mod_proxy_wstunnel Websockets support module for mod_proxy Extension mod_proxy_wstunnel.c proxy_wstunnel_module Available in httpd 2.4.5 and later <a id="deprecation" name="deprecation">Deprecation</a>

Since Apache HTTP Server 2.4.47, protocol Upgrade (tunneling) can be better handled by mod_proxy_http.

See Protocol Upgrade.

This module requires the service of mod_proxy. It provides support for the tunnelling of web socket connections to a backend websockets server. The connection is automatically upgraded to a websocket connection:

HTTP Response Upgrade: WebSocket Connection: Upgrade

Proxying requests to a websockets server like echo.websocket.org can be done using the ProxyPass directive:

ProxyPass "/ws2/" "ws://echo.websocket.org/" ProxyPass "/wss2/" "wss://echo.websocket.org/"

Proxying both HTTP and websockets at the same time can be done by specifying the websockets ProxyPass directive before the HTTP directive:

ProxyPass "/" "ws://backend.example.com:9080/" ProxyPass "/" "http://backend.example.com:9080/"

Load balancing for multiple backends can be achieved using mod_proxy_balancer.

The module can also be used to upgrade to other protocols than WebSocket, by setting the upgrade parameter in the ProxyPass directive to some custom protocol name. Special upgrade=NONE and upgrade=ANY values may be used for testing/forcing the upgrade but they are not recommended in production for security reasons. NONE means that the check for the header is omitted but still the upgrade/tunneling to WebSocket always happens. ANY means that the upgrade/tunneling will happen using any protocol asked by the client.

mod_proxy ProxyWebsocketFallbackToProxyHttp Instructs this module to let mod_proxy_http handle the request ProxyWebsocketFallbackToProxyHttp On|Off ProxyWebsocketFallbackToProxyHttp On server config virtual host Available in httpd 2.4.48 and later

Since httpd 2.4.47, mod_proxy_http can handle WebSocket upgrading and tunneling in accordance to RFC 7230, this directive controls whether mod_proxy_wstunnel should hand over to mod_proxy_http to this, which is the case by default.

Setting to Off lets mod_proxy_wstunnel handle WebSocket requests as in httpd 2.4.46 and earlier.

 ProxyWebsocketAsync Instructs this module to try to create an asynchronous tunnel ProxyWebsocketAsync ON|OFF server config virtual host

This directive instructs the server to try to create an asynchronous tunnel. If the current MPM does not support the necessary features, a synchronous tunnel is used.

Note

Async support is experimental and subject to change.

 ProxyWebsocketIdleTimeout Sets the maximum amount of time to wait for data on the websockets tunnel ProxyWebsocketIdleTimeout num[ms] ProxyWebsocketIdleTimeout 0 server config virtual host

This directive imposes a maximum amount of time for the tunnel to be left open while idle. The timeout is considered in seconds by default, but it is possible to increase the time resolution to milliseconds adding the ms suffix.

 ProxyWebsocketAsyncDelay Sets the amount of time the tunnel waits synchronously for data ProxyWebsocketAsyncDelay num[ms] ProxyWebsocketAsyncDelay 0 server config virtual host

If ProxyWebsocketAsync is enabled, this directive controls how long the server synchronously waits for more data. The timeout is considered in seconds by default, but it is possible to increase the time resolution to milliseconds adding the ms suffix.

Note

Async support is experimental and subject to change.