Blank

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Validates that a value is blank - meaning equal to an empty string or null:

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        if ('' !== $value && null !== $value) {
    // validation will fail
}
    

To force that a value strictly be equal to null, see the IsNull constraint.

To force that a value is not blank, see NotBlank. But be careful as NotBlank is not strictly the opposite of Blank.

Applies to	property or method
Class	Blank
Validator	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/Entity/Author.php
namespace App\Entity;

use Symfony\Component\Validator\Constraints as Assert;

class Author
{
    #[Assert\Blank]
    protected string $firstName;
}
    

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        # config/validator/validation.yaml
App\Entity\Author:
    properties:
        firstName:
            - Blank: ~
    

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        <!-- config/validator/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 https://symfony.com/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">

    <class name="App\Entity\Author">
        <property name="firstName">
            <constraint name="Blank"/>
        </property>
    </class>
</constraint-mapping>
    

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        // src/Entity/Author.php
namespace App\Entity;

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

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

Options

`groups`

type: array | string default: null

It defines the validation group or groups of this constraint. Read more about validation groups.

`message`

type: string default: This value should be blank.

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

You can use the following parameters in this message:

Parameter	Description
`{{ value }}`	The current (invalid) value
`{{ label }}`	Corresponding form field label

`payload`

type: mixed default: null

This option can be used to attach arbitrary domain-specific data to a constraint. The configured payload is not used by the Validator component, but its processing is completely up to you.

For example, you may want to use several error levels to present failed constraints differently in the front-end depending on the severity of the error.

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

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