Symfony2 Custom Validation with DB connection but no Entity - php

Question

I'm simply trying to validate a form (with no entity attached) with one field "username". I want to check if the username exists or not. If it doesn't a proper message has to be displayed at form errors level (or form field errors level, I don't care that much).
Here is the relevant part of my controller:
$formGlobalSearch=$this->createFormBuilder()
->add('username', 'text', array('constraints' => new UsernameExists()))
->add('role', 'choice', array('choices' => $rolesListForForm,'required' => false, 'placeholder' => 'Choose a role', 'label' => false, ))
->add('submitUsername', 'submit', array('label' => 'Search username globally'))
->getForm();
$formGlobalSearch->handleRequest($request);
if ($formGlobalSearch->isValid())
{
// do something in the DB and refresh current page
}
return $this->render(//all the stuff needed to render my page//);
}
Here is the relevant part of service.yml
validator.unique.UsernameExists:
class: AppBundle\Validator\Constraints\UsernameExists
tags:
- { name: validator.constraint_validator, alias: UsernameExists }
Here is the validator class:
use Symfony\Component\Validator\Constraint;
/**
* #Annotation
*/
class UsernameExists extends Constraint
{
public $message = 'The username "%string%" does not exist.';
public function validatedBy()
{
return 'UsernameExists';
}
}
Here is the validator:
<?php
namespace AppBundle\Validator\Constraints;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
class UsernameExistsValidator extends ConstraintValidator
{
public function validate($value)
{
$globalUserToAdd = $this->getDoctrine()->getRepository('AppBundle:User')->findOneBy(
array('username' => $value, 'enabled' => true)
);
if ($globalUserToAdd == null) //I did not find the user
{
$this->context->buildViolation($constraint->message)
->setParameter('%string%', $value)
->addViolation();
}
}
}
The class and the validator are in the directory "AppBundle\Validator\Constraints"
I'm getting the following error:
Expected argument of type
"Symfony\Component\Validator\ConstraintValidatorInterface",
"AppBundle\Validator\Constraints\UsernameExists" given
I of course have the following on top of my controller:
use AppBundle\Validator\Constraints\UsernameExists;
If I add the following to service.yml
arguments: ["string"]
I get the error:
No default option is configured for constraint
AppBundle\Validator\Constraints\UsernameExists

Answer 1

try changing:
public function validatedBy()
{
return 'UsernameExists';
}
validator.unique.UsernameExists:
class: AppBundle\Validator\Constraints\UsernameExists
to:
public function validatedBy()
{
return 'UsernameExistsValidator';
}
validator.unique.UsernameExists:
class: AppBundle\Validator\Constraints\UsernameExistsValidator

Answer 2

Merging (partially) the suggestions and debugging a bit more here is the final code.
Validator:
<?php
namespace AppBundle\Validator\Constraints;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
use Doctrine\ORM\EntityManager;
class UsernameExistsValidator extends ConstraintValidator
{
public function __construct(EntityManager $em) //added
{
$this->em = $em;
}
public function validate($value, Constraint $constraint)
{
$em = $this->em;
$globalUserToAdd = $em->getRepository('AppBundle:User')->findOneBy(
array('username' => $value, 'enabled' => true)
);
if ($globalUserToAdd == null) //I did not find the user
{
$this->context->buildViolation($constraint->message)
->setParameter('%string%', $value)
->addViolation();
}
}
}
service.yml
validator.unique.UsernameExists:
class: AppBundle\Validator\Constraints\UsernameExistsValidator
arguments: [ #doctrine.orm.entity_manager, "string"]
tags:
- { name: validator.constraint_validator, alias: UsernameExists }