Upgrade Controllers ###################

.. contents:: :local: :depth: 2

Documentations

• Controller Documentation CodeIgniter 3.x <http://codeigniter.com/userguide3/general/controllers.html>_
• :doc:Controller Documentation CodeIgniter 4.x </incoming/controllers>

What has been changed

• Since namespaces have been added to CodeIgniter 4, the controllers must be changed to support namespaces.
• The constructor of CI4 Controller does not automatically load core classes into the properties.
• CI4's Controller has a special constructor :ref:initController() <controller-constructor>.
• CI4 provides :doc:Request </incoming/incomingrequest> and :doc:Responses </outgoing/response> objects for you to work with - more powerful than the CI3-way.
• If you want a base controller (MY_Controller in CI3), use app/Controllers/BaseController.php.
• Calling echo within Controllers, as in CI3, is still supported, but it is recommended that a string or Response object be returned from Controllers.

Upgrade Guide

1. First, move all controller files to the folder app/Controllers.
2. Add this line just after the opening php tag: namespace App\Controllers;
3. Replace extends CI_Controller with extends BaseController.
4. Remove the line defined('BASEPATH') OR exit('No direct script access allowed'); if it exists.

| If you use sub-directories in your controller structure, you have to change the namespace according to that. | For example, you have a version 3 controller located in application/controllers/users/auth/Register.php, the namespace has to be namespace App\Controllers\Users\Auth; and the controller path in the version 4 should look like this: app/Controllers/Users/Auth/Register.php. Make sure to have the first letters of the sub-directories as capitalized. | After that you have to insert a use statement below the namespace definition in order to extend the BaseController: use App\Controllers\BaseController;

Code Example

CodeIgniter Version 3.x

Path: application/controllers:

.. literalinclude:: upgrade_controllers/ci3sample/001.php

CodeIgniter Version 4.x

Path: app/Controllers:

.. literalinclude:: upgrade_controllers/001.php