ZF2 + Doctrine2 + DoctrineObject Hydrator: Null value for ManyToOne relation - doctrine-orm

Question

For the category structure on my proejct I'm building an entity. For the add form I use the DoctrineObject hydrator. When there is a value for the $parent this works fine, but whe there is no parent it gives me an error because there is no id to select the parent with. The value of the parent property should be null in this case.
I'd create an filter to do so. This filter is executed but the hydrator doesn't seem to get what I want it to do.
Does anybody know how to solve this?
My entity:
use Gedmo\Mapping\Annotation as Gedmo;
use Doctrine\ORM\Mapping as ORM;
use Flex\Entity\Entity;
/**
* #Gedmo\Tree(type="materializedPath")
* #ORM\Table(name="categories")
* #ORM\Entity(repositoryClass="Gedmo\Tree\Entity\Repository\MaterializedPathRepository")
*/
class Category extends Entity
{
/**
* #ORM\OneToMany(mappedBy="parent", targetEntity="FlexCategories\Entity\Category")
*/
protected $children;
/**
* #ORM\Column(type="integer")
* #ORM\Id
* #ORM\GeneratedValue
*/
protected $id;
/**
* #Gedmo\TreeLevel
* #ORM\Column(nullable=true, type="integer")
*/
protected $level;
/**
* #ORM\Column(length=64, type="string")
*/
protected $name;
/**
* #Gedmo\TreeParent
* #ORM\ManyToOne(inversedBy="children", targetEntity="FlexCategories\Entity\Category")
* #ORM\JoinColumns({
* #ORM\JoinColumn(onDelete="SET NULL", referencedColumnName="id")
* })
*/
protected $parent;
/**
* #Gedmo\TreePath(appendId=false, endsWithSeparator=false, separator="/", startsWithSeparator=true)
* #ORM\Column(length=255, nullable=true, type="string", unique=true)
*/
protected $path;
/**
* #Gedmo\Slug(fields={"name"}, unique=false)
* #Gedmo\TreePathSource
* #ORM\Column(length=64)
*/
protected $slug;
public function setId($value)
{
$this->id = $value;
}
public function setName($value)
{
$this->name = $value;
}
public function setParent($value)
{
$this->parent = $value;
}
}
My form:
use DoctrineModule\Stdlib\Hydrator\DoctrineObject;
use Zend\Form\Form;
use Zend\InputFilter\InputFilterProviderInterface;
use Zend\ServiceManager\ServiceManager;
use Zend\ServiceManager\ServiceManagerAwareInterface;
class CategoryForm extends Form implements InputFilterProviderInterface, ServiceManagerAwareInterface
{
private $_serviceManager;
public function init()
{
// Init hydrator
$hydrator = new DoctrineObject($this->_serviceManager->get('doctrine.entitymanager.orm_default'),
'FlexCategories\Entity\Category');
// Set form basic configurations
$this->setAttribute('method', 'post')
->setHydrator($hydrator);
// Add parent field
$this->add(array(
'name' => 'parent',
'type' => 'Zend\Form\Element\Hidden',
));
// Add name field
$this->add(array(
'attributes' => array(
'required' => 'required',
),
'name' => 'name',
'options' => array(
'label' => 'Name',
),
'type' => 'Zend\Form\Element\Text',
));
// Add description field
$this->add(array(
'name' => 'description',
'options' => array(
'label' => 'Description',
),
'type' => 'Zend\Form\Element\Textarea',
));
// Add CSRF element
$this->add(array(
'name' => 'csrf',
'type' => 'Zend\Form\Element\Csrf',
));
// Add submit button
$this->add(array(
'attributes' => array(
'type' => 'submit',
'value' => 'Save',
),
'name' => 'submit',
));
}
public function getInputFilterSpecification()
{
return array(
'description' => array(
'filters' => array(
array(
'name' => 'Zend\Filter\StringTrim'
),
),
'required' => false,
),
'name' => array(
'filters' => array(
array(
'name' => 'Zend\Filter\StringTrim'
),
),
'required' => true,
'validators' => array(
array(
'name' => 'Flex\Validator\EntityUnique',
'options' => array(
'entity' => 'FlexCategories\Entity\Category',
'filter' => array(
array('property' => 'parent',
'value' => array('_context', 'parent')),
),
'property' => 'name',
'serviceLocator' => $this->_serviceManager,
),
),
),
),
'parent' => array(
'filters' => array(
array(
'name' => 'Flex\Filter\NullIfEmpty'
),
),
'required' => false,
),
);
}
public function setServiceManager(ServiceManager $serviceManager)
{
$this->_serviceManager = $serviceManager;
$this->init();
return $this;
}
}
My controller:
use Flex\Controller\AbstractController;
use FlexCategories\Entity\Category;
use FlexCategories\Form\CategoryForm;
class AdminController extends AbstractController
{
public function addAction()
{
// Load form
$form = $this->getServiceLocator()->get('FlexCategories\Form\CategoryForm');
// Create and bind new entity
$category = new Category();
$form->bind($category);
// Load parent category if present
$parentId = $this->params()->fromRoute('id', null);
if ($parentId !== null)
{
if (!is_numeric($parentId))
throw new \InvalidArgumentException('Invalid parent id specified');
$entityManager = $this->getEntityManager();
$repository = $entityManager->getRepository('FlexCategories\Entity\Category');
$parent = $repository->find($parentId);
if (!$parent)
throw new \InvalidArgumentException('Invalid parent id specified');
$form->get('parent')->setValue($parent->getId());
}
// Process request
$request = $this->getRequest();
if ($request->isPost())
{
$form->setData($request->getPost());
if ($form->isValid())
{
$entityManager = $this->getEntityManager();
$entityManager->persist($category);
$entityManager->flush();
$this->flashMessenger()->addSuccessMessage(sprintf('The category "%1$s" has succesfully been added.', $category->getName()));
return $this->redirect()->toRoute($this->getEvent()->getRouteMatch()->getMatchedRouteName());
}
}
// Return form
return array(
'form' => $form,
);
}
public function indexAction()
{
// Load all categories
$entityManager = $this->getEntityManager();
$repository = $entityManager->getRepository('FlexCategories\Entity\Category');
$categories = $repository->findBy(array(), array('path' => 'asc'));
return array(
'categories' => $categories,
);
}
}
My database:
CREATE TABLE `categories` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`parent_id` int(11) DEFAULT NULL,
`level` int(11) DEFAULT NULL,
`name` varchar(64) COLLATE utf8_unicode_ci NOT NULL,
`path` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
`slug` varchar(64) COLLATE utf8_unicode_ci NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `UNIQ_3AF34668B548B0F` (`path`),
KEY `IDX_3AF34668727ACA70` (`parent_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
ALTER TABLE `categories`
ADD CONSTRAINT `FK_3AF34668727ACA70` FOREIGN KEY (`parent_id`) REFERENCES `categories` (`id`) ON DELETE SET NULL;

Answer 1

I'd solve this problem by create an "HiddenElement" element based on "DoctrineModule\Form\ElementObjectSelect" and use this as the input type.

Answer 2

You need a strategy which handles '' values. ('' != null) as ocramius points out its possible to haven an primary key with ''.
you ran into this problem as soon as you use the "empty_option" currently u cant just set null to it, the form post will always transfer ''.
see https://github.com/doctrine/DoctrineModule/pull/119
see https://github.com/doctrine/DoctrineModule/pull/106
so add a strategy for this field to the hydrator to convert '' to null.
this could look like:
use Zend\Stdlib\Hydrator\Strategy\DefaultStrategy;
class ForeignKey extends DefaultStrategy
{
public function hydrate($value)
{
if($value == '') {
return NULL;
}
return $value;
}
}