symfony validator as service not working - forms

Question

I need a validator that needs to query database. This means I have to create a Constraint a ConstraintValidator and setup a service to inject EntityManager.
I did it, and researched official documentation and lots of posts and couldn't make it work. It seems that validatedBy() is not able to start the service (injecting then the EntityManager).
Here is the code I'm struggling with:
services.yml
validator.frontend.class:
class: Project\UsersBundle\Validation\Constraints\ConstrainsActiveValidator
arguments: [#doctrine.orm.entity_manager]
tags:
- { name: validator.constrain_validator, alias: the_alias }
ConstrainsActive.php
namespace Project\UsersBundle\Validation\Constraints;
use Symfony\Component\Validator\Constraint;
/**
* #Annotation
* */
class ConstrainsActive extends Constraint
{
public function validatedBy()
{
return 'the_alias'; // get_class($this).'Validator';
}
}
ConstrainsActiveValidator.php
namespace Project\UsersBundle\Validation\Constraints;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
use Doctrine\ORM\EntityManager;
class ConstrainsActiveValidator extends ConstraintValidator
{
protected $em;
public function __construct(EntityManager $v)
{
$this->em = $em;
}
public function validate($value, Constraint $constraint)
{
$this->context->buildViolation('This name sounds totally fake2!')
->atPath('useEmail')
->addViolation();
}
}
Update:
Thanks for the typo issue. It was a mistake when adapting code to posting here. I fixed! :)
Here you are the error I'm always getting:
Attempted to load class "the_alias" from the global namespace in /var/www/Project/current/vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/Validator/ConstraintValidatorFactory.php line 71. Did you forget a use statement for this class?
I temporally edited the file ConstraintValidatorFactory.php, and did a var_dump for the var $this->validators and get the response:
array (size=4)
'validator.expression' => string
'validator.expression' (length=20)
'Symfony\Component\Validator\Constraints\EmailValidator' => string
'validator.email' (length=15) 'security.validator.user_password' =>
string 'security.validator.user_password' (length=32)
'doctrine.orm.validator.unique' => string
'doctrine.orm.validator.unique' (length=29)
It seems like symfony framework didn't consider the alias "the_alias" set up in my custom service validator.frontend.class, because it didn't come in the var_dump.
I hope this can give you some clue. Thanks!

Answer 1

You code is ok, check the typo in the construct method where you name the EntityManager as $v and ferer it as $m.
Change the construct of ConstrainsActiveValidatorclass as:
public function __construct(EntityManager $v)
{
$this->em = $v;
}
What error do you have?

Answer 2

Just for people that has the same issue. I finally decided to set checking form parameters inside a type, I mean:
Bundle/Form/addType.php
adding an event listener to the $builder object:
public function buildForm(FormBuilderInterface $builder, array $options) {
...
$builder->addEventListener(FormEvents::POST_SUBMIT, function ($event) {
$data = $event->getData();
$form = $event->getForm();
if (null === $data) return;
// Checking comes here!!!
// ......
}
}
In my opinion, validators are great but when a project gets bigger, checking information inside the event is the best way. You can also use some constraints that provide symfony as EmailConstraints:
use Symfony\Component\Validator\Constraints\Email as EmailConstraint;

Answer 3

Answering myself. Let's validate that an entered slug for a post in a blog is unique:
Let's assume we have a bundle called AppBundle
1) Create the subfolder structure "Validator/Contraints" inside src/AppBundle.
2) Inside .../Validator/Constraints, create a file called SlugUnique.php (The constraint):
namespace AppBundle\Validator\Constraints;
use Symfony\Component\Validator\Constraint;
/**
* #Annotation
*/
class SlugUnique extends Constraint
{
public $message = 'Slug "{{ slug }}" already taken';
public function getTargets()
{
return array(self::PROPERTY_CONSTRAINT);
}
public function validatedBy()
{
return 'app.validator.blog.slug_unique';
}
}
3) Create a file called SlugUniqueValidator.php at the same folder level (The constraint validator):
namespace AppBundle\Validator\Constraints;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
use Doctrine\ORM\EntityManager;
use AppBundle\Entity\Blog as BlogEntity;
/**
* #Annotation
*/
class SlugUniqueValidator extends ConstraintValidator
{
/** #var EntityManager */
private $em;
public function __construct(EntityManager $em)
{
$this->em = $em;
}
public function validate($value, Constraint $constraint)
{
/** #var BlogEntity $blogEntity */
$blogEntity = $this->context->getRoot()->getViewData();
if (null !== $this->em->getRepository('AppBundle:Blog')->findBy(['slug' => $blogEntity->slug])) {
$this->context->buildViolation($blogEntity->slug)
->atPath('slug')
->addViolation();
}
}
}
4) Create an entry into services.yml with properly tag items:
app.validator_constraints_blog.slug_unique_validator:
class:AppBundle\Validator\Constraints\SlugUniqueValidator
arguments: ['#doctrine.orm.entity_manager']
tags:
- { name: 'validator.constraint_validator', alias: 'app.validator.blog.slug_unique' }
Note that the value for the alias parameter must match the value returned by validatedBy in the SlugUnique class constraint.
5) Finally, assign such validation to the corresponding entity field:
namespace AppBundle\Entity;
use AppBundle\Validator\Constraints as ValidatorConstraints;
class Blog
{
...
/**
* #var string
*
* #ORM\Column(name="slug", type="string", length=255, nullable=false)
* #ValidatorConstraints\SlugUnique
*/
private $slug;
public getSlug()
...
Notice that depending on the Entity fieldName and the form fieldName, that you may have to set the parameter 'property_path' when building the form type. Example:
$builder->add(
'slug', TextType::class,
array('required' => false, 'property_path' => 'slug')
);
Please note that you can inject a custom service into SlugUniqueValidator instead on the EntityManager for better separation of concerns and bests practices.