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Length

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Length¶

Validates that a given string length is between some minimum and maximum value.

Caution

null and empty strings are not handled by this constraint. You need to also add the NotBlank or NotNull constraints to validate against these.

Applies to	property or method
Options	charset charsetMessage exactMessage groups max maxMessage min minMessage payload
Class	`Length`
Validator	`LengthValidator`

Basic Usage¶

To verify that the firstName field length of a class is between "2" and "50", you might add the following:

Annotations

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

use Symfony\Component\Validator\Constraints as Assert;

class Participant
{
    /**
     * @Assert\Length(
     *      min = 2,
     *      max = 50,
     *      minMessage = "Your first name must be at least {{ limit }} characters long",
     *      maxMessage = "Your first name cannot be longer than {{ limit }} characters"
     * )
     */
    protected $firstName;
}

YAML

# config/validator/validation.yaml
App\Entity\Participant:
    properties:
        firstName:
            - Length:
                min: 2
                max: 50
                minMessage: 'Your first name must be at least {{ limit }} characters long'
                maxMessage: 'Your first name cannot be longer than {{ limit }} characters'

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\Participant">
        <property name="firstName">
            <constraint name="Length">
                <option name="min">2</option>
                <option name="max">50</option>
                <option name="minMessage">
                    Your first name must be at least {{ limit }} characters long
                </option>
                <option name="maxMessage">
                    Your first name cannot be longer than {{ limit }} characters
                </option>
            </constraint>
        </property>
    </class>
</constraint-mapping>

PHP

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

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

class Participant
{
    public static function loadValidatorMetadata(ClassMetadata $metadata)
    {
        $metadata->addPropertyConstraint('firstName', new Assert\Length([
            'min' => 2,
            'max' => 50,
            'minMessage' => 'Your first name must be at least {{ limit }} characters long',
            'maxMessage' => 'Your first name cannot be longer than {{ limit }} characters',
        ]));
    }
}

Note

As with most of the other constraints, null and empty strings are considered valid values. This is to allow them to be optional values. If the value is mandatory, a common solution is to combine this constraint with NotBlank.

Options¶

charset¶

type: string default: UTF-8

The charset to be used when computing value's length with the mb_check_encoding and mb_strlen PHP functions.

charsetMessage¶

type: string default: This value does not match the expected {{ charset }} charset.

The message that will be shown if the value is not using the given charset.

You can use the following parameters in this message:

Parameter	Description
`{{ charset }}`	The expected charset
`{{ value }}`	The current (invalid) value

exactMessage¶

type: string default: This value should have exactly {{ limit }} characters.

The message that will be shown if min and max values are equal and the underlying value's length is not exactly this value.

You can use the following parameters in this message:

Parameter	Description
`{{ limit }}`	The exact expected length
`{{ value }}`	The current (invalid) value

groups¶

type: array | string

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

max¶

type: integer

This required option is the "max" length value. Validation will fail if the given value's length is greater than this max value.

maxMessage¶

type: string default: This value is too long. It should have {{ limit }} characters or less.

The message that will be shown if the underlying value's length is more than the max option.

You can use the following parameters in this message:

Parameter	Description
`{{ limit }}`	The expected maximum length
`{{ value }}`	The current (invalid) value

min¶

type: integer

This required option is the "min" length value. Validation will fail if the given value's length is less than this min value.

It is important to notice that NULL values and empty strings are considered valid no matter if the constraint required a minimum length. Validators are triggered only if the value is not blank.

minMessage¶

type: string default: This value is too short. It should have {{ limit }} characters or more.

The message that will be shown if the underlying value's length is less than the min option.

You can use the following parameters in this message:

Parameter	Description
`{{ limit }}`	The expected minimum length
`{{ value }}`	The current (invalid) value

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.