Proxying websocket (to e.g. tomcat)

[Nikolai Zhubr]

Hello all!

I've installed the latest version 1.3.13 (supposedly supporing 
websocket) and was trying to push websocket connections through nginx to 
tomcat while leaving all other (static) content to nginx. To do this, 
I've added the following "location" for tomcat:

	location /examples/websocket {
	    proxy_pass       http://127.0.0.1:8080/examples/websocket;
	    proxy_redirect     off;
	    proxy_set_header Host      $host;
	    proxy_set_header X-Real-IP $remote_addr;
	}

I know that tomcat itself accepts some test websocket connection just 
fine. Also, getting static pages from tomcat through nginx works well 
too. However, proxying websocket doesn't seem to work.

So I've stopped tomcat and used netcat to see what gets through. Here it 
goes:

Direct request (firefox -> tomcat):

GET /examples/websocket/echoStream HTTP/1.1
Host: 192.168.0.91:8080
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20100101 
Firefox/17.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: ru-RU,ru;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: keep-alive, Upgrade
Sec-WebSocket-Version: 13
Origin: http://192.168.0.91:8080
Sec-WebSocket-Key: ZffbHEsoryDw1gcX51lt8g==
Pragma: no-cache
Cache-Control: no-cache
Upgrade: websocket

Request passed though nginx (firefox -> nginx -> tomcat):

GET /examples/websocket/echoStream HTTP/1.0
Host: 192.168.0.91
X-Real-IP: 192.168.0.98
Connection: close
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20100101 
Firefox/17.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: ru-RU,ru;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Sec-WebSocket-Version: 13
Origin: http://192.168.0.91
Sec-WebSocket-Key: 9YkdANPMSHDxb8axUbeKwQ==
Pragma: no-cache
Cache-Control: no-cache

One can clearly see that there is a problem. At least, "HTTP/1.1" is 
lost, "Connection: keep-alive, Upgrade" is lost, and "Upgrade: 
websocket" is lost. Generally, it does not look like websocket is 
supported at all (Essentially, apache does this same damage to websocket 
connections).

Honestly I'm not much familiar with nginx, just had to dismiss apache 
because apparently they refused to even consider support for websocket. 
So before trying to dig deep into sources I thoght I should ask here. Is 
it possible to get websocket through nginx really? Maybe I need to 
configure something additionally?

Thank you.
Nikolai