+ +

Hooks - Extending the Framework Core

+ +

Code Igniter's Hooks feature provides a means to tap into and modify the inner workings of the framework without hacking the core files. +When Code Igniter 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. +

+ + +

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:

+ +

class 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.
function The function name you wish to call.
filename The file name containing your class/function.
filepath The name of the directory containing your script. Note: Your script must be located in a directory INSIDE your application folder, so the file path is relative to that folder. For example, if your script is located in application/hooks, you will simply use hooks as your filepath. If your script is located in application/hooks/utilities you will use hooks/utilities as your filepath. No trailing slash.
params Any parameters you wish to pass to your script. This item is optional.

+ + +

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 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.

+ +

pre_system
+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.
pre_controller
+Called immediately prior to any of your controllers being called. All base classes, routing, and security checks have been done.
post_controller
+Called immediately after the controller is called.
display_override
+Overrides the _display() function, 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 the finalized data will be available by calling $this->output->get_output()
cache_override
+Enables you to call your own function instead of the _display_cache() function in the output class. This permits you to use your own cache display mechanism.
scaffolding_override
+Permits a scaffolding request to trigger your own script instead.
post_system
+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.

+ + + + + + + + + + + +

Code Igniter User Guide Version 1.4.0

Hooks - Extending the Framework Core

Defining a Hook

Multiple Calls to the Same Hook

Hook Points