Collection

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Read the updated version of this page for Symfony 7.1 (the current stable version).

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.

Applies to	property or method
Options	fields allowExtraFields extraFieldsMessage allowMissingFields missingFieldsMessage payload
Class	Collection
Validator	CollectionValidator

Basic Usage

The Collection constraint allows you to validate the different keys of a collection individually. Take the following example:

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

class Author
{
    protected $profileData = array(
        '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:

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        // src/AppBundle/Entity/Author.php
namespace AppBundle\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 = array(
         'personal_email' => '...',
         'short_bio' => '...',
     );
}
    

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        # src/AppBundle/Resources/config/validation.yml
AppBundle\Entity\Author:
    properties:
        profileData:
            - Collection:
                fields:
                    personal_email: Email
                    short_bio:
                        - NotBlank: ~
                        - Length:
                            max:   100
                            maxMessage: Your short bio is too long!
                allowMissingFields: true
    

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        <!-- src/AppBundle/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="AppBundle\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>
    

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

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

class Author
{
    private $options = array();

    public static function loadValidatorMetadata(ClassMetadata $metadata)
    {
        $metadata->addPropertyConstraint('profileData', new Assert\Collection(array(
            'fields' => array(
                'personal_email' => new Assert\Email(),
                'short_bio' => array(
                    new Assert\NotBlank(),
                    new Assert\Length(array(
                        'max' => 100,
                        'maxMessage' => 'Your short bio is too long!',
                    )),
                ),
            ),
            'allowMissingFields' => true,
        )));
    }
}
    

Presence and Absence of Fields

By default, this constraint validates more than simply 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.

Required and Optional Field Constraints

2.3

The Required and Optional constraints were moved to the namespace Symfony\Component\Validator\Constraints\ in Symfony 2.3.

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:

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        // src/AppBundle/Entity/Author.php
namespace AppBundle\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 = array('personal_email');
}
    

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        # src/AppBundle/Resources/config/validation.yml
AppBundle\Entity\Author:
    properties:
        profile_data:
            - Collection:
                fields:
                    personal_email:
                        - Required:
                            - NotBlank: ~
                            - Email: ~
                    alternate_email:
                        - Optional:
                            - Email: ~
    

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        <!-- src/AppBundle/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="AppBundle\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>
    

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

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

class Author
{
    protected $profileData = array('personal_email');

    public static function loadValidatorMetadata(ClassMetadata $metadata)
    {
        $metadata->addPropertyConstraint('profileData', new Assert\Collection(array(
            'fields' => array(
                'personal_email'  => new Assert\Required(
                    array(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.

Options

fields

type: array [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.

allowExtraFields

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.

extraFieldsMessage

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

allowMissingFields

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.

missingFieldsMessage

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`

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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