CodeIgniter User Guide Version 2.1.0


Hooks - Extending the Framework Core

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 Application Flow 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.

Enabling Hooks

The hooks feature can be globally enabled/disabled by setting the following item in the application/config/config.php file:

$config['enable_hooks'] = TRUE;

Defining a Hook

Hooks are defined in application/config/hooks.php file. Each hook is specified as an array with this prototype:

$hook['pre_controller'] = array(
                                'class'    => 'MyClass',
                                'function' => 'Myfunction',
                                'filename' => 'Myclass.php',
                                'filepath' => 'hooks',
                                'params'   => array('beer', 'wine', 'snacks')
                                );

Notes:
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:

Multiple Calls to the Same Hook

If want to use the same hook point with more then one script, simply make your array declaration multi-dimensional, like this:

$hook['pre_controller'][] = array(
                                'class'    => 'MyClass',
                                'function' => 'Myfunction',
                                'filename' => 'Myclass.php',
                                'filepath' => 'hooks',
                                'params'   => array('beer', 'wine', 'snacks')
                                );

$hook['pre_controller'][] = array(
                                'class'    => 'MyOtherClass',
                                'function' => 'MyOtherfunction',
                                'filename' => 'Myotherclass.php',
                                'filepath' => 'hooks',
                                'params'   => array('red', 'yellow', 'blue')
                                );

Notice the brackets after each array index:

$hook['pre_controller'][]

This permits you to have the same hook point with multiple scripts. The order you define your array will be the execution order.

Hook Points

The following is a list of available hook points.