php – Symfony2表单验证器 – 在刷新之前比较旧值和新值

public function isAuthorValid(ExecutionContextInterface $context)
{
    $original = ... ; // get old values
    if( $this->status !== $original->status && $this->status === 'Racked' && $original->status === 'Unracked' )
    {
        // check ftp and ssh connection
        // $context->addViolationAt('status','Unable to connect etc etc');
    }
}

Symfony 2.5( http://symfony.com/doc/current/cookbook/validation/custom_constraint.html)的完整示例

在此示例中,实体“NoDecreasingInteger”的“integerField”字段的新值必须高于存储值.

创建约束：

// src/Acme/AcmeBundle/Validator/Constraints/IncrementOnly.PHP;
<?PHP
namespace Acme\AcmeBundle\Validator\Constraints;

use Symfony\Component\Validator\Constraint;

/**
 * @Annotation
 */
class IncrementOnly extends Constraint
{
  public $message = 'The new value %new% is least than the old %old%';

  public function getTargets()
  {
    return self::CLASS_CONSTRAINT;
  }

  public function validatedBy()
  {
    return 'increment_only';
  }
}

创建约束验证器：

// src/Acme/AcmeBundle/Validator/Constraints/IncrementOnlyValidator.PHP
<?PHP
namespace Acme\AcmeBundle\Validator\Constraints;

use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

use Doctrine\ORM\EntityManager;

class IncrementOnlyValidator extends ConstraintValidator
{
  protected $em;

  public function __construct(EntityManager $em)
  {
    $this->em = $em;
  }

  public function validate($object,Constraint $constraint)
  {
    $new_value = $object->getIntegerField();

    $old_data = $this->em
      ->getUnitOfWork()
      ->getoriginalEntityData($object);

    // $old_data is empty if we create a new NoDecreasingInteger object.
    if (is_array($old_data) and !empty($old_data))
      {
        $old_value = $old_data['integerField'];

        if ($new_value < $old_value)
          {
            $this->context->buildViolation($constraint->message)
              ->setParameter("%new%",$new_value)
              ->setParameter('%old%',$old_value)
              ->addViolation();
          }
      }
  }
}

将验证器绑定到实体：

// src/Acme/AcmeBundle/Resources/config/validator.yml
Acme\AcmeBundle\Entity\NoDecreasingInteger:
  constraints:
     - Acme\AcmeBundle\Validator\Constraints\IncrementOnly: ~

将EntityManager注入IncrementOnlyValidator：

// src/Acme/AcmeBundle/Resources/config/services.yml
services:
   validator.increment_only:
        class: Acme\AcmeBundle\Validator\Constraints\IncrementOnlyValidator
        arguments: ["@doctrine.orm.entity_manager"]
        tags:
            - { name: validator.constraint_validator,alias: increment_only }