At Flexiant, we had a need for a general websocket to tcp proxy. A cute apache module to do extensible web-sockets programming has been developed by self.disconnect, and is available on github here. I’ve hacked around with this to produce a generic, apache licensed, websocket proxy. A websocket connection is made over HTTP or HTTPS to apache, this calls the websocket module, which in turn calls my module, which makes an outbound tcp connection.

Some features:

  • It supports base64 and text format sockets. So it will thus process (for instance) VNC which works using base64 encoding.
  • Configuration is supplied through normal apache directory based configuration (see details below).
  • It’s extensible (currently by changing the code, rather than calling additional modules)

The configuration section looks like this, in this case set up to proxy VNC using a novnc client:

<IfModule mod_websocket.c>
      <Location /vncproxy>
        SetHandler websocket-handler
        WebSocketHandler  /usr/lib/apache2/modules/mod_websocket_tcp_proxy.so tcp_proxy_init
        WebSocketTcpProxyBase64 on
        WebSocketTcpProxyHost 192.168.199.199
        WebSocketTcpProxyPort 5900
        WebSocketTcpProxyProtocol base64
      </Location>
 </IfModule>

Note that the parameter you specify for Location must not be a file or directory that exists with your docroot, or you will just get 404 or similar. So, in the above example you must not have a file or directory at ${DOCROOT}/vncproxy.

I discovered that on a default apache install, you may also want to change the RequestReadTimeout, i.e.

<IfModule reqtimeout_module>
  RequestReadTimeout body=300,minrate=1
</IfModule>

I’m going to try and persuade self.disconnect to stick this in the examples directory for apache-websocket, but in the mean time the source is available here. Put it in the examples directory of apache-websocket, then compile, install and enable it with it with:

sudo apxs2 -c -i -a -I.. mod_websocket_tcp_proxy.c

[Update: see new blog post, git repo link here]