We were extremely bored with writing/generating/keeping-up-to-date our FormType classes so we wanted to automate the process and limit required changes only to Entity/Document/Whatever class and get new form out of the box - this is how FormGenerator was invented.

We use annotations on daily basis so it was natural choice for forms' configuration although YAML/XML support is planned.

Consider a class

/**
 * @Form\Form(
 *  personal = { "title", "name", "surname", "photo", "active" },
 *  work = { "salary" },
 *  admin = { "id" = { "type" = "number" }, "surname" }
 * )
 */
class Person
{
    public $id;
    
    /**
     * @Form\Display(type="choice", choices = { "mr" = "Mr.", "ms" = "Ms." })
     */
    public $title;
    
    /**
     * @Form\Display(type="text")
     */
    public $name;
    
    /**
     * @Form\Display(type="text")
     */
    public $surname;
    
    /**
     * @Form\Display(type="file")
     */
    public $photo;
    
    /**
     * @Form\Display(type="checkbox")
     */
    public $active;
    
    /**
     * @Form\Display(type="money")
     */
    public $salary;
}

Now instead of writing whole PersonFormType and populating FormBuilder there we can use instead:

$person = new Person();
$form = $this->get('form_generator')->createFormBuilder($person)
        ->getForm();
$form->handleRequest($request);

Voila! Form for editing all annotated properties is generated for us. We could even omit type=".." in annotations if Symfony will be able to guess field type for us.

Since Symfony 3.0, if you use a custom form type, you must specify the complete namespace when specifying type

We have also defined additional form views in @Form\Form annotation so we can add another argument to createFormBuilder

$form = $this->get('form_generator')->createFormBuilder($person, 'personal')
        ->getForm();

And we will get Form with properties specified in annotation. We can also add/override fields and their properties like this:

/**
 * @Form\Form(
 *  work = { "salary" = { "attr" = { "class" = "foo" } } }
 * )
 */
class Person

But if you need something more sophisticated than Annotations we have prepared few possibilities that can be either added manually or by tagging your services. For each of them FormGenerator allows you to pass any additional informations you want in optional $context argument. Both ways allows you to specify priority which defines order of execution (default is 0, if two or more services have same priority then first added is executed first).

These are used to provide fields list and/or basic configuration for Forms and are doing exactly same thing as @Form\Form annotation.

Tag for service: form_generator.view_provider

These can modify any form configuration provided by class itself or FormViewProviders. Feel free to remove or add more stuff to your Form or tweak existing configuration

Tag for service: form_generator.configuration_modifier

class InactivePersonModifier implements FormConfigurationModifierInterface
{
    public function modify($model, $configuration, $context) 
    {
        unset($configuration['salary']);
        return $configuration;
    }

    public function supports($model, $configuration, $context) 
    {
        return $model instanceof Person && $model->active === false;
    }
}

These are responsible for creating actual field in Form and can be used for instance to attach Transformers to your fields.

Tag for service: form_generator.field_resolver

class PersonSalaryResolver implements FormFieldResolverInterface
{
    public function getFormField(FormBuilderInterface $fb, $field, $type, $options, $context) 
    {
        $transformer = new /* ... */;
        return $fb->create($field, $type, $options)
                ->addViewTransformer($transformer);
    }

    public function supports($model, $field, $type, $options, $context) 
    {
        return $model instanceof Person && $field === 'salary';
    }
}