forms - Conditional field validation that depends on another field

Question

I need to change the validation of some field in a form. The validator is configured via a quite large yml file. I wonder if there is any way to do validation on two fields at once. In my case I have two fields that cannot be both empty. At least one has to be filled.

Unfortunately till now I just could see that the validation are defined on a per-field basis, not on multiple fields together.

The question is: is it possible in the standard yml configurations to perform the aforementioned validation?

thanks!

Answer 1

I suggest you to look at Custom validator, especially Class Constraint Validator.

I won't copy paste the whole code, just the parts which you will have to change.

---

Extends the Constraint class.

src/Acme/DemoBundle/Validator/Constraints/CheckTwoFields.php

<?php

namespace AcmeDemoBundleValidatorConstraints;

use SymfonyComponentValidatorConstraint;

/**
 * @Annotation
 */
class CheckTwoFields extends Constraint
{
    public $message = 'You must fill the foo or bar field.';

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

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

Define the validator by extending the ConstraintValidator class, foo and bar are the 2 fields you want to check:

src/Acme/DemoBundle/Validator/Constraints/CheckTwoFieldsValidator.php

namespace AcmeDemoBundleValidatorConstraints;

use SymfonyComponentValidatorConstraint;
use SymfonyComponentValidatorConstraintValidator;

class CheckTwoFieldsValidator extends ConstraintValidator
{
    public function validate($protocol, Constraint $constraint)
    {
        if ((empty($protocol->getFoo())) && (empty($protocol->getBar()))) {
            $this->context->addViolationAt('foo', $constraint->message, array(), null);
        }
    }
}

Use the validator:

src/Acme/DemoBundle/Resources/config/validation.yml

AcmeDemoBundleEntityAcmeEntity:
    constraints:
        - AcmeDemoBundleValidatorConstraintsCheckTwoFields: ~