Best practice - Check if Entity exist before presist - symfony

Question

Whats the best practice to check if entity fields exist before persisting it.
Here's the example
Entity
class Pile{
/**
* #var \ABC\CoreBundle\Entity\Record
*
* #ORM\OneToMany(targetEntity="Record")
*
*/
private $records;
/**
* #var \CSC\CoreBundle\Entity\Project
*
* #ORM\ManyToOne(targetEntity="Project")
*
*/
private $project;
/**
* #var string
*
* #ORM\Column(name="Block", type="string", length=255)
*/
private $block;
/**
* #var string
*
* #ORM\Column(name="Type", type="string", length=255)
*/
private $type;
}
class Record{
/**
* #var \CSC\CoreBundle\Entity\Pile
*
* #ORM\ManyToOne(targetEntity="Pile")
*
*/
private $records;
}
There are two controllers that handle the CRUD of Pile and Records.
To create Pile there must not be any duplicate fields [project, block, type]
In Record Controllers I could create Pile together with Record.
Here's the problem where and when do I check the db if a similar Pile entity is created?
Whats the Best Practice?
Copy and paste the query checker in both controller?
Can I use $form->valid() to perform any check in PileType class?
Must I use a service and have both controller to call the service?
In entity life-cycle use pre-insert?
Thanks

Answer 1

Therefore, the fields must be unique?
If so, then it is very simple: UniqueEntity
use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
...
/**
* #ORM\Entity
* #UniqueEntity(
* fields={"project", "block", "type"}
* )
*/
class Pile{
/**
* #var \ABC\CoreBundle\Entity\Record
*
* #ORM\OneToMany(targetEntity="Record")
*
*/
private $records;
/**
* #var \CSC\CoreBundle\Entity\Project
*
* #ORM\ManyToOne(targetEntity="Project")
*
*/
private $project;
/**
* #var string
*
* #ORM\Column(name="Block", type="string", length=255, unique=true)
*/
private $block;
/**
* #var string
*
* #ORM\Column(name="Type", type="string", length=255, unique=true)
*/
private $type;
}

Answer 2

You can use a custom validation constraint in your form, so that $form->isValid() will do the check.
Follow this documentation entry on How to create a Custom Validation Constraint to create the custom validator and then inject doctrine into it to do the check.
UPDATE: Well, I didn't know there was an UniqueEntity Constraint already included in Symfony.
To inject doctrine do the following:
services:
validator.unique.unique_pile:
class: ABC\CoreBundle\Validator\Constraints\UniquePileValidator
arguments: [#doctrine.orm.entity_manager]
tags:
- { name: validator.constraint_validator, alias: unique_pile }
The validator class might then look like this:
// src/ABC/CoreBundle/Validator/Constraints/UniquePileValidator.php
namespace ABC\CoreBundle\Validator\Constraints;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
class UniquePileValidator extends ConstraintValidator
{
protected $em;
function __construct($em) {
$this->em = $em;
}
public function validate($value, Constraint $constraint)
{
$repo = $this->em->getRepository('ABC\CoreBundle\Entity\Record');
$duplicate_project = $repo->findByProject($value);
$duplicate_block = $repo->findByBlock($value);
$duplicate_type = $repo->findByType($value);
if ($duplicate_project || $duplicate_block || $duplicate_type) {
$this->context->addViolation(
$constraint->message,
array('%string%' => $value)
);
}
}
}
And to be complete, the constraint class:
// src/ABC/CoreBundle/Validator/Constraints/ContainsAlphanumeric.php
namespace ABC\CoreBundle\Validator\Constraints;
use Symfony\Component\Validator\Constraint;
/**
* #Annotation
*/
class ContainsAlphanumeric extends Constraint
{
public $message = 'This Pile already exists!';
public function validatedBy()
{
return 'unique_pile';
}
}
Should be nearly copy/pasteable...