ValidExpressionValidator.php

<?php

/**
 * This file is part of the Infinite invocation project.
 *
 * (c) Infinite Networks Pty Ltd <http://www.infinite.net.au>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Infinite\ValidationBundle\Constraint;

use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
use Symfony\Component\ExpressionLanguage\SyntaxError;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
use Symfony\Component\Validator\Exception\RuntimeException;
use Symfony\Component\Validator\Exception\UnexpectedTypeException;

class ValidExpressionValidator extends ConstraintValidator
{
    private $expressionLanguage;

    public function __construct(ExpressionLanguage $expressionLanguage = null)
    {
        $this->expressionLanguage = $expressionLanguage;
    }

    public function validate($value, Constraint $constraint)
    {
        if (!$constraint instanceof ValidExpression) {
            throw new UnexpectedTypeException($constraint, __NAMESPACE__.'\ValidExpression');
        }

        if (!$value) {
            return;
        }

        if (!is_string($value)) {
            throw new UnexpectedTypeException($value, 'string');
        }

        try {
            $this->getExpressionLanguage()->parse($value, $constraint->variableNames);
        } catch (SyntaxError $e) {
            $this->context->buildViolation($constraint->message)
                ->setParameter('{{ value }}', $this->formatValue($value))
                ->setParameter('{{ syntaxError }}', $e->getMessage())
                ->setCode($e->getCode())
                ->addViolation();
        }
    }

    private function getExpressionLanguage()
    {
        if (null === $this->expressionLanguage) {
            if (!class_exists(ExpressionLanguage::class)) {
                throw new RuntimeException('Unable to use expressions as the Symfony ExpressionLanguage component is not installed.');
            }
            $this->expressionLanguage = new ExpressionLanguage();
        }

        return $this->expressionLanguage;
    }
}