**Course Title:** Mastering Symfony: Building Enterprise-Level PHP Applications **Section Title:** Routing, Controllers, and Templating **Topic:** Creating and using controllers for handling requests In this topic, we'll explore the world of controllers in Symfony, which are responsible for handling requests and returning responses. You'll learn how to create and use controllers, their role in the MVC architecture, and some best practices for organizing and structuring your controllers. ### What are Controllers? In Symfony, controllers are classes that handle requests and return responses. They act as an interface between the application's logic and the outside world. Controllers receive input from the request object, perform some actions, and then return a response object. ### Creating a Controller To create a controller, simply create a new PHP class that extends the `Symfony\Bundle\FrameworkBundle\Controller\AbstractController` class. Here's an example of a basic controller: ```php // src/Controller/BlogController.php namespace App\Controller; use Symfony\Component\HttpFoundation\Response; use Symfony\Bundle\FrameworkBundle\Controller\AbstractController; class BlogController extends AbstractController { public function index() { return new Response('Hello, world!'); } } ``` In this example, we've created a `BlogController` class with a single method, `index()`, which returns a `Response` object containing the string "Hello, world!". ### Routing to Controllers In Symfony, routes are mapped to controllers using the `@Route` annotation or YAML configuration. Here's an example of how to map a route to a controller using the `@Route` annotation: ```php // src/Controller/BlogController.php namespace App\Controller; use Symfony\Component\HttpFoundation\Response; use Symfony\Bundle\FrameworkBundle\Controller\AbstractController; use Symfony\Component\Routing\Annotation\Route; class BlogController extends AbstractController { /** * @Route("/blog", name="blog_index") */ public function index() { return new Response('Hello, world!'); } } ``` In this example, we've added the `@Route` annotation to the `index()` method, mapping the `/blog` route to the `index()` method. ### Controller Methods Controller methods can return a variety of responses, including: * `Response` objects * Strings (which are automatically converted to `Response` objects) * Arrays (which are automatically converted to `JsonResponse` objects) * Twig templates (which we'll cover in the next topic) Here's an example of a controller method that returns a Twig template: ```php // src/Controller/BlogController.php namespace App\Controller; use Symfony\Component\HttpFoundation\Response; use Symfony\Bundle\FrameworkBundle\Controller\AbstractController; use Symfony\Component\Routing\Annotation\Route; class BlogController extends AbstractController { /** * @Route("/blog", name="blog_index") */ public function index() { return $this->render('blog/index.html.twig'); } } ``` In this example, we've used the `render()` method to return a Twig template. ### Best Practices for Controllers Here are some best practices for organizing and structuring your controllers: * Keep your controllers thin and focused on handling requests and returning responses. * Keep your business logic out of your controllers and in your models or services. * Use services to share logic between controllers. * Use controller inheritance to share common logic between controllers. * Use the `@Route` annotation or YAML configuration to map routes to controllers. For more information on controllers in Symfony, check out the official Symfony documentation: [https://symfony.com/doc/current/controller.html](https://symfony.com/doc/current/controller.html). ### What's Next? Now that you've learned how to create and use controllers, we'll explore the world of templating in Symfony using the Twig templating engine. You'll learn how to render Twig templates, use Twig variables, and create reusable Twig templates. **Your Turn!** * Create a new controller and map a route to it. * Experiment with different response types, including `Response` objects and Twig templates. * Read the official Symfony documentation on controllers: [https://symfony.com/doc/current/controller.html](https://symfony.com/doc/current/controller.html). **Leave a Comment or Ask for Help** If you have any questions or need help with a particular concept, leave a comment below. I'd be happy to help!