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The Validator Component

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The Validator Component

The Validator component provides tools to validate values following the JSR-303 Bean Validation specification.

Installation

You can install the component in two different ways:

Then, require the vendor/autoload.php file to enable the autoloading mechanism provided by Composer. Otherwise, your application won't be able to find the classes of this Symfony component.

Usage

The Validator component behavior is based on two concepts:

  • Contraints, 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:

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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.

Retrieving a Validator Instance

The 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 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.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.