Apply constraint if conditions match

Question

I have a Symfony form. In this form, I have two fields:

"House number" and "Po Box". They're defined like this:

$builder->add('houseNumber', TextType::class, [
    'label' => 'Huisnummer',
    'attr' => [
        'maxlength' => 8,
    ],
    'constraints' => [
        new NotBlank([
            'groups' => $options['constraint_groups']
        ]),
        new Regex([
            'pattern' => '/^[0-9]+$/',
            'message' => 'Vul alleen het huisnummer in cijfers in.'
        ]),
        new Length([
            'groups' => $options['constraint_groups'],
            'max' => 8
        ])
    ]
])->add('poBox', TextType::class, [
    'label' => 'Postbus',
    'attr' => [
        'maxlength' => 10,
    ],
    'constraints' => [
        new Length([
            'groups' => $options['constraint_groups'],
            'max' => 10
        ])
    ]
]);

Is there a way for me to make it so that the Housenumber not required if the PoBox is present and vice versa?

Thanks.

Answer 1

You can create a custom validation constraint

namespace App\Validator\Constraints;

use Symfony\Component\Validator\Constraint;

/**
 * @Annotation
 * @Target({"CLASS", "ANNOTATION"})
 */
class HouseNumber extends Constraint
{
    public $message = 'Some message';

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

Validator

namespace App\Validator\Constraints;

use Symfony\Component\Form\Exception\UnexpectedTypeException;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

class HouseNumberValidator extends ConstraintValidator
{
    public function validate($obj, Constraint $constraint)
    {
        if (!$constraint instanceof HouseNUmber) {
            throw new UnexpectedTypeException($constraint, __NAMESPACE__ . '\HouseNUmber');
        }

        $error = null;

        if (!$this->isValid($obj)) {
            $error = $constraint->message;
        }

        if (!empty($error)) {
            $this->context->buildViolation($error)
                ->atPath('houseNumber')
                ->addViolation();
        }
    }

    private function isValid($obj)
    {    
        if (!$obj instanceof SomeClass) {
            throw new UnexpectedTypeException($obj, SomeClass::class);
        }

        if (!empty($obj->getPoBox())) {
            return true;
        }

        return !empty($obj->getHouseNumber());
    }
}

And to your field $houseNumber in class add annotation

use App\Validator\Constraints as AppAssert;

/**
 * @AppAssert\HouseNumber
 */
class SomeClass 
{
    private $houseNumber;
    ...
}