UPC/EAN Validator

UpcEan.php

<?php

namespace Insig\UtilBundle\Validator\Constraints;

use Symfony\Component\Validator\Constraint;

/**
 * Metadata for the UpcEanValidator.
 *
 * @Annotation
 */
class UpcEan extends Constraint
{
    public $message = '{{ value }} is not a valid UPC/EAN.';
}

UpcEanValidator.php

<?php

namespace Insig\UtilBundle\Validator\Constraints;

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

/**
 * Validates a UPC/EAN using a variation of the Luhn Algorithm
 */
class UpcEanValidator extends ConstraintValidator
{
    /**
     * Validates a UPC/EAN number with a variation of the Luhn algorithm.
     *
     * @param mixed      $value
     * @param Constraint $constraint
     */
    public function validate($value, Constraint $constraint)
    {
        // Must be a string
        if (!is_string($value)) {
            throw new UnexpectedTypeException($value, 'string');
        }
        
        // Must consist of 12 (UPC) or 13 (EAN) digits
        if (!preg_match('/^\d{12,13}$/', $value)) {
            $this->context->addViolation($constraint->message, array('{{ value }}' => $value));
        }

        $lastDigitIndex = strlen($value) - 1;
        $accumulator = 0;
        $checkDigit = (int) $value[$lastDigitIndex];

        // reverse the actual digits (excluding the check digit)
        $str = strrev(substr($value, 0, $lastDigitIndex));

        /**
         *  Moving from right to left
         *  Even digits are just added
         *  Odd digits are multiplied by three
         */
        $accumulator = 0;
        for ($i = 0; $i < $lastDigitIndex; $i++) {
            $accumulator += $i % 2 ? (int) $value[$i] : (int) $value[$i] * 3;
        }

        $checksum = (10 - ($accumulator % 10)) % 10;

        if ($checksum !== $checkDigit) {
            $this->context->addViolation($constraint->message, array('{{ value }}' => $value));
        }
    }
}

There is an error in this code, for example the EAN 3263852666610 will not be validated. The correct code should use $str (reversed EAN without check digit) to calculate the accumulator:

for ($i = 0; $i < $lastDigitIndex; $i++) {
    $accumulator += $i % 2 ? (int) $str[$i] : (int) $str[$i] * 3;
} 

Replace lines 45 to 47 inf file UpcEanValidator.php with above code.

need also a "return;" after the line 29, without you get 2 error messages

        if (!preg_match('/^\d{12,13}$/', $value)) {
            $this->context->addViolation($constraint->message, array('{{ value }}' => $value));
            return;
        }