This constraint is used when the underlying data is a collection (i.e. an
array or an object that implements Traversable and ArrayAccess),
but you'd like to validate different keys of that collection in different
ways. For example, you might validate the email key using the Email
constraint and the inventory key of the collection with the Range
constraint.
This constraint can also make sure that certain collection keys are present and that extra keys are not present.
.. seealso::
If you want to validate that all the elements of the collection are unique
use the :doc:`Unique constraint </reference/constraints/Unique>`.
The Collection constraint allows you to validate the different keys
of a collection individually. Take the following example:
// src/Entity/Author.php
namespace App\Entity;
class Author
{
protected $profileData = [
'personal_email' => '...',
'short_bio' => '...',
];
public function setProfileData($key, $value)
{
$this->profileData[$key] = $value;
}
}
To validate that the personal_email element of the profileData array
property is a valid email address and that the short_bio element is
not blank but is no longer than 100 characters in length, you would do the
following:
.. configuration-block::
.. code-block:: php-annotations
// src/Entity/Author.php
namespace App\Entity;
use Symfony\Component\Validator\Constraints as Assert;
class Author
{
/**
* @Assert\Collection(
* fields = {
* "personal_email" = @Assert\Email,
* "short_bio" = {
* @Assert\NotBlank,
* @Assert\Length(
* max = 100,
* maxMessage = "Your short bio is too long!"
* )
* }
* },
* allowMissingFields = true
* )
*/
protected $profileData = [
'personal_email' => '...',
'short_bio' => '...',
];
}
.. code-block:: php-attributes
// src/Entity/Author.php
namespace App\Entity;
use Symfony\Component\Validator\Constraints as Assert;
// IMPORTANT: nested attributes requires PHP 8.1 or higher
class Author
{
#[Assert\Collection(
fields: [
'personal_email' => new Assert\Email,
'short_bio' => [
new Assert\NotBlank,
new Assert\Length(
max: 100,
maxMessage: 'Your short bio is too long!'
)
]
],
allowMissingFields: true,
)]
protected $profileData = [
'personal_email' => '...',
'short_bio' => '...',
];
}
.. code-block:: yaml
# config/validator/validation.yaml
App\Entity\Author:
properties:
profileData:
- Collection:
fields:
personal_email:
- Email: ~
short_bio:
- NotBlank: ~
- Length:
max: 100
maxMessage: Your short bio is too long!
allowMissingFields: true
.. code-block:: xml
<!-- 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="profileData">
<constraint name="Collection">
<option name="fields">
<value key="personal_email">
<constraint name="Email"/>
</value>
<value key="short_bio">
<constraint name="NotBlank"/>
<constraint name="Length">
<option name="max">100</option>
<option name="maxMessage">Your short bio is too long!</option>
</constraint>
</value>
</option>
<option name="allowMissingFields">true</option>
</constraint>
</property>
</class>
</constraint-mapping>
.. code-block:: php
// 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)
{
$metadata->addPropertyConstraint('profileData', new Assert\Collection([
'fields' => [
'personal_email' => new Assert\Email(),
'short_bio' => [
new Assert\NotBlank(),
new Assert\Length([
'max' => 100,
'maxMessage' => 'Your short bio is too long!',
]),
],
],
'allowMissingFields' => true,
]));
}
}
.. versionadded:: 5.4
The ``#[Collection]`` PHP attribute was introduced in Symfony 5.4 and
requires PHP 8.1 (which added nested attribute support).
By default, this constraint validates more than whether or not the individual fields in the collection pass their assigned constraints. In fact, if any keys of a collection are missing or if there are any unrecognized keys in the collection, validation errors will be thrown.
If you would like to allow for keys to be absent from the collection or
if you would like "extra" keys to be allowed in the collection, you can
modify the allowMissingFields and allowExtraFields options respectively.
In the above example, the allowMissingFields option was set to true,
meaning that if either of the personal_email or short_bio elements
were missing from the $personalData property, no validation error would
occur.
Constraints for fields within a collection can be wrapped in the Required
or Optional constraint to control whether they should always be applied
(Required) or only applied when the field is present (Optional).
For instance, if you want to require that the personal_email field of
the profileData array is not blank and is a valid email but the
alternate_email field is optional but must be a valid email if supplied,
you can do the following:
.. configuration-block::
.. code-block:: php-annotations
// src/Entity/Author.php
namespace App\Entity;
use Symfony\Component\Validator\Constraints as Assert;
class Author
{
/**
* @Assert\Collection(
* fields={
* "personal_email" = @Assert\Required({@Assert\NotBlank, @Assert\Email}),
* "alternate_email" = @Assert\Optional(@Assert\Email)
* }
* )
*/
protected $profileData = ['personal_email' => '[email protected]'];
}
.. code-block:: php-attributes
// src/Entity/Author.php
namespace App\Entity;
use Symfony\Component\Validator\Constraints as Assert;
class Author
{
#[Assert\Collection(
fields: [
'personal_email' => new Assert\Required([
new Assert\NotBlank,
new Assert\Email,
]),
'alternate_email' => new Assert\Optional(
new Assert\Email
),
],
)]
protected $profileData = ['personal_email' => '[email protected]'];
}
.. code-block:: yaml
# config/validator/validation.yaml
App\Entity\Author:
properties:
profile_data:
- Collection:
fields:
personal_email:
- Required:
- NotBlank: ~
- Email: ~
alternate_email:
- Optional:
- Email: ~
.. code-block:: xml
<!-- 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="profile_data">
<constraint name="Collection">
<option name="fields">
<value key="personal_email">
<constraint name="Required">
<constraint name="NotBlank"/>
<constraint name="Email"/>
</constraint>
</value>
<value key="alternate_email">
<constraint name="Optional">
<constraint name="Email"/>
</constraint>
</value>
</option>
</constraint>
</property>
</class>
</constraint-mapping>
.. code-block:: php
// src/Entity/Author.php
namespace App\Entity;
use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Component\Validator\Mapping\ClassMetadata;
class Author
{
protected $profileData = ['personal_email'];
public static function loadValidatorMetadata(ClassMetadata $metadata)
{
$metadata->addPropertyConstraint('profileData', new Assert\Collection([
'fields' => [
'personal_email' => new Assert\Required([
new Assert\NotBlank(),
new Assert\Email(),
]),
'alternate_email' => new Assert\Optional(new Assert\Email()),
],
]));
}
}
Even without allowMissingFields set to true, you can now omit the alternate_email
property completely from the profileData array, since it is Optional.
However, if the personal_email field does not exist in the array,
the NotBlank constraint will still be applied (since it is wrapped in
Required) and you will receive a constraint violation.
When you define groups in nested constraints they are automatically added to
the Collection constraint itself so it can be traversed for all nested
groups. Take the following example:
use Symfony\Component\Validator\Constraints as Assert;
$constraint = new Assert\Collection([
'fields' => [
'name' => new Assert\NotBlank(['groups' => 'basic']),
'email' => new Assert\NotBlank(['groups' => 'contact']),
],
]);
This will result in the following configuration:
$constraint = new Assert\Collection([
'fields' => [
'name' => new Assert\Required([
'constraints' => new Assert\NotBlank(['groups' => 'basic']),
'groups' => ['basic', 'strict'],
]),
'email' => new Assert\Required([
"constraints" => new Assert\NotBlank(['groups' => 'contact']),
'groups' => ['basic', 'strict'],
]),
],
'groups' => ['basic', 'strict'],
]);
The default allowMissingFields option requires the fields in all groups.
So when validating in contact group, $name can be empty but the key is
still required. If this is not the intended behavior, use the Optional
constraint explicitly instead of Required.
type: boolean default: false
If this option is set to false and the underlying collection contains
one or more elements that are not included in the fields option, a validation
error will be returned. If set to true, extra fields are OK.
type: boolean default: false
If this option is set to false and one or more fields from the fields
option are not present in the underlying collection, a validation error
will be returned. If set to true, it's OK if some fields in the fields
option are not present in the underlying collection.
type: string default: This field was not expected.
The message shown if allowExtraFields is false and an extra field is detected.
You can use the following parameters in this message:
| Parameter | Description |
|---|---|
{{ field }} |
The key of the extra field detected |
type: array [:ref:`default option <validation-default-option>`]
This option is required and is an associative array defining all of the keys in the collection and, for each key, exactly which validator(s) should be executed against that element of the collection.
type: string default: This field is missing.
The message shown if allowMissingFields is false and one or more fields are missing from the underlying collection.
You can use the following parameters in this message:
| Parameter | Description |
|---|---|
{{ field }} |
The key of the missing field defined in fields |