1<?xml version="1.0" encoding="ISO-8859-1"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- 4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 5 This file is generated from xml source: DO NOT EDIT 6 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 7 --> 8<title>When not to use mod_rewrite - Apache HTTP Server</title> 9<link href="/style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> 10<link href="/style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> 11<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" /> 12<script src="/style/scripts/prettify.js" type="text/javascript"> 13</script> 14 15<link href="/images/favicon.ico" rel="shortcut icon" /></head> 16<body id="manual-page"><div id="page-header"> 17<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> 18<p class="apache">Apache HTTP Server Version 2.2</p> 19<img alt="" src="/images/feather.gif" /></div> 20<div class="up"><a href="./"><img title="<-" alt="<-" src="/images/left.gif" /></a></div> 21<div id="path"> 22<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.2</a> > <a href="./">Rewrite</a></div><div id="page-content"><div id="preamble"><h1>When not to use mod_rewrite</h1> 23<div class="toplang"> 24<p><span>Available Languages: </span><a href="/en/rewrite/avoid.html" title="English"> en </a></p> 25</div> 26 27 28<p>This document supplements the <code class="module"><a href="/mod/mod_rewrite.html">mod_rewrite</a></code> 29<a href="/mod/mod_rewrite.html">reference documentation</a>. It describes 30perhaps one of the most important concepts about mod_rewrite - namely, 31when to avoid using it.</p> 32 33<p>mod_rewrite should be considered a last resort, when other 34alternatives are found wanting. Using it when there are simpler 35alternatives leads to configurations which are confusing, fragile, and 36hard to maintain. Understanding what other alternatives are available is 37a very important step towards mod_rewrite mastery.</p> 38 39<p>Note that many of these examples won't work unchanged in your 40particular server configuration, so it's important that you understand 41them, rather than merely cutting and pasting the examples into your 42configuration.</p> 43 44<p>The most common situation in which <code class="module"><a href="/mod/mod_rewrite.html">mod_rewrite</a></code> is 45the right tool is when the very best solution requires access to the 46server configuration files, and you don't have that access. Some 47configuration directives are only available in the server configuration 48file. So if you are in a hosting situation where you only have .htaccess 49files to work with, you may need to resort to 50<code class="module"><a href="/mod/mod_rewrite.html">mod_rewrite</a></code>.</p> 51 52</div> 53<div id="quickview"><ul id="toc"><li><img alt="" src="/images/down.gif" /> <a href="#redirect">Simple Redirection</a></li> 54<li><img alt="" src="/images/down.gif" /> <a href="#alias">URL Aliasing</a></li> 55<li><img alt="" src="/images/down.gif" /> <a href="#vhosts">Virtual Hosting</a></li> 56<li><img alt="" src="/images/down.gif" /> <a href="#proxy">Simple Proxying</a></li> 57</ul><h3>See also</h3><ul class="seealso"><li><a href="/mod/mod_rewrite.html">Module documentation</a></li><li><a href="intro.html">mod_rewrite introduction</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 and tricks</a></li></ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div> 58<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 59<div class="section"> 60<h2><a name="redirect" id="redirect">Simple Redirection</a></h2> 61 62 63<p><code class="module"><a href="/mod/mod_alias.html">mod_alias</a></code> provides the <code class="directive"><a href="/mod/mod_alias.html#redirect">Redirect</a></code> and <code class="directive"><a href="/mod/mod_alias.html#redirectmatch">RedirectMatch</a></code> directives, which provide a 64means to redirect one URL to another. This kind of simple redirection of 65one URL, or a class of URLs, to somewhere else, should be accomplished 66using these directives rather than <code class="directive"><a href="/mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>. <code>RedirectMatch</code> 67allows you to include a regular expression in your redirection criteria, 68providing many of the benefits of using <code>RewriteRule</code>.</p> 69 70<p>A common use for <code>RewriteRule</code> is to redirect an entire 71class of URLs. For example, all URLs in the <code>/one</code> directory 72must be redirected to <code>http://one.example.com/</code>, or perhaps 73all <code>http</code> requests must be redirected to 74<code>https</code>.</p> 75 76<p>These situations are better handled by the <code>Redirect</code> 77directive. Remember that <code>Redirect</code> preserves path 78information. That is to say, a redirect for a URL <code>/one</code> will 79also redirect all URLs under that, such as <code>/one/two.html</code> 80and <code>/one/three/four.html</code>.</p> 81 82<p>To redirect URLs under <code>/one</code> to 83<code>http://one.example.com</code>, do the following:</p> 84 85<div class="example"><p><code> 86Redirect /one/ http://one.example.com/ 87</code></p></div> 88 89<p>To redirect <code>http</code> URLs to <code>https</code>, do the 90following:</p> 91 92<div class="example"><p><code> 93<VirtualHost *:80> 94ServerName www.example.com<br /> 95Redirect / https://www.example.com/<br /> 96</VirtualHost > 97<br /> 98<VirtualHost *:443> 99ServerName www.example.com<br /> 100<br /> 101# ... SSL configuration goes here<br /> 102</VirtualHost > 103</code></p></div> 104 105<p>The use of <code>RewriteRule</code> to perform this task may be 106appropriate if there are other <code>RewriteRule</code> directives in 107the same scope. This is because, when there are <code>Redirect</code> 108and <code>RewriteRule</code> directives in the same scope, the 109<code>RewriteRule</code> directives will run first, regardless of the 110order of appearance in the configuration file.</p> 111 112<p>In the case of the <em>http-to-https</em> redirection, the use of 113<code>RewriteRule</code> would be appropriate if you don't have access 114to the main server configuration file, and are obliged to perform this 115task in a <code>.htaccess</code> file instead.</p> 116 117</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 118<div class="section"> 119<h2><a name="alias" id="alias">URL Aliasing</a></h2> 120<p>The <code class="directive"><a href="/mod/mod_alias.html#alias">Alias</a></code> directive 121provides mapping from a URI to a directory - usually a directory outside 122of your <code class="directive"><a href="/mod/core.html#documentroot">DocumentRoot</a></code>. Although it 123is possible to perform this mapping with <code>mod_rewrite</code>, 124<code>Alias</code> is the preferred method, for reasons of simplicity 125and performance.</p> 126 127<div class="example"><h3>Using Alias</h3><p><code> 128Alias /cats /var/www/virtualhosts/felines/htdocs 129</code></p></div> 130 131<p> 132The use of <code>mod_rewrite</code> to perform this mapping may be 133appropriate when you do not have access to the server configuration 134files. Alias may only be used in server or virtualhost context, and not 135in a <code>.htaccess</code> file. 136</p> 137 138<p>Symbolic links would be another way to accomplish the same thing, if 139you have <code>Options FollowSymLinks</code> enabled on your 140server.</p> 141</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 142<div class="section"> 143<h2><a name="vhosts" id="vhosts">Virtual Hosting</a></h2> 144<p>Although it is possible to handle <a href="vhosts.html">virtual hosts 145with mod_rewrite</a>, it is seldom the right way. Creating individual 146<VirtualHost> blocks is almost always the right way to go. In the 147event that you have an enormous number of virtual hosts, consider using 148<code class="module"><a href="/mod/mod_vhost_alias.html">mod_vhost_alias</a></code> to create these hosts automatically.</p> 149 150<p>Third-party modules such as <a href="http://people.apache.org/~fabien/mod_macro/">mod_macro</a> are 151also useful for creating a large number of virtual hosts dynamically.</p> 152 153<p>Using <code class="module"><a href="/mod/mod_rewrite.html">mod_rewrite</a></code> for vitualhost creation may be 154appropriate if you are using a hosting service that does not provide 155you access to the server configuration files, and you are therefore 156restricted to configuration using <code>.htaccess</code> files.</p> 157 158<p>See the <a href="vhosts.html">virtual hosts with mod_rewrite</a> 159document for more details on how you might accomplish this if it still 160seems like the right approach.</p> 161 162</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 163<div class="section"> 164<h2><a name="proxy" id="proxy">Simple Proxying</a></h2> 165 166<p><code>RewriteRule</code> provides the <a href="flags.html#flag_p">[P]</a> flag to pass rewritten URIs through 167<code class="module"><a href="/mod/mod_proxy.html">mod_proxy</a></code>.</p> 168 169<div class="example"><p><code> 170RewriteRule ^/?images(.*) http://imageserver.local/images$1 [P] 171</code></p></div> 172 173<p>However, in many cases, when there is no actual pattern matching 174needed, as in the example shown above, the <code class="directive"><a href="/mod/mod_proxy.html#proxypass">ProxyPass</a></code> directive is a better choice. 175The example here could be rendered as:</p> 176 177<div class="example"><p><code> 178ProxyPass /images/ http://imageserver.local/images/ 179</code></p></div> 180 181<p>Note that whether you use <code class="directive"><a href="/mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> or <code class="directive"><a href="/mod/mod_proxy.html#proxypass">ProxyPass</a></code>, you'll still need to use the 182<code class="directive"><a href="/mod/mod_proxy.html#proxypassreverse">ProxyPassReverse</a></code> directive to 183catch redirects issued from the back-end server:</p> 184 185<div class="example"><p><code> 186ProxyPassReverse /images/ http://imageserver.local/images/ 187</code></p></div> 188 189<p>You may need to use <code>RewriteRule</code> instead when there are 190other <code>RewriteRule</code>s in effect in the same scope, as a 191<code>RewriteRule</code> will usually take effect before a 192<code>ProxyPass</code>, and so may preempt what you're trying to 193accomplish.</p> 194 195</div></div> 196<div class="bottomlang"> 197<p><span>Available Languages: </span><a href="/en/rewrite/avoid.html" title="English"> en </a></p> 198</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&A section. 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