我看到了这个用例的两个不同的实现，但是它们都没有使用扩展系统或嵌入式关系系统。
我已经实现了这个，它让你实现你自己的ProcessorInterface，并传递给它一个DTO。
首先，让我们在ApiKey资源中声明一个自定义的PATCH操作：

#[ApiResource(
    operations: [
        new GetCollection(),
        new Get(),
        new Post(),
        new Patch(),
        new Delete(),
        new Patch(
            uriTemplate: "/api_keys/{id}/log",
            normalizationContext: [
                "groups" => ["log:get:item-collection"],
            ],
            denormalizationContext: [
                "groups" => ["log:write"],
            ],
            input: Log::class,
            output: Log::class,
            processor: ApiKeyLogProcessor::class
        )
    ],
)]
class ApiKey {
    //...
    #[ORM\OneToMany(mappedBy: 'apiKey', targetEntity: Log::class, 
        cascade: ["persist", "remove"], orphanRemoval: true)
    ]
    private Collection $logs;
    
    //...

然后确保您的Log资源在您需要反序列化/序列化的属性上具有序列化组"log:write", "log:get:item-collection"：

// src/Entity/Log.php

class Log {
    // ...
    #[ORM\Column(length: 255)]
    #[Groups(["log:get:item-collection", "log:post"])]
    private ?string $payload = null;
}

然后实现你的ProcessorInterface：

<?php

namespace App\Processor;

use ApiPlatform\Doctrine\Common\State\PersistProcessor;
use ApiPlatform\Metadata\Operation;
use ApiPlatform\State\ProcessorInterface;
use App\Entity\ApiKey;
use App\Repository\ApiKeyRepository;

class ApiKeyLogProcessor implements ProcessorInterface
{
    private ProcessorInterface $decorated;
    private ApiKeyRepository $doctrine;

    public function __construct(
        PersistProcessor $decorated,
        ApiKeyRepository $doctrine,
    )
    {
        $this->decorated = $decorated;
        $this->doctrine = $doctrine;
    }

    public function process(mixed $data, Operation $operation, array $uriVariables = [], array $context = [])
    {
        $apiKey = $this->getApiKeyFromRequestContext($context);
        $apiKey = $this->removeOldestLogFromApiKeyIfNeeded($apiKey);
        $apiKey->addLog($data);
        return $this->decorated->process($data, $operation, $uriVariables, $context);
    }

    private function getApiKeyFromRequestContext(array $context): ?ApiKey
    {
        /** @var ApiKey $clonedApiKey */
        $clonedApiKey = $context["previous_data"];
        $apiKeyId = $clonedApiKey->getId();
        return $this->doctrine->find($apiKeyId);
    }

    private function removeOldestLogFromApiKeyIfNeeded(ApiKey $apiKey): ApiKey
    {
        $apiKeyLogsSet = $apiKey->getLogs();
        if ($apiKeyLogsSet->count() === 5) {
            $oldestLog = $apiKeyLogsSet[0]; // TODO: implements better logic to retrieve the oldest log.
            $apiKey->removeLog($oldestLog); // "orphanRemoval: true" will remove the oldest log from database
        }
        return $apiKey;
    }
}

这个自定义路由的好处是，当ApiKey不存在时，它总是抛出错误404，并且总是在ApiKey不存在时返回成功200。成功。
另一种实现方式是在Log类上声明一个自定义的POST操作，并绑定到ProcessorInterface来完成与前一个操作相同的工作。请求的正文将是：

{ "payload": "my data...", "apiKey": "/api/api_keys/1" }

此操作的好处是它检索ApiKey资源而无需从ApiKeyRepository进行额外调用，但当ApiKey资源不存在时将抛出错误400，并且在成功时总是返回成功201。