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    <p>This document describes the use of Apache's Handlers.</p>
  </div>
<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><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><h3>See also</h3><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
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<h2><a name="definition" id="definition">What is a Handler</a></h2>
    
    <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_imagemap.html">mod_imagemap</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>


    <p>A "handler" is an internal Apache representation of the
    action to be performed when a file is called. Generally, files
    have implicit handlers, based on the file type. Normally, all
    files are simply served by the server, but certain file types
    are "handled" separately.</p>

    <p>Handlers may also be configured explicitly,
    based on either filename extensions or on location,
    without relation to file type. This is
    advantageous both because it is a more elegant solution, and
    because it also allows for both a type <strong>and</strong> a
    handler to be associated with a file. (See also <a href="mod/mod_mime.html#multipleext">Files with Multiple
    Extensions</a>.)</p>

    <p>Handlers can either be built into the server or included in
    a module, or they can be added with the <code class="directive"><a href="./mod/mod_actions.html#action">Action</a></code> directive. The
    built-in handlers in the standard distribution are as
    follows:</p>

    <ul>
      <li><strong>default-handler</strong>: Send the file using the
      <code>default_handler()</code>, which is the handler used by
      default to handle static content. (core)</li>

      <li><strong>send-as-is</strong>: Send file with HTTP headers
      as is. (<code class="module"><a href="./mod/mod_asis.html">mod_asis</a></code>)</li>

      <li><strong>cgi-script</strong>: Treat the file as a CGI
      script. (<code class="module"><a href="./mod/mod_cgi.html">mod_cgi</a></code>)</li>

      <li><strong>imap-file</strong>: Parse as an imagemap rule
      file. (<code class="module"><a href="./mod/mod_imagemap.html">mod_imagemap</a></code>)</li>

      <li><strong>server-info</strong>: Get the server's
      configuration information. (<code class="module"><a href="./mod/mod_info.html">mod_info</a></code>)</li>

      <li><strong>server-status</strong>: Get the server's status
      report. (<code class="module"><a href="./mod/mod_status.html">mod_status</a></code>)</li>

      <li><strong>type-map</strong>: Parse as a type map file for
      content negotiation. (<code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code>)</li>
    </ul>
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<h2><a name="examples" id="examples">Examples</a></h2>
    

    <h3><a name="example1" id="example1">Modifying static content using a CGI script</a></h3>
      

      <p>The following directives will cause requests for files with
      the <code>html</code> extension to trigger the launch of the
      <code>footer.pl</code> CGI script.</p>

      <pre class="prettyprint lang-config">Action add-footer /cgi-bin/footer.pl
AddHandler add-footer .html</pre>


      <p>Then the CGI script is responsible for sending the
      originally requested document (pointed to by the
      <code>PATH_TRANSLATED</code> environment variable) and making
      whatever modifications or additions are desired.</p>

    
    <h3><a name="example2" id="example2">Files with HTTP headers</a></h3>
      

      <p>The following directives will enable the
      <code>send-as-is</code> handler, which is used for files which
      contain their own HTTP headers. All files in the
      <code>/web/htdocs/asis/</code> directory will be processed by
      the <code>send-as-is</code> handler, regardless of their
      filename extensions.</p>

      <pre class="prettyprint lang-config">&lt;Directory "/web/htdocs/asis"&gt;
    SetHandler send-as-is
&lt;/Directory&gt;</pre>


    
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<h2><a name="programmer" id="programmer">Programmer's Note</a></h2>
    

    <p>In order to implement the handler features, an addition has
    been made to the <a href="developer/API.html">Apache API</a> that
    you may wish to make use of. Specifically, a new record has
    been added to the <code>request_rec</code> structure:</p>

    <pre class="prettyprint lang-c">char *handler</pre>


    <p>If you wish to have your module engage a handler, you need
    only to set <code>r-&gt;handler</code> to the name of the
    handler at any time prior to the <code>invoke_handler</code>
    stage of the request. Handlers are implemented as they were
    before, albeit using the handler name instead of a content
    type. While it is not necessary, the naming convention for
    handlers is to use a dash-separated word, with no slashes, so
    as to not invade the media type name-space.</p>
  </div></div>
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