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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head>
+<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" />
+<!--
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ This file is generated from xml source: DO NOT EDIT
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ -->
+<title>Apache mod_rewrite Introduction - Apache HTTP Server Version 2.4</title>
+<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
+<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
+<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" />
+<script src="../style/scripts/prettify.min.js" type="text/javascript">
+</script>
+
+<link href="../images/favicon.ico" rel="shortcut icon" /></head>
+<body id="manual-page"><div id="page-header">
+<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
+<p class="apache">Apache HTTP Server Version 2.4</p>
+<img alt="" src="../images/feather.png" /></div>
+<div class="up"><a href="./"><img title="&lt;-" alt="&lt;-" src="../images/left.gif" /></a></div>
+<div id="path">
+<a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs/">Documentation</a> &gt; <a href="../">Version 2.4</a> &gt; <a href="./">Rewrite</a></div><div id="page-content"><div id="preamble"><h1>Apache mod_rewrite Introduction</h1>
+<div class="toplang">
+<p><span>Available Languages: </span><a href="../en/rewrite/intro.html" title="English">&nbsp;en&nbsp;</a> |
+<a href="../fr/rewrite/intro.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a></p>
+</div>
+
+<p>This document supplements the <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
+<a href="../mod/mod_rewrite.html">reference documentation</a>. It
+describes the basic concepts necessary for use of
+<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. Other documents go into greater detail,
+but this doc should help the beginner get their feet wet.
+</p>
+</div>
+<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#introduction">Introduction</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#regex">Regular Expressions</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#rewriterule">RewriteRule Basics</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#flags">Rewrite Flags</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#rewritecond">Rewrite Conditions</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#rewritemap">Rewrite maps</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#htaccess">.htaccess files</a></li>
+</ul><h3>See also</h3><ul class="seealso"><li><a href="../mod/mod_rewrite.html">Module documentation</a></li><li><a href="remapping.html">Redirection and remapping</a></li><li><a href="access.html">Controlling access</a></li><li><a href="vhosts.html">Virtual hosts</a></li><li><a href="proxy.html">Proxying</a></li><li><a href="rewritemap.html">Using RewriteMap</a></li><li><a href="advanced.html">Advanced techniques</a></li><li><a href="avoid.html">When not to use mod_rewrite</a></li><li><a href="#comments_section">Comments</a></li></ul></div>
+<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="introduction" id="introduction">Introduction</a></h2>
+<p>The Apache module <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> is a very powerful and
+sophisticated module which provides a way to do URL manipulations. With
+it, you can do nearly all types of URL rewriting that you may need. It
+is, however, somewhat complex, and may be intimidating to the beginner.
+There is also a tendency to treat rewrite rules as magic incantation,
+using them without actually understanding what they do.</p>
+
+<p>This document attempts to give sufficient background so that what
+follows is understood, rather than just copied blindly.
+</p>
+
+<p>Remember that many common URL-manipulation tasks don't require the
+full power and complexity of <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. For simple
+tasks, see <code class="module"><a href="../mod/mod_alias.html">mod_alias</a></code> and the documentation
+on <a href="../urlmapping.html">mapping URLs to the
+filesystem</a>.</p>
+
+<p>Finally, before proceeding, be sure to configure
+<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>'s log level to one of the trace levels using
+the <code class="directive"><a href="../mod/core.html#loglevel">LogLevel</a></code> directive. Although this
+can give an overwhelming amount of information, it is indispensable in
+debugging problems with <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> configuration, since
+it will tell you exactly how each rule is processed.</p>
+
+</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="regex" id="regex">Regular Expressions</a></h2>
+
+<p><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> uses the <a href="http://pcre.org/">Perl Compatible
+Regular Expression</a> vocabulary. In this document, we do not attempt
+to provide a detailed reference to regular expressions. For that, we
+recommend the <a href="http://pcre.org/pcre.txt">PCRE man pages</a>, the
+<a href="http://perldoc.perl.org/perlre.html">Perl regular
+expression man page</a>, and <a href="http://shop.oreilly.com/product/9780596528126.do">Mastering
+Regular Expressions, by Jeffrey Friedl</a>.</p>
+
+<p>In this document, we attempt to provide enough of a regex vocabulary
+to get you started, without being overwhelming, in the hope that
+<code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>s will be scientific
+formulae, rather than magical incantations.</p>
+
+<h3><a name="regexvocab" id="regexvocab">Regex vocabulary</a></h3>
+
+<p>The following are the minimal building blocks you will need, in order
+to write regular expressions and <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>s. They certainly do not
+represent a complete regular expression vocabulary, but they are a good
+place to start, and should help you read basic regular expressions, as
+well as write your own.</p>
+
+<table>
+<tr>
+<th>Character</th>
+<th>Meaning</th>
+<th>Example</th>
+</tr>
+
+<tr>
+ <td><code>.</code></td>
+ <td>Matches any single character</td>
+ <td><code>c.t</code> will match <code>cat</code>, <code>cot</code>,
+ <code>cut</code>, etc</td>
+</tr>
+<tr>
+ <td><code>+</code></td>
+ <td>Repeats the previous match one or more times</td>
+ <td><code>a+</code> matches <code>a</code>, <code>aa</code>,
+ <code>aaa</code>, etc</td>
+</tr>
+<tr>
+ <td><code>*</code></td>
+ <td>Repeats the previous match zero or more times</td>
+ <td><code>a*</code> matches all the same things <code>a+</code> matches,
+ but will also match an empty string</td>
+</tr>
+<tr>
+ <td><code>?</code></td>
+ <td>Makes the match optional</td>
+ <td><code>colou?r</code> will match <code>color</code> and
+ <code>colour</code></td>
+</tr>
+<tr>
+ <td><code>\</code></td>
+ <td>Escape the next character</td>
+ <td><code>\.</code> will match <code>.</code> (dot) and not <em>any single
+ character</em> as explain above</td>
+</tr>
+<tr>
+ <td><code>^</code></td>
+ <td>Called an anchor, matches the beginning of the string</td>
+ <td><code>^a</code> matches a string that begins with <code>a</code></td>
+</tr>
+<tr>
+ <td><code>$</code></td>
+ <td>The other anchor, this matches the end of the string</td>
+ <td><code>a$</code> matches a string that ends with <code>a</code></td>
+</tr>
+<tr>
+ <td><code>( )</code></td>
+ <td>Groups several characters into a single unit, and captures a match
+ for use in a backreference</td>
+ <td><code>(ab)+</code> matches <code>ababab</code> - that is, the
+ <code>+</code> applies to the group. For more on backreferences see
+ <a href="#InternalBackRefs">below</a></td>
+</tr>
+<tr>
+ <td><code>[ ]</code></td>
+ <td>A character class - matches one of the characters</td>
+ <td><code>c[uoa]t</code> matches <code>cut</code>, <code>cot</code> or
+ <code>cat</code></td>
+</tr>
+<tr>
+ <td><code>[^ ]</code></td>
+ <td>Negative character class - matches any character not specified</td>
+ <td><code>c[^/]t</code> matches <code>cat</code> or <code>c=t</code> but
+ not <code>c/t</code></td></tr>
+</table>
+
+<p>In <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> the <code>!</code> character can be
+used before a regular expression to negate it. This is, a string will
+be considered to have matched only if it does not match the rest of
+the expression.</p>
+
+
+
+<h3><a name="InternalBackRefs" id="InternalBackRefs">Regex Back-Reference Availability</a></h3>
+
+ <p>One important thing here has to be remembered: Whenever you
+ use parentheses in <em>Pattern</em> or in one of the
+ <em>CondPattern</em>, back-references are internally created
+ which can be used with the strings <code>$N</code> and
+ <code>%N</code> (see below). These are available for creating
+ the <em>Substitution</em> parameter of a
+ <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> or
+ the <em>TestString</em> parameter of a
+ <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code>.</p>
+ <p> Captures in the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> patterns are (counterintuitively) available to
+ all preceding
+ <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code> directives,
+ because the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>
+ expression is evaluated before the individual conditions.</p>
+
+ <p>Figure 1 shows to which
+ locations the back-references are transferred for expansion as
+ well as illustrating the flow of the RewriteRule, RewriteCond
+ matching. In the next chapters, we will be exploring how to use
+ these back-references, so do not fret if it seems a bit alien
+ to you at first.
+ </p>
+
+<p class="figure">
+ <img src="../images/rewrite_backreferences.png" alt="Flow of RewriteRule and RewriteCond matching" /><br />
+ <dfn>Figure 1:</dfn> The back-reference flow through a rule.<br />
+ In this example, a request for <code>/test/1234</code> would be transformed into <code>/admin.foo?page=test&amp;id=1234&amp;host=admin.example.com</code>.
+</p>
+
+
+</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="rewriterule" id="rewriterule">RewriteRule Basics</a></h2>
+<p>A <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> consists
+of three arguments separated by spaces. The arguments are</p>
+<ol>
+<li><var>Pattern</var>: which incoming URLs should be affected by the rule;</li>
+<li><var>Substitution</var>: where should the matching requests be sent;</li>
+<li><var>[flags]</var>: options affecting the rewritten request.</li>
+</ol>
+
+<p>The <var>Pattern</var> is a <a href="#regex">regular expression</a>.
+It is initially (for the first rewrite rule or until a substitution occurs)
+matched against the URL-path of the incoming request (the part after the
+hostname but before any question mark indicating the beginning of a query
+string) or, in per-directory context, against the request's path relative
+to the directory for which the rule is defined. Once a substitution has
+occurred, the rules that follow are matched against the substituted
+value.
+</p>
+
+<p class="figure">
+ <img src="../images/syntax_rewriterule.png" alt="Syntax of the RewriteRule directive" /><br />
+ <dfn>Figure 2:</dfn> Syntax of the RewriteRule directive.
+</p>
+
+
+<p>The <var>Substitution</var> can itself be one of three things:</p>
+
+<dl>
+<dt>1. A full filesystem path to a resource</dt>
+<dd>
+<pre class="prettyprint lang-config">RewriteRule "^/games" "/usr/local/games/web/puzzles.html"</pre>
+
+<p>This maps a request to an arbitrary location on your filesystem, much
+like the <code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code> directive.</p>
+</dd>
+
+<dt>2. A web-path to a resource</dt>
+<dd>
+<pre class="prettyprint lang-config">RewriteRule "^/games$" "/puzzles.html"</pre>
+
+<p>If <code class="directive"><a href="../mod/core.html#documentroot">DocumentRoot</a></code> is set
+to <code>/usr/local/apache2/htdocs</code>, then this directive would
+map requests for <code>http://example.com/games</code> to the
+path <code>/usr/local/apache2/htdocs/puzzles.html</code>.</p>
+
+</dd>
+
+<dt>3. An absolute URL</dt>
+<dd>
+<pre class="prettyprint lang-config">RewriteRule "^/product/view$" "http://site2.example.com/seeproduct.html" [R]</pre>
+
+<p>This tells the client to make a new request for the specified URL.</p>
+</dd>
+</dl>
+
+<div class="warning">Note that <strong>1</strong> and <strong>2</strong> have exactly the same syntax. The difference between them is that in the case of <strong>1</strong>, the top level of the target path (i.e., <code>/usr/</code>) exists on the filesystem, where as in the case of <strong>2</strong>, it does not. (i.e., there's no <code>/bar/</code> as a root-level directory in the filesystem.)</div>
+
+<p>The <var>Substitution</var> can also
+contain <em>back-references</em> to parts of the incoming URL-path
+matched by the <var>Pattern</var>. Consider the following:</p>
+<pre class="prettyprint lang-config">RewriteRule "^/product/(.*)/view$" "/var/web/productdb/$1"</pre>
+
+<p>The variable <code>$1</code> will be replaced with whatever text
+was matched by the expression inside the parenthesis in
+the <var>Pattern</var>. For example, a request
+for <code>http://example.com/product/r14df/view</code> will be mapped
+to the path <code>/var/web/productdb/r14df</code>.</p>
+
+<p>If there is more than one expression in parenthesis, they are
+available in order in the
+variables <code>$1</code>, <code>$2</code>, <code>$3</code>, and so
+on.</p>
+
+
+</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="flags" id="flags">Rewrite Flags</a></h2>
+<p>The behavior of a <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> can be modified by the
+application of one or more flags to the end of the rule. For example, the
+matching behavior of a rule can be made case-insensitive by the
+application of the <code>[NC]</code> flag:
+</p>
+<pre class="prettyprint lang-config">RewriteRule "^puppy.html" "smalldog.html" [NC]</pre>
+
+
+<p>For more details on the available flags, their meanings, and
+examples, see the <a href="flags.html">Rewrite Flags</a> document.</p>
+
+</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="rewritecond" id="rewritecond">Rewrite Conditions</a></h2>
+<p>One or more <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code>
+directives can be used to restrict the types of requests that will be
+subject to the
+following <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>. The
+first argument is a variable describing a characteristic of the
+request, the second argument is a <a href="#regex">regular
+expression</a> that must match the variable, and a third optional
+argument is a list of flags that modify how the match is evaluated.</p>
+
+<p class="figure">
+ <img src="../images/syntax_rewritecond.png" alt="Syntax of the RewriteCond directive" /><br />
+ <dfn>Figure 3:</dfn> Syntax of the RewriteCond directive
+</p>
+
+<p>For example, to send all requests from a particular IP range to a
+different server, you could use:</p>
+<pre class="prettyprint lang-config">RewriteCond "%{REMOTE_ADDR}" "^10\.2\."
+RewriteRule "(.*)" "http://intranet.example.com$1"</pre>
+
+
+<p>When more than
+one <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code> is
+specified, they must all match for
+the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> to be
+applied. For example, to deny requests that contain the word "hack" in
+their query string, unless they also contain a cookie containing
+the word "go", you could use:</p>
+<pre class="prettyprint lang-config">RewriteCond "%{QUERY_STRING}" "hack"
+RewriteCond "%{HTTP_COOKIE}" !go
+RewriteRule "." "-" [F]</pre>
+
+<p>Notice that the exclamation mark specifies a negative match, so the rule is only applied if the cookie does not contain "go".</p>
+
+<p>Matches in the regular expressions contained in
+the <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code>s can be
+used as part of the <var>Substitution</var> in
+the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> using the
+variables <code>%1</code>, <code>%2</code>, etc. For example, this
+will direct the request to a different directory depending on the
+hostname used to access the site:</p>
+<pre class="prettyprint lang-config">RewriteCond "%{HTTP_HOST}" "(.*)"
+RewriteRule "^/(.*)" "/sites/%1/$1"</pre>
+
+<p>If the request was for <code>http://example.com/foo/bar</code>,
+then <code>%1</code> would contain <code>example.com</code>
+and <code>$1</code> would contain <code>foo/bar</code>.</p>
+
+
+
+</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="rewritemap" id="rewritemap">Rewrite maps</a></h2>
+
+<p>The <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code> directive
+provides a way to call an external function, so to speak, to do your
+rewriting for you. This is discussed in greater detail in the <a href="rewritemap.html">RewriteMap supplementary documentation</a>.</p>
+</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="htaccess" id="htaccess">.htaccess files</a></h2>
+
+<p>Rewriting is typically configured in the main server configuration
+setting (outside any <code class="directive"><a href="../mod/core.html#directory">&lt;Directory&gt;</a></code> section) or
+inside <code class="directive"><a href="../mod/core.html#virtualhost">&lt;VirtualHost&gt;</a></code>
+containers. This is the easiest way to do rewriting and is
+recommended. It is possible, however, to do rewriting
+inside <code class="directive"><a href="../mod/core.html#directory">&lt;Directory&gt;</a></code>
+sections or <a href="../howto/htaccess.html"><code>.htaccess</code>
+files</a> at the expense of some additional complexity. This technique
+is called per-directory rewrites.</p>
+
+<p>The main difference with per-server rewrites is that the path
+prefix of the directory containing the <code>.htaccess</code> file is
+stripped before matching in
+the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>. In addition, the <code class="directive"><a href="../mod/mod_rewrite.html#rewritebase">RewriteBase</a></code> should be used to assure the request is properly mapped.</p>
+
+</div></div>
+<div class="bottomlang">
+<p><span>Available Languages: </span><a href="../en/rewrite/intro.html" title="English">&nbsp;en&nbsp;</a> |
+<a href="../fr/rewrite/intro.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a></p>
+</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&amp;A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Libera.chat, or sent to our <a href="https://httpd.apache.org/lists.html">mailing lists</a>.</div>
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