Best practice form/input-filter setup for ZF3

Foo.php

<?php
namespace Application\Entity;

/**
 * Class Foo
 *
 * @package Application\Entity
 */
class Foo
{
    /**
     * @var int
     */
    protected $id;

    /**
     * @var string
     */
    protected $email;

    /**
     * @return int
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * @return string
     */
    public function getEmail()
    {
        return $this->email;
    }

    /**
     * @param string $email
     */
    public function setEmail($email)
    {
        $this->email = $email;
    }
}

FooForm.php

<?php
namespace Application\Form;

use Zend\Form\Element\Email;
use Zend\Form\Form;

/**
 * Class FooForm
 *
 * @package Application\Form
 */
class FooForm extends Form
{
    const EMAIL = 'email';

    /**
     * {@inheritdoc}
     */
    public function init()
    {
        $this->add([
            'name' => self::EMAIL,
            'type' => Email::class,
            'options' => [
                'label' => self::EMAIL,
            ],
        ]);
    }
}

FooFormFactory.php

<?php
namespace Application\Factory\Form;

use Application\Entity\Foo;
use Application\Form\FooForm;
use Application\InputFilter\FooInputFilter;
use Interop\Container\ContainerInterface;
use Zend\Stdlib\Hydrator\ClassMethods;

/**
 * Class FooFormFactory
 * 
 * @package Application\Factory\Form
 */
class FooFormFactory
{
    /**
     * {@inheritdoc}
     */
    public function __invoke(ContainerInterface $container)
    {
        $form = new FooForm('foo');
        $form->setHydrator($container->get('HydratorManager')->get(ClassMethods::class));
        $form->setInputFilter($container->get('InputFilterManager')->get(FooInputFilter::class));
        $form->setObject(new Foo());

        return $form;
    }
}

FooInputFilter.php

<?php
namespace Application\InputFilter;

use Application\Form\FooForm;
use Zend\Filter\StringToLower;
use Zend\Filter\StringTrim;
use Zend\InputFilter\InputFilter;
use Zend\Validator\EmailAddress;

/**
 * Class FooInputFilter
 *
 * @package Application\InputFilter
 */
class FooInputFilter extends InputFilter
{
    /**
     * {@inheritdoc}
     */
    public function init()
    {
        $this->add([
            'name'       => FooForm::EMAIL,
            'required'   => true,
            'filters'    => [
                ['name' => StringToLower::class],
                ['name' => StringTrim::class],
            ],
            'validators' => [
                ['name' => EmailAddress::class],
            ],
        ]);
    }
}

module.config.php

<?php
use Application\Factory\Form\FooFormFactory;
use Application\Form\FooForm;
use Application\InputFilter\FooInputFilter;

return [
    'form_elements' => [
        'factories' => [
            FooForm::class => FooFormFactory::class,
        ],
    ],
    
    'input_filters' => [
        'factories' => [
            FooInputFilter::class => Zend\ServiceManager\Factory\InvokableFactory::class,
        ],
    ],
];

Does this work without the Hydrator and is this also recommended for data that is not confidential? Also im interested in the answer for @bitwombats question.

Considering zend-form's own elements use InputProviderInterface and just have the input spec right there in the class, I'm curious what the reason for deviating from this style is.

:)