What is a Controller?

A Controller receives the user input validates it, and then passes the input to the Model. It performs interaction on the model objects. It is a simple class file. The name of the class is associated with URI. The first letter of a class name must be capital.

Controller Example – CodeIgniter 3

<?php 
class Home extends CI_Controller {
	
	public function index() {
		echo "Welcome to CodeIgniter 3";
	}

}
?>

Run in Browser:

http://localhost/project/index.php/home/

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Controller Example – CodeIgniter 4

<?php
namespace App\Controllers;		

class Home extends BaseController {
	
	public function index() {
		echo "Welcome to CodeIgniter 4";
	}

}
?>

Run the following command in cmd/terminal from the project’s root directory:

> php spark serve
    http://localhost:8080

Run in Browser:

http://localhost:8080/index.php/Home/index

In the above example, Home.php is a default controller. You can alter the default namespace, controller, and method from /app/Config/Routes.php.