forms - [Symfony][Form] 仅当属性发生变化时才向属性添加验证器/约束

Question

我有以下场景:我正在验证约会，并且有一个自定义验证器，它告诉用户他选择的日期是否有效。如果日期已被另一个实体阻止，则无效。这在添加新实体时完美无缺。

现在，我想仅在日期本身已更改时触发编辑时的日期验证。因此，仅更改约会的标题不应验证日期。

我的实体类:

use Doctrine\ORM\Mapping as ORM;
use Acme\Bundle\Validator\Constraints as AcmeAssert;

/**
 * Appointment
 *
 * @ORM\Entity
 * @AcmeAssert\DateIsValid
 */
class Appointment
{
  /**
   * @ORM\Column(name="title", type="string", length=255)
   *
   * @var string
   */
  protected $title;

  /**
   * @ORM\Column(name="date", type="date")
   *
   * @var \DateTime
   */
  protected $date;
}

验证器类(用作服务):

use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
/**
 * Validates the date of an appointment.
 */
class DateIsValidValidator extends ConstraintValidator
{
    /**
     * {@inheritdoc}
     */
    public function validate($appointment, Constraint $constraint)
    {
        if (null === $date = $appointment->getDate()) {
            return;
        }

        /* Do some magic to validate date */
        if (!$valid) {
            $this->context->addViolationAt('date', $constraint->message);
        }
    }
}

相应的 Constraint 类设置为针对实体类。

use Symfony\Component\Validator\Constraint;

/**
 * @Annotation
 */
class DateIsValid extends Constraint
{
    public $message = 'The date is not valid!';

    /**
     * {@inheritdoc}
     */
    public function getTargets()
    {
        return self::CLASS_CONSTRAINT;
    }

    /**
     * {@inheritdoc}
     */
    public function validatedBy()
    {
        return 'acme.validator.appointment.date';
    }
}

现在我找不到依赖日期更改的干净方法。我可以简单地在我的实体中跟踪旧日期，但如果我想实现更复杂的约束，这感觉不是一个合适的解决方案。 :[

干杯

Answer 1

从 symfony 2.3 开始，您可以使用 Form Events来解决这个问题。通过在创建表单时存储(和克隆)原始实体，我将更改检查代码添加到我的 FormType。

然后添加一个 POST_SUBMIT 事件监听器来检查字段是否已更改。监听器可以向您的字段添加验证错误。

use Symfony\Component\Form\FormEvent;
use Symfony\Component\Form\FormEvents;
use Symfony\Component\Form\FormError;
use Acme\Bundle\Entity\Appointment;

class AppointmentType extends AbstractType
{
    private $originalAppointment;

    public function __construct(Appointment $original)
    {
        // save the original entity 
        $this->originalAppointment = clone $original;
    }

    // ...

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        // define your fields

        $builder->addEventListener(FormEvents::POST_SUBMIT, [$this, 'dateCheckListener']);
    }

    public function dateCheckListener(FormEvent $event)
    {
        $appointment = $event->getData();
        $form        = $event->getForm();

        // if no appointments exist, we can skip the check
        if (empty($appointment) || empty($this->originalAppointment)) {
            return;
        }

        if ($appointment->getDate() !== $this->originalAppointment->getDate()) {

            // the dates changed, you can call your validator here

            if ('dates are not valid') {
                $form->get('date')->addError(new FormError('We have a problem.'));
            }
        }
    }
}

在您的 Controller 中，您可以使用原始约会创建此 formType:

$appointment = $this->getYourAppointmentSomehow();

$form = $this->createForm(new AppointmentType($appointment), $appointment);