Symfony REST API 请求数据验证：保持控制器精简与专业

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

use Symfony\Component\Validator\Constraints as Assert;

class Author
{
    /**
     * @Assert\NotBlank(message="作者名称不能为空。")
     * @Assert\Length(
     *     min = 3,
     *     max = 255,
     *     minMessage = "作者名称至少需要 {{ limit }} 个字符。",
     *     maxMessage = "作者名称不能超过 {{ limit }} 个字符。"
     * )
     */
    private ?string $name = null;

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

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

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

use App\Entity\Author;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\Routing\Annotation\Route;
use Symfony\Component\Validator\Validator\ValidatorInterface; // 引入 ValidatorInterface

class AuthorController extends AbstractController
{
    /**
     * @Route("/api/authors", methods={"POST"})
     */
    public function createAuthor(Request $request, ValidatorInterface $validator): JsonResponse
    {
        // 1. 解析请求体中的 JSON 数据
        $data = json_decode($request->getContent(), true);

        // 2. 创建实体对象并填充数据
        $author = new Author();
        // 使用 null 合并运算符 ?? 安全地获取数据，避免在键不存在时报错
        $author->setName($data['name'] ?? null); 
        // ... 假设还有其他属性需要填充

        // 3. 使用验证器验证实体对象
        $errors = $validator->validate($author);

        // 4. 处理验证结果
        if (count($errors) > 0) {
            $errorMessages = [];
            foreach ($errors as $error) {
                // 将错误信息组织成键值对，键为属性路径，值为错误消息
                $errorMessages[$error->getPropertyPath()] = $error->getMessage();
            }
            return $this->json([
                'status' => 'error',
                'message' => '请求数据验证失败',
                'errors' => $errorMessages
            ], JsonResponse::HTTP_BAD_REQUEST); // 返回 400 Bad Request 状态码
        }

        // 5. 数据验证通过，执行业务逻辑（例如持久化到数据库）
        // 假设此处将 $author 持久化到数据库
        // $entityManager = $this->getDoctrine()->getManager();
        // $entityManager->persist($author);
        // $entityManager->flush();

        // 6. 返回成功响应
        return $this->json([
            'status' => 'success',
            'message' => '作者创建成功',
            'author' => ['name' => $author->getName()] // 返回创建成功的作者信息
        ], JsonResponse::HTTP_CREATED); // 返回 201 Created 状态码
    }
}

// src/Dto/CreateAuthorRequest.php
namespace App\Dto;

use Symfony\Component\Validator\Constraints as Assert;

class CreateAuthorRequest
{
    /**
     * @Assert\NotBlank(message="作者名称不能为空。")
     * @Assert\Length(min=3, max=255, minMessage="...", maxMessage="...")
     */
    public ?string $name = null;

    // ... 其他请求字段
}

// ...
use App\Dto\CreateAuthorRequest;

public function createAuthor(Request $request, ValidatorInterface $validator): JsonResponse
{
    $data = json_decode($request->getContent(), true);

    $createAuthorRequest = new CreateAuthorRequest();
    $createAuthorRequest->name = $data['name'] ?? null;
    // ... 填充其他 DTO 属性

    $errors = $validator->validate($createAuthorRequest);
    // ... 处理错误

    // 如果验证通过，再将 DTO 数据映射到 Author 实体
    $author = new Author();
    $author->setName($createAuthorRequest->name);
    // ... 持久化
}

// ...
use Symfony\Component\Serializer\SerializerInterface;

public function createAuthor(
    Request $request, 
    ValidatorInterface $validator, 
    SerializerInterface $serializer
): JsonResponse
{
    // 将 JSON 请求体反序列化为 DTO 对象
    $createAuthorRequest = $serializer->deserialize(
        $request->getContent(), 
        CreateAuthorRequest::class, 
        'json'
    );

    $errors = $validator->validate($createAuthorRequest);
    // ... 处理错误
}