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14 <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>
15 <p class="apache">Apache HTTP Server Version 2.1</p>
16 <img alt="" src="./images/feather.gif" /></div>
17 <div class="up"><a href="./"><img title="<-" alt="<-" src="./images/left.gif" /></a></div>
19 <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 2.1</a></div><div id="page-content"><div id="preamble"><h1>Apache's Handler Use</h1>
20 <p>This document describes the use of Apache's Handlers.</p>
22 <div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#definition">What is a Handler</a></li>
23 <li><img alt="" src="./images/down.gif" /> <a href="#examples">Examples</a></li>
24 <li><img alt="" src="./images/down.gif" /> <a href="#programmer">Programmer's Note</a></li>
26 <div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
28 <h2><a name="definition" id="definition">What is a Handler</a></h2>
30 <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>
33 <p>A "handler" is an internal Apache representation of the
34 action to be performed when a file is called. Generally, files
35 have implicit handlers, based on the file type. Normally, all
36 files are simply served by the server, but certain file types
37 are "handled" separately.</p>
39 <p>Apache 1.1 adds the ability to use handlers explicitly.
40 Based on either filename extensions or on location, handlers
41 can be specified without relation to file type. This is
42 advantageous both because it is a more elegant solution, and
43 because it also allows for both a type <strong>and</strong> a
44 handler to be associated with a file. (See also <a href="mod/mod_mime.html#multipleext">Files with Multiple
47 <p>Handlers can either be built into the server or included in
48 a module, or they can be added with the <code class="directive"><a href="./mod/mod_actions.html#action">Action</a></code> directive. The
49 built-in handlers in the standard distribution are as
53 <li><strong>default-handler</strong>: Send the file using the
54 <code>default_handler()</code>, which is the handler used by
55 default to handle static content. (core)</li>
57 <li><strong>send-as-is</strong>: Send file with HTTP headers
58 as is. (<code class="module"><a href="./mod/mod_asis.html">mod_asis</a></code>)</li>
60 <li><strong>cgi-script</strong>: Treat the file as a CGI
61 script. (<code class="module"><a href="./mod/mod_cgi.html">mod_cgi</a></code>)</li>
63 <li><strong>imap-file</strong>: Parse as an imagemap rule
64 file. (<code class="module"><a href="./mod/mod_imap.html">mod_imap</a></code>)</li>
66 <li><strong>server-info</strong>: Get the server's
67 configuration information. (<code class="module"><a href="./mod/mod_info.html">mod_info</a></code>)</li>
69 <li><strong>server-status</strong>: Get the server's status
70 report. (<code class="module"><a href="./mod/mod_status.html">mod_status</a></code>)</li>
72 <li><strong>type-map</strong>: Parse as a type map file for
73 content negotiation. (<code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code>)</li>
75 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
77 <h2><a name="examples" id="examples">Examples</a></h2>
80 <h3><a name="example1" id="example1">Modifying static content using a CGI script</a></h3>
83 <p>The following directives will cause requests for files with
84 the <code>html</code> extension to trigger the launch of the
85 <code>footer.pl</code> CGI script.</p>
87 <div class="example"><p><code>
88 Action add-footer /cgi-bin/footer.pl<br />
89 AddHandler add-footer .html
92 <p>Then the CGI script is responsible for sending the
93 originally requested document (pointed to by the
94 <code>PATH_TRANSLATED</code> environment variable) and making
95 whatever modifications or additions are desired.</p>
98 <h3><a name="example2" id="example2">Files with HTTP headers</a></h3>
101 <p>The following directives will enable the
102 <code>send-as-is</code> handler, which is used for files which
103 contain their own HTTP headers. All files in the
104 <code>/web/htdocs/asis/</code> directory will be processed by
105 the <code>send-as-is</code> handler, regardless of their
106 filename extensions.</p>
108 <div class="example"><p><code>
109 <Directory /web/htdocs/asis><br />
110 SetHandler send-as-is<br />
115 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
116 <div class="section">
117 <h2><a name="programmer" id="programmer">Programmer's Note</a></h2>
120 <p>In order to implement the handler features, an addition has
121 been made to the <a href="developer/API.html">Apache API</a> that
122 you may wish to make use of. Specifically, a new record has
123 been added to the <code>request_rec</code> structure:</p>
125 <div class="example"><p><code>
129 <p>If you wish to have your module engage a handler, you need
130 only to set <code>r->handler</code> to the name of the
131 handler at any time prior to the <code>invoke_handler</code>
132 stage of the request. Handlers are implemented as they were
133 before, albeit using the handler name instead of a content
134 type. While it is not necessary, the naming convention for
135 handlers is to use a dash-separated word, with no slashes, so
136 as to not invade the media type name-space.</p>
139 <p class="apache">Maintained by the <a href="http://httpd.apache.org/docs-project/">Apache HTTP Server Documentation Project</a></p>
140 <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>