.. index:: single: Validator single: Components; Validator
The Validator component provides tools to validate values following the JSR-303 Bean Validation specification.
$ composer require symfony/validator
Alternatively, you can clone the https://github.com/symfony/validator repository.
The Validator component behavior is based on two concepts:
- Constraints, which define the rules to be validated;
- Validators, which are the classes that contain the actual validation logic.
The following example shows how to validate that a string is at least 10 characters long:
use Symfony\Component\Validator\Validation; use Symfony\Component\Validator\Constraints\Length; use Symfony\Component\Validator\Constraints\NotBlank; $validator = Validation::createValidator(); $violations = $validator->validate('Bernhard', array( new Length(array('min' => 10)), new NotBlank(), )); if (0 !== count($violations)) { // there are errors, now you can show them foreach ($violations as $violation) { echo $violation->getMessage().'<br>'; } }
The validator returns the list of violations.
The :class:`Symfony\\Component\\Validator\\Validator` class is the main access point of the Validator component. To create a new instance of this class, it's recommended to use the :class:`Symfony\\Component\\Validator\\Validation` class:
use Symfony\Component\Validator\Validation; $validator = Validation::createValidator();
This $validator
object can validate simple variables such as strings, numbers
and arrays, but it can't validate objects. To do so, configure the
Validator
class as explained in the next sections.
.. toctree:: :maxdepth: 1 :glob: /components/validator/* /validation /validation/*