Symfony Serializer：精细控制关联实体属性的序列化

// User 实体
class User {
    private $id;
    private $name;
    private $posts; // ArrayCollection of Post objects
}

// Post 实体
class Post {
    private $id;
    private $content;
}

{
    "id": 79,
    "name": "User 1",
    "posts": [
      {
        "id": 73
      },
      {
        "id": 74
      }
    ]
}

# config/serializer/Post.yaml
Post:
    attributes:
        content:
            ignore: true

// src/Entity/User.php
namespace App\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\Collection;

/**
 * @ORM\Entity
 * @ORM\Table()
 */
class User
{
    /**
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     * @ORM\Column(type="integer")
     */
    private ?int $id = null;

    /**
     * @ORM\Column(type="string", nullable=false)
     */
    private ?string $name = null;

    /**
     * @ORM\ManyToMany(targetEntity=Post::class)
     */
    private Collection $posts;

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

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getName(): ?string
    {
        return $this->name;
    }

    public function setName(string $name): self
    {
        $this->name = $name;
        return $this;
    }

    /**
     * @return Collection<int, Post>
     */
    public function getPosts(): Collection
    {
        return $this->posts;
    }

    public function addPost(Post $post): self
    {
        if (!$this->posts->contains($post)) {
            $this->posts[] = $post;
        }
        return $this;
    }

    public function removePost(Post $post): self
    {
        $this->posts->removeElement($post);
        return $this;
    }
}

// src/Entity/Post.php
namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 * @ORM\Table()
 */
class Post
{
    /**
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     * @ORM\Column(type="integer")
     */
    private ?int $id = null;

    /**
     * @ORM\Column(type="string", nullable=false)
     */
    private ?string $content = null;

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getContent(): ?string
    {
        return $this->content;
    }

    public function setContent(string $content): self
    {
        $this->content = $content;
        return $this;
    }
}

// src/Controller/UserController.php
namespace App\Controller;

use App\Entity\User;
use App\Entity\Post;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\Routing\Annotation\Route;
use Symfony\Component\Serializer\SerializerInterface;

class UserController extends AbstractController
{
    /**
     * @Route("/users/{id}", name="get_user", methods={"GET"})
     */
    public function getUserDetails(
        int $id,
        EntityManagerInterface $entityManager,
        SerializerInterface $serializer
    ): JsonResponse {
        $user = $entityManager->getRepository(User::class)->find($id);

        if (!$user) {
            return $this->json(['message' => 'User not found'], 404);
        }

        // 假设我们已经通过某种方式为该User关联了一些Post实体
        // 例如，在数据库中预设数据，或在此处创建并关联（仅为演示）
        // $post1 = (new Post())->setContent("First post content");
        // $post2 = (new Post())->setContent("Second post content");
        // $entityManager->persist($post1);
        // $entityManager->persist($post2);
        // $user->addPost($post1);
        // $user->addPost($post2);
        // $entityManager->flush();

        // 使用Serializer将User对象序列化为JSON
        // 默认情况下，会根据配置加载所有属性
        $jsonContent = $serializer->serialize($user, 'json');

        return new JsonResponse($jsonContent, 200, [], true);
    }
}