symfony4, Dependency injection, no default argument - php

Question

I have setup service to controller function like this
App\Controller\Controller:
calls:
- [new, ['#request_stack','#doctrine.orm.default_entity_manager']]
I needed Entity Manager inside controller action and my function looks like this
public function new(RequestStack $request, EntityManager $em): Response
{
$currentRequest = $request->getCurrentRequest();
$data = json_decode($currentRequest->getContent(), true);
....
return new ApiResponse(['message' => $message['message'], 'body' => 'success']);
}
and when executing comes to line return new ApiResponse it gives error
Controller "Controller::new()" requires that you provide a value for the "$request" argument. Either the argument is nullable and no null value has been provided, no default value has been provided or because there is a non optional argument after this one.
How to get entity manager in controller action or how to resolve this problem?

Answer 1

As the Symfony 4 Doc on Doctrine says :
// you can fetch the EntityManager via $this->getDoctrine()
// or you can add an argument to your action: index(EntityManagerInterface $entityManager)
$entityManager = $this->getDoctrine()->getManager();
So you can just get the entity manager this way in your controller
However, you can also register the Entity Manager as a service to use it.
Be sure to set the autowire to true :
# config/services.yaml
services:
_defaults:
autowire: true
and register it as a service :
# config/services.yaml
services:
#....
controller_em:
class: App\Controller\Controller
arguments: [ '#doctrine.orm.default_entity_manager' ]
public: true
So that you can use it like so in your controller :
private $objectManager;
public function __construct(ObjectManager $objectManager)
{
$this->objectManager = $objectManager;
}
You can also use this way to use the Entity Manager in Voter or Manager.

Answer 2

well. you need to inject your stuff into controller's object constructor - that is called DI in Symfony-way (or via set-methods):
services.yml - if everything ok with your autowire
App\Controller\Controller:
calls:
- [new]
if not add it manually:
App\Controller\Controller:
arguments:
- '#doctrine.orm.default_entity_manager'
calls:
- [new]
Controller.php
/** #var EntityManager */
private $em;
public __construct(EntityManager $em)
{
$this->em = $em;
}
and then just use it in your method:
public function new(RequestStack $request): Response
{
$this->em ...
}

Answer 3

For your information you can create your own AbsractController to inject the EntityManager in all controller extending it like this.
<?php
namespace App\Controller;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController as BaseController;
abstract class AbstractController extends BaseController
{
/**
* #var EntityManagerInterface
*/
protected $em;
/**
* #required
*
* #param EntityManagerInterface $em
*/
public function setEntityManager(EntityManagerInterface $em)
{
$this->em = $em;
}
}
If a controller extends this AbstractController, you could access $this->em everywhere in it.
The "required" annotation here is the key to enable what you tried to do without the need of adding configuration as you did. It's like adding a calls line in your configuration!
You could do something like this for every services you need in all your controllers.