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<manualpage metafile="proxy.xml.meta">

<parentdocument href="./">Rewrite</parentdocument>

<title>Using mod_rewrite for Proxying</title>

<summary>

<p>This document supplements the <module>mod_rewrite</module>

<a href="/mod/mod_rewrite.html">reference documentation</a>. It describes

how to use the RewriteRule's [P] flag to proxy content to another server.

A number of recipes are provided that describe common scenarios.</p>

</summary>

<seealso><a href="/mod/mod_rewrite.html">Module documentation</a></seealso>

<seealso><a href="intro.html">mod_rewrite introduction</a></seealso>

<seealso><a href="remapping.html">Redirection and remapping</a></seealso>

<seealso><a href="access.html">Controlling access</a></seealso>

<seealso><a href="vhosts.html">Virtual hosts</a></seealso>

<seealso><a href="advanced.html">Advanced techniques and tricks</a></seealso>

<seealso><a href="avoid.html">When not to use mod_rewrite</a></seealso>

<section id="dynamic-proxy">

<title>Proxying Content with mod_rewrite</title>

<dl>

<dt>Description:</dt>

<dd>

<p>

mod_rewrite provides the [P] flag, which allows URLs to be passed,

via mod_proxy, to another server. Two examples are given here. In

one example, a URL is passed directly to another server, and served

as though it were a local URL. In the other example, we proxy

missing content to a back-end server.</p>

</dd>

<dt>Solution:</dt>

<dd>

<p>To simply map a URL to another server, we use the [P] flag, as

follows:</p>

<example><pre>

RewriteEngine on

RewriteBase /products/

RewriteRule ^<strong>widget/</strong>(.*)$ <strong>http://product.example.com/widget/</strong>$1 [<strong>P</strong>]

ProxyPassReverse /products/widget/ http://product.example.com/widget/

</pre></example>

<p>In the second example, we proxy the request only if we can't find

the resource locally. This can be very useful when you're migrating

from one server to another, and you're not sure if all the content

has been migrated yet.</p>

<example><pre>

RewriteCond %{REQUEST_FILENAME} <strong>!-f</strong>

RewriteCond %{REQUEST_FILENAME} <strong>!-d</strong>

RewriteRule ^/(.*) http://<strong>old</strong>.example.com$1 [<strong>P</strong>]

ProxyPassReverse / http://old.example.com/

</pre></example>

</dd>

<dt>Discussion:</dt>

<dd><p>In each case, we add a <directive

module="mod_proxy">ProxyPassReverse</directive> directive to ensure

that any redirects issued by the backend are correctly passed on to

the client.</p>

<p>Consider using either <directive

module="mod_proxy">ProxyPass</directive> or <directive

module="mod_rewrite">ProxyPassMatch</directive> whenever possible in

preference to mod_rewrite.</p>

</dd>

</dl>

</section>

</manualpage>