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_xml2enc - 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_xml2enc</h1> 26<div class="toplang"> 27<p><span>Available Languages: </span><a href="/en/mod/mod_xml2enc.html" title="English"> en </a> | 28<a href="/fr/mod/mod_xml2enc.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>Enhanced charset/internationalisation support for libxml2-based 31filter modules</td></tr> 32<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Base</td></tr> 33<tr><th><a href="module-dict.html#ModuleIdentifier">Module�Identifier:</a></th><td>xml2enc_module</td></tr> 34<tr><th><a href="module-dict.html#SourceFile">Source�File:</a></th><td>mod_xml2enc.c</td></tr> 35<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td>Version 2.4 and later. Available as a third-party module 36for 2.2.x versions</td></tr></table> 37<h3>Summary</h3> 38 39 <p>This module provides enhanced internationalisation support for 40 markup-aware filter modules such as <code class="module"><a href="/mod/mod_proxy_html.html">mod_proxy_html</a></code>. 41 It can automatically detect the encoding of input data and ensure 42 they are correctly processed by the <a href="http://xmlsoft.org/">libxml2</a> parser, including converting to Unicode (UTF-8) where 43 necessary. It can also convert data to an encoding of choice 44 after markup processing, and will ensure the correct <var>charset</var> 45 value is set in the HTTP <var>Content-Type</var> header.</p> 46</div> 47<div id="quickview"><h3 class="directives">Directives</h3> 48<ul id="toc"> 49<li><img alt="" src="/images/down.gif" /> <a href="#xml2encalias">xml2EncAlias</a></li> 50<li><img alt="" src="/images/down.gif" /> <a href="#xml2encdefault">xml2EncDefault</a></li> 51<li><img alt="" src="/images/down.gif" /> <a href="#xml2startparse">xml2StartParse</a></li> 52</ul> 53<h3>Topics</h3> 54<ul id="topics"> 55<li><img alt="" src="/images/down.gif" /> <a href="#usage">Usage</a></li> 56<li><img alt="" src="/images/down.gif" /> <a href="#api">Programming API</a></li> 57<li><img alt="" src="/images/down.gif" /> <a href="#sniffing">Detecting an Encoding</a></li> 58<li><img alt="" src="/images/down.gif" /> <a href="#output">Output Encoding</a></li> 59<li><img alt="" src="/images/down.gif" /> <a href="#alias">Unsupported Encodings</a></li> 60</ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div> 61<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 62<div class="section"> 63<h2><a name="usage" id="usage">Usage</a></h2> 64 <p>There are two usage scenarios: with modules programmed to work 65 with mod_xml2enc, and with those that are not aware of it:</p> 66 <dl> 67 <dt>Filter modules enabled for mod_xml2enc</dt><dd> 68 <p>Modules such as <code class="module"><a href="/mod/mod_proxy_html.html">mod_proxy_html</a></code> version 3.1 69 and up use the <code>xml2enc_charset</code> optional function to retrieve 70 the charset argument to pass to the libxml2 parser, and may use the 71 <code>xml2enc_filter</code> optional function to postprocess to another 72 encoding. Using mod_xml2enc with an enabled module, no configuration 73 is necessary: the other module will configure mod_xml2enc for you 74 (though you may still want to customise it using the configuration 75 directives below).</p> 76 </dd> 77 <dt>Non-enabled modules</dt><dd> 78 <p>To use it with a libxml2-based module that isn't explicitly enabled for 79 mod_xml2enc, you will have to configure the filter chain yourself. 80 So to use it with a filter <strong>foo</strong> provided by a module 81 <strong>mod_foo</strong> to improve the latter's i18n support with HTML 82 and XML, you could use</p> 83 <pre><code> 84 FilterProvider iconv xml2enc Content-Type $text/html 85 FilterProvider iconv xml2enc Content-Type $xml 86 FilterProvider markup foo Content-Type $text/html 87 FilterProvider markup foo Content-Type $xml 88 FilterChain iconv markup 89 </code></pre> 90 <p><strong>mod_foo</strong> will now support any character set supported by either 91 (or both) of libxml2 or apr_xlate/iconv.</p> 92 </dd></dl> 93</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 94<div class="section"> 95<h2><a name="api" id="api">Programming API</a></h2> 96 <p>Programmers writing libxml2-based filter modules are encouraged to 97 enable them for mod_xml2enc, to provide strong i18n support for your 98 users without reinventing the wheel. The programming API is exposed in 99 <var>mod_xml2enc.h</var>, and a usage example is 100 <code class="module"><a href="/mod/mod_proxy_html.html">mod_proxy_html</a></code>.</p> 101</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 102<div class="section"> 103<h2><a name="sniffing" id="sniffing">Detecting an Encoding</a></h2> 104 <p>Unlike <code class="module"><a href="/mod/mod_charset_lite.html">mod_charset_lite</a></code>, mod_xml2enc is designed 105 to work with data whose encoding cannot be known in advance and thus 106 configured. It therefore uses 'sniffing' techniques to detect the 107 encoding of HTTP data as follows:</p> 108 <ol> 109 <li>If the HTTP <var>Content-Type</var> header includes a 110 <var>charset</var> parameter, that is used.</li> 111 <li>If the data start with an XML Byte Order Mark (BOM) or an 112 XML encoding declaration, that is used.</li> 113 <li>If an encoding is declared in an HTML <code><META></code> 114 element, that is used.</li> 115 <li>If none of the above match, the default value set by 116 <code class="directive">xml2EncDefault</code> is used.</li> 117 </ol> 118 <p>The rules are applied in order. As soon as a match is found, 119 it is used and detection is stopped.</p> 120</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 121<div class="section"> 122<h2><a name="output" id="output">Output Encoding</a></h2> 123<p><a href="http://xmlsoft.org/">libxml2</a> always uses UTF-8 (Unicode) 124internally, and libxml2-based filter modules will output that by default. 125mod_xml2enc can change the output encoding through the API, but there 126is currently no way to configure that directly.</p> 127<p>Changing the output encoding should (in theory, at least) never be 128necessary, and is not recommended due to the extra processing load on 129the server of an unnecessary conversion.</p> 130</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 131<div class="section"> 132<h2><a name="alias" id="alias">Unsupported Encodings</a></h2> 133<p>If you are working with encodings that are not supported by any of 134the conversion methods available on your platform, you can still alias 135them to a supported encoding using <code class="directive">xml2EncAlias</code>.</p> 136</div> 137<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 138<div class="directive-section"><h2><a name="xml2EncAlias" id="xml2EncAlias">xml2EncAlias</a> <a name="xml2encalias" id="xml2encalias">Directive</a></h2> 139<table class="directive"> 140<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Recognise Aliases for encoding values</td></tr> 141<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>xml2EncAlias <var>charset alias [alias ...]</var></code></td></tr> 142<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr> 143<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr> 144<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_xml2enc</td></tr> 145</table> 146 <p>This server-wide directive aliases one or more encoding to another 147 encoding. This enables encodings not recognised by libxml2 to be handled 148 internally by libxml2's encoding support using the translation table for 149 a recognised encoding. This serves two purposes: to support character sets 150 (or names) not recognised either by libxml2 or iconv, and to skip 151 conversion for an encoding where it is known to be unnecessary.</p> 152 153</div> 154<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 155<div class="directive-section"><h2><a name="xml2EncDefault" id="xml2EncDefault">xml2EncDefault</a> <a name="xml2encdefault" id="xml2encdefault">Directive</a></h2> 156<table class="directive"> 157<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets a default encoding to assume when absolutely no information 158can be <a href="#sniffing">automatically detected</a></td></tr> 159<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>xml2EncDefault <var>name</var></code></td></tr> 160<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr> 161<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr> 162<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_xml2enc</td></tr> 163<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Version 2.4.0 and later; available as a third-party 164module for earlier versions.</td></tr> 165</table> 166 <p>If you are processing data with known encoding but no encoding 167 information, you can set this default to help mod_xml2enc process 168 the data correctly. For example, to work with the default value 169 of Latin1 (<var>iso-8859-1</var> specified in HTTP/1.0, use</p> 170 <pre class="prettyprint lang-config">xml2EncDefault iso-8859-1</pre> 171 172 173</div> 174<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 175<div class="directive-section"><h2><a name="xml2StartParse" id="xml2StartParse">xml2StartParse</a> <a name="xml2startparse" id="xml2startparse">Directive</a></h2> 176<table class="directive"> 177<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Advise the parser to skip leading junk.</td></tr> 178<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>xml2StartParse <var>element [element ...]</var></code></td></tr> 179<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr> 180<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr> 181<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_xml2enc</td></tr> 182</table> 183 <p>Specify that the markup parser should start at the first instance 184 of any of the elements specified. This can be used as a workaround 185 where a broken backend inserts leading junk that messes up the parser (<a href="http://bahumbug.wordpress.com/2006/10/12/mod_proxy_html-revisited/">example here</a>).</p> 186 <p>It should never be used for XML, nor well-formed HTML.</p> 187 188</div> 189</div> 190<div class="bottomlang"> 191<p><span>Available Languages: </span><a href="/en/mod/mod_xml2enc.html" title="English"> en </a> | 192<a href="/fr/mod/mod_xml2enc.html" hreflang="fr" rel="alternate" title="Fran�ais"> fr </a></p> 193</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. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. 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