In a Symfony5 application, how can we utilize the form-component to correctly set up a self-referencing, many-to-many relationship?
Note: this is purely about the form-side of things, Doctrine is already happy.
Let’s say we have a “Person”-entity, and these Person-instances host guests, who are also Persons:
#[Entity(repositoryClass: PersonRepository::class)]
class Person
{
#[Id]
#[GeneratedValue]
#[Column(type: Types::INTEGER)]
private int $id;
#[Column(type: Types::STRING, length: 255)]
private string $firstName;
#[Column(type: Types::STRING, length: 255)]
private string $lastName;
/** @var Collection<Person> */
#[ManyToMany(targetEntity: self::class, inversedBy: 'guestsHosted')]
private Collection $hosts;
/** @var Collection<Person> */
#[ManyToMany(targetEntity: self::class, mappedBy: 'hosts')]
private Collection $guestsHosted;
public function __construct()
{
$this->fellowshipHosts = new ArrayCollection();
$this->fellowsHosted = new ArrayCollection();
}
// getters/setters ommitted for brevity
public function addHost(self $host): self
{
}
public function removeHost(self $host): self
{
}
public function addGuestsHosted(self $guestHosted): self
{
}
public function removeGuestsHosted(self $guestsHosted): self
{
}
What I would like to achieve is a form with a collection of addable/removable rows, where the user then is able to add a row, select an existing other person as their host, add another row, select another person, and so on. A simple mockup:
How do I achieve this using Symfony’s form-component? What I have in there now does not work due to recursion on the same form-type:
class PersonType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options): void
{
$builder
->add('firstName', null, [])
->add('lastName', null, [])
->add('hosts', CollectionType::class, [
'entry_type' => self::class,
'entry_options' => ['label' => false],
'required' => false,
'allow_delete' => true,
'allow_add' => true,
'by_reference' => false,
]);
}
public function configureOptions(OptionsResolver $resolver): void
{
$resolver->setDefaults([
'data_class' => Person::class,
]);
}
}
NB: I’ve built similar UIs like this in the past and know about the little dance involving form.vars.prototype and hooking up the JS to that. Where I’m lost is how to map this association on the form-level, so that I get a dropdown of all Persons, and map that into the $hosts property of the entity.
Any help is appreciated!
