Handling dependencies in Zend Framework 2 Forms

Question

I am trying to build a form in ZF2. The problem comes when I want to populate the options array of a Select input element from a database table. A response to this question Zend FrameWork 2 Get ServiceLocator In Form and populate a drop down list by @timdev pointed me to the ZF2 docs where the 'correct' method is described. I followed this carefully but I suspect that they must have left obvious code out assuming I could fill in the gaps as I cannot get it to work. Can anyone see what I am doing wrong?

I start with a form to which I add a fieldset:

namespace Ctmm\Form;
use Zend\Form\Form;

class AddPropertyForm extends Form {

public function __construct() {

    parent::__construct('AddProperty');

    $this->setName('addProperty');
    $this->setAttribute('method', 'post');

    $this->add(array(
        'name' => 'property',
        'type' => 'PropertyFieldset'
    ));

} }

I then create the fieldset:

namespace Ctmm\Form;
use Ctmm\Model;
use Zend\Form\Fieldset;

class PropertyFieldset extends Fieldset { 

public function __construct(PropertyType $property_type) {
    $this->add(array(
        'name' => 'property_type',
        'type' => 'Zend\Form\Element\Select',
        'attributes' => array(
            'required' => true,
        ),
        'options' => array(
            'label' => 'Property Type',
            'value_options' => array(
                0 => 'Detached house',
                1 => 'Semi-detached house',
                2 => 'Terraced house',
                3 => 'Bungalow',
                4 => 'Maisonette',
                5 => 'Flat',
                6 => 'Land',
                7 => 'Development Opportunity',
            ),
        ),
    ));

}

}

As you can see I inject PropertyType dependency into the fieldset. At this stage, I have not even used this to generate the options array. I have hard coded the array values to avoid adding another source of possible errors. Once I get the form to render I will then try to pull the array data from the PropertyType table.

Now I set up the form element manager in my Module.php:

namespace Ctmm;
use Ctmm\Form\PropertyFieldset;
use Zend\ModuleManager\Feature\FormElementProviderInterface;

class Module implements FormElementProviderInterface {

public function getFormElementConfig() {
    return array(
        'factories' => array(
            'PropertyFieldset' => function($sm) {
                $serviceLocator = $sm->getServiceLocator();
                $property_type = $serviceLocator->get('Ctmm\Model\PropertyType');
                $fieldset = new PropertyFieldset($property_type);
            }
        )
    );
}

}

This code is straight from the docs. I have tried adding

return $fieldset;

to the PropertyFieldset factory, and I have even tried adding

'invokables' => array(
'PropertyFieldset' => 'Ctmm\Form\PropertyFieldset'
)

to the getFormElementConfig array, as well as replacing the factory with the invokable.

The last step is to create the form in my controller action using the form element manager:

public function addAction() {        
$formManager = $this->serviceLocator->get('FormElementManager');
    $form        = $formManager->get('Ctmm\Form\AddPropertyForm');
}

Whatever I do, I get an error saying the Servicemanager cannot create the PropertyFieldset:

Zend\ServiceManager\Exception\ServiceNotFoundException

File:

/home/mike/public_html/ctmm/vendor/zendframework/zendframework/library/Zend/ServiceManager/ServiceManager.php:456

Message:

Zend\ServiceManager\ServiceManager::get was unable to fetch or create an instance for PropertyFieldset

Stack trace:

#0 /home/mike/public_html/ctmm/vendor/zendframework/zendframework/library/Zend/ServiceManager/AbstractPluginManager.php(103): Zend\ServiceManager\ServiceManager->get('PropertyFieldse...', true)
#1 /home/mike/public_html/ctmm/vendor/zendframework/zendframework/library/Zend/Form/Factory.php(110): Zend\ServiceManager\AbstractPluginManager->get('PropertyFieldse...')
#2 /home/mike/public_html/ctmm/vendor/zendframework/zendframework/library/Zend/Form/Form.php(145): Zend\Form\Factory->create(Array)
#3 /home/mike/public_html/ctmm/module/Ctmm/src/Ctmm/Form/AddPropertyForm.php(33): Zend\Form\Form->add(Array)

Line 33 in AddPropertyForm.php is where I try to add my custom PropertyFieldset. Clearly I have an error in the fieldset itself or in the way I am declaring it. I have tried without injecting the PropertyType dependency, but that makes no difference. For completeness, the code for my PropertyType model is:

namespace Ctmm\Model;

class PropertyType {
public $id;
public $property_type;
protected $adapter;

public function __construct($adapter) {
    $this->adapter = $adapter;
}

public function exchangeArray($data) {
    $this->id = (isset($data['id'])) ? $data['id'] : null;
    $this->property_type = (isset($data['property_type'])) ? $data['property_type'] : null;
}

public function getPropertyType() {
    return $this->property_type;
}

public function fetchAll() {

    $sql_query = "SELECT id, property_type from property_type";
    $statement = $this->adapter->createStatement($sql_query);
    $results = $statement->execute();
    return $results;
}

}

Edit:

I don't have an answer but I have done some more investigation. I created a fieldset directly in the controller to test my PropertyFieldset class and it's dependent model.

$property_type = $this->getServiceLocator()->get('Ctmm\Model\PropertyType');
$fieldset = new PropertyFieldset($property_type);

This did not work immediately. First, I had to take the hinting out of the Fieldset contructor

public function __construct(PropertyFieldset $property_type) {

became

public function __construct($property_type) {

I then had to add

parent::__construct('propertyfieldset');

before it would allow me to add an element.

Once I had added these changes I was able to create a PropertyFieldset object in the controller. I could test this by var_dump()ing it.

Unfortunately, these changes to the PropertyFieldset class did not fix the basic problem, so that when I try to create the form in the controller, it generates the same error as before. I have, at least exonerated the PropertyFieldset class and it's dependent model, which says to me that I have something wrong in the getFormElementConfig() in my Module.php class

Answer 1

So I got this to work with a few minor changes:

As you noted the PropertyFieldSet should call the parents construct like so:

parent::__construct('propertyfieldset'); 

ElementConfig should be like so:

public function getFormElementConfig() {
    return array(
        'factories' => array(
            'PropertyFieldset' => function($sm) {
                $serviceLocator = $sm->getServiceLocator();
                $property_type = $serviceLocator->get('Ctmm\Model\PropertyType');
                $fieldset = new PropertyFieldset($property_type);
                return $fieldset;
            },
        )
    );
}

And the AddPropertyForm should be like so:

namespace Ctmm\Form;
use Zend\Form\Form;

class AddPropertyForm extends Form {

    public function init() {

        parent::__construct('AddProperty');

        $this->setName('addProperty');
        $this->setAttribute('method', 'post');

        $this->add(array(
            'name' => 'addproperty',
            'type' => 'PropertyFieldset',
        ));
    }
}

Instead of using __construct we use init(). This function is apparently called when instantiated by factory: http://framework.zend.com/apidoc/2.1/classes/Zend.Form.Form.html#init

Regarding building the select, I would pass a TableGateway object to the fieldSet instead of a model. Then using a fetchAll function we could do the following in the form:

class PropertyFieldset extends Fieldset {

    public function __construct(PropertyTypeTable $propertyTypeTable) {
        parent::__construct('propertyfieldset');


        $propertyValOpts = array();
        foreach($propertyTypeTable->fetchAll() as $propertyRow) {
            array_push($propertyValOpts,$propertyRow->property_type);
        }

        $this->add(array(
            'name' => 'property_type',
            'type' => 'Zend\Form\Element\Select',
            'attributes' => array(
                'required' => true,
            ),
            'options' => array(
                'label' => 'Property Type',
                'value_options' => $propertyValOpts
            ),
        ));
    }
}

Hope this helps :)