How to get an error message with a unique constraint - php

Question

I have a form where a reference number gets added for a product. I've made this field unique because there will be no duplicate reference numbers.
The problem I'm having is when I add a reference number that is already attached to another product, I run into an exception Integrity constraint violation: 1062 Duplicate entry for key 'reference'. Instead I would like the form to display a message to the user to inform them that reference is already in use.
Edit: I have created a custom validator to check if the given reference already exists but I get the following error with this:
Type error: Too few arguments to function Backend\Modules\Glasses\Domain\Glasses\Validator\Constraints\DuplicateReferenceValidator::__construct(), 0 passed in /var/www/html/vendor/symfony/symfony/src/Symfony/Component/Validator/ContainerConstraintValidatorFactory.php on line 52 and exactly 1 expected
I can't seem to get my GlassesRepository in the DuplicateReferenceValidator
Data transfer object:
<?php
namespace Backend\Modules\Glasses\Domain\Glasses;
use Backend\Modules\Glasses\Domain\Brand\Brand;
use Backend\Modules\MediaLibrary\Domain\MediaGroup\MediaGroup;
use Common\Doctrine\Entity\Meta;
use Symfony\Component\Validator\Constraints as Assert;
use Backend\Modules\Glasses\Domain\Glasses\Validator\Constraints as CustomAssert;
class GlassesDataTransferObject
{
/*** Other fields ***/
/**
* #var string
*
* #Assert\NotBlank(message="err.FieldIsRequired")
* #CustomAssert\DuplicateReference
*/
public $reference;
/*** Other fields ***/
DuplicateReference.php
<?php
namespace Backend\Modules\Glasses\Domain\Glasses\Validator\Constraints;
use Symfony\Component\Validator\Constraint;
/**
* #Annotation
*/
class DuplicateReference extends Constraint
{
public $message = '"{{ reference }}" already exists.';
}
DuplicateReferenceValidator.php
<?php
namespace Backend\Modules\Glasses\Domain\Glasses\Validator\Constraints;
use Backend\Modules\Glasses\Domain\Glasses\GlassesRepository;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
use Symfony\Component\Validator\Exception\UnexpectedTypeException;
class DuplicateReferenceValidator extends ConstraintValidator
{
private $repository;
/**
* DuplicateUserValidator constructor.
*/
public function __construct(GlassesRepository $repository)
{
$this->repository = $repository;
}
public function validate($value, Constraint $constraint)
{
if (!$constraint instanceof DuplicateReference) {
throw new UnexpectedTypeException($constraint, DuplicateReference::class);
}
// custom constraints should ignore null and empty values to allow
// other constraints (NotBlank, NotNull, etc.) take care of that
if (null === $value || '' === $value) {
return;
}
if (!is_string($value)) {
// throw this exception if your validator cannot handle the passed type so that it can be marked as invalid
throw new UnexpectedTypeException($value, 'string');
}
$qb = $this->repository->createQueryBuilder('g');
$qb->select('g.reference')
->where('g.reference = :reference')
->setParameter('reference', $value);
$match = $qb->getQuery()->execute();
if ($match) {
$this->context->buildViolation($constraint->message)
->setParameter('{{ reference }}', $value)
->addViolation();
}
}
}

Answer 1

I figured it out myself.
I needed to add the entity manager to my services.yml file in order to be able to access it in the validator.
Backend\Modules\Glasses\Domain\Glasses\Validator\Constraints\DuplicateReferenceValidator:
attributes:
- "#doctrine.orm.entity_manager"