NotBlank
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Validates that a value is not blank - meaning not equal to a blank string,
a blank array, false
or null
(null behavior is configurable). To check
that a value is not equal to null
, see the
NotNull constraint.
Applies to | property or method |
Class | NotBlank |
Validator | NotBlankValidator |
Basic Usage
If you wanted to ensure that the firstName
property of an Author
class were not 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\NotBlank]
protected string $firstName;
}
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# config/validator/validation.yaml
App\Entity\Author:
properties:
firstName:
- NotBlank: ~
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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="NotBlank"/>
</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\NotBlank());
}
}
Options
allowNull
type: boolean
default: false
If set to true
, null
values are considered valid and won't trigger a
constraint violation.
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 not be blank.
This is the message that will be shown if the value is blank.
You can use the following parameters in this message:
Parameter | Description |
---|---|
{{ value }} |
The current (invalid) value |
{{ label }} |
Corresponding form field label |
normalizer
type: a PHP callable default: null
This option allows to define the PHP callable applied to the given value before checking if it is valid.
For example, you may want to pass the 'trim'
string to apply the
trim PHP function in order to ignore leading and trailing
whitespace during validation.
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.