PHP MVC架构中数据服务层的应用与模型层协同解析

// 传统MVC (简化)
class UserController {
    private $userModel;

    public function __construct(UserModel $userModel) {
        $this->userModel = $userModel;
    }

    public function register(Request $request) {
        // 1. 获取请求数据
        $userData = $request->post();

        // 2. 执行复杂的业务逻辑：
        //    - 数据验证 (例如：邮箱格式、密码强度、用户名唯一性)
        //    - 数据清理 (例如：去除空格、转义特殊字符)
        //    - 密码哈希
        //    - 可能需要发送欢迎邮件或通知其他系统

        if (!$this->validateUserData($userData)) {
            // 返回错误信息
            return $this->view->render('register_form', ['errors' => 'Invalid data']);
        }

        $userData['password'] = password_hash($userData['password'], PASSWORD_BCRYPT);

        // 3. 调用模型进行数据持久化
        $this->userModel->create($userData); 

        // 4. 返回成功响应
        return $this->view->render('registration_success');
    }

    private function validateUserData(array $data): bool {
        // 复杂的验证逻辑...
        return true;
    }
}

// MVCS (简化)

// 1. 控制器 (UserController) - 负责接收请求并委托给服务层
class UserController {
    private $userService;

    public function __construct(UserService $userService) {
        $this->userService = $userService;
    }

    public function register(Request $request) {
        $userData = $request->post();
        try {
            $this->userService->registerUser($userData); // 委托给服务层处理业务逻辑
            return $this->view->render('registration_success');
        } catch (ValidationException $e) {
            return $this->view->render('register_form', ['errors' => $e->getMessage()]);
        } catch (Exception $e) {
            // 处理其他异常
            return $this->view->render('error_page', ['message' => 'An error occurred']);
        }
    }
}

// 2. 服务层 (UserService) - 负责封装业务逻辑
class UserService {
    private $userModel;
    private $emailService; // 假设有一个邮件服务

    public function __construct(UserModel $userModel, EmailService $emailService) {
        $this->userModel = $userModel;
        $this->emailService = $emailService;
    }

    public function registerUser(array $userData): void {
        // 2.1 执行复杂的业务逻辑：
        //    - 数据验证
        if (!$this->isValid($userData)) {
            throw new ValidationException("Invalid user data provided.");
        }
        //    - 数据清理
        $sanitizedData = $this->sanitize($userData);
        //    - 密码哈希
        $sanitizedData['password'] = password_hash($sanitizedData['password'], PASSWORD_BCRYPT);

        // 2.2 调用模型层进行数据持久化
        $this->userModel->create($sanitizedData); 

        // 2.3 可能需要发送欢迎邮件（调用其他服务）
        $this->emailService->sendWelcomeEmail($sanitizedData['email']);
    }

    private function isValid(array $data): bool {
        // 详细的数据验证逻辑
        // 例如：检查邮箱格式、密码长度、用户名是否已存在等
        return true; // 简化
    }

    private function sanitize(array $data): array {
        // 详细的数据清理逻辑
        return $data; // 简化
    }
}

// 3. 模型层 (UserModel) - 负责数据持久化操作
class UserModel {
    public function create(array $data): void {
        // 执行数据库插入操作
        // INSERT INTO users (username, email, password) VALUES (:username, :email, :password)
        echo "User '{$data['username']}' created in database.\n";
    }

    public function findById(int $id): ?array {
        // 执行数据库查询操作
        return ['id' => $id, 'username' => 'testuser']; // 简化
    }
}

// 辅助类 (用于示例)
class Request {
    public function post(): array {
        return ['username' => 'john_doe', 'email' => 'john@example.com', 'password' => 'secure_password'];
    }
}
class View {
    public function render(string $template, array $data = []): string {
        return "Rendering template: {$template} with data: " . json_encode($data);
    }
}
class EmailService {
    public function sendWelcomeEmail(string $email): void {
        echo "Sending welcome email to {$email}.\n";
    }
}
class ValidationException extends Exception {}

// 示例运行
$userModel = new UserModel();
$emailService = new EmailService();
$userService = new UserService($userModel, $emailService);
$userController = new UserController($userService);

$request = new Request();
echo $userController->register($request);