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Helper</a></li> </ul> </li> </ul> </div> </nav> <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap"> <nav class="wy-nav-top" role="navigation" aria-label="top navigation"> <i data-toggle="wy-nav-top" class="fa fa-bars"></i> <a href="../index.html">CodeIgniter</a> </nav> <div class="wy-nav-content"> <div class="rst-content"> <div role="navigation" aria-label="breadcrumbs navigation"> <ul class="wy-breadcrumbs"> <li><a href="../index.html">Docs</a> »</li> <li><a href="index.html">General Topics</a> »</li> <li>Hooks - Extending the Framework Core</li> <li class="wy-breadcrumbs-aside"> </li> <div style="float:right;margin-left:5px;" id="closeMe"> <img title="Classic Layout" alt="classic layout" src="data:image/gif;base64,R0lGODlhFAAUAJEAAAAAADMzM////wAAACH5BAUUAAIALAAAAAAUABQAAAImlI+py+0PU5gRBRDM3DxbWoXis42X13USOLauUIqnlsaH/eY6UwAAOw==" /> </div> </ul> <hr/> </div> <div role="main" class="document"> <div class="section" id="hooks-extending-the-framework-core"> <h1>Hooks - Extending the Framework Core<a class="headerlink" href="#hooks-extending-the-framework-core" title="Permalink to this headline">¶</a></h1> <p>CodeIgniter’s Hooks feature provides a means to tap into and modify the inner workings of the framework without hacking the core files. When CodeIgniter runs it follows a specific execution process, diagramed in the <a class="reference internal" href="../overview/appflow.html"><span class="doc">Application Flow</span></a> page. There may be instances, however, where you’d like to cause some action to take place at a particular stage in the execution process. For example, you might want to run a script right before your controllers get loaded, or right after, or you might want to trigger one of your own scripts in some other location.</p> <div class="section" id="enabling-hooks"> <h2>Enabling Hooks<a class="headerlink" href="#enabling-hooks" title="Permalink to this headline">¶</a></h2> <p>The hooks feature can be globally enabled/disabled by setting the following item in the <strong>application/config/config.php</strong> file:</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$config</span><span class="p">[</span><span class="s1">'enable_hooks'</span><span class="p">]</span> <span class="o">=</span> <span class="k">TRUE</span><span class="p">;</span> </pre></div> </div> </div> <div class="section" id="defining-a-hook"> <h2>Defining a Hook<a class="headerlink" href="#defining-a-hook" title="Permalink to this headline">¶</a></h2> <p>Hooks are defined in the <strong>application/config/hooks.php</strong> file. Each hook is specified as an array with this prototype:</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$hook</span><span class="p">[</span><span class="s1">'pre_controller'</span><span class="p">]</span> <span class="o">=</span> <span class="k">array</span><span class="p">(</span> <span class="s1">'class'</span> <span class="o">=></span> <span class="s1">'MyClass'</span><span class="p">,</span> <span class="s1">'function'</span> <span class="o">=></span> <span class="s1">'Myfunction'</span><span class="p">,</span> <span class="s1">'filename'</span> <span class="o">=></span> <span class="s1">'Myclass.php'</span><span class="p">,</span> <span class="s1">'filepath'</span> <span class="o">=></span> <span class="s1">'hooks'</span><span class="p">,</span> <span class="s1">'params'</span> <span class="o">=></span> <span class="k">array</span><span class="p">(</span><span class="s1">'beer'</span><span class="p">,</span> <span class="s1">'wine'</span><span class="p">,</span> <span class="s1">'snacks'</span><span class="p">)</span> <span class="p">);</span> </pre></div> </div> <p><strong>Notes:</strong></p> <p>The array index correlates to the name of the particular hook point you want to use. In the above example the hook point is pre_controller. A list of hook points is found below. The following items should be defined in your associative hook array:</p> <ul class="simple"> <li><strong>class</strong> The name of the class you wish to invoke. If you prefer to use a procedural function instead of a class, leave this item blank.</li> <li><strong>function</strong> The function (or method) name you wish to call.</li> <li><strong>filename</strong> The file name containing your class/function.</li> <li><strong>filepath</strong> The name of the directory containing your script. Note: Your script must be located in a directory INSIDE your <em>application/</em> directory, so the file path is relative to that directory. For example, if your script is located in <em>application/hooks/</em>, you will simply use ‘hooks’ as your filepath. If your script is located in <em>application/hooks/utilities/</em> you will use ‘hooks/utilities’ as your filepath. No trailing slash.</li> <li><strong>params</strong> Any parameters you wish to pass to your script. This item is optional.</li> </ul> <p>You can also use lambda/anoymous functions (or closures) as hooks, with a simpler syntax:</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$hook</span><span class="p">[</span><span class="s1">'post_controller'</span><span class="p">]</span> <span class="o">=</span> <span class="k">function</span><span class="p">()</span> <span class="p">{</span> <span class="cm">/* do something here */</span> <span class="p">};</span> </pre></div> </div> </div> <div class="section" id="multiple-calls-to-the-same-hook"> <h2>Multiple Calls to the Same Hook<a class="headerlink" href="#multiple-calls-to-the-same-hook" title="Permalink to this headline">¶</a></h2> <p>If want to use the same hook point with more than one script, simply make your array declaration multi-dimensional, like this:</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$hook</span><span class="p">[</span><span class="s1">'pre_controller'</span><span class="p">][]</span> <span class="o">=</span> <span class="k">array</span><span class="p">(</span> <span class="s1">'class'</span> <span class="o">=></span> <span class="s1">'MyClass'</span><span class="p">,</span> <span class="s1">'function'</span> <span class="o">=></span> <span class="s1">'MyMethod'</span><span class="p">,</span> <span class="s1">'filename'</span> <span class="o">=></span> <span class="s1">'Myclass.php'</span><span class="p">,</span> <span class="s1">'filepath'</span> <span class="o">=></span> <span class="s1">'hooks'</span><span class="p">,</span> <span class="s1">'params'</span> <span class="o">=></span> <span class="k">array</span><span class="p">(</span><span class="s1">'beer'</span><span class="p">,</span> <span class="s1">'wine'</span><span class="p">,</span> <span class="s1">'snacks'</span><span class="p">)</span> <span class="p">);</span> <span class="nv">$hook</span><span class="p">[</span><span class="s1">'pre_controller'</span><span class="p">][]</span> <span class="o">=</span> <span class="k">array</span><span class="p">(</span> <span class="s1">'class'</span> <span class="o">=></span> <span class="s1">'MyOtherClass'</span><span class="p">,</span> <span class="s1">'function'</span> <span class="o">=></span> <span class="s1">'MyOtherMethod'</span><span class="p">,</span> <span class="s1">'filename'</span> <span class="o">=></span> <span class="s1">'Myotherclass.php'</span><span class="p">,</span> <span class="s1">'filepath'</span> <span class="o">=></span> <span class="s1">'hooks'</span><span class="p">,</span> <span class="s1">'params'</span> <span class="o">=></span> <span class="k">array</span><span class="p">(</span><span class="s1">'red'</span><span class="p">,</span> <span class="s1">'yellow'</span><span class="p">,</span> <span class="s1">'blue'</span><span class="p">)</span> <span class="p">);</span> </pre></div> </div> <p>Notice the brackets after each array index:</p> <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$hook</span><span class="p">[</span><span class="s1">'pre_controller'</span><span class="p">][]</span> </pre></div> </div> <p>This permits you to have the same hook point with multiple scripts. The order you define your array will be the execution order.</p> </div> <div class="section" id="hook-points"> <h2>Hook Points<a class="headerlink" href="#hook-points" title="Permalink to this headline">¶</a></h2> <p>The following is a list of available hook points.</p> <ul class="simple"> <li><strong>pre_system</strong> Called very early during system execution. Only the benchmark and hooks class have been loaded at this point. No routing or other processes have happened.</li> <li><strong>pre_controller</strong> Called immediately prior to any of your controllers being called. All base classes, routing, and security checks have been done.</li> <li><strong>post_controller_constructor</strong> Called immediately after your controller is instantiated, but prior to any method calls happening.</li> <li><strong>post_controller</strong> Called immediately after your controller is fully executed.</li> <li><strong>display_override</strong> Overrides the <code class="docutils literal"><span class="pre">_display()</span></code> method, used to send the finalized page to the web browser at the end of system execution. This permits you to use your own display methodology. Note that you will need to reference the CI superobject with <code class="docutils literal"><span class="pre">$this->CI</span> <span class="pre">=&</span> <span class="pre">get_instance()</span></code> and then the finalized data will be available by calling <code class="docutils literal"><span class="pre">$this->CI->output->get_output()</span></code>.</li> <li><strong>cache_override</strong> Enables you to call your own method instead of the <code class="docutils literal"><span class="pre">_display_cache()</span></code> method in the <a class="reference internal" href="../libraries/output.html"><span class="doc">Output Library</span></a>. This permits you to use your own cache display mechanism.</li> <li><strong>post_system</strong> Called after the final rendered page is sent to the browser, at the end of system execution after the finalized data is sent to the browser.</li> </ul> </div> </div> </div> <footer> <div class="rst-footer-buttons" role="navigation" aria-label="footer navigation"> <a href="autoloader.html" class="btn btn-neutral float-right" title="Auto-loading Resources">Next <span class="fa fa-arrow-circle-right"></span></a> <a href="ancillary_classes.html" class="btn btn-neutral" title="Creating Ancillary Classes"><span class="fa fa-arrow-circle-left"></span> Previous</a> </div> <hr/> <div role="contentinfo"> <p> © Copyright 2014 - 2019, British Columbia Institute of Technology. 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