Question

I’ve spent a while looking through the symfony2 docs trying to find a suitable method of doing what I need to do, maybe I’m looking in the wrong place.

Basically, I have an entity called Album, which can have many Subalbums associated with it. As the user is creating an Album entity using a form, I want them to be able to create quick Subalbum entities in-line, which will get saved later on. I also want to display the field in a custom format, so I don’t want to use a select tag with a multiple attribute, instead I’m manually rendering it in Twig (I haven’t had a problem with this).

The relationship on Subalbum is defined as follows:

/**
 * @ORM\ManyToOne(targetEntity="Vhoto\AlbumBundle\Entity\Album")
 * @ORM\JoinColumn(name="parent_id", referencedColumnName="id")
 */
protected $parent;

Here’s what I’ve tried so far…

1. Use an entity type field in the form builder, and then manually output the field. The issue I have with using the entity field is that if the user creates a Subalbum inline, symfony2 doesn’t like it when I submit the form because it has no ID.

2. Use a hidden field type and try submitting multiple entries under the same field name (album[subalbums][]). Symfony2 also doesn’t like this when I submit the form

I guess I’m going to have to have a prePersist method in my Album entity to create any Subalbum entities that the user has created inline?

Hopefully there is a far more graceful solution that I’m just completely overlooking.

Let me know if anything is unclear.

Answer 1

There is indeed a better way to do it.

Entity creation

Create the two Entity POPOs and assign a many-to-one relationship to one of the fields of the child entity (you have done this correctly). You might also want to define a one-to-many relationship in the parent

/**
 * @var ArrayCollection
 *
 * @ORM\OneToMany(targetEntity="Child", mappedBy="parent", cascade={"persist", "remove" }, orphanRemoval=true)
 */
protected $children;

I am not sure if it’s necessary, but you should explicitly set the relationship in your setters just to be sure. For example in your owning entity:

public function addChild(ChildInterface $child)
{
    if(!$this->hasChild($child))
    {
        $this->children->add($child);
        $child->setParent($this);
    }
}

Doctrine doesn’t probably use these methods to bind the post data, but having this for yourself might take care of several persisting issues.

Form type creation

Create a form type for both entities

/**
 * This would be the form type for your sub-albums.
 */
class ChildType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        //$builder->add(...);
        //...
    }

    public function getDefaultOptions(array $options) {
        return array(
            'data_class' => 'Acme\Bundle\DemoBundle\Entity\Child'
        );
    }

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

/**
 * This would be the form type for your albums.
 */
class ParentType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        // This part here describes the relationship between the two
        // form types.
        $builder->add('children', 'collection', array(
            'type' => new ChildType(),
            'allow_add' => true,
            'allow_delete' => true,
            'prototype' => true
        ));
    }

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

With the options allow_add and allow_delete you’ve effectively told Symfony, that a user can add or remove entities from the collection. The prototype option lets you have a prototype of the so-called sub-form on your page.

Controller

You should enforce the relationship here as well just to be safe. I have tucked this away in a separate entity manager layer (I have separate managers for more complicated entities), but you can most certainly do this in your controllers as well.

foreach($parent->getChildren() as $child)
{
    if($child->getParent() === NULL)
    {
        $child->setParent($parent);
    }
}

View

Prepare your form’s template. The prototype should be rendered by calling form_rest(form) somewhere in your template. In case it doesn’t or you’d like to customize the prototype, here’s a sample of how to do it.

<script id="ParentType_children_prototype" type="text/html">
    <li class="custom_prototype_sample">
        <div class="content grid_11 alpha">
            {{ form_widget(form.children.get('prototype').field1) }}
            {{ form_widget(form.children.get('prototype').field2) }}
            {{ form_rest(form.children.get('prototype') ) }}
        </div>
    </li>
</script>

You’d have to make the form dynamic by using JavaScript. If you use jQuery, you can access the prototype by calling $('ParentType_children_prototype').html(). It is important to replace all occurrences of $$name$$ in the prototype with the proper index number when adding a new child to the parent.

I hope this helps.

EDIT I just noticed there’s an article in the Symfony2 Form Type reference about CollectionType. It has a nice alternative on how to implement the front-end for this.