fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<?xml version="1.0"?>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<!DOCTYPE modulesynopsis SYSTEM "/style/modulesynopsis.dtd">

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<?xml-stylesheet type="text/xsl" href="/style/manual.en.xsl"?>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<modulesynopsis metafile="mod_rewrite.xml.meta">

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<name>mod_rewrite</name>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<description>Provides a rule-based rewriting engine to rewrite requested

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessURLs on the fly</description>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<status>Extension</status>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<sourcefile>mod_rewrite.c</sourcefile>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<identifier>rewrite_module</identifier>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<compatibility>Available in Apache 1.3 and later</compatibility>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<summary>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>This module uses a rule-based rewriting engine (based on a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess regular-expression parser) to rewrite requested URLs on the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess fly. It supports an unlimited number of rules and an

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess unlimited number of attached rule conditions for each rule to

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess provide a really flexible and powerful URL manipulation

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess mechanism. The URL manipulations can depend on various tests,

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess for instance server variables, environment variables, HTTP

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess headers, time stamps and even external database lookups in

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess various formats can be used to achieve a really granular URL

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess matching.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>This module operates on the full URLs (including the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess path-info part) both in per-server context

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess (<code>httpd.conf</code>) and per-directory context

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess (<code>.htaccess</code>) and can even generate query-string

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess parts on result. The rewritten result can lead to internal

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess sub-processing, external request redirection or even to an

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess internal proxy throughput.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>Further details, discussion, and examples, are provided in the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <a href="/rewrite/">detailed mod_rewrite documentation</a>.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</summary>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<section id="quoting"><title>Quoting Special Characters</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>As of Apache 1.3.20, special characters in

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>TestString</em> and <em>Substitution</em> strings can be

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess escaped (that is, treated as normal characters without their

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess usual special meaning) by prefixing them with a slash ('\')

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess character. In other words, you can include an actual

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess dollar-sign character in a <em>Substitution</em> string by

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess using '<code>\$</code>'; this keeps mod_rewrite from trying

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess to treat it as a backreference.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</section>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<section id="EnvVar"><title>Environment Variables</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>This module keeps track of two additional (non-standard)

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess CGI/SSI environment variables named <code>SCRIPT_URL</code>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess and <code>SCRIPT_URI</code>. These contain the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>logical</em> Web-view to the current resource, while the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess standard CGI/SSI variables <code>SCRIPT_NAME</code> and

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <code>SCRIPT_FILENAME</code> contain the <em>physical</em>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess System-view. </p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>Notice: These variables hold the URI/URL <em>as they were

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess initially requested</em>, <em>i.e.</em>, <em>before</em> any

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess rewriting. This is important because the rewriting process is

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess primarily used to rewrite logical URLs to physical

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess pathnames.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example><title>Example</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessSCRIPT_NAME=/sw/lib/w3s/tree/global/u/rse/.www/index.html

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessSCRIPT_FILENAME=/u/rse/.www/index.html

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessSCRIPT_URL=/u/rse/

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessSCRIPT_URI=http://en1.engelschall.com/u/rse/

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</section>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<section id="Solutions"><title>Practical Solutions</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>For numerous examples of common, and not-so-common, uses for

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess mod_rewrite, see the <a href="/rewrite/rewrite_guide.html">Rewrite

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess Guide</a>, and the <a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess href="/rewrite/rewrite_guide_advanced.html">Advanced Rewrite

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess Guide</a> documents.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</section>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<name>RewriteEngine</name>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<description>Enables or disables runtime rewriting engine</description>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<syntax>RewriteEngine on|off</syntax>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<default>RewriteEngine off</default>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<contextlist><context>server config</context><context>virtual host</context>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<context>directory</context><context>.htaccess</context></contextlist>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<override>FileInfo</override>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>The <directive>RewriteEngine</directive> directive enables or

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess disables the runtime rewriting engine. If it is set to

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <code>off</code> this module does no runtime processing at

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess all. It does not even update the <code>SCRIPT_URx</code>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess environment variables.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>Use this directive to disable the module instead of

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess commenting out all the <directive

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess module="mod_rewrite">RewriteRule</directive> directives!</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>Note that, by default, rewrite configurations are not

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess inherited. This means that you need to have a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <code>RewriteEngine on</code> directive for each virtual host

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess in which you wish to use it.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<name>RewriteOptions</name>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<description>Sets some special options for the rewrite engine</description>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<syntax>RewriteOptions <var>Options</var></syntax>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<contextlist><context>server config</context><context>virtual host</context>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<context>directory</context><context>.htaccess</context></contextlist>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<override>FileInfo</override>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<compatibility><code>MaxRedirects</code> is no longer available in version 2.1 and

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kesslater</compatibility>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>The <directive>RewriteOptions</directive> directive sets some

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess special options for the current per-server or per-directory

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess configuration. The <em>Option</em> string can be currently only one:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <dl>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <dt><code>inherit</code></dt>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <dd>This forces the current configuration to inherit the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess configuration of the parent. In per-virtual-server context

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess this means that the maps, conditions and rules of the main

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess server are inherited. In per-directory context this means

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess that conditions and rules of the parent directory's

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <code>.htaccess</code> configuration are inherited.</dd>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </dl>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<name>RewriteLog</name>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<description>Sets the name of the file used for logging rewrite engine

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessprocessing</description>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<syntax>RewriteLog <em>file-path</em></syntax>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<contextlist><context>server config</context><context>virtual host</context>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</contextlist>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>The <directive>RewriteLog</directive> directive sets the name

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess of the file to which the server logs any rewriting actions it

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess performs. If the name does not begin with a slash

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess ('<code>/</code>') then it is assumed to be relative to the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>Server Root</em>. The directive should occur only once per

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess server config.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<note> To disable the logging of

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess rewriting actions it is not recommended to set

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>Filename</em> to <code>/dev/null</code>, because

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess although the rewriting engine does not then output to a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess logfile it still creates the logfile output internally.

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <strong>This will slow down the server with no advantage

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess to the administrator!</strong> To disable logging either

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess remove or comment out the <directive>RewriteLog</directive>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess directive or use <code>RewriteLogLevel 0</code>!

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</note>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<note type="securitywarning"><title>Security</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessSee the <a href="/misc/security_tips.html">Apache Security Tips</a>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessdocument for details on why your security could be compromised if the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessdirectory where logfiles are stored is writable by anyone other than

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessthe user that starts the server.

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</note>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example><title>Example</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessRewriteLog "/usr/local/var/apache/logs/rewrite.log"

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<name>RewriteLogLevel</name>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<description>Sets the verbosity of the log file used by the rewrite

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessengine</description>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<syntax>RewriteLogLevel <em>Level</em></syntax>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<default>RewriteLogLevel 0</default>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<contextlist><context>server config</context><context>virtual host</context>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</contextlist>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>The <directive>RewriteLogLevel</directive> directive sets the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess verbosity level of the rewriting logfile. The default level 0

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess means no logging, while 9 or more means that practically all

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess actions are logged.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>To disable the logging of rewriting actions simply set

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>Level</em> to 0. This disables all rewrite action

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess logs.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<note> Using a high value for

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>Level</em> will slow down your Apache server

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess dramatically! Use the rewriting logfile at a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>Level</em> greater than 2 only for debugging!

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</note>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example><title>Example</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessRewriteLogLevel 3

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<name>RewriteLock</name>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<description>Sets the name of the lock file used for <directive

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessmodule="mod_rewrite">RewriteMap</directive>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kesssynchronization</description>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<syntax>RewriteLock <em>file-path</em></syntax>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<contextlist><context>server config</context></contextlist>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>This directive sets the filename for a synchronization

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess lockfile which mod_rewrite needs to communicate with <directive

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess module="mod_rewrite">RewriteMap</directive>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>programs</em>. Set this lockfile to a local path (not on a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess NFS-mounted device) when you want to use a rewriting

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess map-program. It is not required for other types of rewriting

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess maps.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<name>RewriteMap</name>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<description>Defines a mapping function for key-lookup</description>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<syntax>RewriteMap <em>MapName</em> <em>MapType</em>:<em>MapSource</em>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</syntax>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<contextlist><context>server config</context><context>virtual host</context>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</contextlist>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<compatibility>The choice of different dbm types is available in

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessApache 2.0.41 and later</compatibility>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>The <directive>RewriteMap</directive> directive defines a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>Rewriting Map</em> which can be used inside rule

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess substitution strings by the mapping-functions to

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess insert/substitute fields through a key lookup. The source of

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess this lookup can be of various types.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>The <a id="mapfunc" name="mapfunc"><em>MapName</em></a> is

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess the name of the map and will be used to specify a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess mapping-function for the substitution strings of a rewriting

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess rule via one of the following constructs:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p class="indent">

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <strong><code>${</code> <em>MapName</em> <code>:</code>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>LookupKey</em> <code>}</code><br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <code>${</code> <em>MapName</em> <code>:</code>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>LookupKey</em> <code>|</code> <em>DefaultValue</em>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <code>}</code></strong>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>When such a construct occurs the map <em>MapName</em> is

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess consulted and the key <em>LookupKey</em> is looked-up. If the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess key is found, the map-function construct is substituted by

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>SubstValue</em>. If the key is not found then it is

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess substituted by <em>DefaultValue</em> or by the empty string

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess if no <em>DefaultValue</em> was specified.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>For example, you might define a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <directive>RewriteMap</directive> as:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess RewriteMap examplemap txt:/path/to/file/map.txt

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>You would then be able to use this map in a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <directive>RewriteRule</directive> as follows:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess RewriteRule ^/ex/(.*) ${examplemap:$1}

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>The following combinations for <em>MapType</em> and

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>MapSource</em> can be used:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <ul>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <strong>Standard Plain Text</strong><br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess MapType: <code>txt</code>, MapSource: Unix filesystem

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess path to valid regular file

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>This is the standard rewriting map feature where the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>MapSource</em> is a plain ASCII file containing

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess either blank lines, comment lines (starting with a '#'

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess character) or pairs like the following - one per

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess line.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p class="indent">

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <strong><em>MatchingKey</em>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>SubstValue</em></strong>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example><title>Example</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess##

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess## map.txt -- rewriting map

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess##

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessRalf.S.Engelschall rse # Bastard Operator From Hell

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessMr.Joe.Average joe # Mr. Average

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessRewriteMap real-to-user txt:/path/to/file/map.txt

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <strong>Randomized Plain Text</strong><br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess MapType: <code>rnd</code>, MapSource: Unix filesystem

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess path to valid regular file

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>This is identical to the Standard Plain Text variant

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess above but with a special post-processing feature: After

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess looking up a value it is parsed according to contained

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess ``<code>|</code>'' characters which have the meaning of

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess ``or''. In other words they indicate a set of

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess alternatives from which the actual returned value is

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess chosen randomly. For example, you might use the following map

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess file and directives to provide a random load balancing between

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess several back-end server, via a reverse-proxy. Images are sent

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess to one of the servers in the 'static' pool, while everything

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess else is sent to one of the 'dynamic' pool.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>Example:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example><title>Rewrite map file</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess##

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess## map.txt -- rewriting map

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess##

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessstatic www1|www2|www3|www4

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessdynamic www5|www6

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example><title>Configuration directives</title>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessRewriteMap servers rnd:/path/to/file/map.txt<br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessRewriteRule ^/(.*\.(png|gif|jpg)) http://${servers:static}/$1

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess[NC,P,L]<br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessRewriteRule ^/(.*) http://${servers:dynamic}/$1 [P,L]

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <strong>Hash File</strong><br /> MapType:

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <code>dbm[=<em>type</em>]</code>, MapSource: Unix filesystem

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess path to valid regular file

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>Here the source is a binary format DBM file containing

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess the same contents as a <em>Plain Text</em> format file, but

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess in a special representation which is optimized for really

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess fast lookups. The <em>type</em> can be sdbm, gdbm, ndbm, or

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess db depending on <a href="/install.html#dbm">compile-time

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess settings</a>. If the <em>type</em> is omitted, the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess compile-time default will be chosen. You can create such a

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess file with any DBM tool or with the following Perl

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess script. Be sure to adjust it to create the appropriate

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess type of DBM. The example creates an NDBM file.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess#!/path/to/bin/perl

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess##

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess## txt2dbm -- convert txt map to dbm format

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess##

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessuse NDBM_File;

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessuse Fcntl;

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess($txtmap, $dbmmap) = @ARGV;

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessopen(TXT, "&lt;$txtmap") or die "Couldn't open $txtmap!\n";

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kesstie (%DB, 'NDBM_File', $dbmmap,O_RDWR|O_TRUNC|O_CREAT, 0644)

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess or die "Couldn't create $dbmmap!\n";

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kesswhile (&lt;TXT&gt;) {

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess next if (/^\s*#/ or /^\s*$/);

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess $DB{$1} = $2 if (/^\s*(\S+)\s+(\S+)/);

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess}

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessuntie %DB;

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessclose(TXT);

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess$ txt2dbm map.txt map.db

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <strong>Internal Function</strong><br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess MapType: <code>int</code>, MapSource: Internal Apache

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess function

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>Here the source is an internal Apache function.

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess Currently you cannot create your own, but the following

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess functions already exists:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <ul>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li><strong>toupper</strong>:<br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess Converts the looked up key to all upper case.</li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li><strong>tolower</strong>:<br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess Converts the looked up key to all lower case.</li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li><strong>escape</strong>:<br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess Translates special characters in the looked up key to

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess hex-encodings.</li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li><strong>unescape</strong>:<br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess Translates hex-encodings in the looked up key back to

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess special characters.</li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </ul>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <strong>External Rewriting Program</strong><br />

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess MapType: <code>prg</code>, MapSource: Unix filesystem

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess path to valid regular file

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>Here the source is a program, not a map file. To

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess create it you can use the language of your choice, but

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess the result has to be a executable (<em>i.e.</em>, either

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess object-code or a script with the magic cookie trick

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess '<code>#!/path/to/interpreter</code>' as the first

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess line).</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>This program is started once at startup of the Apache

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess servers and then communicates with the rewriting engine

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess over its <code>stdin</code> and <code>stdout</code>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess file-handles. For each map-function lookup it will

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess receive the key to lookup as a newline-terminated string

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess on <code>stdin</code>. It then has to give back the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess looked-up value as a newline-terminated string on

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <code>stdout</code> or the four-character string

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess ``<code>NULL</code>'' if it fails (<em>i.e.</em>, there

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess is no corresponding value for the given key). A trivial

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess program which will implement a 1:1 map (<em>i.e.</em>,

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess key == value) could be:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess#!/usr/bin/perl

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess$| = 1;

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kesswhile (&lt;STDIN&gt;) {

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess # ...put here any transformations or lookups...

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess print $_;

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess}

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>But be very careful:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <ol>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li>``<em>Keep it simple, stupid</em>'' (KISS), because

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess if this program hangs it will hang the Apache server

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess when the rule occurs.</li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li>Avoid one common mistake: never do buffered I/O on

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <code>stdout</code>! This will cause a deadloop! Hence

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess the ``<code>$|=1</code>'' in the above example...</li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <li>Use the <directive

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess module="mod_rewrite">RewriteLock</directive> directive to

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess define a lockfile mod_rewrite can use to synchronize the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess communication to the program. By default no such

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess synchronization takes place.</li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </ol>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </li>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess </ul>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>The <directive>RewriteMap</directive> directive can occur more than

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess once. For each mapping-function use one

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <directive>RewriteMap</directive> directive to declare its rewriting

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess mapfile. While you cannot <strong>declare</strong> a map in

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess per-directory context it is of course possible to

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <strong>use</strong> this map in per-directory context. </p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<note><title>Note</title> For plain text and DBM format files the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kesslooked-up keys are cached in-core until the <code>mtime</code> of the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessmapfile changes or the server does a restart. This way you can have

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessmap-functions in rules which are used for <strong>every</strong>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessrequest. This is no problem, because the external lookup only happens

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessonce!

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</note>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<directivesynopsis>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<name>RewriteBase</name>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<description>Sets the base URL for per-directory rewrites</description>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<syntax>RewriteBase <em>URL-path</em></syntax>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<default>See usage for information.</default>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<contextlist><context>directory</context><context>.htaccess</context>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</contextlist>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<override>FileInfo</override>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<usage>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>The <directive>RewriteBase</directive> directive explicitly

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess sets the base URL for per-directory rewrites. As you will see

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess below, <directive module="mod_rewrite">RewriteRule</directive>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess can be used in per-directory config files

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess (<code>.htaccess</code>). There it will act locally,

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <em>i.e.</em>, the local directory prefix is stripped at this

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess stage of processing and your rewriting rules act only on the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess remainder. At the end it is automatically added back to the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess path. The default setting is; <directive>RewriteBase</directive> <em>physical-directory-path</em></p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p>When a substitution occurs for a new URL, this module has

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess to re-inject the URL into the server processing. To be able

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess to do this it needs to know what the corresponding URL-prefix

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess or URL-base is. By default this prefix is the corresponding

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess filepath itself. <strong>But at most websites URLs are NOT

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess directly related to physical filename paths, so this

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess assumption will usually be wrong!</strong> There you have to

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess use the <code>RewriteBase</code> directive to specify the

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess correct URL-prefix.</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<note> If your webserver's URLs are <strong>not</strong> directly

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessrelated to physical file paths, you have to use

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<directive>RewriteBase</directive> in every <code>.htaccess</code>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessfiles where you want to use <directive

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kessmodule="mod_rewrite">RewriteRule</directive> directives.

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess</note>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess <p> For example, assume the following per-directory config file:</p>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<example>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess<pre>

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess#

fefb8b844b6286bfc41bb2e0c4cc003b8e7d4ff2kess# /abc/def/.htaccess -- per-dir config file for directory /abc/def

# Remember: /abc/def is the physical path of /xyz, <em>i.e.</em>, the server

# has a 'Alias /xyz /abc/def' directive <em>e.g.</em>

#

RewriteEngine On

# let the server know that we were reached via /xyz and not

# via the physical path prefix /abc/def

RewriteBase /xyz

# now the rewriting rules

RewriteRule ^oldstuff\.html$ newstuff.html

</pre>

</example>

<p>In the above example, a request to

<code>/xyz/oldstuff.html</code> gets correctly rewritten to

the physical file <code>/abc/def/newstuff.html</code>.</p>

<note><title>For Apache Hackers</title>

<p>The following list gives detailed information about

the internal processing steps:</p>

<pre>

Request:

/xyz/oldstuff.html

Internal Processing:

/xyz/oldstuff.html -&gt; /abc/def/oldstuff.html (per-server Alias)

/abc/def/oldstuff.html -&gt; /abc/def/newstuff.html (per-dir RewriteRule)

/abc/def/newstuff.html -&gt; /xyz/newstuff.html (per-dir RewriteBase)

/xyz/newstuff.html -&gt; /abc/def/newstuff.html (per-server Alias)

Result:

/abc/def/newstuff.html

</pre>

<p>This seems very complicated but is

the correct Apache internal processing, because the

per-directory rewriting comes too late in the

process. So, when it occurs the (rewritten) request

has to be re-injected into the Apache kernel! BUT:

While this seems like a serious overhead, it really

isn't, because this re-injection happens fully

internally to the Apache server and the same

procedure is used by many other operations inside

Apache. So, you can be sure the design and

implementation is correct.</p>

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>RewriteCond</name>

<description>Defines a condition under which rewriting will take place

</description>

<syntax> RewriteCond

<em>TestString</em> <em>CondPattern</em></syntax>

<contextlist><context>server config</context><context>virtual host</context>

<context>directory</context><context>.htaccess</context></contextlist>

<override>FileInfo</override>

<usage>

<p>The <directive>RewriteCond</directive> directive defines a

rule condition. Precede a <directive

module="mod_rewrite">RewriteRule</directive> directive with one

or more <directive>RewriteCond</directive> directives. The following

rewriting rule is only used if its pattern matches the current

state of the URI <strong>and</strong> if these additional

conditions apply too.</p>

<p><em>TestString</em> is a string which can contains the

following expanded constructs in addition to plain text:</p>

<ul>

<li>

<strong>RewriteRule backreferences</strong>: These are

backreferences of the form

<p class="indent">

<strong><code>$N</code></strong>

</p>

(0 &lt;= N &lt;= 9) which provide access to the grouped

parts (parenthesis!) of the pattern from the

corresponding <code>RewriteRule</code> directive (the one

following the current bunch of <code>RewriteCond</code>

directives).

</li>

<li>

<strong>RewriteCond backreferences</strong>: These are

backreferences of the form

<p class="indent">

<strong><code>%N</code></strong>

</p>

(1 &lt;= N &lt;= 9) which provide access to the grouped

parts (parentheses!) of the pattern from the last matched

<code>RewriteCond</code> directive in the current bunch

of conditions.

</li>

<li>

<strong>RewriteMap expansions</strong>: These are

expansions of the form

<p class="indent">

<strong><code>${mapname:key|default}</code></strong>

</p>

See <a href="#mapfunc">the documentation for

RewriteMap</a> for more details.

</li>

<li>

<strong>Server-Variables</strong>: These are variables of

the form

<p class="indent">

<strong><code>%{</code> <em>NAME_OF_VARIABLE</em>

<code>}</code></strong>

</p>

where <em>NAME_OF_VARIABLE</em> can be a string taken

from the following list:

<table>

<columnspec><column width=".3"/><column width=".3"/>

<column width=".3"/></columnspec>

<tr>

<th>HTTP headers:</th> <th>connection &amp; request:</th> <th></th>

</tr>

<tr>

<td>

HTTP_USER_AGENT<br />

HTTP_REFERER<br />

HTTP_COOKIE<br />

HTTP_FORWARDED<br />

HTTP_HOST<br />

HTTP_PROXY_CONNECTION<br />

HTTP_ACCEPT<br />

</td>

<td>

REMOTE_ADDR<br />

REMOTE_HOST<br />

REMOTE_PORT<br />

REMOTE_USER<br />

REMOTE_IDENT<br />

REQUEST_METHOD<br />

SCRIPT_FILENAME<br />

PATH_INFO<br />

QUERY_STRING<br />

AUTH_TYPE<br />

</td>

<td></td>

</tr>

<tr>

<th>server internals:</th> <th>date and time:</th> <th>specials:</th>

</tr>

<tr>

<td>

DOCUMENT_ROOT<br />

SERVER_ADMIN<br />

SERVER_NAME<br />

SERVER_ADDR<br />

SERVER_PORT<br />

SERVER_PROTOCOL<br />

SERVER_SOFTWARE<br />

</td>

<td>

TIME_YEAR<br />

TIME_MON<br />

TIME_DAY<br />

TIME_HOUR<br />

TIME_MIN<br />

TIME_SEC<br />

TIME_WDAY<br />

TIME<br />

</td>

<td>

API_VERSION<br />

THE_REQUEST<br />

REQUEST_URI<br />

REQUEST_FILENAME<br />

IS_SUBREQ<br />

HTTPS<br />

</td>

</tr>

</table>

<note>

<p>These variables all

correspond to the similarly named HTTP

MIME-headers, C variables of the Apache server or

<code>struct tm</code> fields of the Unix system.

Most are documented elsewhere in the Manual or in

the CGI specification. Those that are special to

mod_rewrite include:</p>

<dl>

<dt><code>IS_SUBREQ</code></dt>

<dd>Will contain the text "true" if the request

currently being processed is a sub-request,

"false" otherwise. Sub-requests may be generated

by modules that need to resolve additional files

or URIs in order to complete their tasks.</dd>

<dt><code>API_VERSION</code></dt>

<dd>This is the version of the Apache module API

(the internal interface between server and

module) in the current httpd build, as defined in

include/ap_mmn.h. The module API version

corresponds to the version of Apache in use (in

the release version of Apache 1.3.14, for

instance, it is 19990320:10), but is mainly of

interest to module authors.</dd>

<dt><code>THE_REQUEST</code></dt>

<dd>The full HTTP request line sent by the

browser to the server (e.g., "<code>GET

/index.html HTTP/1.1</code>"). This does not

include any additional headers sent by the

browser.</dd>

<dt><code>REQUEST_URI</code></dt>

<dd>The resource requested in the HTTP request

line. (In the example above, this would be

"/index.html".)</dd>

<dt><code>REQUEST_FILENAME</code></dt>

<dd>The full local filesystem path to the file or

script matching the request.</dd>

<dt><code>HTTPS</code></dt>

<dd>Will contain the text "on" if the connection is

using SSL/TLS, or "off" otherwise. (This variable

can be safely used regardless of whether

<module>mod_ssl</module> is loaded).</dd>

</dl>

</note>

</li>

</ul>

<p>Special Notes:</p>

<ol>

<li>The variables SCRIPT_FILENAME and REQUEST_FILENAME

contain the same value, <em>i.e.</em>, the value of the

<code>filename</code> field of the internal

<code>request_rec</code> structure of the Apache server.

The first name is just the commonly known CGI variable name

while the second is the consistent counterpart to

REQUEST_URI (which contains the value of the

<code>uri</code> field of <code>request_rec</code>).</li>

<li>There is the special format:

<code>%{ENV:variable}</code> where <em>variable</em> can be

any environment variable. This is looked-up via internal

Apache structures and (if not found there) via

<code>getenv()</code> from the Apache server process.</li>

<li>There is the special format:

<code>%{SSL:variable}</code> where <em>variable</em> is the

name of an <a href="mod_ssl.html#envvars">SSL environment

variable</a>; this can be used whether or not

<module>mod_ssl</module> is loaded, but will always expand to

the empty string if it is not. Example:

<code>%{SSL:SSL_CIPHER_USEKEYSIZE}</code> may expand to

<code>128</code>.</li>

<li>There is the special format:

<code>%{HTTP:header}</code> where <em>header</em> can be

any HTTP MIME-header name. This is looked-up from the HTTP

request. Example: <code>%{HTTP:Proxy-Connection}</code> is

the value of the HTTP header

``<code>Proxy-Connection:</code>''.</li>

<li>There is the special format

<code>%{LA-U:variable}</code> for look-aheads which perform

an internal (URL-based) sub-request to determine the final

value of <em>variable</em>. Use this when you want to use a

variable for rewriting which is actually set later in an

API phase and thus is not available at the current stage.

For instance when you want to rewrite according to the

<code>REMOTE_USER</code> variable from within the

per-server context (<code>httpd.conf</code> file) you have

to use <code>%{LA-U:REMOTE_USER}</code> because this

variable is set by the authorization phases which come

<em>after</em> the URL translation phase where mod_rewrite

operates. On the other hand, because mod_rewrite implements

its per-directory context (<code>.htaccess</code> file) via

the Fixup phase of the API and because the authorization

phases come <em>before</em> this phase, you just can use

<code>%{REMOTE_USER}</code> there.</li>

<li>There is the special format:

<code>%{LA-F:variable}</code> which performs an internal

(filename-based) sub-request to determine the final value

of <em>variable</em>. Most of the time this is the same as

LA-U above.</li>

</ol>

<p><em>CondPattern</em> is the condition pattern,

<em>i.e.</em>, a regular expression which is applied to the

current instance of the <em>TestString</em>, <em>i.e.</em>,

<em>TestString</em> is evaluated and then matched against

<em>CondPattern</em>.</p>

<p><strong>Remember:</strong> <em>CondPattern</em> is a

<em>perl compatible regular expression</em> with some

additions:</p>

<ol>

<li>You can prefix the pattern string with a

'<code>!</code>' character (exclamation mark) to specify a

<strong>non</strong>-matching pattern.</li>

<li>

There are some special variants of <em>CondPatterns</em>.

Instead of real regular expression strings you can also

use one of the following:

<ul>

<li>'<strong>&lt;CondPattern</strong>' (is lexically

lower)<br />

Treats the <em>CondPattern</em> as a plain string and

compares it lexically to <em>TestString</em>. True if

<em>TestString</em> is lexically lower than

<em>CondPattern</em>.</li>

<li>'<strong>&gt;CondPattern</strong>' (is lexically

greater)<br />

Treats the <em>CondPattern</em> as a plain string and

compares it lexically to <em>TestString</em>. True if

<em>TestString</em> is lexically greater than

<em>CondPattern</em>.</li>

<li>'<strong>=CondPattern</strong>' (is lexically

equal)<br />

Treats the <em>CondPattern</em> as a plain string and

compares it lexically to <em>TestString</em>. True if

<em>TestString</em> is lexically equal to

<em>CondPattern</em>, i.e the two strings are exactly

equal (character by character). If <em>CondPattern</em>

is just <code>""</code> (two quotation marks) this

compares <em>TestString</em> to the empty string.</li>

<li>'<strong>-d</strong>' (is

<strong>d</strong>irectory)<br />

Treats the <em>TestString</em> as a pathname and tests

if it exists and is a directory.</li>

<li>'<strong>-f</strong>' (is regular

<strong>f</strong>ile)<br />

Treats the <em>TestString</em> as a pathname and tests

if it exists and is a regular file.</li>

<li>'<strong>-s</strong>' (is regular file with

<strong>s</strong>ize)<br />

Treats the <em>TestString</em> as a pathname and tests

if it exists and is a regular file with size greater

than zero.</li>

<li>'<strong>-l</strong>' (is symbolic

<strong>l</strong>ink)<br />

Treats the <em>TestString</em> as a pathname and tests

if it exists and is a symbolic link.</li>

<li>'<strong>-x</strong>' (has e<strong>x</strong>ecutable

permissions)<br />

Treats the <em>TestString</em> as a pathname and tests

if it exists and has execution permissions. These permissions

are determined depending on the underlying OS.</li>

<li>'<strong>-F</strong>' (is existing file via

subrequest)<br />

Checks if <em>TestString</em> is a valid file and

accessible via all the server's currently-configured

access controls for that path. This uses an internal

subrequest to determine the check, so use it with care

because it decreases your servers performance!</li>

<li>'<strong>-U</strong>' (is existing URL via

subrequest)<br />

Checks if <em>TestString</em> is a valid URL and

accessible via all the server's currently-configured

access controls for that path. This uses an internal

subrequest to determine the check, so use it with care

because it decreases your server's performance!</li>

</ul>

<note><title>Notice</title>

All of these tests can

also be prefixed by an exclamation mark ('!') to

negate their meaning.

</note>

</li>

</ol>

<p>Additionally you can set special flags for

<em>CondPattern</em> by appending</p>

<p class="indent">

<strong><code>[</code><em>flags</em><code>]</code></strong>

</p>

<p>as the third argument to the <code>RewriteCond</code>

directive. <em>Flags</em> is a comma-separated list of the

following flags:</p>

<ul>

<li>'<strong><code>nocase|NC</code></strong>'

(<strong>n</strong>o <strong>c</strong>ase)<br />

This makes the test case-insensitive, <em>i.e.</em>, there

is no difference between 'A-Z' and 'a-z' both in the

expanded <em>TestString</em> and the <em>CondPattern</em>.

This flag is effective only for comparisons between

<em>TestString</em> and <em>CondPattern</em>. It has no

effect on filesystem and subrequest checks.</li>

<li>

'<strong><code>ornext|OR</code></strong>'

(<strong>or</strong> next condition)<br />

Use this to combine rule conditions with a local OR

instead of the implicit AND. Typical example:

<example>

<pre>

RewriteCond %{REMOTE_HOST} ^host1.* [OR]

RewriteCond %{REMOTE_HOST} ^host2.* [OR]

RewriteCond %{REMOTE_HOST} ^host3.*

RewriteRule ...some special stuff for any of these hosts...

</pre>

</example>

Without this flag you would have to write the cond/rule

three times.

</li>

</ul>

<p><strong>Example:</strong></p>

<p>To rewrite the Homepage of a site according to the

``<code>User-Agent:</code>'' header of the request, you can

use the following: </p>

<example>

<pre>

RewriteCond %{HTTP_USER_AGENT} ^Mozilla.*

RewriteRule ^/$ /homepage.max.html [L]

RewriteCond %{HTTP_USER_AGENT} ^Lynx.*

RewriteRule ^/$ /homepage.min.html [L]

RewriteRule ^/$ /homepage.std.html [L]

</pre>

</example>

<p>Interpretation: If you use Netscape Navigator as your

browser (which identifies itself as 'Mozilla'), then you

get the max homepage, which includes Frames, <em>etc.</em>

If you use the Lynx browser (which is Terminal-based), then

you get the min homepage, which contains no images, no

tables, <em>etc.</em> If you use any other browser you get

the standard homepage.</p>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>RewriteRule</name>

<description>Defines rules for the rewriting engine</description>

<syntax>RewriteRule

<em>Pattern</em> <em>Substitution</em></syntax>

<contextlist><context>server config</context><context>virtual host</context>

<context>directory</context><context>.htaccess</context></contextlist>

<override>FileInfo</override>

<compatibility>The cookie-flag is available in Apache 2.0.40 and later.</compatibility>

<usage>

<p>The <directive>RewriteRule</directive> directive is the real

rewriting workhorse. The directive can occur more than once.

Each directive then defines one single rewriting rule. The

<strong>definition order</strong> of these rules is

<strong>important</strong>, because this order is used when

applying the rules at run-time.</p>

<p><a id="patterns" name="patterns"><em>Pattern</em></a> is

a perl compatible <a id="regexp" name="regexp">regular

expression</a> which gets applied to the current URL. Here

``current'' means the value of the URL when this rule gets

applied. This may not be the originally requested URL,

because any number of rules may already have matched and made

alterations to it.</p>

<p>Some hints about the syntax of regular expressions:</p>

<note><pre>

<strong>Text:</strong>

<strong><code>.</code></strong> Any single character

<strong><code>[</code></strong>chars<strong><code>]</code></strong> Character class: One of chars

<strong><code>[^</code></strong>chars<strong><code>]</code></strong> Character class: None of chars

text1<strong><code>|</code></strong>text2 Alternative: text1 or text2

<strong>Quantifiers:</strong>

<strong><code>?</code></strong> 0 or 1 of the preceding text

<strong><code>*</code></strong> 0 or N of the preceding text (N &gt; 0)

<strong><code>+</code></strong> 1 or N of the preceding text (N &gt; 1)

<strong>Grouping:</strong>

<strong><code>(</code></strong>text<strong><code>)</code></strong> Grouping of text

(either to set the borders of an alternative or

for making backreferences where the <strong>N</strong>th group can

be used on the RHS of a RewriteRule with <code>$</code><strong>N</strong>)

<strong>Anchors:</strong>

<strong><code>^</code></strong> Start of line anchor

<strong><code>$</code></strong> End of line anchor

<strong>Escaping:</strong>

<strong><code>\</code></strong>char escape that particular char

(for instance to specify the chars "<code>.[]()</code>" <em>etc.</em>)

</pre></note>

<p>For more information about regular expressions have a look at the

perl regular expression manpage ("<a

href="http://www.perldoc.com/perl5.6.1/pod/perlre.html">perldoc

perlre</a>"). If you are interested in more detailed

information about regular expressions and their variants

(POSIX regex <em>etc.</em>) have a look at the

following dedicated book on this topic:</p>

<p class="indent">

<em>Mastering Regular Expressions, 2nd Edition</em><br />

Jeffrey E.F. Friedl<br />

O'Reilly &amp; Associates, Inc. 2002<br />

ISBN 0-596-00289-0<br />

</p>

<p>Additionally in mod_rewrite the NOT character

('<code>!</code>') is a possible pattern prefix. This gives

you the ability to negate a pattern; to say, for instance:

``<em>if the current URL does <strong>NOT</strong> match this

pattern</em>''. This can be used for exceptional cases, where

it is easier to match the negative pattern, or as a last

default rule.</p>

<note><title>Notice</title>

When using the NOT character

to negate a pattern you cannot have grouped wildcard

parts in the pattern. This is impossible because when the

pattern does NOT match, there are no contents for the

groups. In consequence, if negated patterns are used, you

cannot use <code>$N</code> in the substitution

string!

</note>

<p><a id="rhs" name="rhs"><em>Substitution</em></a> of a

rewriting rule is the string which is substituted for (or

replaces) the original URL for which <em>Pattern</em>

matched. Beside plain text you can use</p>

<ol>

<li>back-references <code>$N</code> to the RewriteRule

pattern</li>

<li>back-references <code>%N</code> to the last matched

RewriteCond pattern</li>

<li>server-variables as in rule condition test-strings

(<code>%{VARNAME}</code>)</li>

<li><a href="#mapfunc">mapping-function</a> calls

(<code>${mapname:key|default}</code>)</li>

</ol>

<p>Back-references are <code>$</code><strong>N</strong>

(<strong>N</strong>=0..9) identifiers which will be replaced

by the contents of the <strong>N</strong>th group of the

matched <em>Pattern</em>. The server-variables are the same

as for the <em>TestString</em> of a <code>RewriteCond</code>

directive. The mapping-functions come from the

<code>RewriteMap</code> directive and are explained there.

These three types of variables are expanded in the order of

the above list. </p>

<p>As already mentioned above, all the rewriting rules are

applied to the <em>Substitution</em> (in the order of

definition in the config file). The URL is <strong>completely

replaced</strong> by the <em>Substitution</em> and the

rewriting process goes on until there are no more rules

unless explicitly terminated by a

<code><strong>L</strong></code> flag - see below.</p>

<p>There is a special substitution string named

'<code>-</code>' which means: <strong>NO

substitution</strong>! Sounds silly? No, it is useful to

provide rewriting rules which <strong>only</strong> match

some URLs but do no substitution, <em>e.g.</em>, in

conjunction with the <strong>C</strong> (chain) flag to be

able to have more than one pattern to be applied before a

substitution occurs.</p>

<note><title>Query String</title>

<p>The <em>Pattern</em> will not match against the query string.

Instead, you must use a <directive

module="mod_rewrite">RewriteCond</directive> with the

<code>%{QUERY_STRING}</code> variable. You can, however, create

URLs in the substitution string containing a query string

part. Just use a question mark inside the substitution string to

indicate that the following stuff should be re-injected into the

query string. When you want to erase an existing query string,

end the substitution string with just the question mark. To

combine a new query string with an old one, use the

<code>[QSA]</code> flag (see below).</p>

</note>

<note><title>Substitution of Absolute URLs</title>

<p>There is a special feature:

When you prefix a substitution field with

<code>http://</code><em>thishost</em>[<em>:thisport</em>]

then <strong>mod_rewrite</strong> automatically strips it

out. This auto-reduction on implicit external redirect

URLs is a useful and important feature when used in

combination with a mapping-function which generates the

hostname part. Have a look at the first example in the

example section below to understand this.</p>

<p><strong>Remember:</strong> An unconditional external

redirect to your own server will not work with the prefix

<code>http://thishost</code> because of this feature. To

achieve such a self-redirect, you have to use the

<strong>R</strong>-flag (see below).</p>

</note>

<p>Additionally you can set special <a name="rewriteflags"

id="rewriteflags">flags</a> for <em>Substitution</em> by

appending</p>

<p class="indent">

<strong><code>[</code><em>flags</em><code>]</code></strong>

</p>

<p>

as the third argument to the <code>RewriteRule</code>

directive. <em>Flags</em> is a comma-separated list of the

following flags: </p>

<ul>

<li>'<strong><code>chain|C</code></strong>'

(<strong>c</strong>hained with next rule)<br />

This flag chains the current rule with the next rule

(which itself can be chained with the following rule,

<em>etc.</em>). This has the following effect: if a rule

matches, then processing continues as usual, <em>i.e.</em>,

the flag has no effect. If the rule does

<strong>not</strong> match, then all following chained

rules are skipped. For instance, use it to remove the

``<code>.www</code>'' part inside a per-directory rule set

when you let an external redirect happen (where the

``<code>.www</code>'' part should not to occur!).</li>

<li>

'<strong><code>cookie|CO=</code></strong><em>NAME</em>:<em>VAL</em>:<em>domain</em>[:<em>lifetime</em>[:<em>path</em>]]'

(set <strong>co</strong>okie)<br />

This sets a cookie on the client's browser. The cookie's name

is specified by <em>NAME</em> and the value is

<em>VAL</em>. The <em>domain</em> field is the domain of the

cookie, such as '.apache.org',the optional <em>lifetime</em>

is the lifetime of the cookie in minutes, and the optional

<em>path</em> is the path of the cookie</li>

<li>

'<strong><code>env|E=</code></strong><em>VAR</em>:<em>VAL</em>'

(set <strong>e</strong>nvironment variable)<br />

This forces an environment variable named <em>VAR</em> to

be set to the value <em>VAL</em>, where <em>VAL</em> can

contain regexp backreferences <code>$N</code> and

<code>%N</code> which will be expanded. You can use this

flag more than once to set more than one variable. The

variables can be later dereferenced in many situations, but

usually from within XSSI (via <code>&lt;!--#echo

var="VAR"--&gt;</code>) or CGI (<em>e.g.</em>

<code>$ENV{'VAR'}</code>). Additionally you can dereference

it in a following RewriteCond pattern via

<code>%{ENV:VAR}</code>. Use this to strip but remember

information from URLs.</li>

<li>'<strong><code>forbidden|F</code></strong>' (force URL

to be <strong>f</strong>orbidden)<br />

This forces the current URL to be forbidden,

<em>i.e.</em>, it immediately sends back a HTTP response of

403 (FORBIDDEN). Use this flag in conjunction with

appropriate RewriteConds to conditionally block some

URLs.</li>

<li>'<strong><code>gone|G</code></strong>' (force URL to be

<strong>g</strong>one)<br />

This forces the current URL to be gone, <em>i.e.</em>, it

immediately sends back a HTTP response of 410 (GONE). Use

this flag to mark pages which no longer exist as gone.</li>

<li>

'<strong><code>handler|H</code></strong>=<em>Content-handler</em>'

(force Content <strong>h</strong>andler)<br />

Force the Content-handler of the target file to be

<em>Content-handler</em>. For instance, this can be used to

simulate the <code>mod_alias</code> directive

<code>ScriptAlias</code> which internally forces all files

inside the mapped directory to have a handler of

``<code>cgi-script</code>''.</li>

<li>'<strong><code>last|L</code></strong>'

(<strong>l</strong>ast rule)<br />

Stop the rewriting process here and don't apply any more

rewriting rules. This corresponds to the Perl

<code>last</code> command or the <code>break</code> command

from the C language. Use this flag to prevent the currently

rewritten URL from being rewritten further by following

rules. For example, use it to rewrite the root-path URL

('<code>/</code>') to a real one, <em>e.g.</em>,

'<code>/e/www/</code>'.</li>

<li>'<strong><code>next|N</code></strong>'

(<strong>n</strong>ext round)<br />

Re-run the rewriting process (starting again with the

first rewriting rule). Here the URL to match is again not

the original URL but the URL from the last rewriting rule.

This corresponds to the Perl <code>next</code> command or

the <code>continue</code> command from the C language. Use

this flag to restart the rewriting process, <em>i.e.</em>,

to immediately go to the top of the loop.<br />

<strong>But be careful not to create an infinite

loop!</strong></li>

<li>'<strong><code>nocase|NC</code></strong>'

(<strong>n</strong>o <strong>c</strong>ase)<br />

This makes the <em>Pattern</em> case-insensitive,

<em>i.e.</em>, there is no difference between 'A-Z' and

'a-z' when <em>Pattern</em> is matched against the current

URL.</li>

<li>

'<strong><code>noescape|NE</code></strong>'

(<strong>n</strong>o URI <strong>e</strong>scaping of

output)<br />

This flag keeps mod_rewrite from applying the usual URI

escaping rules to the result of a rewrite. Ordinarily,

special characters (such as '%', '$', ';', and so on)

will be escaped into their hexcode equivalents ('%25',

'%24', and '%3B', respectively); this flag prevents this

from being done. This allows percent symbols to appear in

the output, as in

<example>

RewriteRule /foo/(.*) /bar?arg=P1\%3d$1 [R,NE]

</example>

which would turn '<code>/foo/zed</code>' into a safe

request for '<code>/bar?arg=P1=zed</code>'.

</li>

<li>

'<strong><code>nosubreq|NS</code></strong>' (used only if

<strong>n</strong>o internal

<strong>s</strong>ub-request)<br />

This flag forces the rewriting engine to skip a

rewriting rule if the current request is an internal

sub-request. For instance, sub-requests occur internally

in Apache when <code>mod_include</code> tries to find out

information about possible directory default files

(<code>index.xxx</code>). On sub-requests it is not

always useful and even sometimes causes a failure to if

the complete set of rules are applied. Use this flag to

exclude some rules.<br />

<p>Use the following rule for your decision: whenever you

prefix some URLs with CGI-scripts to force them to be

processed by the CGI-script, the chance is high that you

will run into problems (or even overhead) on

sub-requests. In these cases, use this flag.</p>

</li>

<li>

'<strong><code>proxy|P</code></strong>' (force

<strong>p</strong>roxy)<br />

This flag forces the substitution part to be internally

forced as a proxy request and immediately (<em>i.e.</em>,

rewriting rule processing stops here) put through the <a

href="mod_proxy.html">proxy module</a>. You have to make

sure that the substitution string is a valid URI

(<em>e.g.</em>, typically starting with

<code>http://</code><em>hostname</em>) which can be

handled by the Apache proxy module. If not you get an

error from the proxy module. Use this flag to achieve a

more powerful implementation of the <a

href="mod_proxy.html#proxypass">ProxyPass</a> directive,

to map some remote stuff into the namespace of the local

server.

<p>Notice: To use this functionality make sure you have

the proxy module compiled into your Apache server

program. If you don't know please check whether

<code>mod_proxy.c</code> is part of the ``<code>httpd

-l</code>'' output. If yes, this functionality is

available to mod_rewrite. If not, then you first have to

rebuild the <program>httpd</program> program with mod_proxy

enabled.</p>

</li>

<li>

'<strong><code>passthrough|PT</code></strong>'

(<strong>p</strong>ass <strong>t</strong>hrough to next

handler)<br />

This flag forces the rewriting engine to set the

<code>uri</code> field of the internal

<code>request_rec</code> structure to the value of the

<code>filename</code> field. This flag is just a hack to

be able to post-process the output of

<code>RewriteRule</code> directives by

<code>Alias</code>, <code>ScriptAlias</code>,

<code>Redirect</code>, <em>etc.</em> directives from

other URI-to-filename translators. A trivial example to

show the semantics: If you want to rewrite

<code>/abc</code> to <code>/def</code> via the rewriting

engine of <code>mod_rewrite</code> and then

<code>/def</code> to <code>/ghi</code> with

<code>mod_alias</code>:

<example>

RewriteRule ^/abc(.*) /def$1 [PT]<br />

Alias /def /ghi

</example>

If you omit the <code>PT</code> flag then

<code>mod_rewrite</code> will do its job fine,

<em>i.e.</em>, it rewrites <code>uri=/abc/...</code> to

<code>filename=/def/...</code> as a full API-compliant

URI-to-filename translator should do. Then

<code>mod_alias</code> comes and tries to do a

URI-to-filename transition which will not work.

<p>Note: <strong>You have to use this flag if you want to

intermix directives of different modules which contain

URL-to-filename translators</strong>. The typical example

is the use of <code>mod_alias</code> and

<code>mod_rewrite</code>..</p>

</li>

<li>'<strong><code>qsappend|QSA</code></strong>'

(<strong>q</strong>uery <strong>s</strong>tring

<strong>a</strong>ppend)<br />

This flag forces the rewriting engine to append a query

string part in the substitution string to the existing one

instead of replacing it. Use this when you want to add more

data to the query string via a rewrite rule.</li>

<li>'<strong><code>redirect|R</code>

[=<em>code</em>]</strong>' (force <a id="redirect"

name="redirect"><strong>r</strong>edirect</a>)<br />

Prefix <em>Substitution</em> with

<code>http://thishost[:thisport]/</code> (which makes the

new URL a URI) to force a external redirection. If no

<em>code</em> is given a HTTP response of 302 (MOVED

TEMPORARILY) is used. If you want to use other response

codes in the range 300-400 just specify them as a number

or use one of the following symbolic names:

<code>temp</code> (default), <code>permanent</code>,

<code>seeother</code>. Use it for rules which should

canonicalize the URL and give it back to the client,

<em>e.g.</em>, translate ``<code>/~</code>'' into

``<code>/u/</code>'' or always append a slash to

<code>/u/</code><em>user</em>, etc.<br />

<p><strong>Note:</strong> When you use this flag, make

sure that the substitution field is a valid URL! If not,

you are redirecting to an invalid location! And remember

that this flag itself only prefixes the URL with

<code>http://thishost[:thisport]/</code>, rewriting

continues. Usually you also want to stop and do the

redirection immediately. To stop the rewriting you also

have to provide the 'L' flag.</p>

</li>