JMSSerializerBundle serialization groups in entities with relations

Question

I have a problem with serializing entity with many relations using groups. I have a problem with serializing related entities this way.

Let's say I have two entities: Product and related Element.

/**
 *
 * @Serializer\ExclusionPolicy("none")
 */
class Product {

    /**
     * Primary key
     * @var integer $id
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     * 
     * @Serializer\Groups({"list","details"})
     * @Serializer\Type("integer")
     */
    protected $id;

    /**
     * @Serializer\Groups({"list","details"})
     * @Serializer\Type("string")
     */
    protected $name;

    /**
     * @ORM\Column(name="description", type="string", length=4096, nullable=true)
     * 
     * @Serializer\Groups({"details"})
     * @Serializer\Type("string")
     */
    protected $description;

    /**
     * @var ArrayCollection
     * 
     * @ORM\OneToMany(targetEntity="Madden\ProjectBundle\Entity\ProjectResource", mappedBy="project")
     * @Serializer\Groups({"details"})
     * @Serializer\Type("ArrayCollection<Element>")
     */
    protected $details1;

    /**
     * Relation to project tasks
     * @ORM\OneToMany(targetEntity="Madden\ProjectBundle\Entity\ProjectTask", mappedBy="project")
     * @Serializer\Exclude()
     * @Serializer\Type("ArrayCollection<Element>")
     */
    protected $details2;

    ...

}

Element entity has a similar structure:

/**
 *
 * @Serializer\ExclusionPolicy("none")
 */
class Element {

    /**
     * Primary key
     * @var integer $id
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     * 
     * @Serializer\Groups({"list","details"})
     * @Serializer\Type("integer")
     */
    protected $id;

    /**
     * @Serializer\Groups({"list","details"})
     * @Serializer\Type("string")
     */
    protected $name;

    /**
     * @ORM\Column(name="description", type="string", length=4096, nullable=true)
     * 
     * @Serializer\Groups({"details"})
     * @Serializer\Type("string")
     */
    protected $description;

    ...
}

My problem is that when I'm serializing Product with 'details' group entity I want to serialize only id's of Elements but as you see entity has defined same groups as Product (in case that I would need details of element object) because I want have unified groups on all my entities and prevent making hundreds of groups like 'product_details','element_details', and so on.

Is there a way to eventualy change serialization group when I visit relation or something like that? Handler maybe or something like that?

Regards and thanks for any help

Answer 1

Unfortunately, you can't really (but keep reading ;-)), well at least not without changes to the serializer library. The culprit is that the list of groups is fixed within a GroupExclusionStrategy (which is referenced by the Context) the minute you start the serialization process. There is actually an assertion within the code that prevents modification of the exclusion strategy once the (de-)serialization is running.

But as it happens, I had the exact same problem in a project of mine as well, and I hacked the necessary changes into the serializer code. I have cleaned the code up a bit and uploaded it to Github (https://github.com/andreasferber/serializer/tree/recursion-groups).

It adds new property metadata with which you can add, remove or override the groups when descending into subobjects. With annotations it looks like this:

/**
 * @Serializer\RecursionGroups(set={"foo", "bar"}, add={"baz"}, remove={"Default"})
 */
private $myProperty;

You should be able to use XML or Yaml metadata as well, however this is untested since I don't use them and I haven't added test cases yet. Have a look at the reference documentation. Since I haven't done any optimizations yet either, if your entities are really large and deeply nested, it might have a noticable performance impact.

Please let me know if you find this useful, or if you have any suggestions, because if this isn't only needed by me, I will add some tests and try to submit it upstream.