Making the most out of Symfony Forms

All web applications have forms, either simple or complex. This talk will address some of the complex scenarios with forms that change depending on the data entered and have dynamically generated fields (server and client side). Using form events and taking advantage of the form rendering flexibility can create some impressive results. The examples are based on real-life scenarios I have encountered in the five years of using the Symfony Framework.

Transcript

1. Making the most out
   of Symfony Forms
   Mihai Nica
   
   @redecs
   

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2. View Slide

3. I’m going to talk about
   • Custom Form Types
   
   • Data Transformers
   
   • Form Events
   
   • Validation Groups
   
   • Collections and Form Themes
   3
   

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4. Custom Form Types
   Reuse common parts of your forms
   4
   

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5. namespace AppBundle\Form;
   use Symfony\Component\Form\AbstractType;
   use Symfony\Component\Form\FormBuilderInterface;
   use Symfony\Component\Form\FormTypeInterface;
   use Symfony\Component\OptionsResolver\OptionsResolver;
   use Doctrine\Common\Persistence\ObjectManager;
   use AppBundle\DataTransformer\EntityToIdTransformer;
   class EntityHiddenType extends AbstractType implements FormTypeInterface
   {
   protected $objectManager;
   public function __construct(ObjectManager $objectManager)
   {
   $this->objectManager = $objectManager;
   }
   public function buildForm(FormBuilderInterface $builder, array $options)
   {
   $transformer = new EntityToIdTransformer($this->objectManager, $options['class']);
   $builder->addModelTransformer($transformer);
   }
   public function setDefaultOptions(OptionsResolver $resolver)
   {
   $resolver->setDefaults(array(
   'class' => null,
   'invalid_message' => 'The entity does not exist.',
   ));
   }
   }
   5
   

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6. Form Events
   Dynamically change your form depending on data
   6
   

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7. namespace AppBundle\Form;
   use AppBundle\Entity\User;
   use Symfony\Component\Form\AbstractType;
   use Symfony\Component\Form\FormBuilderInterface;
   use Symfony\Component\Form\FormEvent;
   use Symfony\Component\Form\FormEvents;
   use Symfony\Component\OptionsResolver\OptionsResolver;
   class UserForm extends AbstractType
   {
   public function buildForm(FormBuilderInterface $builder, array $options) {
   $builder
   ->add('email', 'email', array(
   'required' => false,
   'translation_domain' => 'FOSUserBundle'
   ))
   ->add('plainPassword', 'repeated', array(
   'required' => false,
   'type' => 'password',
   'options' => ['translation_domain' => 'FOSUserBundle'],
   ))
   ->addEventListener(FormEvents::PRE_SUBMIT, function(FormEvent $event) {
   $data = $event->getData()->getData();
   $form = $event->getForm();
   $object = $form->getData();
   if($object) {
   if($data['plainPassword'] && $object->getId()) {
   $formData->setUpdatedAt(new \DateTime());
   }
   }
   })
   ;
   }
   }
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8. namespace AppBundle\Form;
   use AppBundle\Entity\Company;
   use Symfony\Component\Form\AbstractType;
   use Symfony\Component\Form\FormBuilderInterface;
   use Symfony\Component\Form\FormEvent;
   use Symfony\Component\Form\FormEvents;
   use Symfony\Component\Form\FormInterface;
   use Symfony\Component\OptionsResolver\OptionsResolver;
   class CompanyForm extends AbstractType
   {
   public function buildForm(FormBuilderInterface $builder, array $options) {
   // some fields
   $builder
   ->addEventListener(FormEvents::POST_SET_DATA, function(FormEvent $event) {
   /** @var Company $company */
   $company = $event->getData();
   $form = $event->getForm();
   if(empty($company->getId())) {
   $form->add('user', UserForm::class, ['label' => false]);
   }
   });
   }
   }
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9. Validation Groups
   Callback Validation FTW!
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10. namespace AppBundle\Form;
    use AppBundle\Entity\Company;
    use Symfony\Component\Form\AbstractType;
    use Symfony\Component\Form\FormBuilderInterface;
    use Symfony\Component\Form\FormEvent;
    use Symfony\Component\Form\FormEvents;
    use Symfony\Component\Form\FormInterface;
    use Symfony\Component\OptionsResolver\OptionsResolver;
    class CompanyForm extends AbstractType
    {
    // build form here
    public function configureOptions(OptionsResolver $resolver) {
    $resolver->setDefaults(array(
    'data_class' => Company::class,
    'membershipTypes' => array(),
    'validation_groups' =>function(FormInterface $form) {
    $data = $form->getData();
    $validationGroups = ['Default', 'registrationCompany', 'registrationUser'];
    if(!$data->getId()) {
    $validationGroups[] = 'registrationUser';
    }
    return $validationGroups;
    },
    ));
    }
    }
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11. Data Transformers
    View or Model Transformer
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12. namespace AppBundle\DataTransformer;
    use Symfony\Component\Form\DataTransformerInterface;
    use Symfony\Component\Form\Exception\TransformationFailedException;
    use Doctrine\Common\Persistence\ObjectManager;
    class EntityToIdTransformer implements DataTransformerInterface
    {
    protected $objectManager;
    protected $class;
    public function __construct(ObjectManager $objectManager, $class)
    {
    $this->objectManager = $objectManager;
    $this->class = $class;
    }
    public function transform($entity)
    {
    if (null === $entity) {
    return null;
    }
    return $entity->getId();
    }
    public function reverseTransform($id)
    {
    if (!$id) {
    return null;
    }
    $entity = $this->objectManager->getRepository($this->class)->find($id);
    if (null === $entity) {
    throw new TransformationFailedException();
    }
    return $entity;
    }
    }
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13. namespace AppBundle\Form;
    use AppBundle\Entity\User;
    use Doctrine\ORM\EntityManager;
    use Symfony\Component\Form\AbstractType;
    use Symfony\Component\Form\CallbackTransformer;
    use Symfony\Component\Form\Extension\Core\Type\HiddenType;
    use Symfony\Component\Form\Extension\Core\Type\TextType;
    use Symfony\Component\Form\FormBuilderInterface;
    use Symfony\Component\Form\FormTypeInterface;
    class UserTaskType extends AbstractType implements FormTypeInterface
    {
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
    /** @var EntityManager $em */
    $em = $options['em'];
    $builder
    ->add('title', TextType::class)
    ->add('user', HiddenType::class)
    ;
    $builder->get('user')->addModelTransformer(new CallbackTransformer(
    function ($user) {
    return $user instanceof User ? $user->getId() : 0;
    },
    function ($id) use ($em){
    return $em->find(User::class, $id);
    }
    ))
    ;
    }
    }
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14. Collection “magic”
    14
    

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15. namespace AppBundle\Form;
    use Symfony\Component\Form\AbstractType;
    use Symfony\Component\Form\FormBuilderInterface;
    use AppBundle\Entity\Shoot;
    class ShootType extends AbstractType
    {
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
    $builder
    // some other fields here
    ->add('shootContacts', 'collection', array(
    'type' => new ShootContactType(),
    'allow_add' => true,
    'allow_delete' => true,
    'prototype_name' => '__KEY__',
    'label' => false,
    ));
    }
    }
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16. namespace AppBundle\Form;
    use App\Entity\ShootContact;
    use AppBundle\Entity\Shoot;
    use Symfony\Component\Form\AbstractType;
    use Symfony\Component\Form\FormBuilderInterface;
    use Symfony\Component\OptionsResolver\OptionsResolver;
    use AppBundle\Entity\Contact;
    class ShootContactType extends AbstractType
    {
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
    $builder
    ->add('shoot', 'entity_hidden', array(
    'class' => Shoot::class
    ))
    ->add('contact', 'entity_hidden', array(
    'class' => Contact::class
    ))
    ->add('isMainContact', 'checkbox', array(
    'required' => false,
    ))
    ->add('role', 'choice', array(
    'empty_value' => 'none',
    'choices' => Contact::getRolesList(),
    'required' => false,
    ));
    }
    public function setDefaultOptions(OptionsResolver $resolver)
    {
    $resolver->setDefaults(array(
    'data_class' => ShootContact::class,
    'csrf_protection' => false,
    ));
    }
    }
    16
    

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17. {% form_theme form _self %}
    {% block _frontendbundle_shoot_shootContacts_row %}
    {{ form_widget(form) }}
    {% endblock %}
    {% block _frontendbundle_shoot_shootContacts_widget %}
    {% spaceless %}
    {% for collection_form in form %}
    {{ block('contact_collection_item') }}
    {% endfor %}
    {% endspaceless %}
    {% endblock %}
    {% block contact_collection_item %}
    {% spaceless %}
    {% set shoot = collection_form is defined ? collection_form.vars.value.shoot : null %}
    {% set contact = collection_form is defined ? collection_form.vars.value.contact : null %}
    {% set form = collection_form is defined ? collection_form : form.shootContacts.vars.prototype %}
    
    {{ contact ? contact.nameFull : '__NAME_FULL__' }}
    
    {{ form_widget(form.children.isMainContact) }}
    
    
    {{ form_widget(form.children.role) }}
    
    
    {{ form_widget(form.shoot, {'value': shoot ? shoot.id : '__SHOOT_ID__'}) }}
    {{ form_widget(form.contact, {'value': contact ? contact.id : '__CONTACT_ID__'}) }}
    url="{{ path('frontend_contacts_save', {'id': contact ? contact.id : '__CONTACT_ID__'}) }}">{{ 'form.label.edit'|
    trans }} 
    {{ 'form.label.remove'|trans }}
    
    
    {% endspaceless %}
    {% endblock %}
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19. Take-away
    • Symfony Forms are very powerful and flexible
    
    • Form Events, Data Transformers and Validation Groups
    enable you do amazing things
    
    • Form themes and block overriding can be customised any
    way you want.
    
    • Don’t be discourage by the learning curve. The results are
    well worth the effort
    19
    

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20. Questions?
    Feedback is welcome!
    
    https://joind.in/talk/8148e
    20
    

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21. Thank you!
    Mihai Nica
    mihai@wisesystems.co
    https://twitter.com/redecs
    
    https://www.linkedin.com/in/redecs
    

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22. Reference
    • https://symfony.com/doc/current/form/data_transformers.html
    
    • https://symfony.com/doc/current/form/dynamic_form_modification.html
    
    • https://symfony.com/doc/current/form/data_based_validation.html
    
    • https://symfony.com/doc/current/form/form_themes.html#form-fragment-naming
    
    • https://symfony.com/doc/current/components/form.html#learn-more
    
    • https://github.com/Glifery/EntityHiddenTypeBundle
    

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