Symfony 2 forms+validator demonstration.php

<?php

use Symfony\Components\Form\Form;
use Symfony\Components\Form\FieldGroup;
use Symfony\Components\Form\ChoiceField;
use Symfony\Components\Form\TextField;
use Symfony\Components\Form\CheckboxField;
use Symfony\Components\Form\NumberField;
use Symfony\Components\Form\PasswordField;
use Symfony\Components\Form\DoubleTextField;
use Symfony\Components\Validator\Validator;
use Symfony\Components\Validator\ConstraintValidatorFactory;
use Symfony\Components\Validator\Constraints\Min;
use Symfony\Components\Validator\Constraints\Max;
use Symfony\Components\Validator\Constraints\MinLength;
use Symfony\Components\Validator\Constraints\MaxLength;
use Symfony\Components\Validator\Constraints\AssertType;
use Symfony\Components\Validator\Constraints\Email;
use Symfony\Components\Validator\Constraints\Choice;
use Symfony\Components\Validator\Constraints\Valid;
use Symfony\Components\Validator\Mapping\ClassMetadataFactory;
use Symfony\Components\Validator\Mapping\ClassMetadata;
use Symfony\Components\Validator\Mapping\Loader\LoaderChain;
use Symfony\Components\Validator\Mapping\Loader\StaticMethodLoader;
use Symfony\Components\Validator\Mapping\Loader\XmlFileLoader;
use Symfony\Components\Validator\MessageInterpolator\XliffMessageInterpolator;
use Symfony\Foundation\UniversalClassLoader;

// path pointing to Symfony 2
define('SYMFONY_DIR', __DIR__);

require_once SYMFONY_DIR.'/src/Symfony/Foundation/UniversalClassLoader.php';


class User
{
  public $firstName;
  public $lastName;
  public $email;
  public $married = false;
  public $age = 3;
  public $gender = 'male';
  public $address;

  public static function loadValidatorMetadata(ClassMetadata $metadata)
  {
    $metadata->addPropertyConstraint('firstName', new MinLength(2));
    $metadata->addPropertyConstraint('lastName', new MinLength(2));
    $metadata->addPropertyConstraint('email', new Email());
    $metadata->addPropertyConstraint('age', new Min(6));
    $metadata->addPropertyConstraint('gender', new Choice(array('choices' => self::getGenders())));
    $metadata->addPropertyConstraint('address', new Valid());
  }

  public static function getGenders()
  {
    return array('male', 'female');
  }
}

class Address
{
  public $street;
  public $zipCode;
  public $city;

  public static function loadValidatorMetadata(ClassMetadata $metadata)
  {
    $metadata->addPropertyConstraint('street', new MinLength(6));
    $metadata->addPropertyConstraint('zipCode', new MinLength(4));
    $metadata->addPropertyConstraint('zipCode', new MaxLength(5));
    $metadata->addPropertyConstraint('zipCode', new AssertType('numeric'));
    $metadata->addPropertyConstraint('city', new MinLength(3));
  }
}

class UserAdmin
{
  public $user;
  public $hasAddress;
  public $address;

  public static function loadValidatorMetadata(ClassMetadata $metadata)
  {
    $metadata->addPropertyConstraint('user', new Valid());
    $metadata->addPropertyConstraint('address', new Valid());
  }

  public function __construct(User $user)
  {
    $this->user = $user;
    $this->hasAddress = ($this->user->address !== null);
    $this->address = $this->hasAddress ? $this->user->address : new Address();
  }
  
  public function persist()
  {
    $this->user->address = $this->hasAddress ? $this->address : null;

    // etc
    var_dump($this->user);
  }
}


\Locale::setDefault('de_AT');

// initialize autoloader
$loader = new UniversalClassLoader();
$loader->registerNamespace('Symfony', SYMFONY_DIR.'/src');
$loader->register();

// initialize validator
$metadataFactory = new ClassMetadataFactory(new LoaderChain(array(
  new StaticMethodLoader('loadValidatorMetadata'),
  new XmlFileLoader(SYMFONY_DIR.'/src/Symfony/Components/Form/Resources/config/validation.xml'),
)));
$validatorFactory = new ConstraintValidatorFactory();
$messageInterpolator = new XliffMessageInterpolator(SYMFONY_DIR.'/src/Symfony/Components/Validator/Resources/i18n/messages.en.xml');
$validator = new Validator($metadataFactory, $validatorFactory, $messageInterpolator);

// Note: the above code will be taken care of by the Symfony 2 core

// create new business object
$user = new User();
$userAdmin = new UserAdmin($user);

// create form to interact with the business object
$form = new Form('admin', $userAdmin, $validator);

$userGroup = new FieldGroup('user');
$userGroup->add(new TextField('firstName'));
$userGroup->add(new TextField('lastName'));
$userGroup->add(new DoubleTextField('email'));
$userGroup->add(new CheckboxField('married'));
$userGroup->add(new NumberField('age'));
$userGroup->add(new ChoiceField('gender', array('choices' => array_combine(User::getGenders(), User::getGenders()))));

$addressGroup = new FieldGroup('address');
$addressGroup->add(new TextField('street'));
$addressGroup->add(new TextField('zipCode'));
$addressGroup->add(new TextField('city'));

$form->add($userGroup);
$form->add(new CheckboxField('hasAddress'));
$form->add($addressGroup);

// bind POST data to the form
if (isset($_POST['admin']))
{
  $form->bind($_POST['admin']);

  if ($form->isValid())
  {
    $userAdmin->persist();
  }
}

?>

<form action="#" method="post">
  <?php echo $form->renderErrors() ?>
  <?php echo $form->render() ?>
  <input type="submit" value="Submit" />
</form>

Yes. It seems to be necessary to override getDisplayedData() in ChoiceField to achieve this, but I'll look into that more closely.

As for your implementation: I don't recommend to usually override the Form's constructor. You have the configure() method at your disposal.
The form name and validator should usually be injected from outside. The form name, because it belongs to the action (which must know the name, too, to get data from the POST request). The validator, because it should usually be shared globally in an application by all processes that require validation.

Ok, I'll move the code out of the constructor, thx.
About the name and validator injection, I agree. But I suppose their will be a Bundle to integrate Forms with Symfony, providing an easy way to inject complex dependencies such as the validator.
Waiting for it, I didn't want to clutter my controller with the validator creation, so I moved it temporarly to the Form.

Thanks for your suggestions. We'll continue working on this project, so have a look at it if you are curious about how people use your work.

The validator will most probably be created by the DIC and injected into the controller. When creating a form, you can thus simply refer to the controller property.

I will have a look at your project. Let me know if you find any more limitations or bugs.