mod_proxy_wstunnel intermittent empty response

[Jonathon Koyle <litereader@xxxxxxxxx>]

I am running httpd-2.4.6 on CentOS7. I have an https virtual host configured to proxy requests to a specific location as wss

<location /ws>

  ProxyPass "wss://127.0.0.1:9000/"

  ProxyPassReverse "wss://${server_name}/ws/"

</location>

However, attempts to connect occasionally fail, using curl to test:

    curl -i -N -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Protocols: stomp" https://127.0.0.1/ws -H "Sec-WebSocket-Version: 13" -H "Sec-WebSocket-Key: asdfghjkl;qwertzxcvbnmlk" -k

A failure results in:

  curl: (52) Empty reply from server

Looking around I found this thread http://apache-http-server.18135.x6.nabble.com/mod-proxy-wstunnel-ignores-proxy-wstunnel-transfer-errors-td5020240.html that discusses what seems like a similar problem to me, and mentions a patch, but doesn't actual mention a specific release, only 2.4.x.  I'm also not certain, from the thread, if the problem addressed was intermittent or not.

Has anybody else seen this behavior or have any suggestions?  Updating to a version of httpd not in a Centos repo is not an option for me, unfortunately.

Any help is appreciated.

--

Jonathon Koyle