PHP中的CQRS模式：如何分离读写操作提升性能

// 命令
class CreateUserCommand {
    public $name;
    public $email;

    public function __construct(string $name, string $email) {
        $this->name = $name;
        $this->email = $email;
    }
}

// 命令处理器
class CreateUserCommandHandler {
    private $userRepository;

    public function __construct(UserRepository $userRepository) {
        $this->userRepository = $userRepository;
    }

    public function handle(CreateUserCommand $command) {
        $user = new User($command->name, $command->email);
        $this->userRepository->save($user);
    }
}

// 查询
class GetUserByIdQuery {
    public $id;

    public function __construct(int $id) {
        $this->id = $id;
    }
}

// 查询处理器
class GetUserByIdQueryHandler {
    private $userRepository;

    public function __construct(UserRepository $userRepository) {
        $this->userRepository = $userRepository;
    }

    public function handle(GetUserByIdQuery $query) {
        return $this->userRepository->findById($query->id);
    }
}

// 消息总线 (简化版)
class MessageBus {
    private $handlers = [];

    public function registerHandler(string $messageType, callable $handler) {
        $this->handlers[$messageType] = $handler;
    }

    public function dispatch(object $message) {
        $messageType = get_class($message);
        if (isset($this->handlers[$messageType])) {
            $handler = $this->handlers[$messageType];
            return $handler($message);
        } else {
            throw new Exception("No handler registered for message type: " . $messageType);
        }
    }
}

// 使用示例
$messageBus = new MessageBus();
$userRepository = new UserRepository(); // 假设UserRepository已经实现

$createUserCommandHandler = new CreateUserCommandHandler($userRepository);
$getUserByIdQueryHandler = new GetUserByIdQueryHandler($userRepository);

$messageBus->registerHandler(CreateUserCommand::class, function(CreateUserCommand $command) use ($createUserCommandHandler) {
    $createUserCommandHandler->handle($command);
});
$messageBus->registerHandler(GetUserByIdQuery::class, function(GetUserByIdQuery $query) use ($getUserByIdQueryHandler) {
    return $getUserByIdQueryHandler->handle($query);
});

$createUserCommand = new CreateUserCommand("John Doe", "john.doe@example.com");
$messageBus->dispatch($createUserCommand);

$getUserByIdQuery = new GetUserByIdQuery(1);
$user = $messageBus->dispatch($getUserByIdQuery);

echo "User name: " . $user->name . "\n";