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>mod_substitute - 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.min.js" type="text/javascript"> 13</script> 14 15<link href="/images/favicon.ico" rel="shortcut icon" /></head> 16<body> 17<div id="page-header"> 18<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> 19<p class="apache">Apache HTTP Server Version 2.4</p> 20<img alt="" src="/images/feather.gif" /></div> 21<div class="up"><a href="./"><img title="<-" alt="<-" src="/images/left.gif" /></a></div> 22<div id="path"> 23<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 2.4</a> > <a href="./">Modules</a></div> 24<div id="page-content"> 25<div id="preamble"><h1>Apache Module mod_substitute</h1> 26<div class="toplang"> 27<p><span>Available Languages: </span><a href="/en/mod/mod_substitute.html" title="English"> en </a> | 28<a href="/fr/mod/mod_substitute.html" hreflang="fr" rel="alternate" title="Fran�ais"> fr </a></p> 29</div> 30<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Perform search and replace operations on response bodies</td></tr> 31<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr> 32<tr><th><a href="module-dict.html#ModuleIdentifier">Module�Identifier:</a></th><td>substitute_module</td></tr> 33<tr><th><a href="module-dict.html#SourceFile">Source�File:</a></th><td>mod_substitute.c</td></tr> 34<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache HTTP Server 2.2.7 and later</td></tr></table> 35<h3>Summary</h3> 36 37 <p><code class="module"><a href="/mod/mod_substitute.html">mod_substitute</a></code> provides a mechanism to perform 38 both regular expression and fixed string substitutions on 39 response bodies.</p> 40</div> 41<div id="quickview"><h3 class="directives">Directives</h3> 42<ul id="toc"> 43<li><img alt="" src="/images/down.gif" /> <a href="#substitute">Substitute</a></li> 44</ul> 45<ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div> 46 47<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 48<div class="directive-section"><h2><a name="Substitute" id="Substitute">Substitute</a> <a name="substitute" id="substitute">Directive</a></h2> 49<table class="directive"> 50<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Pattern to filter the response content</td></tr> 51<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Substitute <var>s/pattern/substitution/[infq]</var></code></td></tr> 52<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr> 53<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr> 54<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> 55<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_substitute</td></tr> 56</table> 57 <p>The <code class="directive">Substitute</code> directive specifies a 58 search and replace pattern to apply to the response body.</p> 59 60 <p>The meaning of the pattern can be modified by using any 61 combination of these flags:</p> 62 63 <dl> 64 <dt><code>i</code></dt> 65 <dd>Perform a case-insensitive match.</dd> 66 <dt><code>n</code></dt> 67 <dd>By default the pattern is treated as a regular expression. 68 Using the <code>n</code> flag forces the pattern to be treated 69 as a fixed string.</dd> 70 <dt><code>f</code></dt> 71 <dd>The <code>f</code> flag causes mod_substitute to flatten the 72 result of a substitution allowing for later substitutions to 73 take place on the boundary of this one. This is the default.</dd> 74 <dt><code>q</code></dt> 75 <dd>The <code>q</code> flag causes mod_substitute to not 76 flatten the buckets after each substitution. This can 77 result in much faster response and a decrease in memory 78 utilization, but should only be used if there is no possibility 79 that the result of one substitution will ever match a pattern 80 or regex of a subsequent one.</dd> 81 </dl> 82 83 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config"><Location /> 84 AddOutputFilterByType SUBSTITUTE text/html 85 Substitute s/foo/bar/ni 86</Location></pre> 87</div> 88 89 <p>If either the pattern or the substitution contain a slash 90 character then an alternative delimiter should be used:</p> 91 92 <div class="example"><h3>Example of using an alternate delimiter</h3><pre class="prettyprint lang-config"><Location /> 93 AddOutputFilterByType SUBSTITUTE text/html 94 Substitute "s|<BR */?>|<br />|i" 95</Location></pre> 96</div> 97 98 <p>Backreferences can be used in the comparison and in the substitution, 99 when regular expressions are used, as illustrated in the following example: </p> 100 <div class="example"><h3>Example of using backreferences and captures</h3><pre class="prettyprint lang-config"><Location /> 101 AddOutputFilterByType SUBSTITUTE text/html 102 # "foo=k,bar=k" -> "foo/bar=k" 103 Substitute "s|foo=(\w+),bar=\1|foo/bar=$1" 104</Location></pre> 105</div> 106 107 <p>A common use scenario for <code>mod_substitute</code> is the 108 situation in which a front-end server proxies requests to a back-end 109 server which returns HTML with hard-coded embedded URLs that refer 110 to the back-end server. These URLs don't work for the end-user, 111 since the back-end server is unreachable.</p> 112 113 <p>In this case, <code>mod_substutite</code> can be used to rewrite 114 those URLs into something that will work from the front end:</p> 115 116 <div class="example"><h3>Rewriting URLs embedded in proxied content</h3><pre class="prettyprint lang-config">ProxyPass /blog/ http://internal.blog.example.com 117ProxyPassReverse /blog/ http://internal.blog.example.com/ 118 119Substitute "s|http://internal.blog.example.com/|http://www.example.com/blog/|i"</pre> 120</div> 121 122 <p><code class="directive"><a href="/mod/mod_proxy.html#proxypassreverse">ProxyPassReverse</a></code> 123 modifies any <code>Location</code> (redirect) headers that are sent 124 by the back-end server, and, in this example, 125 <code>Substitute</code> takes care of the rest of the problem by 126 fixing up the HTML response as well.</p> 127 128 129</div> 130</div> 131<div class="bottomlang"> 132<p><span>Available Languages: </span><a href="/en/mod/mod_substitute.html" title="English"> en </a> | 133<a href="/fr/mod/mod_substitute.html" hreflang="fr" rel="alternate" title="Fran�ais"> fr </a></p> 134</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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