Symfony2.3 Better way to get EntityManager inside a Controller

Question

I'm using Symfony2.3 and I currently using EntityManager as shown inside __construct()

Which its a better aproach using EntityManager from __construct() or using inside each method ? as shown in public indexAction()

/**
 * QuazBar controller.
 *
 */
class QuazBarController extends Controller
{

    public function __construct()
    {
        $this->em = $GLOBALS['kernel']->getContainer()->get('doctrine')->getManager();
    }

    /**
     * Lists all QuazBar entities.
     *
     */
    public function indexAction(Request $request)
    {
        $session    = $request->getSession();
        $pagina     = $request->query->get('page', 1);
        $em         = $this->getDoctrine()->getManager();
    }

Answer 1

If you must have the EntityManager available in your constructor, a good way to get it is injecting it to the constructor.

To do this you must define your controller as a service.

# src/Acme/DemoBundle/Resources/config/services.yml
parameters:
    # ...
    acme.controller.quazbar.class: Acme\DemoBundle\Controller\QuazBarController

services:
    acme.quazbar.controller:
        class: "%acme.controller.quazbar.class%"
    # inject doctrine to the constructor as an argument
    arguments: [ @doctrine.orm.entity_manager ] 

Now all you have to do is modify your controller:

use Doctrine\ORM\EntityManager;

/**
 * QuazBar controller.
 *
 */
class QuazBarController extends Controller
{

    public function __construct(EntityManager $em)
    {
        $this->em = $em;
    }
    // ...
}

If you do not require the Entity Manager in the constructor, you can simply get it using the Dependency Injection Container from any method in your controller:

$this->getDoctrine()->getManager();

OR

$this->container->get('doctrine')->getManager();

Controller/setter injection is a good choice because you are not coupling your controller implementation to the DI Container.

At the end which one you use is up to your needs.