Arguments not being supplied to service - symfony

Question

My validator service is not being supplied to validator. I get an error:
"Warning: Missing argument 1 for My\Bundle\Validator\Constraints\MyCustomValidator::__construct()..."
Here is my services.yml
// My\Bundle\Resources\config\services.yml
services:
my.validator.service:
class: My\Bundle\Validator\Constraints\MyCustomValidator
arguments: [ #doctrine.orm.entity_manager ]
Here is my validator class:
// My\Bundle\Validator\Constraints\MyCustomValidator
namespace My\Bundle\Validator\Constraints;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
use Symfony\Component\DependencyInjection\ContainerInterface as Container;
use Doctrine\ORM\EntityManager;
class MyCustomValidator extends ConstraintValidator
{
private $em;
public function __construct($em)
{
$this->em = $em;
}
public function validate($value, Constraint $constraint)
{
// Do something
}
}
Here's my validation.yml
// My\Bundle\Resources\config\validation.yml
My\Bundle\Entity\Page:
properties:
name:
- NotBlank: ~
- My\Bundle\Validator\Constraints\MyCustom: ~
Here's my Constraint class
namespace My\Bundle\Validator\Constraints;
use Symfony\Component\Validator\Constraint;
class MyCustom extends Constraint
{
public $message = 'Something is wrong with "%string%".';
public function validatedBy()
{
return get_class($this) . 'Validator';
}
}
I'd be very appreciative if someone could help me with this.
I've tried changing the argument name to "#doctrine.orm.default_entity_manager" as well, but no luck.

Answer 1

The problem was my services.yml. Because the service is being used as a validator, I MUST use the validator.constraint_validator tag. This is in the documentation. Whoops!
services:
my.validator.service:
class: My\Bundle\Validator\Constraints\MyCustomValidator
arguments: [ #doctrine.orm.entity_manager ]
tags:
- { name: validator.constraint_validator, alias: my_custom_alias}
I also need to override the Constraint classes validatedBy() method so that it returns the alias above, e.g.:
// My\Bundle\Validator\Constrains\MyCustom.php
public function validatedBy()
{
return 'my_custom_alias';
}

Answer 2

You should be passing the doctrine registry to your service and using that to retrieve an entity manager instance.
Change your constructor to this:
public function __construct(RegistryInterface $registry)
{
$this->registry = $registry;
}
Then amend your service configuration to this:
// My\Bundle\Resources\config\services.yml
services:
my.validator.service:
class: My\Bundle\Validator\Constraints\MyCustomValidator
arguments: [ #doctrine ]
Now anytime you need to get an entity manager in MyCustomValidator you can do this
$em = $this->registry->getManager()