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
:doc:`/reference/constraints/Null` constraint. To force that a value is not
blank, see :doc:`/reference/constraints/NotBlank`.
If, for some reason, you wanted to ensure that the firstName property
of an Author class were blank, you could do the following:
.. configuration-block::
.. code-block:: yaml
# src/BlogBundle/Resources/config/validation.yml
Acme\BlogBundle\Entity\Author:
properties:
firstName:
- Blank: ~
.. code-block:: php-annotations
// src/Acme/BlogBundle/Entity/Author.php
namespace Acme\BlogBundle\Entity;
use Symfony\Component\Validator\Constraints as Assert;
class Author
{
/**
* @Assert\Blank()
*/
protected $firstName;
}
.. code-block:: xml
<!-- 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>
.. code-block:: php
// 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());
}
}
type: string default: This value should be blank.
This is the message that will be shown if the value is not blank.