Luhn ==== This constraint is used to ensure that a credit card number passes the `Luhn algorithm`_. It is useful as a first step to validating a credit card: before communicating with a payment gateway. ========== =================================================================== Applies to :ref:`property or method ` Options - `groups`_ - `message`_ - `payload`_ Class :class:`Symfony\\Component\\Validator\\Constraints\\Luhn` Validator :class:`Symfony\\Component\\Validator\\Constraints\\LuhnValidator` ========== =================================================================== Basic Usage ----------- To use the Luhn validator, apply it to a property on an object that will contain a credit card number. .. configuration-block:: .. code-block:: php-annotations // src/Entity/Transaction.php namespace App\Entity; use Symfony\Component\Validator\Constraints as Assert; class Transaction { /** * @Assert\Luhn(message="Please check your credit card number.") */ protected $cardNumber; } .. code-block:: yaml # config/validator/validation.yaml App\Entity\Transaction: properties: cardNumber: - Luhn: message: Please check your credit card number. .. code-block:: xml .. code-block:: php // src/Entity/Transaction.php namespace App\Entity; use Symfony\Component\Validator\Constraints as Assert; use Symfony\Component\Validator\Mapping\ClassMetadata; class Transaction { public static function loadValidatorMetadata(ClassMetadata $metadata) { $metadata->addPropertyConstraint('cardNumber', new Assert\Luhn([ 'message' => 'Please check your credit card number', ])); } } .. include:: /reference/constraints/_empty-values-are-valid.rst.inc Options ------- .. include:: /reference/constraints/_groups-option.rst.inc ``message`` ~~~~~~~~~~~ **type**: ``string`` **default**: ``Invalid card number.`` The default message supplied when the value does not pass the Luhn check. You can use the following parameters in this message: =============== ============================================================== Parameter Description =============== ============================================================== ``{{ value }}`` The current (invalid) value =============== ============================================================== .. include:: /reference/constraints/_payload-option.rst.inc .. _`Luhn algorithm`: https://en.wikipedia.org/wiki/Luhn_algorithm