Apache HTTP Server Version 2.2
This document refers to the 2.2 version of Apache httpd, which is no longer maintained. The active release is documented here. If you have not already upgraded, please follow this link for more information.
You may follow this link to go to the current version of this document.
This document supplements the mod_rewrite
reference documentation. 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.
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.
To simply map a URL to another server, we use the [P] flag, as follows:
RewriteEngine on
RewriteBase /products/
RewriteRule ^widget/(.*)$ http://product.example.com/widget/$1 [P]
ProxyPassReverse /products/widget/ http://product.example.com/widget/
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.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^/(.*) http://old.example.com/$1 [P]
ProxyPassReverse / http://old.example.com/
In each case, we add a ProxyPassReverse
directive to ensure
that any redirects issued by the backend are correctly passed on to
the client.
Consider using either ProxyPass
or ProxyPassMatch
whenever possible in
preference to mod_rewrite.