Apache HTTP Server Version 2.5
mod_rewrite provides a way to modify incoming
URL requests, dynamically, based on regular
expression rules. This allows you to map arbitrary URLs onto
your internal URL structure in any way you like.
It supports an unlimited number of rules and an unlimited number of attached rule conditions for each rule to provide a really flexible and powerful URL manipulation mechanism. The URL manipulations can depend on various tests: server variables, environment variables, HTTP headers, time stamps, external database lookups, and various other external programs or handlers, can be used to achieve granular URL matching.
Rewrite rules can operate on the full URLs, including the path-info
and query string portions, and may be used in per-server context
httpd.conf), per-virtualhost context (
<VirtualHost> blocks), or
per-directory context (
.htaccess files and
<Directory> blocks). The
rewritten result can lead to further rules, internal
sub-processing, external request redirection, or proxy
passthrough, depending on what flags you
attach to the rules.
Since mod_rewrite is so powerful, it can indeed be rather complex. This document supplements the reference documentation, and attempts to allay some of that complexity, and provide highly annotated examples of common scenarios that you may handle with mod_rewrite. But we also attempt to show you when you should not use mod_rewrite, and use other standard Apache features instead, thus avoiding this unnecessary complexity.