Controller (CodeIgniter)

In CodeIgniter, a controller is a class that acts as an intermediary between the user and the model and manages user requests. Controllers are responsible for handling HTTP requests, processing and validating data, and returning appropriate responses to the user.

Syntax

The syntax for creating a controller in CodeIgniter is as follows:

class MyController extends CI_Controller {

  public function index() {
    // Controller logic
  }

}

Example

Consider the following example of a CodeIgniter controller that handles a user request to view a product:

class ProductController extends CI_Controller {

  public function view($product_id) {
    // Load the product model
    $this->load->model('ProductModel');

    // Get the product by ID
    $product = $this->ProductModel->get($product_id);

    // Pass the product as data to the view
    $this->load->view('product_view', $product);
  }

}

In the example above, the ProductController class defines a view() method that handles HTTP requests to view a product. The method loads the ProductModel, retrieves the product by ID, and passes the product data to the product_view view.

Explanation

A controller in CodeIgniter is a PHP class that extends the CI_Controller base class. Controllers contain public methods that are responsible for handling HTTP requests and returning responses. When a user requests a resource from the server, CodeIgniter routes the request to the appropriate controller method based on the URL and HTTP method.

Controllers typically contain logic for loading models, validating user input, and rendering views. Controllers can also be used to set up data for views and manage HTTP redirects.

Use

Controllers are an essential component of the CodeIgniter MVC architecture. They are responsible for handling user requests, processing data, and returning responses. Controllers can be used to implement application logic and manage the flow of control between models and views.

Important Points

• Controller class names must start with an uppercase letter.
• Controller filenames should match the controller class name, with the .php extension.
• Controller methods should correspond to HTTP methods (e.g. index() for GET requests, store() for POST requests).
• CodeIgniter routes requests to controllers based on URL segments and HTTP methods.

Summary

In CodeIgniter, a controller is a PHP class that manages user requests, processes data, and returns responses. Controllers are responsible for handling HTTP requests, loading models, validating user input, and rendering views. Controllers are essential components of the CodeIgniter MVC architecture and are responsible for managing the flow of control between models and views.