controllers.md

Controllers

Create controller

bin/console make:controller

File src/Controller/ArticleController.php:

namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;

class ArticleController extends AbstractController
{
    public function toggleArticleHeart($slug)
    {
        return $this->json(['hearts' => rand(5, 100)]);
    }
}

Autowiring

Before Symfony executes our controller, it looks at each argument. For simple arguments like $slug, it passes us the wildcard value from the router:

public function toggleArticleHeart($slug, LoggerInterface $logger) { ... }

But for $logger (we call it type-hinted argument), it looks at the type-hint and realizes that we want Symfony to pass us the logger object. Oh, and the order of the arguments does not matter.

Autowiring works in 2 places:

• the controller actions
• the __construct() method of services

The container's job is really to instantiate services. And so autowiring should really only work for __construct() functions! In fact, the only reason that it also works for controller actions is for convenience!

This is a very powerful idea called autowiring: if you need a service object, you just need to know the correct type-hint to use!

Every service is stored inside another object called the container. And each service has an internal name, just like routes.

And what exactly puts these services into the container? The answer: bundles - Symfony's plugin system.

What can we autowire in controller

• type-hint a service class or interface - Symfony will give us that service;
• type-hint an entity class - Symfony will query for that entity by using the wildcard in the route;
• type-hint the Request class - Symfony will give you Request.

Example file src/Controller/CommentAdminController.php:

class CommentAdminController extends AbstractController
{
    /**
     * @Route("/admin/comment", name="comment_admin")
     */
    public function index(CommentRepository $repository, Request $request)
    {
        $q = $request->query->get('q');
        $comments = $repository->findAllWithSearch($q);
        
        return $this->render('comment_admin/index.html.twig', [
            'comments' => $comments,
        ]);
    }
}

RequestStack service

While the Request object is not in the service container, there is a service called RequestStack. We can fetch it like any service and call getCurrentRequest() to get the Request:

public function index(RequestStack $requestStack)
{
    $request = $requestStack->getCurrentRequest();
}

Show list of type-hints / Find service

./bin/console debug:autowiring

This command will show a full list of all of the type-hints that you can use to get a service. Notice that most of them say that they are an alias to something. Whenever you install a new package, you'll get more and more services in this list.

Return JSON in action

To return JSON in action we can use:

$this->json(['amount' => 100]);

Redirect in controller

class SecurityController extends AbstractController
{
    /**
     * @Route("/register", name="app_register")
     */
    public function register(Request $request, UserPasswordEncoderInterface $passwordEncoder)
    {
        if ($request->isMethod('POST')) {
            // ...
            return $this->redirectToRoute('app_account');
        }

        return $this->render('security/register.html.twig');
    }
}