MOD REWRITE Guide & Common Requests

*** The regular expressions used in rewrites are used to determine what is rewritten, not how it is rewritten. While you may not find an example that matches your needs verbatim, a quick modification to the regular expression will get you what you need. However, the example will provide you with the information on how the match is rewritten.

The following two rule sets differ only in what files are matched, not how the match is rewritten.

Code:

rewrite all HTML files

RewriteRule ^(.+)\.html$ $1.php

Code:

rewrite HTML files with numeric name (eg 1.html)

RewriteRule ^([0-9]+)\.html$ $1.php

Apache's Official Documentation
Apache's URL Rewriting Guide

mod_rewrite Cheat Sheet

1. open install_directory/conf/httpd.conf
2. uncomment or add the following line
   Code:

   LoadModule rewrite_module modules/mod_rewrite.so

3. Apache 1.3 users may need to uncomment or add the following line:
   Code:

   AddModule mod_rewrite.c

4. restart Apache

NOTE: the use of mod_rewrite requires Apache 1.3 or Apache 2.0+

NOTE: to prevent an error from affecting your entire domain, it is recommended that you create a sub-directory in your web root and run this test in that folder by using its .htaccess file.

RewriteEngine On

NOTE: When placing Rewrite* directives in .htaccess, you must have FileInfo privileges. In other words, AllowOverride FileInfo must be in httpd.conf for the directory (or one of its parents) in which .htaccess exists.

NOTE: When placing Rewrite* directives in .htaccess, you must enable FollowSymLinks. In other words, Options FollowSymLinks must be in httpd.conf for the directory (or one of its parents) in which .htaccess exists, or you must add it to .htaccess.

NOTE: .htaccess is the default access file on all Apache servers; it can be or could have been changed using the AccessFileName directive.

NOTE: not all Rewrite* directives are allowed in all contexts.

*** According to the documentation on .htaccess, it's always more efficient and secure to use httpd.conf instead of .htaccess. Using mod_rewrite in .htaccess is potentially more inefficient than other modules/directives because, according to Internal Processing » API Phases, by the time Apache gets to the point in an HTTP request where it reads .htaccess files, it's officially too late for a rewrite to occur. To solve this, mod_rewrite undoes some of Apache's work, does what it needs, then asks Apache to start its work over again.

RewriteEngine On

<Directory /usr/foo/public_html>
  RewriteEngine On
</Directory>

RewriteRule ^(.+)\.html$ $1.php

domain.com/foo.html -> domain.com/foo.php

RewriteRule ^(.+\.html)$ http://anotherdomain.com/$1 [R]

domain.com/foo.html -> anotherdomain.com/foo.html

NOTE: External redirects can also be obtained using Apache's mod_alias through the Redirect and RedirectMatch directive. These do not require mod_rewrite to be enabled. If you find yourself using a RewriteRule that results in an external redirect, and there is no corresponding RewriteCond, Redirect or RedirectMatch is the recommended alternative.

In the following example, RedirectMatch is used to create an external redirect equivalent to the previous mod_rewrite rule set.

Code:

RedirectMatch ^(.+\.html)$ http://anotherdomain.com$1

RewriteRule ^(.+)\.gif$ $1.jpg

domain.com/foo.gif -> domain.com/foo.jpg

domain.com/bar/baz.gif -> domain.com/bar/baz.jpg

RewriteCond %{REQUEST_URI} ^/png/
RewriteRule ^(.+)\.jpg$ $1.png

domain.com/foo.jpg -> domain.com/foo.jpg

domain.com/png/foo.jpg -> domain.com/png/foo.png

NOTE: There is no need to prepend "/png/"; mod_rewrite will do this for you.