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Symfony 5: The Fast Track is the best book to learn modern Symfony development, from zero to production. +300 pages in full color showing how to combine Symfony with Docker, APIs, queues & async tasks, Webpack, Single-Page Applications, etc.

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  4. Constraints
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WARNING: You are browsing the documentation for Symfony 2.4 which is not maintained anymore. Consider upgrading your projects to Symfony 5.1.

Blank

2.4 version
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Blank

Validates that a value is blank, defined as equal to a blank string or equal to null. To force that a value strictly be equal to null, see the Null constraint. To force that a value is not blank, see NotBlank.

Applies to property or method
Options
Class Symfony\Component\Validator\Constraints\Blank
Validator Symfony\Component\Validator\Constraints\BlankValidator

Basic Usage

If, for some reason, you wanted to ensure that the firstName property of an Author class were blank, you could do the following:

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    # src/Acme/BlogBundle/Resources/config/validation.yml
Acme\BlogBundle\Entity\Author:
    properties:
        firstName:
            - Blank: ~
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    // src/Acme/BlogBundle/Entity/Author.php
namespace Acme\BlogBundle\Entity;

use Symfony\Component\Validator\Constraints as Assert;

class Author
{
    /**
     * @Assert\Blank()
     */
    protected $firstName;
}
  • XML
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    <!-- src/Acme/BlogBundle/Resources/config/validation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<constraint-mapping xmlns="http://symfony.com/schema/dic/constraint-mapping"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/constraint-mapping http://symfony.com/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">

    <class name="Acme\BlogBundle\Entity\Author">
        <property name="firstName">
            <constraint name="Blank" />
        </property>
    </class>
</constraint-mapping>
  • PHP
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    // src/Acme/BlogBundle/Entity/Author.php
namespace Acme\BlogBundle\Entity;

use Symfony\Component\Validator\Mapping\ClassMetadata;
use Symfony\Component\Validator\Constraints as Assert;

class Author
{
    public static function loadValidatorMetadata(ClassMetadata $metadata)
    {
        $metadata->addPropertyConstraint('firstName', new Assert\Blank());
    }
}

Options

message

type: string default: This value should be blank.

This is the message that will be shown if the value is not blank.

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