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<?xml version="1.0" encoding="ISO-8859-1"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
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This file is generated from xml source: DO NOT EDIT
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-->
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<title>Developing modules for the Apache HTTP Server 2.4 - Apache HTTP Server</title>
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<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
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<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
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<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" />
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<link href="../images/favicon.ico" rel="shortcut icon" /></head>
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<body id="manual-page"><div id="page-header">
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<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>
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<p class="apache">Apache HTTP Server Version 2.5</p>
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<img alt="" src="../images/feather.gif" /></div>
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<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div>
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<div id="path">
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<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 2.5</a> > <a href="./">Developer</a></div><div id="page-content"><div id="preamble"><h1>Developing modules for the Apache HTTP Server 2.4</h1>
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<div class="toplang">
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<p><span>Available Languages: </span><a href="../en/developer/modguide.html" title="English"> en </a></p>
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</div>
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<p>This document explains how you can develop modules for the Apache HTTP Server 2.4</p>
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</div>
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<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#introduction">Introduction</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#basics">Defining a module</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#hooking">Getting started: Hooking into Apache</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#handling">Building a handler</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#configuration">Adding configuration options</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#context">Context aware configurations</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#summary">Summing up</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#snippets">Some useful snippets of code</a></li>
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</ul><h3>See also</h3><ul class="seealso"><li><a href="request.html">Request Processing in Apache 2.4</a></li><li><a href="hooks.html">Apache 2.x Hook Functions</a></li></ul></div>
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<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
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<div class="section">
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<h2><a name="introduction" id="introduction">Introduction</a></h2>
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<h3><a name="what" id="what">What we will be discussing in this document</a></h3>
|
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<p>
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This document will discuss how you can easily create modules for the Apache HTTP Server 2.4 ("Apache"),
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by exploring an example module called <code>mod_example</code>. In the first part of this document, the purpose of this
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module will be to calculate and print out various digest values for existing files on your web server, whenever we
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access the URL <code>http://hostname/filename.sum</code>. For instance, if we want to know the MD5 digest value of the file
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located at <code>http://www.example.com/index.html</code>, we would visit <code>http://www.example.com/index.html.sum</code>.
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</p>
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<p>
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In the second part of this document, which deals with configuration directive and context awareness, we will be looking at
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a module that simply write out its own configuration to the client.
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</p>
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<h3><a name="prerequisites" id="prerequisites">Prerequisites</a></h3>
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<p>
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First and foremost, you are expected to have a basic knowledge of how the C programming language works. In most cases,
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we will try to be as pedagogical as possible and link to documents describing the functions used in the examples,
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but there are also many cases where it is necessary to either just assume that "it works" or do some digging youself
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into what the hows and whys of various function calls.
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</p>
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<p>
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Lastly, you will need to have a basic understanding of how modules are loaded and configured in Apache, as well as
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how to get the headers for Apache if you do not have them already, as these are needed for compiling new modules.
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</p>
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<h3><a name="compiling" id="compiling">Compiling your module</a></h3>
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<p>
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To compile the source code we are building in this document, we will be using <a href="../programs/apxs.html">APXS</a>.
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|
Assuming your source file is called mod_example.c, compiling, installing and activating the module is as simple as:
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|
<div class="example"><pre>
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apxs -i -a -c mod_example.c
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</pre></div>
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</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
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<div class="section">
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<h2><a name="basics" id="basics">Defining a module</a></h2>
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<img src="../images/build_a_mod_3.png" /><br />
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<p>Every module starts with the same declaration, or name tag if you will, that defines a module as <em>a separate entity within Apache</em>:
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<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
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module AP_MODULE_DECLARE_DATA example_module <code style="color:#806030; ">=</code>
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<code style="color:#806030; ">{</code>
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STANDARD20_MODULE_STUFF<code style="color:#806030; ">,</code>
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create_dir_conf<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-directory configuration handler */</code>
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merge_dir_conf<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-directory configurations */</code>
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create_svr_conf<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-server configuration handler */</code>
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merge_svr_conf<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-server configurations */</code>
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directives<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Any directives we may have for httpd */</code>
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register_hooks <code style="color:#c34e00; ">/* Our hook registering function */</code>
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<code style="color:#806030; ">}</code><code style="color:#806030; ">;</code>
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</pre>
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This bit of code lets Apache know that we have now registered a new module in the system,
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and that its name is <code>example_module</code>. The name of the module is used primarilly
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for two things:<br />
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<ul>
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<li>Letting Apache know how to load the module using the LoadModule</li>
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<li>Setting up a namespace for the module to use in configurations</li>
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</ul>
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For now, we're only concerned with the first purpose of the module name,
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which comes into play when we need to load the module:<br />
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<div class="example"><pre><a href="../mod/mod_so.html#LoadModule">LoadModule</a> example_module modules/mod_example.so</pre></div>
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In essence, this tells Apache to open up <code>mod_example.so</code> and look for a module
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called <code>example_module</code>.
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</p>
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<p>
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Within this name tag of ours is also a bunch of references to how we would like to handle things:
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Which directives do we respond to in a configuration file or .htaccess, how do we operate
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within specific contexts, and what handlers are we interested in registering with the Apache
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service. We'll return to all these elements later in this document.
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</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
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<div class="section">
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<h2><a name="hooking" id="hooking">Getting started: Hooking into Apache</a></h2>
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<h3><a name="hook_intro" id="hook_intro">An introduction to hooks</a></h3>
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<p>
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When handling requests in Apache, the first thing you will need to do is create a hook into
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the request handling process. A hook is essentially a message telling Apache that you are
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willing to either serve or at least take a glance at certain requests given by clients. All
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handlers, whether it's mod_rewrite, mod_authn_*, mod_proxy and so on, are hooked into specific
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parts of the request process. As you are probably aware, modules serve different purposes; Some
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are authentication/authorization handlers, others are file or script handlers while some third
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modules rewrite URIs or proxies content. Furthermore, in the end, it is up to the user of Apache
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how and when each module will come into place. Thus, Apache itself does not presume to know
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which module is responsible for handling a specific request, and will ask each module whether
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they have an interest in a given request or not. It is then up to each module to either gently
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decline serving a request, accept serving it or flat out deny the request from being served,
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as authentication/authorization modules do: <br />
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<img src="../images/build_a_mod_2.png" /><br />
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To make it a bit easier for handlers such as our mod_example to know whether the client is
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requesting content we should handle or not, Apache has directives for hinting to modules whether
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their assistance is needed or not. Two of these are <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> and <code class="directive"><a href="../mod/core.html#sethandler">SetHandler</a></code>.
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Let's take a look at an example using <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code>.
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In our example case, we want every request ending with .sum to be served by <code>mod_example</code>,
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so we'll add a configuration directive that tells Apache to do just that:
|
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<div class="example"><pre>
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AddHandler example-handler .sum
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</pre></div>
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What this tells Apache is the following: <em>Whenever we receive a request for a URI ending in .sum,
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we are to let all modules know that we are looking for whoever goes by the name of "example-handler"
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</em>. Thus, when a request is being served that ends in .sum, Apache will let all modules know, that
|
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this request should be served by "example-handler". As you will see later, when we start
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building mod_example, we will check for this handler tag relayed by <code>AddHandler</code> and
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reply to Apache based on the value of this tag.
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</p>
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<h3><a name="hook_declaration" id="hook_declaration">Hooking into httpd</a></h3>
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<p>
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To begin with, we only want to create a simple handler, that replies to the client browser
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when a specific URL is requested, so we won't bother setting up configuration handlers and
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directives just yet. Our initial module definition will look like this:<br />
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|
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|
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<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
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module AP_MODULE_DECLARE_DATA example_module =
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{
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STANDARD20_MODULE_STUFF,
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<code style="color:#7f0055; font-weight:bold; ">NULL</code>,
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<code style="color:#7f0055; font-weight:bold; ">NULL</code>,
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<code style="color:#7f0055; font-weight:bold; ">NULL</code>,
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<code style="color:#7f0055; font-weight:bold; ">NULL</code>,
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<code style="color:#7f0055; font-weight:bold; ">NULL</code>,
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<code style="color:#800040; ">register_hooks</code> <code style="color:#c34e00; "><code style="color:#c34e00; ">/* Our hook registering function */</code></code>
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};
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</pre>
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This lets Apache know that we are not interesting in anything fancy, we just want to hook onto
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the requests and possibly handle some of them.
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</p>
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<p>
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The reference in our example declaration, <code>register_hooks</code> is the name of a function
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we will create to manage how we hook onto the request process. In this example module, the function
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has just one purpose; To create a simple hook that gets called after all the rewrites, access
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control etc has been handled. Thus, we will let Apache know, that we want to hook into its process
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as one of the last modules:
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|
|
|
|
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<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
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<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">void</code> register_hooks<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">)</code>
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<code style="color:#806030; ">{</code>
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<code style="color:#c34e00; ">/* Create a hook in the request handler, so we get called when a request arrives */</code>
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<code style="color:#800040; ">ap_hook_handler</code><code style="color:#806030; ">(</code>example_handler<code style="color:#806030; ">,</code> <code style="color:#7f0055; font-weight:bold; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#7f0055; font-weight:bold; ">NULL</code><code style="color:#806030; ">,</code> APR_HOOK_LAST<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
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<code style="color:#806030; ">}</code>
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</pre>
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|
|
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The <code>example_handler</code> reference is the function that will handle the request. We will
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discuss how to create a handler in the next chapter.
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</p>
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|
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|
<h3><a name="hook_others" id="hook_others">Other useful hooks</a></h3>
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|
<p>
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|
Hooking into the request handling phase is but one of many hooks that you can create. Some other ways of hooking are:
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<ul>
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<li><code>ap_hook_child_init</code>: Place a hook that executes when a child process is spawned (commonly used for initializing modules after Apache has forked)</li>
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|
<li><code>ap_hook_pre_config</code>: Place a hook that executes before any configuration data has been read (very early hook)</li>
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|
<li><code>ap_hook_post_config</code>: Place a hook that executes after configuration has been parsed, but before Apache has forked</li>
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<li><code>ap_hook_translate_name</code>: Place a hook that executes when a URI needs to be translated into a filename on the server (think <code>mod_rewrite</code>)</li>
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|
</ul>
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</p>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
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<div class="section">
|
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<h2><a name="handling" id="handling">Building a handler</a></h2>
|
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<p>
|
|
A handler is essentially a function that receives a callback when a request to Apache is made.
|
|
It is passed a record of the current request (how it was made, which headers and requests were
|
|
passed along, who's giving the request and so on), and is put in charge of either telling
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Apache that it's not interested in the request or handle the request with the tools provided.
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</p>
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<h3><a name="simple_handler" id="simple_handler">A simple "Hello, world!" handler</a></h3>
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Let's start off by making a very simple request handler that does the following: <br />
|
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<ol>
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<li>Check that this is a request that should be served by "example-handler"</li>
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<li>Set the content type of our output to <code>text/html</code></li>
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<li>Write "Hello, world!" back to the client browser</li>
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<li>Let Apache know that we took care of this request and everything went fine</li>
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</ol>
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In C code, our example handler will now look like this:<br />
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|
|
|
|
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<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
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<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
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<code style="color:#806030; ">{</code>
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<code style="color:#c34e00; ">/* First off, we need to check if this is a call for the "example-handler" handler.</code>
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<code style="color:#c34e00; "> * If it is, we accept it and do our things, if not, we simply return DECLINED,</code>
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<code style="color:#c34e00; "> * and Apache will try somewhere else.</code>
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<code style="color:#c34e00; "> */</code>
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<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code> <code style="color:#806030; ">|</code><code style="color:#806030; ">|</code> <code style="color:#800040; ">strcmp</code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code><code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">example-handler</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#806030; ">(</code>DECLINED<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Now that we are handling this request, we'll write out "Hello, world!" to the client.</code>
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<code style="color:#c34e00; "> * To do so, we must first set the appropriate content type, followed by our output.</code>
|
|
<code style="color:#c34e00; "> */</code>
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|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#gaa2f8412c400197338ec509f4a45e4579">ap_set_content_type</a><code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">text/html</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#ga5e91eb6ca777c9a427b2e82bf1eeb81d">ap_rprintf</a><code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Hello, world!</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Lastly, we must tell Apache that we took care of this request and everything went fine.</code>
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|
<code style="color:#c34e00; "> * We do so by simply returning the value OK to Apache.</code>
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|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
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|
|
|
|
|
|
|
Now, we put all we have learned together and end up with a program that looks like <a href="mod_example_1.c">
|
|
mod_example_1.c</a>. The functions used in this example will be explained later in the section
|
|
<a href="#functions">"Some useful functions you should know"</a>.
|
|
|
|
<h3><a name="request_rec" id="request_rec">The request_rec structure</a></h3>
|
|
<p>The most essential part of any request is the <em>request record</em>. In a call to a handler function, this
|
|
is represented by the <code>request_req*</code> structure passed along with every call that is made. This
|
|
struct, typically just refered to as <code>r</code> in modules, contains all the information you need for
|
|
your module to fully process any HTTP request and respond accordingly.</p>
|
|
<p>Some key elements of the <code>request_req</code> structure are:
|
|
<ul>
|
|
<li><code><code style="color:#008833">r->handler</code> (char*)</code>: Contains the name of the handler Apache is currently asking to do the handling of this request</li>
|
|
<li><code><code style="color:#008833">r->method</code> (char*)</code>: Contains the HTTP method being used, f.x. GET or POST</li>
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|
<li><code><code style="color:#008833">r->filename</code> (char*)</code>: Contains the translated filename the client is requesting</li>
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<li><code><code style="color:#008833">r->args</code> (char*)</code>: Contains the query string of the request, if any</li>
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<li><code><code style="color:#008833">r->headers_in</code> (apr_table_t*)</code>: Contains all the headers sent by the client</li>
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<li><code><code style="color:#008833">r->connection</code> (conn_rec*)</code>: A record containing information about the current connection</li>
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<li><code><code style="color:#008833">r->useragent_ip</code> (char*)</code>: The IP address of the client connecting to us</li>
|
|
<li><code><code style="color:#008833">r->pool</code> (apr_pool_t*)</code>: The memory pool of this request. We'll discuss this in the "
|
|
<a href="#memory">Memory management</a>" chapter.</li>
|
|
</ul>
|
|
A complete list of all the values contained with in the <code>request_req</code> structure can be found in
|
|
the <a href="http://svn.apache.org/repos/asf/httpd/httpd/trunk/include/httpd.h"><code>httpd.h</code></a> header
|
|
file or at <a href="http://ci.apache.org/projects/httpd/trunk/doxygen/structrequest__rec.html">http://ci.apache.org/projects/httpd/trunk/doxygen/structrequest__rec.html</a>.
|
|
</p>
|
|
<p>
|
|
Let's try out some of these variables in another example handler:<br />
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/* Set the appropriate content type */</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#gaa2f8412c400197338ec509f4a45e4579">ap_set_content_type</a><code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">text/html</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Print out the IP address of the client connecting to us: */</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#ga5e91eb6ca777c9a427b2e82bf1eeb81d">ap_rprintf</a><code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; "><h2>Hello, </code><code style="color:#0f6900; ">%s</code><code style="color:#e60000; ">!</h2></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">useragent_ip</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* If we were reached through a GET or a POST request, be happy, else sad. */</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code> <code style="color:#806030; ">!</code><code style="color:#800040; ">strcmp</code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">method</code><code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">POST</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">|</code><code style="color:#806030; ">|</code> <code style="color:#806030; ">!</code><code style="color:#800040; ">strcmp</code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">method</code><code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">GET</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
ap_rputs<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">You used a GET or a POST method, that makes us happy!<br></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code> <code style="color:#806030; ">{</code>
|
|
ap_rputs<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">You did not use POST or GET, that makes us sad :(<br></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/* Lastly, if there was a query string, let's print that too! */</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">args</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#ga5e91eb6ca777c9a427b2e82bf1eeb81d">ap_rprintf</a><code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Your query string was: </code><code style="color:#0f6900; ">%s</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">args</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
|
|
|
|
|
|
</p>
|
|
|
|
|
|
<h3><a name="return_value" id="return_value">Return values</a></h3>
|
|
<p>
|
|
Apache relies on return values from handlers to signify whether a request was handled or not,
|
|
and if so, whether the request went well or not. If a module is not interested in handling
|
|
a specific request, it should always return the value <code>DECLINED</code>. If it is handling
|
|
a request, it should either return the generic value <code>OK</code>, or a specific HTTP status
|
|
code, for example:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/* Return 404: Not found */</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> HTTP_NOT_FOUND<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
|
|
|
|
|
|
Returning <code>OK</code> or a HTTP status code does not necessarilly mean that the request will end. Apache
|
|
may still have other handlers that are interested in this request, for instance the logging modules
|
|
which, upon a successful request, will write down a summary of what was requested and how it went.
|
|
To do a full stop and prevent any further processing after your module is done, you can return the
|
|
value <code>DONE</code> to let Apache know that it should cease all activity on this request and
|
|
carry on with the next, without informing other handlers.
|
|
<br />
|
|
<strong>General response codes:</strong>
|
|
<ul>
|
|
<li><code>DECLINED</code>: We are not handling this request</li>
|
|
<li><code>OK</code>: We handled this request and it went well</li>
|
|
<li><code>DONE</code>: We handled this request and Apache should just close this thread without further processing</li>
|
|
</ul><br />
|
|
<strong>HTTP specific return codes (excerpt):</strong>
|
|
<ul>
|
|
<li><code>HTTP_OK (200)</code>: Request was okay</li>
|
|
<li><code>HTTP_MOVED_PERMANENTLY (301)</code>: The resource has moved to a new URL</li>
|
|
<li><code>HTTP_UNAUTHORIZED (401)</code>: Client is not authorized to visit this page</li>
|
|
<li><code>HTTP_FORBIDDEN (403)</code>: Permission denied</li>
|
|
<li><code>HTTP_NOT_FOUND (404)</code>: File not found</li>
|
|
<li><code>HTTP_INTERNAL_SERVER_ERROR (500)</code>: Internal server error (self explanatory)</li>
|
|
</ul>
|
|
</p>
|
|
|
|
|
|
<h3><a name="functions" id="functions">Some useful functions you should know</a></h3>
|
|
|
|
<ul>
|
|
<li>
|
|
<code>ap_rputs(const char *string, request_req *r)</code>: <br />
|
|
Sends a string of text to the client. This is a shorthand version of <a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#gac827cd0537d2b6213a7c06d7c26cc36e">
|
|
ap_rwrite</a>.
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">ap_rputs<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">Hello, world!</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code></pre>
|
|
|
|
|
|
|
|
</li>
|
|
<li>
|
|
<code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#ga5e91eb6ca777c9a427b2e82bf1eeb81d">ap_rprintf</a></code>: <br />
|
|
This function works just like <code>printf</code>, except it sends the result to the client.
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;"><code style="color:#2e8800; "><a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#ga5e91eb6ca777c9a427b2e82bf1eeb81d">ap_rprintf</a></code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Hello, </code><code style="color:#0f6900; ">%s</code><code style="color:#e60000; ">!</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">useragent_ip</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code></pre>
|
|
|
|
|
|
</li>
|
|
<li>
|
|
<code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#gaa2f8412c400197338ec509f4a45e4579">ap_set_content_type</a>(request_req *r, const char *type)</code>: <br />
|
|
Sets the content type of the output you are sending.
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;"><code style="color:#2e8800; "><a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__PROTO.html#gaa2f8412c400197338ec509f4a45e4579">ap_set_content_type</a></code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">text/plain</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* force a raw text output */</code></pre>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
<h3><a name="memory" id="memory">Memory management</a></h3>
|
|
<p>
|
|
Managing your resources in Apache is quite easy, thanks to the memory pool system. In essence,
|
|
each server, connection and request have their own memory pool that gets cleaned up when its
|
|
scope ends, e.g. when a request is done or when a server process shuts down. All your module
|
|
needs to do is latch onto this memory pool, and you won't have to worry about having to clean
|
|
up after yourself - pretty neat, huh?</p>
|
|
|
|
<p>
|
|
In our module, we will primarilly be allocating memory for each request, so it's appropriate to
|
|
use the <code><code style="color:#008833">r->pool</code></code> reference when creating new objects. A few of the functions for
|
|
allocating memory within a pool are:
|
|
<ul>
|
|
<li><code>void* <a href="http://apr.apache.org/docs/apr/0.9/group__apr__pools.html#g85f1e193c31d109affda72f9a92c6915">apr_palloc</a>(
|
|
apr_pool_t *p, apr_size_t size)</code>: Allocates <code>size</code> number of bytes in the pool for you</li>
|
|
<li><code>void* <a href="http://apr.apache.org/docs/apr/0.9/group__apr__pools.html#gf61c098ad258069d64cdf8c0a9369f9e">apr_pcalloc</a>(
|
|
apr_pool_t *p, apr_size_t size)</code>: Allocates <code>size</code> number of bytes in the pool for you and sets all bytes to 0</li>
|
|
<li><code>char* <a href="http://apr.apache.org/docs/apr/0.9/group__apr__strings.html#gbc79e99ff19abbd7cfd18308c5f85d47">apr_pstrdup</a>(
|
|
apr_pool_t *p, const char *s)</code>: Creates a duplicate of the string <code>s</code>. This is useful for copying constant values so you can edit them</li>
|
|
</ul>
|
|
Let's put these functions into an example handler:<br />
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; ">*</code> original <code style="color:#806030; ">=</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">You can't edit this!</code><code style="color:#800000; ">"</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/* Allocate space for 10 integer values and set them all to zero. */</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code><code style="color:#806030; ">*</code> integers <code style="color:#806030; ">=</code> apr_pcalloc<code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">pool</code><code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">sizeof</code><code style="color:#806030; ">(</code><code style="color:#400000; font-weight:bold; ">int</code><code style="color:#806030; ">)</code><code style="color:#806030; ">*</code><code style="color:#c00000; ">10</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Create a copy of the 'original' variable that we can edit. */</code>
|
|
<code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; ">*</code> copy <code style="color:#806030; ">=</code> apr_pstrdup<code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">pool</code><code style="color:#806030; ">,</code> original<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
|
|
|
|
This is all well and good for our module, which won't need any pre-initialized variables or structures.
|
|
However, if we wanted to initialize something early on, before the requests come rolling in, we could
|
|
simply add a call to a function in our <code>register_hooks</code> function to sort it out:
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">void</code> register_hooks<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/* Call a function that initializes some stuff */</code>
|
|
<code style="color:#800040; ">example_init_function</code><code style="color:#806030; ">(</code>pool<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/* Create a hook in the request handler, so we get called when a request arrives */</code>
|
|
<code style="color:#800040; ">ap_hook_handler</code><code style="color:#806030; ">(</code>example_handler<code style="color:#806030; ">,</code> <code style="color:#7f0055; font-weight:bold; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#7f0055; font-weight:bold; ">NULL</code><code style="color:#806030; ">,</code> APR_HOOK_LAST<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
|
|
|
|
In this, pre-request initialization function, we would not be using the same pool as we did when
|
|
allocating resources for request-based functions. Instead, we would use the pool given to us by
|
|
Apache for allocating memory on a per-process based level.
|
|
|
|
</p>
|
|
|
|
|
|
<h3><a name="parsing" id="parsing">Parsing request data</a></h3>
|
|
<p>
|
|
In our example module, we would like to add a feature, that checks which type of digest, MD5 or SHA1
|
|
the client would like to see. This could be solved by adding a query string to the request. A query
|
|
string is typically comprised of several keys and values put together in a string, for instance
|
|
<code>valueA=yes&valueB=no&valueC=maybe</code>. It is up to the module itself to parse these
|
|
and get the data it requires. In our example, we'll be looking for a key called <code>digest</code>,
|
|
and if set to <code>md5</code>, we'll produce an MD5 digest, otherwise we'll produce a SHA1 digest.
|
|
</p>
|
|
<p>
|
|
Since the introduction of Apache 2.4, parsing request data from GET and POST requests have never
|
|
been easier. All we require to parse both GET and POST data is four simple lines:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__apr__tables.html#gad7ea82d6608a4a633fc3775694ab71e4">apr_table_t</a> *GET;
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/structapr__array__header__t.html">apr_array_header_t</a> *POST;
|
|
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__SCRIPT.html#gaed25877b529623a4d8f99f819ba1b7bd">ap_args_to_table</a>(r, &GET);
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__DAEMON.html#ga9d426b6382b49754d4f87c55f65af202">ap_parse_form_data</a>(r, <code style="color:#7f0055; font-weight:bold; ">NULL</code>, &POST, -1, 8192);
|
|
</pre>
|
|
|
|
|
|
|
|
In our specific example module, we're looking for the <code>digest</code> value from the query string,
|
|
which now resides inside a table called <code>GET</code>. To extract this value, we need only perform
|
|
a simple operation:<br />
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#c34e00; ">/* Get the "digest" key from the query string, if any. */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; "> *</code>digestType <code style="color:#806030; ">=</code> <a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__apr__tables.html#ga4db13e3915c6b9a3142b175d4c15d915">apr_table_get</a><code style="color:#806030; ">(</code>GET<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">digest</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
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<code style="color:#c34e00; ">/* If no key was returned, we will set a default value instead. */</code>
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<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>digestType<code style="color:#806030; ">)</code> digestType <code style="color:#806030; ">=</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">sha1</code><code style="color:#800000; ">"</code><code style="color:#806030; ">;</code>
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</pre>
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The structures used for the POST and GET data are not exactly the same, so if we were to fetch a value from
|
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POST data instead of the query string, we would have to resort to a few more lines, as outlined in
|
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<a href="#get_post">this example</a> in the last chapter of this document.
|
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</p>
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<h3><a name="advanced_handler" id="advanced_handler">Making an advanced handler</a></h3>
|
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Now that we have learned how to parse form data and manage our resources, we can move on to creating an advanced
|
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version of our module, that spits out the MD5 or SHA1 digest of files:<br />
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|
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<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> rc<code style="color:#806030; ">,</code> exists<code style="color:#806030; ">;</code>
|
|
apr_finfo_t finfo<code style="color:#806030; ">;</code>
|
|
apr_file_t<code style="color:#806030; "> *</code>file<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>filename<code style="color:#806030; ">;</code>
|
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<code style="color:#400000; font-weight:bold; ">char</code> buffer<code style="color:#806030; ">[</code><code style="color:#c00000; ">256</code><code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
apr_size_t readBytes<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> n<code style="color:#806030; ">;</code>
|
|
apr_table_t<code style="color:#806030; "> *</code>GET<code style="color:#806030; ">;</code>
|
|
apr_array_header_t<code style="color:#806030; "> *</code>POST<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; "> *</code>digestType<code style="color:#806030; ">;</code>
|
|
|
|
|
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<code style="color:#c34e00; ">/* Check that the "example-handler" handler is being called. */</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code> <code style="color:#806030; ">|</code><code style="color:#806030; ">|</code> <code style="color:#800040; ">strcmp</code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code><code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">example-handler</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#806030; ">(</code>DECLINED<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Figure out which file is being requested by removing the .sum from it */</code>
|
|
filename <code style="color:#806030; ">=</code> apr_pstrdup<code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">pool</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">filename</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
filename<code style="color:#806030; ">[</code><code style="color:#800040; ">strlen</code><code style="color:#806030; ">(</code>filename<code style="color:#806030; ">)</code><code style="color:#806030; ">-</code><code style="color:#c00000; ">4</code><code style="color:#806030; ">]</code> <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* Cut off the last 4 characters. */</code>
|
|
|
|
<code style="color:#c34e00; ">/* Figure out if the file we request a sum on exists and isn't a directory */</code>
|
|
rc <code style="color:#806030; ">=</code> apr_stat<code style="color:#806030; ">(</code><code style="color:#806030; ">&</code>finfo<code style="color:#806030; ">,</code> filename<code style="color:#806030; ">,</code> APR_FINFO_MIN<code style="color:#806030; ">,</code> r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">pool</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code>rc <code style="color:#806030; ">=</code><code style="color:#806030; ">=</code> APR_SUCCESS<code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
exists <code style="color:#806030; ">=</code>
|
|
<code style="color:#806030; ">(</code>
|
|
<code style="color:#806030; ">(</code>finfo<code style="color:#806030; ">.</code>filetype <code style="color:#806030; ">!</code><code style="color:#806030; ">=</code> APR_NOFILE<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">&</code><code style="color:#806030; ">&</code> <code style="color:#806030; ">!</code><code style="color:#806030; ">(</code>finfo<code style="color:#806030; ">.</code>filetype <code style="color:#806030; ">&</code> APR_DIR<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>exists<code style="color:#806030; ">)</code> <code style="color:#400000; font-weight:bold; ">return</code> HTTP_NOT_FOUND<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* Return a 404 if not found. */</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#c34e00; ">/* If apr_stat failed, we're probably not allowed to check this file. */</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code> <code style="color:#400000; font-weight:bold; ">return</code> HTTP_FORBIDDEN<code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Parse the GET and, optionally, the POST data sent to us */</code>
|
|
|
|
ap_args_to_table<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>GET<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_parse_form_data<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>POST<code style="color:#806030; ">,</code> <code style="color:#806030; ">-</code><code style="color:#c00000; ">1</code><code style="color:#806030; ">,</code> <code style="color:#c00000; ">8192</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Set the appropriate content type */</code>
|
|
ap_set_content_type<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">text/html</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Print a title and some general information */</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; "><h2>Information on </code><code style="color:#0f6900; ">%s</code><code style="color:#e60000; ">:</h2></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> filename<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; "><b>Size:</b> </code><code style="color:#0f6900; ">%u</code><code style="color:#e60000; "> bytes<br/></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> finfo<code style="color:#806030; ">.</code>size<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Get the digest type the client wants to see */</code>
|
|
digestType <code style="color:#806030; ">=</code> apr_table_get<code style="color:#806030; ">(</code>GET<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">digest</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>digestType<code style="color:#806030; ">)</code> digestType <code style="color:#806030; ">=</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">MD5</code><code style="color:#800000; ">"</code><code style="color:#806030; ">;</code>
|
|
|
|
|
|
rc <code style="color:#806030; ">=</code> apr_file_open<code style="color:#806030; ">(</code><code style="color:#806030; ">&</code>file<code style="color:#806030; ">,</code> filename<code style="color:#806030; ">,</code> APR_READ<code style="color:#806030; ">,</code> APR_OS_DEFAULT<code style="color:#806030; ">,</code> r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">pool</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code>rc <code style="color:#806030; ">=</code><code style="color:#806030; ">=</code> APR_SUCCESS<code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
|
|
<code style="color:#c34e00; ">/* Are we trying to calculate the MD5 or the SHA1 digest? */</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>digestType<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">md5</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/* Calculate the MD5 sum of the file */</code>
|
|
<code style="color:#400000; font-weight:bold; ">union</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">char</code> chr<code style="color:#806030; ">[</code><code style="color:#c00000; ">16</code><code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
uint32_t num<code style="color:#806030; ">[</code><code style="color:#c00000; ">4</code><code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code> digest<code style="color:#806030; ">;</code>
|
|
apr_md5_ctx_t md5<code style="color:#806030; ">;</code>
|
|
apr_md5_init<code style="color:#806030; ">(</code><code style="color:#806030; ">&</code>md5<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
readBytes <code style="color:#806030; ">=</code> <code style="color:#c00000; ">256</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">while</code> <code style="color:#806030; ">(</code> apr_file_read<code style="color:#806030; ">(</code>file<code style="color:#806030; ">,</code> buffer<code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>readBytes<code style="color:#806030; ">)</code> <code style="color:#806030; ">=</code><code style="color:#806030; ">=</code> APR_SUCCESS <code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
apr_md5_update<code style="color:#806030; ">(</code><code style="color:#806030; ">&</code>md5<code style="color:#806030; ">,</code> buffer<code style="color:#806030; ">,</code> readBytes<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
apr_md5_final<code style="color:#806030; ">(</code>digest<code style="color:#806030; ">.</code>chr<code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>md5<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Print out the MD5 digest */</code>
|
|
ap_rputs<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; "><b>MD5: </b><code></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">for</code> <code style="color:#806030; ">(</code>n <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code> n <code style="color:#806030; "><</code> APR_MD5_DIGESTSIZE<code style="color:#806030; ">/</code><code style="color:#c00000; ">4</code><code style="color:#806030; ">;</code> n<code style="color:#806030; ">+</code><code style="color:#806030; ">+</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#0f6900; ">%08x</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> digest<code style="color:#806030; ">.</code>num<code style="color:#806030; ">[</code>n<code style="color:#806030; ">]</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
ap_rputs<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; "></code></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/* Print a link to the SHA1 version */</code>
|
|
ap_rputs<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; "><br/><a href='?digest=sha1'>View the SHA1 hash instead</a></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/* Calculate the SHA1 sum of the file */</code>
|
|
<code style="color:#400000; font-weight:bold; ">union</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">char</code> chr<code style="color:#806030; ">[</code><code style="color:#c00000; ">20</code><code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
uint32_t num<code style="color:#806030; ">[</code><code style="color:#c00000; ">5</code><code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code> digest<code style="color:#806030; ">;</code>
|
|
apr_sha1_ctx_t sha1<code style="color:#806030; ">;</code>
|
|
apr_sha1_init<code style="color:#806030; ">(</code><code style="color:#806030; ">&</code>sha1<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
readBytes <code style="color:#806030; ">=</code> <code style="color:#c00000; ">256</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">while</code> <code style="color:#806030; ">(</code> apr_file_read<code style="color:#806030; ">(</code>file<code style="color:#806030; ">,</code> buffer<code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>readBytes<code style="color:#806030; ">)</code> <code style="color:#806030; ">=</code><code style="color:#806030; ">=</code> APR_SUCCESS <code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
apr_sha1_update<code style="color:#806030; ">(</code><code style="color:#806030; ">&</code>sha1<code style="color:#806030; ">,</code> buffer<code style="color:#806030; ">,</code> readBytes<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
apr_sha1_final<code style="color:#806030; ">(</code>digest<code style="color:#806030; ">.</code>chr<code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>sha1<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Print out the SHA1 digest */</code>
|
|
ap_rputs<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; "><b>SHA1: </b><code></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">for</code> <code style="color:#806030; ">(</code>n <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code> n <code style="color:#806030; "><</code> APR_SHA1_DIGESTSIZE<code style="color:#806030; ">/</code><code style="color:#c00000; ">4</code><code style="color:#806030; ">;</code> n<code style="color:#806030; ">+</code><code style="color:#806030; ">+</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#0f6900; ">%08x</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> digest<code style="color:#806030; ">.</code>num<code style="color:#806030; ">[</code>n<code style="color:#806030; ">]</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
ap_rputs<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; "></code></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/* Print a link to the MD5 version */</code>
|
|
ap_rputs<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; "><br/><a href='?digest=md5'>View the MD5 hash instead</a></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
apr_file_close<code style="color:#806030; ">(</code>file<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
|
|
|
|
<code style="color:#c34e00; ">/* Let Apache know that we responded to this request. */</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
|
|
|
|
|
|
This version in its entirity can be found here: <a href="mod_example_2.c">mod_example_2.c</a>.
|
|
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="configuration" id="configuration">Adding configuration options</a></h2>
|
|
<p>
|
|
In this next segment of this document, we will turn our eyes away from the digest module and create a new
|
|
example module, whose only function is to write out its own configuration. The purpose of this is to
|
|
examine how Apache works with configuration, and what happens when you start writing advanced configurations
|
|
for your modules.
|
|
</p>
|
|
<h3><a name="config_intro" id="config_intro">An introduction to configuration directives</a></h3>
|
|
If you are reading this, then you probably already know what a configuration directive is. Simply put,
|
|
a directive is a way of telling an individual module (or a set of modules) how to behave, such as these
|
|
directives control how <code>mod_rewrite</code> works:
|
|
<div class="example"><pre>
|
|
RewriteEngine On
|
|
RewriteCond %{REQUEST_URI} ^/foo/bar
|
|
RewriteRule ^/foo/bar/(.*)$ /foobar?page=$1
|
|
</pre></div>
|
|
Each of these configuration directives are handled by a separate function, that parses the parameters given
|
|
and sets up a configuration accordingly.
|
|
|
|
<h3><a name="config_simple" id="config_simple">Making an example configuration</a></h3>
|
|
To begin with, we'll create a basic configuration in C-space:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">typedef</code> <code style="color:#400000; font-weight:bold; ">struct</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> enabled<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* Enable or disable our module */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>path<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* Some path to...something */</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> typeOfAction<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* 1 means action A, 2 means action B and so on */</code>
|
|
<code style="color:#806030; ">}</code> example_config<code style="color:#806030; ">;</code>
|
|
</pre>
|
|
|
|
|
|
|
|
Now, let's put this into perspective by creating a very small module that just prints out a hard-coded
|
|
configuration. You'll notice that we use the <code>register_hooks</code> function for initializing the
|
|
configuration values to their defaults:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">typedef</code> <code style="color:#400000; font-weight:bold; ">struct</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> enabled<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* Enable or disable our module */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>path<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* Some path to...something */</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> typeOfAction<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* 1 means action A, 2 means action B and so on */</code>
|
|
<code style="color:#806030; ">}</code> example_config<code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">static</code> example_config config<code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code> <code style="color:#806030; ">|</code><code style="color:#806030; ">|</code> <code style="color:#800040; ">strcmp</code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code><code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">example-handler</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#400000; font-weight:bold; ">return</code><code style="color:#806030; ">(</code>DECLINED<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_set_content_type<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">text/plain</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(r, </code><code style="color:#800000; ">"</code><code style="color:#e60000; ">Enabled: </code><code style="color:#0f6900; ">%u</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">.</code>enabled<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(r, </code><code style="color:#800000; ">"</code><code style="color:#e60000; ">Path: </code><code style="color:#0f6900; ">%s</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">.</code>path<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(r, </code><code style="color:#800000; ">"</code><code style="color:#e60000; ">TypeOfAction: </code><code style="color:#0f6900; ">%x</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">.</code>typeOfAction<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">void</code> register_hooks<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
config<code style="color:#806030; ">.</code>enabled <code style="color:#806030; ">=</code> <code style="color:#c00000; ">1</code><code style="color:#806030; ">;</code>
|
|
config<code style="color:#806030; ">.</code>path <code style="color:#806030; ">=</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">/foo/bar</code><code style="color:#800000; ">"</code><code style="color:#806030; ">;</code>
|
|
config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x00</code><code style="color:#806030; ">;</code>
|
|
ap_hook_handler<code style="color:#806030; ">(</code>example_handler<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> APR_HOOK_LAST<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/* Define our module as an entity and assign a function for registering hooks */</code>
|
|
|
|
module AP_MODULE_DECLARE_DATA example_module <code style="color:#806030; ">=</code>
|
|
<code style="color:#806030; ">{</code>
|
|
STANDARD20_MODULE_STUFF<code style="color:#806030; ">,</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-directory configuration handler */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-directory configurations */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-server configuration handler */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-server configurations */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Any directives we may have for httpd */</code>
|
|
register_hooks <code style="color:#c34e00; ">/* Our hook registering function */</code>
|
|
<code style="color:#806030; ">}</code><code style="color:#806030; ">;</code>
|
|
</pre>
|
|
|
|
|
|
|
|
So far so good. To access our new handler, we could add the following to our configuration:
|
|
<div class="example"><pre>
|
|
<Location /example>
|
|
SetHandler example-handler
|
|
</Location>
|
|
</pre></div>
|
|
When we visit, we'll see our current configuration being spit out by our module.
|
|
|
|
|
|
<h3><a name="register_directive" id="register_directive">Registering directives with Apache</a></h3>
|
|
What if we want to change our configuration, not by hard-coding new values into the module,
|
|
but by using either the httpd.conf file or possibly a .htaccess file? It's time to let Apache
|
|
know that we want this to be possible. To do so, we must first change our <em>name tag</em>
|
|
to include a reference to the configuration directives we want to register with Apache:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
module AP_MODULE_DECLARE_DATA example_module =
|
|
{
|
|
STANDARD20_MODULE_STUFF,
|
|
<code style="color:#7f0055; font-weight:bold; ">NULL</code>, <code style="color:#c34e00; ">/* Per-directory configuration handler */</code>
|
|
<code style="color:#7f0055; font-weight:bold; ">NULL</code>, <code style="color:#c34e00; ">/* Merge handler for per-directory configurations */</code>
|
|
<code style="color:#7f0055; font-weight:bold; ">NULL</code>, <code style="color:#c34e00; ">/* Per-server configuration handler */</code>
|
|
<code style="color:#7f0055; font-weight:bold; ">NULL</code>, <code style="color:#c34e00; ">/* Merge handler for per-server configurations */</code>
|
|
example_directives, <code style="color:#c34e00; ">/* Any directives we may have for httpd */</code>
|
|
register_hooks <code style="color:#c34e00; ">/* Our hook registering function */</code>
|
|
};
|
|
</pre>
|
|
|
|
|
|
|
|
This will tell Apache that we are now accepting directives from the configuration files, and that the
|
|
structure called <code>example_directives</code> holds information on what our directives are and how
|
|
they work. Since we have three different variables in our module configuration, we will add a structure
|
|
with three directives and a NULL at the end:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
static const command_rec example_directives[] =
|
|
{
|
|
<code style="color:#2e8800; "><a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#ga07c7d22ae17805e61204463326cf9c34">AP_INIT_TAKE1</a></code>("exampleEnabled", example_set_enabled, <code style="color:#7f0055; font-weight:bold; ">NULL</code>, RSRC_CONF, "Enable or disable mod_example"),
|
|
<code style="color:#2e8800; "><a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#ga07c7d22ae17805e61204463326cf9c34">AP_INIT_TAKE1</a></code>("examplePath", example_set_path, <code style="color:#7f0055; font-weight:bold; ">NULL</code>, RSRC_CONF, "The path to whatever"),
|
|
<code style="color:#2e8800; "><a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#gafaec43534fcf200f37d9fecbf9247c21">AP_INIT_TAKE2</a></code>("exampleAction", example_set_action, <code style="color:#7f0055; font-weight:bold; ">NULL</code>, RSRC_CONF, "Special action value!"),
|
|
{ <code style="color:#7f0055; font-weight:bold; ">NULL</code> }
|
|
};
|
|
</pre>
|
|
|
|
|
|
|
|
<img src="../images/build_a_mod_4.png" border="1" /><br />
|
|
<p>
|
|
As you can see, each directive needs at least 5 parameters set:
|
|
<ol>
|
|
<li><code><a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#ga07c7d22ae17805e61204463326cf9c34">AP_INIT_TAKE1</a></code>: This is a macro that tells Apache that this directive takes one and only one argument.
|
|
If we required two arguments, we could use the macro <code><a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#gafaec43534fcf200f37d9fecbf9247c21">AP_INIT_TAKE2</a></code> and so on (refer to httpd_conf.h
|
|
for more macros).</li>
|
|
<li><code>exampleEnabled</code>: This is the name of our directive. More precisely, it is what the user must put in his/her
|
|
configuration in order to invoke a configuration change in our module.</li>
|
|
<li><code>example_set_enabled</code>: This is a reference to a C function that parses the directive and sets the configuration
|
|
accordingly. We will discuss how to make this in the following paragraph.</li>
|
|
<li><code>RSRC_CONF</code>: This tells Apache where the directive is permissable. We'll go into details on this value in the
|
|
later chapters, but for now, <code>RSRC_CONF</code> means that Apache will only accept these directives in a server context.</li>
|
|
<li><code>"Enable or disable...."</code>: This is simply a brief description of what the directive does.</li>
|
|
</ol>
|
|
(<em>The "missing" parameter in our definition, which is usually set to <code>NULL</code>, is an optional function that can be
|
|
run after the initial function to parse the arguments have been run. This is usually omitted, as the function for verifying
|
|
arguments might as well be used to set them.</em>)
|
|
</p>
|
|
|
|
<h3><a name="directive_handler" id="directive_handler">The directive handler function</a></h3>
|
|
<p>
|
|
Now that we've told Apache to expect some directives for our module, it's time to make a few functions for handling these. What
|
|
Apache reads in the configuration file(s) is text, and so naturally, what it passes along to our directive handler is one or
|
|
more strings, that we ourselves need to recognize and act upon. You'll notice, that since we set our <code>exampleAction</code>
|
|
directive to accept two arguments, its C function also has an additional parameter defined:<br />
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#c34e00; ">/* Handler for the "exambleEnabled" directive */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; "> *</code>example_set_enabled<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>arg<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">on</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> config<code style="color:#806030; ">.</code>enabled <code style="color:#806030; ">=</code> <code style="color:#c00000; ">1</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code> config<code style="color:#806030; ">.</code>enabled <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/* Handler for the "examplePath" directive */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; "> *</code>example_set_path<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
config<code style="color:#806030; ">.</code>path <code style="color:#806030; ">=</code> arg<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/* Handler for the "exampleAction" directive */</code>
|
|
<code style="color:#c34e00; ">/* Let's pretend this one takes one argument (file or db), and a second (deny or allow), */</code>
|
|
<code style="color:#c34e00; ">/* and we store it in a bit-wise manner. */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; "> *</code>example_set_action<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg1<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; ">*</code> arg2<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>arg1<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">file</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x01</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code> config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x02</code><code style="color:#806030; ">;</code>
|
|
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<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>arg2<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">deny</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">+</code><code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x10</code><code style="color:#806030; ">;</code>
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|
<code style="color:#400000; font-weight:bold; ">else</code> config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">+</code><code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x20</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
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|
</pre>
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</p>
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<h3><a name="directive_complete" id="directive_complete">Putting it all together</a></h3>
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<p>
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|
Now that we have our directives set up, and handlers configured for them, we can assemble our module
|
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into one big file:
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|
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<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
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<code style="color:#c34e00; ">/* mod_example_config_simple.c: */</code>
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|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; "><</code><code style="color:#40015a; ">stdio.h</code><code style="color:#800000; ">></code>
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|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">apr_hash.h</code><code style="color:#800000; ">"</code>
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|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">ap_config.h</code><code style="color:#800000; ">"</code>
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|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">ap_provider.h</code><code style="color:#800000; ">"</code>
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|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">httpd.h</code><code style="color:#800000; ">"</code>
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|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_core.h</code><code style="color:#800000; ">"</code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_config.h</code><code style="color:#800000; ">"</code>
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|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_log.h</code><code style="color:#800000; ">"</code>
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|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_protocol.h</code><code style="color:#800000; ">"</code>
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|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_request.h</code><code style="color:#800000; ">"</code>
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<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> Our configuration prototype and declaration:</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">typedef</code> <code style="color:#400000; font-weight:bold; ">struct</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> enabled<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* Enable or disable our module */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>path<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* Some path to...something */</code>
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|
<code style="color:#400000; font-weight:bold; ">int</code> typeOfAction<code style="color:#806030; ">;</code> <code style="color:#c34e00; ">/* 1 means action A, 2 means action B and so on */</code>
|
|
<code style="color:#806030; ">}</code> example_config<code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">static</code> example_config config<code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> Our directive handlers:</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#c34e00; ">/* Handler for the "exambleEnabled" directive */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; "> *</code>example_set_enabled<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>arg<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">on</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> config<code style="color:#806030; ">.</code>enabled <code style="color:#806030; ">=</code> <code style="color:#c00000; ">1</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code> config<code style="color:#806030; ">.</code>enabled <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/* Handler for the "examplePath" directive */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; "> *</code>example_set_path<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
config<code style="color:#806030; ">.</code>path <code style="color:#806030; ">=</code> arg<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/* Handler for the "exampleAction" directive */</code>
|
|
<code style="color:#c34e00; ">/* Let's pretend this one takes one argument (file or db), and a second (deny or allow), */</code>
|
|
<code style="color:#c34e00; ">/* and we store it in a bit-wise manner. */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; "> *</code>example_set_action<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg1<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; ">*</code> arg2<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>arg1<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">file</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x01</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code> config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x02</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>arg2<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">deny</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">+</code><code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x10</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code> config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">+</code><code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x20</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> The directive structure for our name tag:</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">const</code> command_rec example_directives<code style="color:#806030; ">[</code><code style="color:#806030; ">]</code> <code style="color:#806030; ">=</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#ga07c7d22ae17805e61204463326cf9c34">AP_INIT_TAKE1</a><code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">exampleEnabled</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> example_set_enabled<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> RSRC_CONF<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Enable or disable mod_example</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">,</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#ga07c7d22ae17805e61204463326cf9c34">AP_INIT_TAKE1</a><code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">examplePath</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> example_set_path<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> RSRC_CONF<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">The path to whatever</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">,</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#gafaec43534fcf200f37d9fecbf9247c21">AP_INIT_TAKE2</a><code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">exampleAction</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> example_set_action<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> RSRC_CONF<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Special action value!</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">,</code>
|
|
<code style="color:#806030; ">{</code> <code style="color:#007d45; ">NULL</code> <code style="color:#806030; ">}</code>
|
|
<code style="color:#806030; ">}</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> Our module handler:</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code> <code style="color:#806030; ">|</code><code style="color:#806030; ">|</code> <code style="color:#800040; ">strcmp</code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code><code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">example-handler</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#400000; font-weight:bold; ">return</code><code style="color:#806030; ">(</code>DECLINED<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_set_content_type<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">text/plain</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Enabled: </code><code style="color:#0f6900; ">%u</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">.</code>enabled<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Path: </code><code style="color:#0f6900; ">%s</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">.</code>path<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">TypeOfAction: </code><code style="color:#0f6900; ">%x</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">.</code>typeOfAction<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> The hook registration function (also initializes the default config values):</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">void</code> register_hooks<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
config<code style="color:#806030; ">.</code>enabled <code style="color:#806030; ">=</code> <code style="color:#c00000; ">1</code><code style="color:#806030; ">;</code>
|
|
config<code style="color:#806030; ">.</code>path <code style="color:#806030; ">=</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">/foo/bar</code><code style="color:#800000; ">"</code><code style="color:#806030; ">;</code>
|
|
config<code style="color:#806030; ">.</code>typeOfAction <code style="color:#806030; ">=</code> <code style="color:#c00000; ">3</code><code style="color:#806030; ">;</code>
|
|
ap_hook_handler<code style="color:#806030; ">(</code>example_handler<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> APR_HOOK_LAST<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> Our module name tag:</code>
|
|
<code style="color:#c34e00; "> ==============================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
module AP_MODULE_DECLARE_DATA example_module <code style="color:#806030; ">=</code>
|
|
<code style="color:#806030; ">{</code>
|
|
STANDARD20_MODULE_STUFF<code style="color:#806030; ">,</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-directory configuration handler */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-directory configurations */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-server configuration handler */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-server configurations */</code>
|
|
example_directives<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Any directives we may have for httpd */</code>
|
|
register_hooks <code style="color:#c34e00; ">/* Our hook registering function */</code>
|
|
<code style="color:#806030; ">}</code><code style="color:#806030; ">;</code>
|
|
</pre>
|
|
|
|
|
|
|
|
</p>
|
|
<p>
|
|
In our httpd.conf file, we can now change the hard-coded configuration by adding a few lines:
|
|
<div class="example"><pre>
|
|
ExampleEnabled On
|
|
ExamplePath "/usr/bin/foo"
|
|
ExampleAction file allow
|
|
</pre></div>
|
|
And thus we apply the configuration, visit <code>/example</code> on our web site, and we see the configuration has
|
|
adapted to what we wrote in our configuration file.
|
|
</p>
|
|
|
|
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="context" id="context">Context aware configurations</a></h2>
|
|
<h3><a name="context_intro" id="context_intro">Introduction to context aware configurations</a></h3>
|
|
<p>
|
|
In Apache, different URLs, virtual hosts, directories etc can have very different meanings
|
|
to the user of Apache, and thus different contexts within which modules must operate. For example,
|
|
let's assume you have this configuration set up for mod_rewrite:
|
|
<div class="example"><pre>
|
|
<Directory "/var/www">
|
|
RewriteCond %{HTTP_HOST} ^example.com$
|
|
RewriteRule (.*) http://www.example.com/$1
|
|
</Directory>
|
|
<Directory "/var/www/sub">
|
|
RewriteRule ^foobar$ index.php?foobar=true
|
|
</Directory>
|
|
</pre></div>
|
|
In this example, you will have set up two different contexts for mod_rewrite:
|
|
<ol>
|
|
<li>Inside <code>/var/www</code>, all requests for <code>http://example.com</code> must go to <code>http://www.example.com</code></li>
|
|
<li>Inside <code>/var/www/sub</code>, all requests for <code>foobar</code> must go to <code>index.php?foobar=true</code></li>
|
|
</ol>
|
|
If mod_rewrite (or Apache for that matter) wasn't context aware, then these rewrite rules would just apply to every and any request made,
|
|
regardless of where and how they were made, but since the module can pull the context specific configuration straight from Apache, it
|
|
does not need to know itself, which of the directives are valid in this context, since Apache takes care of this.</p>
|
|
|
|
<p>
|
|
So how does a module get the specific configuration for the server, directory or location in question? It does so by making one simple call:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
|
|
|
|
|
|
example_config *config = (example_config*) <a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#ga1093a5908a384eacc929b028c79f2a02">ap_get_module_config</a>(<code style="color:#008833">r->per_dir_config</code>, &example_module);
|
|
</pre>
|
|
That's it! Of course, a whole lot goes on behind the scenes, which we will discuss in this chapter, starting with how
|
|
Apache came to know what our configuration looks like, and how it came to be set up as it is in the specific context.
|
|
</p>
|
|
|
|
|
|
<h3><a name="context_base" id="context_base">Our basic configuration setup</a></h3>
|
|
<p>In this chapter, we will be working with a slightly modified version of our previous
|
|
context structure. We will set a <code>context</code> variable that we can use to track
|
|
which context configuration is being used by Apache in various places:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">typedef</code> <code style="color:#400000; font-weight:bold; ">struct</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">char</code> context<code style="color:#806030; ">[</code><code style="color:#c00000; ">256</code><code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">char</code> path<code style="color:#806030; ">[</code><code style="color:#c00000; ">256</code><code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> typeOfAction<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> enabled<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code> example_config<code style="color:#806030; ">;</code>
|
|
</pre>
|
|
|
|
|
|
|
|
</p>
|
|
|
|
<p>Our handler for requests will also be modified, yet still very simple:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code> <code style="color:#806030; ">|</code><code style="color:#806030; ">|</code> <code style="color:#800040; ">strcmp</code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code><code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">example-handler</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#400000; font-weight:bold; ">return</code><code style="color:#806030; ">(</code>DECLINED<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
example_config<code style="color:#806030; "> *</code>config <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code>example_config<code style="color:#806030; ">*</code><code style="color:#806030; ">)</code> ap_get_module_config<code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">per_dir_config</code><code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>example_module<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_set_content_type<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">text/plain</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">Enabled: </code><code style="color:#0f6900; ">%u</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">Path: </code><code style="color:#0f6900; ">%s</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">TypeOfAction: </code><code style="color:#0f6900; ">%x</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">Context: </code><code style="color:#0f6900; ">%s</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">context</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
|
<h3><a name="context_which" id="context_which">Choosing a context</a></h3>
|
|
<p>
|
|
Before we can start making our module context aware, we must first define, which contexts we will accept.
|
|
As we saw in the previous chapter, defining a directive required five elements be set:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#2e8800; "><a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#ga07c7d22ae17805e61204463326cf9c34">AP_INIT_TAKE1</a></code>("exampleEnabled", example_set_enabled, <code style="color:#7f0055; font-weight:bold; ">NULL</code>, RSRC_CONF, "Enable or disable mod_example"),
|
|
</pre>
|
|
|
|
|
|
|
|
The <code>RSRC_CONF</code> definition told Apache that we would only allow this directive in a global server context, but
|
|
since we are now trying out a context aware version of our module, we should set this to something more lenient, namely
|
|
the value <code>ACCESS_CONF</code>, which lets us use the directive inside <Directory> and <Location> blocks.
|
|
</p>
|
|
|
|
|
|
<h3><a name="context_pool" id="context_pool">Using Apache to allocate configuration slots</a></h3>
|
|
<p> A much smarter way to manage your configurations is by letting Apache help you create them.
|
|
To do so, we must first start off by chancing our <em>name tag</em> to let Apache know, that
|
|
it should assist us in creating and managing our configurations. Since we have chosen the per-directory
|
|
(or per-location) context for our module configurations, we'll add a per-directory creator and merger
|
|
function reference in our tag:
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
module AP_MODULE_DECLARE_DATA example_module <code style="color:#806030; ">=</code>
|
|
<code style="color:#806030; ">{</code>
|
|
STANDARD20_MODULE_STUFF<code style="color:#806030; ">,</code>
|
|
create_dir_conf<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-directory configuration handler */</code>
|
|
merge_dir_conf<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-directory configurations */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-server configuration handler */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-server configurations */</code>
|
|
directives<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Any directives we may have for httpd */</code>
|
|
register_hooks <code style="color:#c34e00; ">/* Our hook registering function */</code>
|
|
<code style="color:#806030; ">}</code><code style="color:#806030; ">;</code>
|
|
</pre>
|
|
|
|
|
|
|
|
</p>
|
|
|
|
|
|
|
|
|
|
|
|
<h3><a name="context_which" id="context_which">Creating new context configurations</a></h3>
|
|
<p>
|
|
Now that we have told Apache to help us create and manage configurations, our first step is to
|
|
make a function for creating new, blank configurations. We do so by creating the function we just
|
|
referenced in our name tag as the Per-directory configuration handler:
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">void</code><code style="color:#806030; ">*</code> example_create_dir_conf<code style="color:#806030; ">(</code>apr_pool_t<code style="color:#806030; ">*</code> pool<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">char</code><code style="color:#806030; ">*</code> context<code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
context <code style="color:#806030; ">=</code> context <code style="color:#806030; ">?</code> context <code style="color:#806030; ">:</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">(undefined context)</code><code style="color:#800000; ">"</code><code style="color:#806030; ">;</code>
|
|
example_config<code style="color:#806030; "> *</code>cfg <code style="color:#806030; ">=</code> apr_pcalloc<code style="color:#806030; ">(</code>pool<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">sizeof</code><code style="color:#806030; ">(</code>example_config<code style="color:#806030; ">)</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code>cfg<code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/* Set some default values */</code>
|
|
<code style="color:#800040; ">strcpy</code><code style="color:#806030; ">(</code>cfg<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">context</code><code style="color:#806030; ">,</code> x<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
cfg<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code>
|
|
cfg<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code> <code style="color:#806030; ">=</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">/foo/bar</code><code style="color:#800000; ">"</code><code style="color:#806030; ">;</code>
|
|
cfg<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x11</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> dir<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
|
|
|
|
|
|
</p>
|
|
|
|
|
|
<h3><a name="context_which" id="context_which">Merging configurations</a></h3>
|
|
<p>
|
|
Our next step in creating a context aware configuration is merging configurations. This part of the process
|
|
particularly apply to scenarios where you have a parent configuration and a child, such as the following:
|
|
<div class="example"><pre>
|
|
<Directory "/var/www">
|
|
ExampleEnable On
|
|
ExamplePath /foo/bar
|
|
ExampleAction file allow
|
|
</Directory>
|
|
<Directory "/var/www/subdir">
|
|
ExampleAction file deny
|
|
</Directory>
|
|
</pre></div>
|
|
In this example, it is natural to assume that the directory <code>/var/www/subdir</code> should inherit the
|
|
value set for the <code>/var/www</code> directory, as we did not specify a <code>ExampleEnable</code> nor an
|
|
<code>ExamplePath</code> for this directory. Apache does not presume to know if this is true, but cleverly
|
|
does the following:
|
|
<ol>
|
|
<li>Creates a new configuration for <code>/var/www</code></li>
|
|
<li>Sets the configuration values according to the directives given for <code>/var/www</code></li>
|
|
<li>Creates a new configuration for <code>/var/www/subdir</code></li>
|
|
<li>Sets the configuration values according to the directives given for <code>/var/www/subdir</code></li>
|
|
<li><strong>Proposes a merge</strong> of the two configurations into a new configuration for <code>/var/www/subdir</code></li>
|
|
</ol>
|
|
This proposal is handled by the <code>merge_dir_conf</code> function we referenced in our name tag. The purpose of
|
|
this function is to assess the two configurations and decide how they are to be merged:
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">void</code><code style="color:#806030; ">*</code> merge_dir_conf<code style="color:#806030; ">(</code>apr_pool_t<code style="color:#806030; ">*</code> pool<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code><code style="color:#806030; ">*</code> BASE<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code><code style="color:#806030; ">*</code> ADD<code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
example_config<code style="color:#806030; ">*</code> base <code style="color:#806030; ">=</code> BASE <code style="color:#806030; ">;</code>
|
|
example_config<code style="color:#806030; ">*</code> add <code style="color:#806030; ">=</code> ADD <code style="color:#806030; ">;</code>
|
|
example_config<code style="color:#806030; ">*</code> conf <code style="color:#806030; ">=</code> create_dir_conf<code style="color:#806030; ">(</code>pool<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Merged configuration</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code> add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">=</code><code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code> <code style="color:#806030; ">)</code> <code style="color:#806030; ">?</code> base<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">:</code> add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">;</code>
|
|
conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">=</code> add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">?</code> add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">:</code> base<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#800040; ">strcpy</code><code style="color:#806030; ">(</code>conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">,</code> <code style="color:#800040; ">strlen</code><code style="color:#806030; ">(</code>add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">?</code> add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code> <code style="color:#806030; ">:</code> base<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">return</code> conf <code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
|
|
|
|
</p>
|
|
|
|
|
|
<h3><a name="context_which" id="context_which">Trying out our new context aware configurations</a></h3>
|
|
<p>
|
|
Now, let's try putting it all together to create a new module that it context aware. First off, we'll
|
|
create a configuration that lets us test how the module works:
|
|
<div class="example"><pre>
|
|
<Location "/a">
|
|
SetHandler example-handler
|
|
ExampleEnabled on
|
|
ExamplePath "/foo/bar"
|
|
ExampleAction file allow
|
|
</Location>
|
|
|
|
<Location "/a/b">
|
|
ExampleAction file deny
|
|
ExampleEnabled off
|
|
</Location>
|
|
|
|
<Location "/a/b/c">
|
|
ExampleAction db deny
|
|
ExamplePath "/foo/bar/baz"
|
|
ExampleEnabled on
|
|
</Location>
|
|
</pre></div>
|
|
Then we'll assemble our module code. Note, that since we are now using our name tag as reference when fetching
|
|
configurations in our handler, I have added some prototypes to keep the compiler happy:
|
|
</p>
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#c34e00; ">/*$6</code>
|
|
<code style="color:#c34e00; "> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++</code>
|
|
<code style="color:#c34e00; "> * mod_example_config.c</code>
|
|
<code style="color:#c34e00; "> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
|
|
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; "><</code><code style="color:#40015a; ">stdio.h</code><code style="color:#800000; ">></code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">apr_hash.h</code><code style="color:#800000; ">"</code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">ap_config.h</code><code style="color:#800000; ">"</code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">ap_provider.h</code><code style="color:#800000; ">"</code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">httpd.h</code><code style="color:#800000; ">"</code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_core.h</code><code style="color:#800000; ">"</code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_config.h</code><code style="color:#800000; ">"</code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_log.h</code><code style="color:#800000; ">"</code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_protocol.h</code><code style="color:#800000; ">"</code>
|
|
<code style="color:#004a43; ">#</code><code style="color:#004a43; ">include </code><code style="color:#800000; ">"</code><code style="color:#40015a; ">http_request.h</code><code style="color:#800000; ">"</code>
|
|
|
|
<code style="color:#c34e00; ">/*$1</code>
|
|
<code style="color:#c34e00; "> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</code>
|
|
<code style="color:#c34e00; "> Configuration structure</code>
|
|
<code style="color:#c34e00; "> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">typedef</code> <code style="color:#400000; font-weight:bold; ">struct</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">char</code> context<code style="color:#806030; ">[</code><code style="color:#c00000; ">256</code><code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">char</code> path<code style="color:#806030; ">[</code><code style="color:#c00000; ">256</code><code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> typeOfAction<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> enabled<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code> example_config<code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/*$1</code>
|
|
<code style="color:#c34e00; "> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</code>
|
|
<code style="color:#c34e00; "> Prototypes</code>
|
|
<code style="color:#c34e00; "> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>example_set_enabled<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>example_set_path<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>example_set_action<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg1<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg2<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>create_dir_conf<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>context<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>merge_dir_conf<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>BASE<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>ADD<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">void</code> register_hooks<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/*$1</code>
|
|
<code style="color:#c34e00; "> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</code>
|
|
<code style="color:#c34e00; "> Configuration directives</code>
|
|
<code style="color:#c34e00; "> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">const</code> command_rec directives<code style="color:#806030; ">[</code><code style="color:#806030; ">]</code> <code style="color:#806030; ">=</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#ga07c7d22ae17805e61204463326cf9c34">AP_INIT_TAKE1</a><code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">exampleEnabled</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> example_set_enabled<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> ACCESS_CONF<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Enable or disable mod_example</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">,</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#ga07c7d22ae17805e61204463326cf9c34">AP_INIT_TAKE1</a><code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">examplePath</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> example_set_path<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> ACCESS_CONF<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">The path to whatever</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">,</code>
|
|
<a href="http://ci.apache.org/projects/httpd/trunk/doxygen/group__APACHE__CORE__CONFIG.html#gafaec43534fcf200f37d9fecbf9247c21">AP_INIT_TAKE2</a><code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">exampleAction</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> example_set_action<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> ACCESS_CONF<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Special action value!</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">,</code>
|
|
<code style="color:#806030; ">{</code> <code style="color:#007d45; ">NULL</code> <code style="color:#806030; ">}</code>
|
|
<code style="color:#806030; ">}</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/*$1</code>
|
|
<code style="color:#c34e00; "> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</code>
|
|
<code style="color:#c34e00; "> Our name tag</code>
|
|
<code style="color:#c34e00; "> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
|
|
module AP_MODULE_DECLARE_DATA example_module <code style="color:#806030; ">=</code>
|
|
<code style="color:#806030; ">{</code>
|
|
STANDARD20_MODULE_STUFF<code style="color:#806030; ">,</code>
|
|
create_dir_conf<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-directory configuration handler */</code>
|
|
merge_dir_conf<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-directory configurations */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Per-server configuration handler */</code>
|
|
<code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Merge handler for per-server configurations */</code>
|
|
directives<code style="color:#806030; ">,</code> <code style="color:#c34e00; ">/* Any directives we may have for httpd */</code>
|
|
register_hooks <code style="color:#c34e00; ">/* Our hook registering function */</code>
|
|
<code style="color:#806030; ">}</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> Hook registration function</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">void</code> register_hooks<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
ap_hook_handler<code style="color:#806030; ">(</code>example_handler<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> APR_HOOK_LAST<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> Our example web service handler</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code> <code style="color:#806030; ">|</code><code style="color:#806030; ">|</code> <code style="color:#800040; ">strcmp</code><code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">handler</code><code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">example-handler</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#400000; font-weight:bold; ">return</code><code style="color:#806030; ">(</code>DECLINED<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
example_config <code style="color:#806030; ">*</code>config <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code>example_config <code style="color:#806030; ">*</code><code style="color:#806030; ">)</code> ap_get_module_config<code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">per_dir_config</code><code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>example_module<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
|
|
ap_set_content_type<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">text/plain</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Enabled: </code><code style="color:#0f6900; ">%u</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Path: </code><code style="color:#0f6900; ">%s</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">TypeOfAction: </code><code style="color:#0f6900; ">%x</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Context: </code><code style="color:#0f6900; ">%s</code><code style="color:#0f6900; ">\n</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> config<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">context</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> Handler for the "exambleEnabled" directive</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>example_set_enabled<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
example_config <code style="color:#806030; ">*</code>conf <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code>example_config <code style="color:#806030; ">*</code><code style="color:#806030; ">)</code> cfg<code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
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<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code>conf<code style="color:#806030; ">)</code>
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<code style="color:#806030; ">{</code>
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<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>arg<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">on</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code>
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conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">=</code> <code style="color:#c00000; ">1</code><code style="color:#806030; ">;</code>
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<code style="color:#400000; font-weight:bold; ">else</code>
|
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conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code>
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<code style="color:#806030; ">}</code>
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<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">;</code>
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<code style="color:#806030; ">}</code>
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<code style="color:#c34e00; ">/*</code>
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<code style="color:#c34e00; "> =======================================================================================================================</code>
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<code style="color:#c34e00; "> Handler for the "examplePath" directive</code>
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<code style="color:#c34e00; "> =======================================================================================================================</code>
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<code style="color:#c34e00; "> */</code>
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<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>example_set_path<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg<code style="color:#806030; ">)</code>
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<code style="color:#806030; ">{</code>
|
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<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
example_config <code style="color:#806030; ">*</code>conf <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code>example_config <code style="color:#806030; ">*</code><code style="color:#806030; ">)</code> cfg<code style="color:#806030; ">;</code>
|
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<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
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<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code>conf<code style="color:#806030; ">)</code>
|
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<code style="color:#806030; ">{</code>
|
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<code style="color:#800040; ">strcpy</code><code style="color:#806030; ">(</code>conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">,</code> arg<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
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<code style="color:#806030; ">}</code>
|
|
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|
<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> Handler for the "exampleAction" directive ;</code>
|
|
<code style="color:#c34e00; "> Let's pretend this one takes one argument (file or db), and a second (deny or allow), ;</code>
|
|
<code style="color:#c34e00; "> and we store it in a bit-wise manner.</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
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<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>example_set_action<code style="color:#806030; ">(</code>cmd_parms <code style="color:#806030; ">*</code>cmd<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>cfg<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg1<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>arg2<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
example_config <code style="color:#806030; ">*</code>conf <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code>example_config <code style="color:#806030; ">*</code><code style="color:#806030; ">)</code> cfg<code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code>conf<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>arg1<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">file</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code>
|
|
conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x01</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code>
|
|
conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x02</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>strcasecmp<code style="color:#806030; ">(</code>arg2<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">deny</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code>
|
|
conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">+</code><code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x10</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code>
|
|
conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">+</code><code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x20</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> Function for creating new configurations for per-directory contexts</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>create_dir_conf<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>context<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
context <code style="color:#806030; ">=</code> context <code style="color:#806030; ">?</code> context <code style="color:#806030; ">:</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Newly created configuration</code><code style="color:#800000; ">"</code><code style="color:#806030; ">;</code>
|
|
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
example_config <code style="color:#806030; ">*</code>cfg <code style="color:#806030; ">=</code> apr_pcalloc<code style="color:#806030; ">(</code>pool<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">sizeof</code><code style="color:#806030; ">(</code>example_config<code style="color:#806030; ">)</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code>cfg<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/* Set some default values */</code>
|
|
<code style="color:#800040; ">strcpy</code><code style="color:#806030; ">(</code>cfg<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">context</code><code style="color:#806030; ">,</code> context<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
cfg<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#800040; ">memset</code><code style="color:#806030; ">(</code>cfg<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">,</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">,</code> <code style="color:#c00000; ">256</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
cfg<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0x00</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">return</code> cfg<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#c34e00; ">/*</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> Merging function for configurations</code>
|
|
<code style="color:#c34e00; "> =======================================================================================================================</code>
|
|
<code style="color:#c34e00; "> */</code>
|
|
<code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>merge_dir_conf<code style="color:#806030; ">(</code>apr_pool_t <code style="color:#806030; ">*</code>pool<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>BASE<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">void</code> <code style="color:#806030; ">*</code>ADD<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
example_config <code style="color:#806030; ">*</code>base <code style="color:#806030; ">=</code> BASE<code style="color:#806030; ">;</code>
|
|
example_config <code style="color:#806030; ">*</code>add <code style="color:#806030; ">=</code> ADD<code style="color:#806030; ">;</code>
|
|
example_config <code style="color:#806030; ">*</code>conf <code style="color:#806030; ">=</code> create_dir_conf<code style="color:#806030; ">(</code>pool<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">Merged configuration</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
|
|
conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code>add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">=</code><code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">?</code> base<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code> <code style="color:#806030; ">:</code> add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">enabled</code><code style="color:#806030; ">;</code>
|
|
conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">=</code> add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">?</code> add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code> <code style="color:#806030; ">:</code> base<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">typeOfAction</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#800040; ">strcpy</code><code style="color:#806030; ">(</code>conf<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">,</code> <code style="color:#800040; ">strlen</code><code style="color:#806030; ">(</code>add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">?</code> add<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code> <code style="color:#806030; ">:</code> base<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">path</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> conf<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="summary" id="summary">Summing up</a></h2>
|
|
<p>
|
|
We have now looked at how to create simple modules for Apache and configuring them. What you do next is entirely up
|
|
to you, but it is my hope that something valuable has come out of reading this documentation. If you have questions
|
|
on how to further develop modules, you are welcome to join our <a href="http://httpd.apache.org/lists.html">mailing lists</a>
|
|
or check out the rest of our documentation for further tips.
|
|
</p>
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="snippets" id="snippets">Some useful snippets of code</a></h2>
|
|
|
|
<h3><a name="get_post" id="get_post">Retrieve a variable from POST form data</a></h3>
|
|
|
|
|
|
|
|
<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>read_post_value<code style="color:#806030; ">(</code><code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>key<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> apr_array_header_t <code style="color:#806030; ">*</code>fields<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> i<code style="color:#806030; ">;</code>
|
|
apr_table_entry_t <code style="color:#806030; ">*</code>e <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
e <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code>apr_table_entry_t <code style="color:#806030; ">*</code><code style="color:#806030; ">)</code> fields<code style="color:#806030; ">-</code><code style="color:#806030; ">></code>elts<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">for</code><code style="color:#806030; ">(</code>i <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code> i <code style="color:#806030; "><</code> fields<code style="color:#806030; ">-</code><code style="color:#806030; ">></code>nelts<code style="color:#806030; ">;</code> i<code style="color:#806030; ">+</code><code style="color:#806030; ">+</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">!</code><code style="color:#800040; ">strcmp</code><code style="color:#806030; ">(</code>e<code style="color:#806030; ">[</code>i<code style="color:#806030; ">]</code><code style="color:#806030; ">.</code>key<code style="color:#806030; ">,</code> key<code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#400000; font-weight:bold; ">return</code> e<code style="color:#806030; ">[</code>i<code style="color:#806030; ">]</code><code style="color:#806030; ">.</code>val<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_req <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
apr_array_header_t <code style="color:#806030; ">*</code>POST<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>value<code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~*/</code>
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ap_parse_form_data<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#007d45; ">NULL</code><code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>POST<code style="color:#806030; ">,</code> <code style="color:#806030; ">-</code><code style="color:#c00000; ">1</code><code style="color:#806030; ">,</code> <code style="color:#c00000; ">8192</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
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value <code style="color:#806030; ">=</code> read_post_value<code style="color:#806030; ">(</code>POST<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">valueA</code><code style="color:#800000; ">"</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
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<code style="color:#400000; font-weight:bold; ">if</code> <code style="color:#806030; ">(</code><code style="color:#806030; ">!</code>value<code style="color:#806030; ">)</code> value <code style="color:#806030; ">=</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">(undefined)</code><code style="color:#800000; ">"</code><code style="color:#806030; ">;</code>
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ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; ">The value of valueA is: </code><code style="color:#0f6900; ">%s</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> value<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
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<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
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<code style="color:#806030; ">}</code>
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</pre>
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<h3><a name="headers_out" id="headers_out">Printing out every HTTP header received</a></h3>
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<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
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<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_req <code style="color:#806030; ">*</code>r<code style="color:#806030; ">)</code>
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<code style="color:#806030; ">{</code>
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<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
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<code style="color:#400000; font-weight:bold; ">const</code> apr_array_header_t <code style="color:#806030; ">*</code>fields<code style="color:#806030; ">;</code>
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<code style="color:#400000; font-weight:bold; ">int</code> i<code style="color:#806030; ">;</code>
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apr_table_entry_t <code style="color:#806030; ">*</code>e <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code>
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<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
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fields <code style="color:#806030; ">=</code> <a href="http://apr.apache.org/docs/apr/1.4/group__apr__tables.html#gaea3005541cce67481f48ab201b5c0cf3">apr_table_elts</a><code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code>headers_in<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
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e <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code>apr_table_entry_t <code style="color:#806030; ">*</code><code style="color:#806030; ">)</code> fields<code style="color:#806030; ">-</code><code style="color:#806030; ">></code>elts<code style="color:#806030; ">;</code>
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<code style="color:#400000; font-weight:bold; ">for</code><code style="color:#806030; ">(</code>i <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code> i <code style="color:#806030; "><</code> fields<code style="color:#806030; ">-</code><code style="color:#806030; ">></code>nelts<code style="color:#806030; ">;</code> i<code style="color:#806030; ">+</code><code style="color:#806030; ">+</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
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ap_rprintf<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#800000; ">"</code><code style="color:#e60000; "><b></code><code style="color:#0f6900; ">%s</code><code style="color:#e60000; "></b>: </code><code style="color:#0f6900; ">%s</code><code style="color:#e60000; "><br/></code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> e<code style="color:#806030; ">[</code>i<code style="color:#806030; ">]</code><code style="color:#806030; ">.</code>key<code style="color:#806030; ">,</code> e<code style="color:#806030; ">[</code>i<code style="color:#806030; ">]</code><code style="color:#806030; ">.</code>val<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
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<code style="color:#806030; ">}</code>
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<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
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<code style="color:#806030; ">}</code>
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</pre>
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<h3><a name="request_body" id="request_body">Reading the request body into memory</a></h3>
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<pre style="color:#000000;background:#ffffef;border: 1px dashed #333; padding: 0.5em; margin: 1em 2em 1em 1em;">
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<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> util_read<code style="color:#806030; ">(</code>request_rec <code style="color:#806030; ">*</code>r<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code><code style="color:#806030; ">*</code>rbuf<code style="color:#806030; ">,</code> apr_off_t <code style="color:#806030; ">*</code>size<code style="color:#806030; ">)</code>
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<code style="color:#806030; ">{</code>
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<code style="color:#c34e00; ">/*~~~~~~~~*/</code>
|
|
<code style="color:#400000; font-weight:bold; ">int</code> rc <code style="color:#806030; ">=</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~*/</code>
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<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">(</code>rc <code style="color:#806030; ">=</code> ap_setup_client_block<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> REQUEST_CHUNKED_ERROR<code style="color:#806030; ">)</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
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<code style="color:#400000; font-weight:bold; ">return</code><code style="color:#806030; ">(</code>rc<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
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<code style="color:#806030; ">}</code>
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<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code>ap_should_client_block<code style="color:#806030; ">(</code>r<code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
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<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
|
|
<code style="color:#400000; font-weight:bold; ">char</code> argsbuffer<code style="color:#806030; ">[</code>HUGE_STRING_LEN<code style="color:#806030; ">]</code><code style="color:#806030; ">;</code>
|
|
apr_off_t rsize<code style="color:#806030; ">,</code> len_read<code style="color:#806030; ">,</code> rpos <code style="color:#806030; ">=</code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">;</code>
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|
apr_off_t length <code style="color:#806030; ">=</code> r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">remaining</code><code style="color:#806030; ">;</code>
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|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/</code>
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|
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<code style="color:#806030; ">*</code>rbuf <code style="color:#806030; ">=</code> <code style="color:#806030; ">(</code><code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code><code style="color:#806030; ">)</code> apr_pcalloc<code style="color:#806030; ">(</code>r<code style="color:#806030; ">-</code><code style="color:#806030; ">></code><code style="color:#008833">pool</code><code style="color:#806030; ">,</code> <code style="color:#806030; ">(</code>apr_size_t<code style="color:#806030; ">)</code> <code style="color:#806030; ">(</code>length <code style="color:#806030; ">+</code> <code style="color:#c00000; ">1</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">*</code>size <code style="color:#806030; ">=</code> length<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">while</code><code style="color:#806030; ">(</code><code style="color:#806030; ">(</code>len_read <code style="color:#806030; ">=</code> ap_get_client_block<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> argsbuffer<code style="color:#806030; ">,</code> <code style="color:#400000; font-weight:bold; ">sizeof</code><code style="color:#806030; ">(</code>argsbuffer<code style="color:#806030; ">)</code><code style="color:#806030; ">)</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">></code> <code style="color:#c00000; ">0</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code><code style="color:#806030; ">(</code>rpos <code style="color:#806030; ">+</code> len_read<code style="color:#806030; ">)</code> <code style="color:#806030; ">></code> length<code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
rsize <code style="color:#806030; ">=</code> length <code style="color:#806030; ">-</code> rpos<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#400000; font-weight:bold; ">else</code> <code style="color:#806030; ">{</code>
|
|
rsize <code style="color:#806030; ">=</code> len_read<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#800040; ">memcpy</code><code style="color:#806030; ">(</code><code style="color:#806030; ">(</code><code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code><code style="color:#806030; ">)</code> <code style="color:#806030; ">*</code>rbuf <code style="color:#806030; ">+</code> rpos<code style="color:#806030; ">,</code> argsbuffer<code style="color:#806030; ">,</code> <code style="color:#806030; ">(</code><code style="color:#800040; ">size_t</code><code style="color:#806030; ">)</code> rsize<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
rpos <code style="color:#806030; ">+</code><code style="color:#806030; ">=</code> rsize<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code><code style="color:#806030; ">(</code>rc<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">static</code> <code style="color:#400000; font-weight:bold; ">int</code> example_handler<code style="color:#806030; ">(</code>request_req<code style="color:#806030; ">*</code> r<code style="color:#806030; ">)</code>
|
|
<code style="color:#806030; ">{</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~*/</code>
|
|
apr_off_t size<code style="color:#806030; ">;</code>
|
|
<code style="color:#400000; font-weight:bold; ">const</code> <code style="color:#400000; font-weight:bold; ">char</code> <code style="color:#806030; ">*</code>buffer<code style="color:#806030; ">;</code>
|
|
<code style="color:#c34e00; ">/*~~~~~~~~~~~~~~~~*/</code>
|
|
|
|
<code style="color:#400000; font-weight:bold; ">if</code><code style="color:#806030; ">(</code>util_read<code style="color:#806030; ">(</code>r<code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>data<code style="color:#806030; ">,</code> <code style="color:#806030; ">&</code>size<code style="color:#806030; ">)</code> <code style="color:#806030; ">=</code><code style="color:#806030; ">=</code> OK<code style="color:#806030; ">)</code> <code style="color:#806030; ">{</code>
|
|
ap_rprintf<code style="color:#806030; ">(</code><code style="color:#800000; ">"</code><code style="color:#e60000; ">We read a request body that was </code><code style="color:#0f6900; ">%u</code><code style="color:#e60000; "> bytes long</code><code style="color:#800000; ">"</code><code style="color:#806030; ">,</code> size<code style="color:#806030; ">)</code><code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
<code style="color:#400000; font-weight:bold; ">return</code> OK<code style="color:#806030; ">;</code>
|
|
<code style="color:#806030; ">}</code>
|
|
</pre>
|
|
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</div></div>
|
|
<div class="bottomlang">
|
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<p><span>Available Languages: </span><a href="../en/developer/modguide.html" title="English"> en </a></p>
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</div><div id="footer">
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<p class="apache">Copyright 2012 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
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