docs/manual/mod/mod_proxy_wstunnel.xml

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<modulesynopsis metafile="mod_proxy_wstunnel.xml.meta">

<name>mod_proxy_wstunnel</name>
<description>Websockets support module for
<module>mod_proxy</module></description>
<status>Extension</status>
<sourcefile>mod_proxy_wstunnel.c</sourcefile>
<identifier>proxy_wstunnel_module</identifier>
<compatibility>Available in httpd 2.4.5 and later</compatibility>

<summary>
  <note type="warning"><title><a id="deprecation" name="deprecation">Deprecation</a></title>
    <p>Since Apache HTTP Server 2.4.47, protocol Upgrade (tunneling) can be better handled by
    <module>mod_proxy_http</module>.</p>
    <p>See <a href="mod_proxy.html#protoupgrade">Protocol Upgrade</a>.</p>
  </note>

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

    <example><title>HTTP Response</title>
        <highlight language="config">
Upgrade: WebSocket
Connection: Upgrade
        </highlight>
    </example>

<p>Proxying requests to a websockets server like <code>echo.websocket.org</code> can be done using the
<directive type="ProxyPass" module="mod_proxy">ProxyPass</directive> directive:</p>
    <highlight language="config">
ProxyPass "/ws2/"  "ws://echo.websocket.org/"
ProxyPass "/wss2/" "wss://echo.websocket.org/"
    </highlight>
    
<p>Proxying both HTTP and websockets at the same time can be done by specifying the websockets
<directive type="ProxyPass" module="mod_proxy">ProxyPass</directive> directive before the 
    HTTP directive:</p>
    <highlight language="config">
ProxyPass "/"  "ws://backend.example.com:9080/"
ProxyPass "/"  "http://backend.example.com:9080/"
    </highlight>


<p>Load balancing for multiple backends can be achieved using <module>mod_proxy_balancer</module>.</p>

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

<seealso><module>mod_proxy</module></seealso>

<directivesynopsis>
<name>ProxyWebsocketFallbackToProxyHttp</name>
<description>Instructs this module to let <module>mod_proxy_http</module> handle the request</description>
<syntax>ProxyWebsocketFallbackToProxyHttp On|Off</syntax>
<default>ProxyWebsocketFallbackToProxyHttp On</default>
<contextlist><context>server config</context>
<context>virtual host</context>
</contextlist>
<compatibility>Available in httpd 2.4.48 and later</compatibility>

<usage>
    <p>Since httpd 2.4.47, <module>mod_proxy_http</module> can handle WebSocket
    upgrading and tunneling in accordance to RFC 7230, this directive controls
    whether <module>mod_proxy_wstunnel</module> should hand over to
    <module>mod_proxy_http</module> to this, which is the case by default.</p>
    <p>Setting to <em>Off</em> lets <module>mod_proxy_wstunnel</module> handle
    WebSocket requests as in httpd 2.4.46 and earlier.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>ProxyWebsocketAsync</name>
<description>Instructs this module to try to create an asynchronous tunnel</description>
<syntax>ProxyWebsocketAsync ON|OFF</syntax>
<contextlist><context>server config</context>
<context>virtual host</context>
</contextlist>

<usage>
    <p>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.</p>
    <note><title>Note</title><p>Async support is experimental and subject
    to change.</p></note>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>ProxyWebsocketIdleTimeout</name>
<description>Sets the maximum amount of time to wait for data on the websockets tunnel</description>
<syntax>ProxyWebsocketIdleTimeout <var>num</var>[ms]</syntax>
<default>ProxyWebsocketIdleTimeout 0</default>
<contextlist><context>server config</context>
<context>virtual host</context>
</contextlist>

<usage>
    <p>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 <em>ms</em> suffix.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>ProxyWebsocketAsyncDelay</name>
<description>Sets the amount of time the tunnel waits synchronously for data</description>
<syntax>ProxyWebsocketAsyncDelay <var>num</var>[ms]</syntax>
<default>ProxyWebsocketAsyncDelay 0</default>
<contextlist><context>server config</context>
<context>virtual host</context>
</contextlist>

<usage>
    <p>If <directive>ProxyWebsocketAsync</directive> 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 <em>ms</em> suffix.</p>

    <note><title>Note</title><p>Async support is experimental and subject
    to change. </p></note>

</usage>
</directivesynopsis>
</modulesynopsis>