can't use nginx for this currently^{[it's not true anymore]}, but I would suggest looking at HAProxy. I have used it for exactly this purpose.

The trick is to set long timeouts so that the socket connections are not closed. Something like:

timeout client  86400000 # In the frontend
timeout server  86400000 # In the backend

If you want to serve say a rails and cramp application on the same port you can use ACL rules to detect a websocket connection and use a different backend. So your haproxy frontend config would look something like

frontend all 0.0.0.0:80
  timeout client    86400000
  default_backend   rails_backend
  acl websocket hdr(Upgrade)    -i WebSocket
  use_backend   cramp_backend   if websocket

For completeness the backend would look like

backend cramp_backend
  timeout server  86400000
  server cramp1 localhost:8090 maxconn 200 check