Symfony Messenger消息处理器“参数过少”错误解析与最佳实践

// 期望的__invoke方法签名
public function __invoke(UserRegistrationEmail $userRegistrationEmail)
{
    // ... 处理逻辑 ...
}

// App\Message\UserRegistrationEmail.php
namespace App\Message;

class UserRegistrationEmail
{
    private $userEmail;

    public function __construct(string $userEmail)
    {
        $this->userEmail = $userEmail;
    }

    public function getUserEmail(): string
    {
        return $this->userEmail;
    }
}

// App\Message\MessageHandler\UserRegistrationEmailHandler.php (错误示例)
namespace App\Message\MessageHandler;

use App\Message\UserRegistrationEmail;
use Symfony\Component\Messenger\Handler\MessageHandlerInterface;
// use Symfony\Component\Mailer\MailerInterface; // 假设这里需要邮件服务但未正确注入

class UserRegistrationEmailHandler implements MessageHandlerInterface
{
    // 假设在__invoke中需要MailerInterface，但未在构造函数中注入
    // 或者Symfony尝试自动注入到__invoke中
    public function __invoke(UserRegistrationEmail $userRegistrationEmail)
    {
        // 如果这里直接尝试使用MailerInterface，或者Symfony误以为__invoke需要它
        // MailerInterface $mailer; // 错误示例：不应在方法参数中声明服务
        // $mailer->send(...);
        sleep(15);
        echo('sending email right now'); // 原始代码中的测试输出
    }
}

// App\Controller\RegistrationController.php (相关部分)
namespace App\Controller;

use App\Message\UserRegistrationEmail;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\Messenger\MessageBusInterface;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;

class RegistrationController extends AbstractController
{
    /**
     * @Route(path="/register", name="user_registration")
     */
    public function register(MessageBusInterface $bus): Response
    {
        // ... 用户注册逻辑 ...
        $userEmail = "test@example.com"; // 假设获取到用户邮箱
        $bus->dispatch(new UserRegistrationEmail($userEmail));
        return new Response("User has been registered.");
    }
}

// App\Message\UserRegistrationEmail.php (保持不变)
namespace App\Message;

class UserRegistrationEmail
{
    private $userEmail;

    public function __construct(string $userEmail)
    {
        $this->userEmail = $userEmail;
    }

    public function getUserEmail(): string
    {
        return $this->userEmail;
    }
}

// App\Message\MessageHandler\UserRegistrationEmailHandler.php (修正后)
namespace App\Message\MessageHandler;

use App\Message\UserRegistrationEmail;
use Symfony\Component\Messenger\Handler\MessageHandlerInterface;
use Symfony\Component\Mailer\MailerInterface; // 假设需要MailerInterface

class UserRegistrationEmailHandler implements MessageHandlerInterface
{
    private MailerInterface $mailer;

    /**
     * 通过构造函数注入所有依赖服务
     * @param MailerInterface $mailer Symfony Mailer服务
     */
    public function __construct(MailerInterface $mailer)
    {
        $this->mailer = $mailer;
    }

    /**
     * 核心处理方法，只接收消息对象
     * @param UserRegistrationEmail $userRegistrationEmail 注册邮件消息
     */
    public function __invoke(UserRegistrationEmail $userRegistrationEmail)
    {
        // 实际的邮件发送逻辑
        $email = (new \Symfony\Component\Mime\Email())
            ->from('no-reply@yourdomain.com')
            ->to($userRegistrationEmail->getUserEmail())
            ->subject('欢迎注册！')
            ->text('感谢您注册我们的服务。');

        $this->mailer->send($email);

        // 原文中的测试输出，实际应用中应移除
        // sleep(15);
        // echo('sending email right now');
    }
}

// App\Controller\RegistrationController.php (相关部分，保持不变，因为调度消息本身是正确的)
namespace App\Controller;

use App\Message\UserRegistrationEmail;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\Messenger\MessageBusInterface;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;

class RegistrationController extends AbstractController
{
    /**
     * @Route(path="/register", name="user_registration")
     */
    public function register(MessageBusInterface $bus): Response
    {
        // ... 用户注册逻辑 ...
        $userEmail = "test@example.com"; // 假设获取到用户邮箱
        $bus->dispatch(new UserRegistrationEmail($userEmail));
        return new Response("User has been registered.");
    }
}