Relasi Antar Entity di API Platform

Dalam API Platform, relasi antar entitas (OneToMany, ManyToOne, ManyToMany, OneToOne) secara otomatis dikonversi menjadi relasi API, termasuk pengelolaan data dan serialisasi JSON.

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Contoh Kasus: Book & Author

Misalnya kita memiliki 2 entitas: Author dan Book. Setiap Book ditulis oleh satu Author (ManyToOne), dan satu Author bisa menulis banyak Book (OneToMany).

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1. Entity Author

<?php

namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity]
#[ApiResource]
class Author
{
    #[ORM\Id, ORM\GeneratedValue, ORM\Column]
    private ?int $id = null;

    #[ORM\Column]
    private string $name;

    #[ORM\OneToMany(mappedBy: 'author', targetEntity: Book::class)]
    private Collection $books;

    public function __construct()
    {
        $this->books = new ArrayCollection();
    }

    // Getter dan Setter
}

2. Entity Book

<?php

namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity]
#[ApiResource]
class Book
{
    #[ORM\Id, ORM\GeneratedValue, ORM\Column]
    private ?int $id = null;

    #[ORM\Column]
    private string $title;

    #[ORM\ManyToOne(targetEntity: Author::class, inversedBy: 'books')]
    #[ORM\JoinColumn(nullable: false)]
    private ?Author $author = null;

    // Getter dan Setter
}

Struktur JSON (Default) Endpoint GET /api/books/1 akan mengembalikan:

{
  "@id": "/api/books/1",
  "@type": "Book",
  "id": 1,
  "title": "Judul Buku",
  "author": "/api/authors/2"
}

Endpoint GET /api/authors/2 akan mengembalikan:

{
  "@id": "/api/authors/2",
  "@type": "Author",
  "id": 2,
  "name": "Penulis",
  "books": ["/api/books/1", "/api/books/3"]
}

Serialization Groups (Menampilkan Data Relasi) Secara default, relasi hanya menampilkan IRI (URL). Jika ingin menampilkan detail objek, Anda bisa menggunakan Serialization Groups.

Tambahkan Group

use Symfony\Component\Serializer\Annotation\Groups;

#[ApiResource(normalizationContext: ['groups' => ['book:read']])]
class Book
{
    #[Groups(['book:read'])]
    #[ORM\Column]
    private string $title;

    #[Groups(['book:read'])]
    #[ORM\ManyToOne(targetEntity: Author::class)]
    private ?Author $author = null;
}

Dan di Author:

#[Groups(['book:read'])]
#[ORM\Column]
private string $name;

Dengan konfigurasi ini, endpoint GET /api/books/1 akan mengembalikan:

{
  "id": 1,
  "title": "Judul Buku",
  "author": {
    "id": 2,
    "name": "Penulis"
  }
}

Cascade Persist (Opsional) Jika ingin saat menyimpan Book sekaligus menyimpan Author:

#[ORM\ManyToOne(targetEntity: Author::class, cascade: ['persist'])]
private ?Author $author = null;

Filtering Berdasarkan Relasi Aktifkan filter berdasarkan relasi:

use ApiPlatform\Doctrine\Orm\Filter\SearchFilter;
use ApiPlatform\Metadata\ApiFilter;

#[ApiFilter(SearchFilter::class, properties: ['author' => 'exact'])]
class Book { ... }

Gunakan query:

GET /api/books?author=/api/authors/2