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7 --><title>Apache's Handler Use - Apache HTTP Server</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 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="./faq/">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p><p class="apache">Apache HTTP Server Version 2.0</p><img alt="" src="./images/feather.gif" /></div><div class="up"><a href="./"><img title="<-" alt="<-" src="./images/left.gif" /></a></div><div id="path"><a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs-project/">Documentation</a> > <a href="./">Version 2.0</a></div><div id="page-content"><div id="preamble"><h1>Apache's Handler Use</h1>
8 <p>This document describes the use of Apache's Handlers.</p>
9 </div><div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#definition">What is a Handler</a></li><li><img alt="" src="./images/down.gif" /> <a href="#examples">Examples</a></li><li><img alt="" src="./images/down.gif" /> <a href="#programmer">Programmer's Note</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="definition" id="definition">What is a Handler</a></h2>
11 <table class="related"><tr><th>Related Modules</th><th>Related Directives</th></tr><tr><td><ul><li><code class="module"><a href="./mod/mod_actions.html">mod_actions</a></code></li><li><code class="module"><a href="./mod/mod_asis.html">mod_asis</a></code></li><li><code class="module"><a href="./mod/mod_cgi.html">mod_cgi</a></code></li><li><code class="module"><a href="./mod/mod_imap.html">mod_imap</a></code></li><li><code class="module"><a href="./mod/mod_info.html">mod_info</a></code></li><li><code class="module"><a href="./mod/mod_mime.html">mod_mime</a></code></li><li><code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code></li><li><code class="module"><a href="./mod/mod_status.html">mod_status</a></code></li></ul></td><td><ul><li><code class="directive"><a href="./mod/mod_actions.html#action">Action</a></code></li><li><code class="directive"><a href="./mod/mod_mime.html#addhandler">AddHandler</a></code></li><li><code class="directive"><a href="./mod/mod_mime.html#removehandler">RemoveHandler</a></code></li><li><code class="directive"><a href="./mod/core.html#sethandler">SetHandler</a></code></li></ul></td></tr></table>
14 <p>A "handler" is an internal Apache representation of the
15 action to be performed when a file is called. Generally, files
16 have implicit handlers, based on the file type. Normally, all
17 files are simply served by the server, but certain file types
18 are "handled" separately.</p>
20 <p>Apache 1.1 adds the ability to use handlers explicitly.
21 Based on either filename extensions or on location, handlers
22 can be specified without relation to file type. This is
23 advantageous both because it is a more elegant solution, and
24 because it also allows for both a type <strong>and</strong> a
25 handler to be associated with a file. (See also <a href="mod/mod_mime.html#multipleext">Files with Multiple
28 <p>Handlers can either be built into the server or included in
29 a module, or they can be added with the <code class="directive"><a href="./mod/mod_actions.html#action">Action</a></code> directive. The
30 built-in handlers in the standard distribution are as
34 <li><strong>default-handler</strong>: Send the file using the
35 <code>default_handler()</code>, which is the handler used by
36 default to handle static content. (core)</li>
38 <li><strong>send-as-is</strong>: Send file with HTTP headers
39 as is. (<code class="module"><a href="./mod/mod_asis.html">mod_asis</a></code>)</li>
41 <li><strong>cgi-script</strong>: Treat the file as a CGI
42 script. (<code class="module"><a href="./mod/mod_cgi.html">mod_cgi</a></code>)</li>
44 <li><strong>imap-file</strong>: Parse as an imagemap rule
45 file. (<code class="module"><a href="./mod/mod_imap.html">mod_imap</a></code>)</li>
47 <li><strong>server-info</strong>: Get the server's
48 configuration information. (<code class="module"><a href="./mod/mod_info.html">mod_info</a></code>)</li>
50 <li><strong>server-status</strong>: Get the server's status
51 report. (<code class="module"><a href="./mod/mod_status.html">mod_status</a></code>)</li>
53 <li><strong>type-map</strong>: Parse as a type map file for
54 content negotiation. (<code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code>)</li>
56 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div><div class="section"><h2><a name="examples" id="examples">Examples</a></h2>
59 <h3><a name="example1" id="example1">Modifying static content using a CGI script</a></h3>
62 <p>The following directives will cause requests for files with
63 the <code>html</code> extension to trigger the launch of the
64 <code>footer.pl</code> CGI script.</p>
66 <div class="example"><p><code>
67 Action add-footer /cgi-bin/footer.pl<br />
68 AddHandler add-footer .html
71 <p>Then the CGI script is responsible for sending the
72 originally requested document (pointed to by the
73 <code>PATH_TRANSLATED</code> environment variable) and making
74 whatever modifications or additions are desired.</p>
77 <h3><a name="example2" id="example2">Files with HTTP headers</a></h3>
80 <p>The following directives will enable the
81 <code>send-as-is</code> handler, which is used for files which
82 contain their own HTTP headers. All files in the
83 <code>/web/htdocs/asis/</code> directory will be processed by
84 the <code>send-as-is</code> handler, regardless of their
85 filename extensions.</p>
87 <div class="example"><p><code>
88 <Directory /web/htdocs/asis><br />
89 SetHandler send-as-is<br />
94 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div><div class="section"><h2><a name="programmer" id="programmer">Programmer's Note</a></h2>
97 <p>In order to implement the handler features, an addition has
98 been made to the <a href="developer/API.html">Apache API</a> that
99 you may wish to make use of. Specifically, a new record has
100 been added to the <code>request_rec</code> structure:</p>
102 <div class="example"><p><code>
106 <p>If you wish to have your module engage a handler, you need
107 only to set <code>r->handler</code> to the name of the
108 handler at any time prior to the <code>invoke_handler</code>
109 stage of the request. Handlers are implemented as they were
110 before, albeit using the handler name instead of a content
111 type. While it is not necessary, the naming convention for
112 handlers is to use a dash-separated word, with no slashes, so
113 as to not invade the media type name-space.</p>
114 </div></div><div id="footer"><p class="apache">Maintained by the <a href="http://httpd.apache.org/docs-project/">Apache HTTP Server Documentation Project</a></p><p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="./faq/">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p></div></body></html>