Information

CraueFormFlowBundle provides a facility for building and handling multi-step forms in your Symfony2 project.

Features:

• navigation (next, back, start over)
• step labels
• skipping of steps
• different validation group for each step
• dynamic step navigation

A live demo showcasing these features is available at http://craue.de/sf2playground/en/CraueFormFlow/.

Installation

Please use tag 1.0.0 of this bundle if you need Symfony 2.0.x compatibility.

Get the bundle

Let Composer download and install the bundle by first adding it to your composer.json

{
	"require": {
		"craue/formflow-bundle": "~2.0.0"
	}
}

and then running

php composer.phar update craue/formflow-bundle

in a shell.

Enable the bundle

// in app/AppKernel.php
public function registerBundles() {
	$bundles = array(
		// ...
		new Craue\FormFlowBundle\CraueFormFlowBundle(),
	);
	// ...
}

Usage

This section shows how to create a 3-step form flow for creating a vehicle. You have to choose between two approaches on how to setup your flow.

Approach A: One form type for the entire flow

This approach makes it easy to turn an existing (usual) form into a form flow.

Create a flow class

// src/MyCompany/MyBundle/Form/CreateVehicleFlow.php
use Craue\FormFlowBundle\Form\FormFlow;
use Craue\FormFlowBundle\Form\FormFlowInterface;
use Symfony\Component\Form\FormTypeInterface;

class CreateVehicleFlow extends FormFlow {

	/**
	 * @var FormTypeInterface
	 */
	protected $formType;

	public function setFormType(FormTypeInterface $formType) {
		$this->formType = $formType;
	}

	public function getName() {
		return 'createVehicle';
	}

	protected function loadStepsConfig() {
		return array(
			array(
				'label' => 'wheels',
				'type' => $this->formType,
			),
			array(
				'label' => 'engine',
				'type' => $this->formType,
				'skip' => function($estimatedCurrentStepNumber, FormFlowInterface $flow) {
					return $estimatedCurrentStepNumber > 1 && !$flow->getFormData()->canHaveEngine();
				},
			),
			array(
				'label' => 'confirmation',
				'type' => $this->formType, // needed to avoid InvalidOptionsException regarding option 'flowStep'
			),
		);
	}

	public function getFormOptions($step, array $options = array()) {
		$options = parent::getFormOptions($step, $options);

		$options['flowStep'] = $step;

		return $options;
	}

}

Create a form type class

You only have to create one form type class for a flow. Since you're passing an option called flowStep to the form type, it can decide which fields will be added to the form according to the step to render.

// src/MyCompany/MyBundle/Form/CreateVehicleForm.php
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

class CreateVehicleForm extends AbstractType {

	public function buildForm(FormBuilderInterface $builder, array $options) {
		switch ($options['flowStep']) {
			case 1:
				$validValues = array(2, 4);
				$builder->add('numberOfWheels', 'choice', array(
					'choices' => array_combine($validValues, $validValues),
					'empty_value' => '',
				));
				break;
			case 2:
				$builder->add('engine', 'form_type_vehicleEngine', array(
					'empty_value' => '',
				));
				break;
		}
	}

	public function setDefaultOptions(OptionsResolverInterface $resolver) {
		$resolver->setDefaults(array(
			'flowStep' => null,
		));
	}

	public function getName() {
		return 'createVehicle';
	}

}

Register your form type and flow as services

<services>
	<service id="myCompany.form.createVehicle"
			class="MyCompany\MyBundle\Form\CreateVehicleForm">
		<tag name="form.type" alias="createVehicle" />
	</service>

	<service id="myCompany.form.flow.createVehicle"
			class="MyCompany\MyBundle\Form\CreateVehicleFlow"
			parent="craue.form.flow"
			scope="request">
		<call method="setFormType">
			<argument type="service" id="myCompany.form.createVehicle" />
		</call>
	</service>
</services>

Approach B: One form type per step

This approach makes it easy to reuse the form types to compose other forms.

Create a flow class

// src/MyCompany/MyBundle/Form/CreateVehicleFlow.php
use Craue\FormFlowBundle\Form\FormFlow;
use Craue\FormFlowBundle\Form\FormFlowInterface;

class CreateVehicleFlow extends FormFlow {

	public function getName() {
		return 'createVehicle';
	}

	protected function loadStepsConfig() {
		return array(
			array(
				'label' => 'wheels',
				'type' => new CreateVehicleStep1Form(),
			),
			array(
				'label' => 'engine',
				'type' => new CreateVehicleStep2Form(),
				'skip' => function($estimatedCurrentStepNumber, FormFlowInterface $flow) {
					return $estimatedCurrentStepNumber > 1 && !$flow->getFormData()->canHaveEngine();
				},
			),
			array(
				'label' => 'confirmation',
			),
		);
	}

}

Create form type classes

// src/MyCompany/MyBundle/Form/CreateVehicleStep1Form.php
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;

class CreateVehicleStep1Form extends AbstractType {

	public function buildForm(FormBuilderInterface $builder, array $options) {
		$validValues = array(2, 4);
		$builder->add('numberOfWheels', 'choice', array(
			'choices' => array_combine($validValues, $validValues),
			'empty_value' => '',
		));
	}

	public function getName() {
		return 'createVehicleStep1';
	}

}

// src/MyCompany/MyBundle/Form/CreateVehicleStep2Form.php
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;

class CreateVehicleStep2Form extends AbstractType {

	public function buildForm(FormBuilderInterface $builder, array $options) {
		$builder->add('engine', 'form_type_vehicleEngine', array(
			'empty_value' => '',
		));
	}

	public function getName() {
		return 'createVehicleStep2';
	}

}

Register your flow as a service

<services>
	<service id="myCompany.form.flow.createVehicle"
			class="MyCompany\MyBundle\Form\CreateVehicleFlow"
			parent="craue.form.flow"
			scope="request">
	</service>
</services>

Create a form template

You only need one template for a flow. The instance of your flow class is passed to the template in a variable called flow so you can use it to render the form according to the current step.

{# in src/MyCompany/MyBundle/Resources/views/Vehicle/createVehicle.html.twig #}
<div>
	Steps:
	{% include 'CraueFormFlowBundle:FormFlow:stepList.html.twig' %}
</div>
<form method="post" {{ form_enctype(form) }}>
	{% include 'CraueFormFlowBundle:FormFlow:stepField.html.twig' %}

	{{ form_errors(form) }}

	{% if flow.getCurrentStepNumber() == 1 %}
		<div>
			When selecting four wheels you have to choose the engine in the next step.<br />
			{{ form_row(form.numberOfWheels) }}
		</div>
	{% endif %}

	{{ form_rest(form) }}

	{% include 'CraueFormFlowBundle:FormFlow:buttons.html.twig' %}
</form>

For the buttons to render correctly you need to tell Assetic to include a CSS file. So place this in your base template:

{% stylesheets '@CraueFormFlowBundle/Resources/assets/css/buttons.css' %}
	<link type="text/css" rel="stylesheet" href="{{ asset_url }}" />
{% endstylesheets %}

Create an action

// in src/MyCompany/MyBundle/Controller/VehicleController.php
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Template;

/**
 * @Template
 */
public function createVehicleAction() {
	$formData = new Vehicle(); // Your form data class. Has to be an object, won't work properly with an array.

	$flow = $this->get('myCompany.form.flow.createVehicle'); // must match the flow's service id
	$flow->bind($formData);

	// form of the current step
	$form = $flow->createForm();
	if ($flow->isValid($form)) {
		$flow->saveCurrentStepData($form);

		if ($flow->nextStep()) {
			// form for the next step
			$form = $flow->createForm();
		} else {
			// flow finished
			$em = $this->getDoctrine()->getEntityManager();
			$em->persist($formData);
			$em->flush();

			return $this->redirect($this->generateUrl('home')); // redirect when done
		}
	}

	return array(
		'form' => $form->createView(),
		'flow' => $flow,
	);
}

Explanations

How the flow works

1. Dispatch PreBindEvent.
2. Dispatch GetStepsEvent.
3. Update the form data class with previously saved data of all steps. For each one, dispatch PostBindSavedDataEvent.
4. Evaluate which steps are skipped. Determine the current step.
5. Dispatch PostBindFlowEvent.
6. Create the form for the current step.
7. Bind the request to that form.
8. Dispatch PostBindRequestEvent.
9. Validate the form data.
10. Dispatch PostValidateEvent.
11. Save the form data.
12. Proceed to the next step.

Method loadStepsConfig

The array returned by that method is used to create all steps of the flow. The first item will be the first step. You can, however, explicitly index the array for easier readability.

Valid options per step are:

• label (string|null)
  • If you'd like to render an overview of all steps you have to set the label option for each step.
  • By default, the labels will be translated using the messages domain when rendered in Twig.
• type (FormTypeInterface|string|null)
  • The form type used to build the form for that step.
  • If using a string, it has to be the registered alias of the form type.
• skip (callable|boolean)
  • Decides whether the step will be skipped.
  • If using a callable...
    • it has to return a boolean value and will receive the estimated current step number and the flow as arguments;
    • it might be called more than once until the actual current step number has been determined.

Examples

protected function loadStepsConfig() {
	return array(
		array(
			'type' => new CreateVehicleStep1Form(),
		),
		array(
			'type' => new CreateVehicleStep2Form(),
			'skip' => true,
		),
		array(
		),
	);
}

protected function loadStepsConfig() {
	return array(
		1 => array(
			'label' => 'wheels',
			'type' => new CreateVehicleStep1Form(),
		),
		2 => array(
			'label' => 'engine',
			'type' => 'createVehicleStep2',
			'skip' => function($estimatedCurrentStepNumber, FormFlowInterface $flow) {
				return $estimatedCurrentStepNumber > 1 && !$flow->getFormData()->canHaveEngine();
			},
		),
		3 => array(
			'label' => 'confirmation',
		),
	);
}

Advanced stuff

Validation groups

To validate the form data class a step-based validation group is passed to the form type. By default, if getName() of the flow returns createVehicle, such a group is named flow_createVehicle_step1 for the first step.

Passing step-based options to the form type

If your form type needs options to build the form (e.g. conditional fields) you can override method getFormOptions of your flow class. Before you can use the options you have to define them in your form type class:

// in src/MyCompany/MyBundle/Form/CreateVehicleStep2Form.php
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

public function setDefaultOptions(OptionsResolverInterface $resolver) {
	$resolver->setDefaults(array(
		// ...
		'numberOfWheels' => null,
	));
}

Then you can set them in your flow class.

// in src/MyCompany/MyBundle/Form/CreateVehicleFlow.php
public function getFormOptions($step, array $options = array()) {
	$options = parent::getFormOptions($step, $options);

	$formData = $this->getFormData();

	if ($step === 2) {
		$options['numberOfWheels'] = $formData->getNumberOfWheels();
	}

	return $options;
}

Enabling dynamic step navigation

Dynamic step navigation means that the step list rendered will contain links to go back/forth to a specific step (which has been done already) directly. To enable it you could extend the flow class mentioned in the example above as follows:

// in src/MyCompany/MyBundle/Form/CreateVehicleFlow.php
class CreateVehicleFlow extends FormFlow {

	protected $allowDynamicStepNavigation = true;

	// ...

}

To force clearing of saved step data when finishing the flow you should call $flow->reset() in the action:

// in src/MyCompany/MyBundle/Controller/VehicleController.php
public function createVehicleAction() {
	// ...

	// flow finished
	// ...
	$flow->reset();

	// ...
}

To ensure starting a flow with clean data, it would be a good idea to add a separate action as an entry point which just resets the flow and redirects to the usual action:

// in src/MyCompany/MyBundle/Controller/VehicleController.php
public function createVehicleStartAction() {
	// ...

	$flow = $this->get('myCompany.form.flow.createVehicle');
	$flow->reset();

	return $this->redirect($this->generateUrl('...')); // route name for createVehicleAction
}

Furthermore, if you'd like to remove the step parameter (added by using such a direct link) when submitting the form you should modify the opening form tag in the form template like this:

<form method="post" action="{{ path(app.request.attributes.get('_route'),
		app.request.query.all | craue_removeDynamicStepNavigationParameter(flow)) }}" {{ form_enctype(form) }}>

Using events

There are some events which you can subscribe to. Using all of them right inside your flow class could look like this:

// in src/MyCompany/MyBundle/Form/CreateVehicleFlow.php
use Craue\FormFlowBundle\Event\GetStepsEvent;
use Craue\FormFlowBundle\Event\PostBindFlowEvent;
use Craue\FormFlowBundle\Event\PostBindRequestEvent;
use Craue\FormFlowBundle\Event\PostBindSavedDataEvent;
use Craue\FormFlowBundle\Event\PostValidateEvent;
use Craue\FormFlowBundle\Event\PreBindEvent;
use Craue\FormFlowBundle\Form\FormFlowEvents;
use Symfony\Component\EventDispatcher\EventDispatcherInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

class CreateVehicleFlow extends FormFlow implements EventSubscriberInterface {

	public function setEventDispatcher(EventDispatcherInterface $dispatcher) {
		parent::setEventDispatcher($dispatcher);
		$dispatcher->addSubscriber($this);
	}

	public static function getSubscribedEvents() {
		return array(
			FormFlowEvents::PRE_BIND => 'onPreBind',
			FormFlowEvents::GET_STEPS => 'onGetSteps',
			FormFlowEvents::POST_BIND_SAVED_DATA => 'onPostBindSavedData',
			FormFlowEvents::POST_BIND_FLOW => 'onPostBindFlow',
			FormFlowEvents::POST_BIND_REQUEST => 'onPostBindRequest',
			FormFlowEvents::POST_VALIDATE => 'onPostValidate',
		);
	}

	public function onPreBind(PreBindEvent $event) {
		// ...
	}

	public function onGetSteps(GetStepsEvent $event) {
		// ...
	}

	public function onPostBindSavedData(PostBindSavedDataEvent $event) {
		// ...
	}

	public function onPostBindFlow(PostBindFlowEvent $event) {
		// ...
	}

	public function onPostBindRequest(PostBindRequestEvent $event) {
		// ...
	}

	public function onPostValidate(PostValidateEvent $event) {
		// ...
	}

	// ...

}