Apache HTTP Server Version 2.4

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# Apache Module mod_proxy_wstunnel

Description: | Websockets support module for `mod_proxy`
Status: | Extension
Module Identifier: | proxy_wstunnel_module
Source File: | mod_proxy_wstunnel.c
Compatibility: | Available in httpd 2.4.5 and later

### Summary

### Deprecation

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, with a specific set of URL's being websocket-only, can be done by specifying the websockets `ProxyPass` directive before the HTTP directive:

    ProxyPassMatch ^/(myApp/ws)$  ws://backend.example.com:9080/$1
    ProxyPass / http://backend.example.com:9080/

Proxying both HTTP and websockets at the same time, where the websockets URL's are not websocket-only or not known in advance can be done by using the `RewriteRule` directive to configure the websockets proxying:

    ProxyPass / http://example.com:9080/
    RewriteEngine on
    RewriteCond %{HTTP:Upgrade} websocket [NC]
    RewriteCond %{HTTP:Connection} upgrade [NC]
    RewriteRule ^/?(.*) "ws://example.com:9080/$1" [P,L]

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.

### Directives

### Bugfix checklist

- httpd changelog
- Known issues
- Report a bug

### See also

- `mod_proxy`

## ProxyWebsocketFallbackToProxyHttp Directive

Description: | Instructs this module to let `mod_proxy_http` handle the request
Syntax: | `ProxyWebsocketFallbackToProxyHttp On|Off`
Default: | `ProxyWebsocketFallbackToProxyHttp On`
Context: | server config, virtual host
Status: | Extension
Module: | mod_proxy_wstunnel
Compatibility: | 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.