using nginx as a websocket reverse proxy

nginx.conf

location / {
	chunked_transfer_encoding off;
	proxy_http_version 1.1;
	proxy_pass        http://localhost:9001;
	proxy_buffering   off;
	proxy_set_header  X-Real-IP  $remote_addr;
	proxy_set_header  Host $host:9001;
	proxy_set_header  Connection "Upgrade";
	proxy_set_header  Upgrade websocket;
}