How to process nested json with FOSRestBundle and symfony forms

This is a pretty good question. One solution that comes to mind is making an unmapped form and binding data manually using a form event, for example:

public function buildForm(FormBuilderInterface $builder, array $options){    // Make a "nested" address form to resemble JSON structure    $addressBuilder = $builder->create('address', 'form')        ->add('place')        ->add('street');    $builder->add('username');    $builder->add('email', 'email');    $builder->add('password', 'password');    // add that subform to main form, and make it unmapped    // this will tell symfony not to bind any data to user object    $builder->add($addressBuilder, null, ['mapped' => false]);    // Once form is submitted, get data from address form    // and set it on user object manually    $builder->addEventListener(FormEvents::POST_SUBMIT, function (FormEvent $event) {        $user = $event->getData();        $addressData = $event->getForm()->get('address')->getData();        $user->setStreet($addressData['street']);        $user->setPlace($addressData['place']);    })}