Symfony2 Form Validator - Comparing old and new values before flush

Question

I was wondering if there is a way to compare old and new values in a validator within an entity prior to a flush.

I have a Server entity which renders to a

Answer 1

A complete example for Symfony 2.5 (http://symfony.com/doc/current/cookbook/validation/custom_constraint.html)

In this example, the new value for the field "integerField" of the entity "NoDecreasingInteger" must be higher of the stored value.

Creating the constraint:

// src/Acme/AcmeBundle/Validator/Constraints/IncrementOnly.php;

Creating the constraint validator:

// src/Acme/AcmeBundle/Validator/Constraints/IncrementOnlyValidator.php
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();
          }
      }
  }
}

Binding the validator to entity:

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

Injecting the EntityManager to 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 }