3_5.md

3.5 The Callback constraint

3.5.1 Callback by a method name

For a callback defined on the entity:

<?php

namespace App\Entity;

use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Component\Validator\Context\ExecutionContextInterface;

#[Assert\Callback('checkEmail')]
class User
{
    public function checkEmail(ExecutionContextInterface $context): void
    {
        if (...) {
            $context
                ->buildViolation('Email is not valid')
                ->atPath('email')
                ->addViolation()
            ;
        }
    }
}

or a callback placed on the method:

#[Assert\Callback]
public function checkEmail(ExecutionContextInterface $context): void
{
    if (...) {
        $context
            ->buildViolation('Email is not valid')
            ->atPath('email')
            ->addViolation()
        ;
    }
}

provide the matching JavaScript callback. Pass a stable sourceId when you display errors manually:

$('form#user').jsFormValidator({
    callbacks: {
        checkEmail: function() {
            var errors = [];

            if (...) {
                errors.push('Email is not valid');
            }

            $('#user_email').jsFormValidator('showErrors', {
                errors: errors,
                sourceId: 'check-email-callback'
            });
        }
    }
});

Pure JavaScript:

var field = document.getElementById('user');
FpJsFormValidator.customize(field, {
    callbacks: {
        checkEmail: function() {
            var errors = [];

            if (...) {
                errors.push('Email is not valid');
            }

            var email = document.getElementById('user_email');
            FpJsFormValidator.customize(email, 'showErrors', {
                errors: errors,
                sourceId: 'check-email-callback'
            });
        }
    }
});

3.5.2 Callback by class and method names

For an external callback:

<?php

namespace App\Entity;

use App\Validator\ExternalValidator;
use Symfony\Component\Validator\Constraints as Assert;

#[Assert\Callback([ExternalValidator::class, 'checkEmail'])]
class User
{
    // ...
}

define the same class and method path in JavaScript:

$('form#user').jsFormValidator({
    callbacks: {
        'App\\Validator\\ExternalValidator': {
            checkEmail: function () {
                // ...
            }
        }
    }
});

You can also define it without nesting, as in 3.5.1, but only if the method name is unique:

$('form#user').jsFormValidator({
    callbacks: {
        checkEmail: function () {
            // ...
        }
    }
});