CodeIgniter is an open-source and MVC-based framework used for web application development on PHP. This framework contains libraries, an easier interface with a logical structure to access these libraries, helpers, plug-ins, and other resources as well. It is easy to use compared to other PHP frameworks

In CodeIgniter, hooks provide a way to modify the behavior of the framework's core components and extend its functionality without directly modifying the core files. Hooks allow you to execute your own custom code at specific points during the application's execution flow.

Hooks are defined in the config/hooks.php file and are used to call specific functions or methods at predefined execution points in the framework's processing cycle. Here's how you can use hooks in CodeIgniter:

Enable Hooks: Open the config/config.php file and set the following configuration item to TRUE to enable hooks:
$config['enable_hooks'] = TRUE;

Define Hooks: Open the config/hooks.php file and define your hooks. Each hook is an associative array with the following structure:

$hook['pre_controller'] = array(
    'class'    => 'MyClass',
    'function' => 'MyFunction',
    'filename' => 'MyClass.php',
    'filepath' => 'hooks'
);

In this example, the hook named 'pre_controller' will execute the 'MyFunction' method of the 'MyClass' class before the main controller is called. The 'filename' and 'filepath' specify the location of the file containing the hook code.

Create Hook File: In the specified 'filepath', create a PHP file named 'MyClass.php' (or whatever you specified as 'filename' in the hook definition). In this file, define the 'MyClass' class and the 'MyFunction' method:

// application/hooks/MyClass.php
class MyClass {
    public function MyFunction() {
        // Your custom code here
    }
}

 

Hooks can be used at various execution points in the CodeIgniter request cycle, such as 'pre_system', 'pre_controller', 'post_controller_constructor', 'post_controller', and more. The flexibility provided by hooks allows you to perform tasks like authentication checks, logging, modifying output, and extending core functionality.

It's important to note that while hooks provide a way to extend CodeIgniter's behavior, they should be used judiciously. Overusing hooks can make your application harder to maintain and debug. Always ensure that your hook code is well-organized and thoroughly tested.

Keep in mind that CodeIgniter's features and practices might have evolved since my last update in September 2021. Always refer to the official CodeIgniter documentation for the most up-to-date and accurate information.