Controllers

Controllers

Symfony follows the philosophy of "thin controllers and fat models". This means that controllers should hold just the thin layer of glue-code needed to coordinate the different parts of the application.

As a rule of thumb, you should follow the 5-10-20 rule, where controllers should only define 5 variables or less, contain 10 actions or less and include 20 lines of code or less in each action. This isn't an exact science, but it should help you realize when code should be refactored out of the controller and into a service.

Best Practice

Best Practice

Make your controller extend the FrameworkBundle base controller and use annotations to configure routing, caching and security whenever possible.

Coupling the controllers to the underlying framework allows you to leverage all of its features and increases your productivity.

And since your controllers should be thin and contain nothing more than a few lines of glue-code, spending hours trying to decouple them from your framework doesn't benefit you in the long run. The amount of time wasted isn't worth the benefit.

In addition, using annotations for routing, caching and security simplifies configuration. You don't need to browse tens of files created with different formats (YAML, XML, PHP): all the configuration is just where you need it and it only uses one format.

Overall, this means you should aggressively decouple your business logic from the framework while, at the same time, aggressively coupling your controllers and routing to the framework in order to get the most out of it.

Routing Configuration

To load routes defined as annotations in your controllers, add the following configuration to the main routing configuration file:

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# app/config/routing.yml
app:
    resource: '@AppBundle/Controller/'
    type:     annotation

This configuration will load annotations from any controller stored inside the src/AppBundle/Controller/ directory and even from its subdirectories. So if your application defines lots of controllers, it's perfectly ok to reorganize them into subdirectories:

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<your-project>/
├─ ...
└─ src/
   └─ AppBundle/
      ├─ ...
      └─ Controller/
         ├─ DefaultController.php
         ├─ ...
         ├─ Api/
         │  ├─ ...
         │  └─ ...
         └─ Backend/
            ├─ ...
            └─ ...

Template Configuration

Best Practice

Best Practice

Don't use the @Template annotation to configure the template used by the controller.

The @Template annotation is useful, but also involves some magic. We don't think its benefit is worth the magic, and so recommend against using it.

Most of the time, @Template is used without any parameters, which makes it more difficult to know which template is being rendered. It also makes it less obvious to beginners that a controller should always return a Response object (unless you're using a view layer).

What does the Controller look like

Considering all this, here is an example of what the controller should look like for the homepage of our app:

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namespace AppBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;

class DefaultController extends Controller
{
    /**
     * @Route("/", name="homepage")
     */
    public function indexAction()
    {
        $posts = $this->getDoctrine()
            ->getRepository('AppBundle:Post')
            ->findLatest();

        return $this->render('default/index.html.twig', array(
            'posts' => $posts
        ));
    }
}

Using the ParamConverter

If you're using Doctrine, then you can optionally use the ParamConverter to automatically query for an entity and pass it as an argument to your controller.

Best Practice

Best Practice

Use the ParamConverter trick to automatically query for Doctrine entities when it's simple and convenient.

For example:

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use AppBundle\Entity\Post;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;

/**
 * @Route("/{id}", name="admin_post_show")
 */
public function showAction(Post $post)
{
    $deleteForm = $this->createDeleteForm($post);

    return $this->render('admin/post/show.html.twig', array(
        'post'        => $post,
        'delete_form' => $deleteForm->createView(),
    ));
}

Normally, you'd expect a $id argument to showAction(). Instead, by creating a new argument ($post) and type-hinting it with the Post class (which is a Doctrine entity), the ParamConverter automatically queries for an object whose $id property matches the {id} value. It will also show a 404 page if no Post can be found.

When Things Get More Advanced

The above example works without any configuration because the wildcard name {id} matches the name of the property on the entity. If this isn't true, or if you have even more complex logic, the easiest thing to do is just query for the entity manually. In our application, we have this situation in CommentController:

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/**
 * @Route("/comment/{postSlug}/new", name = "comment_new")
 */
public function newAction(Request $request, $postSlug)
{
    $post = $this->getDoctrine()
        ->getRepository('AppBundle:Post')
        ->findOneBy(array('slug' => $postSlug));

    if (!$post) {
        throw $this->createNotFoundException();
    }

    // ...
}

You can also use the @ParamConverter configuration, which is infinitely flexible:

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use AppBundle\Entity\Post;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\ParamConverter;
use Symfony\Component\HttpFoundation\Request;

/**
 * @Route("/comment/{postSlug}/new", name = "comment_new")
 * @ParamConverter("post", options={"mapping": {"postSlug": "slug"}})
 */
public function newAction(Request $request, Post $post)
{
    // ...
}

The point is this: the ParamConverter shortcut is great for simple situations. But you shouldn't forget that querying for entities directly is still very easy.

Pre and Post Hooks

If you need to execute some code before or after the execution of your controllers, you can use the EventDispatcher component to set up before and after filters.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.