codeigniterUse of hooks

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 the 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')
);

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 (or method) name you wish to call.

filename The file name containing your class/function.

file-path The name of the directory containing your script.

params Any parameters you wish to pass to your script. This item is optional.

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_constructor

Called immediately after your controller is instantiated, but prior to any method calls happening.

post_controller

Called immediately after your controller is fully executed.

display_override

Overrides the _display() 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 super-object with $this->CI =& get_instance() and then the finalized data will be available by calling $this->CI->output->get_output().

cache_override

Enables you to call your own method instead of the _display_cache() method in the Output Library. This permits you to use your own cache display mechanism.

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.

Pre Controller Hook example using CodeIgniter

In application/hooks folder, create a file with name Blocker.php and paste the below code.

<?php
class Blocker {

    function Blocker(){
    }
    
    /**
     * This function used to block the every request except allowed ip address
     */
    function requestBlocker(){
        
        if($_SERVER["REMOTE_ADDR"] != "49.248.51.230"){
            echo "not allowed";
            die;
        }
    }
}
?>

In application/config/hooks.php, declare the following hook.

$hook['pre_controller'] = array(
        'class'    => 'Blocker',
        'function' => 'requestBlocker',
        'filename' => 'Blocker.php',
        'filepath' => 'hooks',
        'params'   => ""
);

In application/config/config.php, set following value as 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('bread', 'wine', 'butter')
);
  • CLASS- The class that you wish to invoke if it is procedural code leave it as blank.
  • FUNCTION- The function name you wish to call.
  • FILENAME- The file name containing your class/function.
  • FILEPATH- Location of the hook file.
  • PARAMS-Additional parameter if needed it is optional