Controllers in CodeIgniter

A Controller in CodeIgniter acts as the middle layer between the Model and the View. It receives user requests, processes data, and returns a response.

1. What Is a Controller?

• Handles HTTP requests

• Calls models to fetch/update data

• Loads views or returns responses (JSON, text, etc.)

• Controls application flow

2. Controller Location

app/Controllers/

3. Creating a Controller

Using Spark CLI (Recommended)

php spark make:controller Home

Manual Creation

namespace App\Controllers;

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

4. Default Controller

Configured in:

app/Config/Routes.php

$routes->setDefaultController('Home');
$routes->setDefaultMethod('index');

Access:

http://localhost:8080/

5. Controller with View

public function about()
{
    return view('about');
}

View file:

app/Views/about.php

6. Controller with Parameters

public function profile($id)
{
    return "User ID: $id";
}

Route:

$routes->get('user/(:num)', 'User::profile/$1');

7. Loading a Model in Controller

use App\Models\UserModel;

class User extends BaseController
{
    public function index()
    {
        $model = new UserModel();
        $data['users'] = $model->findAll();
        return view('users', $data);
    }
}

8. Returning Different Responses

Text

return "Hello";

JSON

return $this->response->setJSON(['status' => 'success']);

Redirect

return redirect()->to('/login');

9. Using Request & Response

public function save()
{
    $name = $this->request->getPost('name');
    return "Saved: $name";
}

10. Controller Filters (Middleware)

Apply authentication or validation filters.

$routes->get('dashboard', 'Dashboard::index', ['filter' => 'auth']);

11. Resource Controller (REST API)

php spark make:controller Users --resource

Provides methods:

• index()

• show($id)

• create()

• update($id)

• delete($id)

12. Best Practices

✅ Keep controllers thin
✅ Move logic to Models/Services
✅ One responsibility per controller
❌ Avoid database logic directly in controllers

Summary

• Controllers handle user requests

• Stored in app/Controllers

• Communicate with Models & Views

• Support views, JSON, redirects, APIs