constraints.md

Constraints

Constraints allow you to validate a field type. The current built in constraints are:

Constraint	Description
NotBlank	Ensures the field is not empty. Allows values of '0'
Email	Ensures the field is a valid email address
Number	Ensures the field is numeric and optionally between a range
Length	Ensures the field has a minimum and/or maximum length of characters
Matching	Ensures the field matches another fields value. Useful for password confirmations

By default, all required fields have a NotBlank constraint. Email fields have an email constraint and number fields a Number constraint.

Using Constraints

// Add an age field where the value must be between 18 and 80
$builder->add('age', 'number', [
    'constraints' => [
        new Constraint\Number(['min' => 18, 'max' => 80])
    ]
]);

// Add a password and confirm password field with a minimum length of 8 characters
$builder->add('password', 'repeated', [
    'repeatable_type' => 'password',
    'constraints' => [
        new Constraint\Length(['min' => 8])
    ]
]);

You can also implement your own constraints, they just need to implement the ConstraintInterface.

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