xforms

        <p>The first hook that does <em>not</em> return <code>DECLINED</code>

        stops the loop and its return value is returned from the hook

        caller. Note that <code>DECLINED</code> is the tradition Apache

        hook return meaning "I didn't do anything", but it can be

        caller. Note that <code>DECLINED</code> is the traditional 

        hook return value meaning "I didn't do anything", but it can be

        whatever suits you.</p>

        <p>Alternatively, all hooks can be run until an error occurs.

    <h3><a name="hooking-add" id="hooking-add">Add a hook registering function</a></h3>

      <p>During initialisation, Apache will call each modules hook

      <p>During initialisation, the server will call each modules hook

      registering function, which is included in the module

      structure:</p>

      order relative to each other, but, of course, all modules using

      <code>APR_HOOK_FIRST</code> will be run before <code>APR_HOOK_MIDDLE</code>

      which are before <code>APR_HOOK_LAST</code>. Modules that don't care

      when they are run should use <code>APR_HOOK_MIDDLE</code>. <em>(I spaced

      these out so people could do stuff like <code>APR_HOOK_FIRST-2</code>

      to get in slightly earlier, but is this wise? - Ben)</em></p>

      when they are run should use <code>APR_HOOK_MIDDLE</code>. <em>These 

      values are spaced out, so that positions like <code>APR_HOOK_FIRST-2</code>

      are possible to hook slightly earlier than other functions.</em></p>

      <p>Note that there are two more values,

      <code>APR_HOOK_REALLY_FIRST</code> and <code>APR_HOOK_REALLY_LAST</code>. These

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<title>Request Processing in Apache 2.0 - Apache HTTP Server</title>

<title>Request Processing in the Apache HTTP Server 2.x - Apache HTTP Server</title>

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<a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs/">Documentation</a> &gt; <a href="../">Version 2.2</a> &gt; <a href="./">Developer Documentation</a></div><div id="page-content"><div id="preamble"><h1>Request Processing in Apache 2.0</h1>

<a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs/">Documentation</a> &gt; <a href="../">Version 2.2</a> &gt; <a href="./">Developer Documentation</a></div><div id="page-content"><div id="preamble"><h1>Request Processing in the Apache HTTP Server 2.x</h1>

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<p><span>Available Languages: </span><a href="../en/developer/request.html" title="English">&nbsp;en&nbsp;</a></p>

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      revision!</p>

    </div>

    <p>Several changes in Apache 2.0 affect the internal request

    <p>Several changes in 2.0 and above affect the internal request

    processing mechanics. Module authors need to be aware of these

    changes so they may take advantage of the optimizations and

    security enhancements.</p>

    <p>The first major change is to the subrequest and redirect

    mechanisms. There were a number of different code paths in

    Apache 1.3 to attempt to optimize subrequest or redirect

    behavior. As patches were introduced to 2.0, these

    the Apache HTTP Server 1.3 to attempt to optimize subrequest 

    or redirect behavior. As patches were introduced to 2.0, these

    optimizations (and the server behavior) were quickly broken due

    to this duplication of code. All duplicate code has been folded

    back into <code>ap_process_request_internal()</code> to prevent

    and correct implementation of the HTTP server RFC. Additional

    goals include security, scalability and optimization. New

    methods were sought to optimize the server (beyond the

    performance of Apache 1.3) without introducing fragile or

    performance of 1.3) without introducing fragile or

    insecure code.</p>

</div>

<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#processing">The Request Processing Cycle</a></li>

    <p>To streamline requests, the module author can take advantage

    of the hooks offered to drop out of the request cycle early, or

    to bypass core Apache hooks which are irrelevant (and costly in

    to bypass core hooks which are irrelevant (and costly in

    terms of CPU.)</p>

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      <code>parsed_uri.path</code> element is unset. The module has no further

      control of this one-time unescape operation, either failing to

      unescape or multiply unescaping the URL leads to security

      reprecussions.</p>

      repercussions.</p>

    <h3><a name="strip" id="strip">Strips Parent and This Elements from the