php - 域对象和数据映射器应如何在使用 MVC 的身份验证系统的服务类中交互

Question

我正在使用后端的 Slim 3 PHP 和前端的 Angular 创建一个身份验证/登录系统，我试图了解 MVC 中模型层的“域对象”和“数据映射器”部分结构体。我已经阅读了很多关于诸如此类的各种问题的有用答案，从中我了解到模型应该由“域对象”、“数据映射器”和“服务”组成。

但是，我不确定在用户能够注册和登录网站的情况下应该如何构建它。

据我了解，我可以拥有一个具有用户名和密码等属性的用户“域对象”。它还可以具有诸如注册或登录之类的方法来表示业务逻辑。

然后我是否会有一个服务类来创建用户对象的新实例，在其中我会将表单数据传递给对象？那么现在我的用户对象实例会设置用户名和密码值吗？

现在我不确定如何将这些对象属性数据插入数据库。我会使用用户对象注册方法通过将用户名和密码作为参数传递来将数据插入数据库吗？

显然，服务应该是域对象和数据映射器交互的地方，但我不确定如果注册方法在用户域对象中，这将如何工作。

我希望有人可以向我展示一些代码示例，说明服务类中应该包含什么以及域对象和数据映射器之间的交互如何在用户注册和登录的上下文中工作。

注意我不想使用任何框架，我想尝试手动实现一个适当的 MVC 结构，因为我觉得我会学到更多。

到目前为止，我有这个用于注册用户的结构：

我有一个带有方法 registerUser 的 AuthenticationController 来允许用户创建一个帐户：

 class AuthenticationController
{
    protected $authenticationService;

    public function __construct(AuthenticationService $authenticationService)
    {
        $this->authenticationService = $authenticationService;
    }

    public function registerUser($request, $response)
    {
        $this->authenticationService->registerUser($request, $response);
    }
}

然后我有 AuthenticationService 类和 registerUser 方法：

class AuthenticationService
{
    protected $database;

    public function __construct(PDO $database)
    {
        $this->database = $database;
    }

    public function registerUser ($request, $response)
    {
        $strings = $request→getParsedBody(); // will be sanitised / validated later
        $username = $strings['username'];
        $password = $strings['password'];
        $email = "temp random email";

        $stmt = $this->database->prepare("INSERT INTO users (email, username, password) values (:email, :username, :password)");
        $stmt->bindParam(':email', $email);
        $stmt->bindParam(':username', $username);
        $stmt->bindParam(':password', $password);
        $stmt->execute();
    }
}

稍后我打算将 SQL 放入 AuthenticationRepository 并将 PDO 逻辑放入它自己的类中。此 AuthenticationService 方法还将确保使用 PHP 的内置函数清理用户详细信息。

我不确定提议的 PDO 数据库类或 AuthenticationRepository 是否算作数据映射器。

score 4 · Accepted Answer

注册将由服务执行。
该服务可以“直接”使用数据映射器，以便将实体“传输”到/从数据库中。不过，另外，可以实现存储库。服务将看到它并与它进行通信，就像与一个或多个实体的集合一样。
由于服务是模型层（域模型）的一部分，它应该对任何请求或响应对象一无所知。控制器应该从请求中提取所需的值并将它们作为参数传递给服务方法。响应可以由控制器或视图发回，具体取决于您尝试实现的 MVC 变体。
您说“我打算将 [...] PDO 逻辑放入它自己的类中”。您真的不需要为 PDO 扩展实现包装器。

这里是一个注册示例。我根本没有测试它。有关更多详细信息，请参阅此答案末尾的资源列表。也许从最后一个开始，这 - 我刚刚意识到 - 是你的问题的答案。

使用的文件系统结构：

a) 扩展的“MyApp/UI”：

b) 扩展的“我的应用程序/域”：

控制器：

<?php

namespace MyApp\UI\Web\Controller\Users;

use Psr\Http\Message\ServerRequestInterface;
use MyApp\Domain\Model\Users\Exception\InvalidData;
use MyApp\Domain\Service\Users\Exception\FailedRegistration;
use MyApp\Domain\Service\Users\Registration as RegistrationService;

class Registration {

    private $registration;

    public function __construct(RegistrationService $registration) {
        $this->registration = $registration;
    }

    public function register(ServerRequestInterface $request) {
        $username = $request->getParsedBody()['username'];
        $password = $request->getParsedBody()['password'];
        $email = $request->getParsedBody()['email'];

        try {
            $user = $this->registration->register($username, $password, $email);
        } catch (InvalidData $exc) {
            // Write the exception message to a flash messenger, for example, 
            // in order to be read and displayed by the specific view component.
            var_dump($exc->getMessage());
        } catch (FailedRegistration $exc) {
            // Write the exception message to the flash messenger.
            var_dump($exc->getMessage());
        }

        // In the view component, if no exception messages are found in the flash messenger, display a success message.
        var_dump('Successfully registered.');
    }

}

服务：

<?php

namespace MyApp\Domain\Service\Users;

use MyApp\Domain\Model\Users\User;
use MyApp\Domain\Model\Users\Email;
use MyApp\Domain\Model\Users\Password;
use MyApp\Domain\Service\Users\Exception\UserExists;
use MyApp\Domain\Model\Users\UserCollection as UserCollectionInterface;

class Registration {

    /**
     * User collection, e.g. user repository.
     * 
     * @var UserCollectionInterface
     */
    private $userCollection;

    public function __construct(UserCollectionInterface $userCollection) {
        $this->userCollection = $userCollection;
    }

    /**
     * Register user.
     * 
     * @param string $username Username.
     * @param string $password Password.
     * @param string $email Email.
     * @return User User.
     */
    public function register(string $username, string $password, string $email) {
        $user = $this->createUser($username, $password, $email);

        return $this->storeUser($user);
    }

    /**
     * Create user.
     * 
     * @param string $username Username.
     * @param string $password Password.
     * @param string $email Email.
     * @return User User.
     */
    private function createUser(string $username, string $password, string $email) {
        // Create the object values (containing specific validation).
        $email = new Email($email);
        $password = new Password($password);

        // Create the entity (e.g. the domain object).
        $user = new User();

        $user->setUsername($username);
        $user->setEmail($email);
        $user->setPassword($password);

        return $user;
    }

    /**
     * Store user.
     * 
     * @param User $user User.
     * @return User User.
     */
    private function storeUser(User $user) {
        // Check if user already exists.
        if ($this->userCollection->exists($user)) {
            throw new UserExists();
        }

        return $this->userCollection->store($user);
    }

}

尝试注册已经存在的用户时抛出的异常：

<?php

namespace MyApp\Domain\Service\Users\Exception;

use MyApp\Domain\Service\Users\Exception\FailedRegistration;

class UserExists extends FailedRegistration {

    public function __construct(\Exception $previous = null) {
        $message = 'User already exists.';
        $code = 123;

        parent::__construct($message, $code, $previous);
    }

}

<?php

namespace MyApp\Domain\Service\Users\Exception;

abstract class FailedRegistration extends \Exception {

    public function __construct(string $message, int $code = 0, \Exception $previous = null) {
        $message = 'Registration failed: ' . $message;

        parent::__construct($message, $code, $previous);
    }

}

域对象（实体）：

<?php

namespace MyApp\Domain\Model\Users;

use MyApp\Domain\Model\Users\Email;
use MyApp\Domain\Model\Users\Password;

/**
 * User entity (e.g. domain object).
 */
class User {

    private $id;
    private $username;
    private $email;
    private $password;

    public function getId() {
        return $this->id;
    }

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

    public function getUsername() {
        return $this->username;
    }

    public function setUsername(string $username) {
        $this->username = $username;
        return $this;
    }

    public function getEmail() {
        return $this->email;
    }

    public function setEmail(Email $email) {
        $this->email = $email;
        return $this;
    }

    public function getPassword() {
        return $this->password;
    }

    public function setPassword(Password $password) {
        $this->password = $password;
        return $this;
    }

}

实体使用的值对象：

<?php

namespace MyApp\Domain\Model\Users;

use MyApp\Domain\Model\Users\Exception\InvalidEmail;

/**
 * Email object value.
 */
class Email {

    private $email;

    public function __construct(string $email) {
        if (!$this->isValid($email)) {
            throw new InvalidEmail();
        }

        $this->email = $email;
    }

    private function isValid(string $email) {
        return (isEmpty($email) || !isWellFormed($email)) ? false : true;
    }

    private function isEmpty(string $email) {
        return empty($email) ? true : false;
    }

    private function isWellFormed(string $email) {
        return !filter_var($email, FILTER_VALIDATE_EMAIL) ? false : true;
    }

    public function __toString() {
        return $this->email;
    }

}

<?php

namespace MyApp\Domain\Model\Users;

use MyApp\Domain\Model\Users\Exception\InvalidPassword;

/**
 * Password object value.
 */
class Password {

    private const MIN_LENGTH = 8;

    private $password;


    public function __construct(string $password) {
        if (!$this->isValid($password)) {
            throw new InvalidPassword();
        }

        $this->password = $password;
    }

    private function isValid(string $password) {
        return (isEmpty($password) || isTooShort($password)) ? false : true;
    }

    private function isEmpty(string $password) {
        return empty($password) ? true : false;
    }

    private function isTooShort(string $password) {
        return strlen($password) < self::MIN_LENGTH ? true : false;
    }

    public function __toString() {
        return $this->password;
    }

}

值对象抛出的异常：

<?php

namespace MyApp\Domain\Model\Users\Exception;

use MyApp\Domain\Model\Users\Exception\InvalidData;

class InvalidEmail extends InvalidData {

    public function __construct(\Exception $previous = null) {
        $message = 'The email address is not valid.';
        $code = 123402;

        parent::__construct($message, $code, $previous);
    }

}

<?php

namespace MyApp\Domain\Model\Users\Exception;

use MyApp\Domain\Model\Users\Exception\InvalidData;

class InvalidPassword extends InvalidData {

    public function __construct(\Exception $previous = null) {
        $message = 'The password is not valid.';
        $code = 123401;

        parent::__construct($message, $code, $previous);
    }

}

<?php

namespace MyApp\Domain\Model\Users\Exception;

abstract class InvalidData extends \LogicException {

    public function __construct(string $message, int $code = 0, \Exception $previous = null) {
        $message = 'Invalid data: ' . $message;

        parent::__construct($message, $code, $previous);
    }

}

仓库界面：

<?php

namespace MyApp\Domain\Model\Users;

use MyApp\Domain\Model\Users\User;

/**
 * User collection, e.g. user repository.
 */
interface UserCollection {

    /**
     * Find a user by id.
     * 
     * @param int $id User id.
     * @return User|null User.
     */
    public function findById(int $id);

    /**
     * Find all users.
     * 
     * @return User[] User list.
     */
    public function findAll();

    /**
     * Check if the given user exists.
     * 
     * @param User $user User
     * @return bool True if user exists, false otherwise.
     */
    public function exists(User $user);

    /**
     * Store a user.
     * 
     * @param User $user User
     * @return User User.
     */
    public function store(User $user);

}

存储库：

<?php

namespace MyApp\Domain\Infrastructure\Repository\Users;

use MyApp\Domain\Model\Users\User;
use MyApp\Domain\Infrastructure\Mapper\Users\UserMapper;
use MyApp\Domain\Model\Users\UserCollection as UserCollectionInterface;

/**
 * User collection, e.g. user repository.
 */
class UserCollection implements UserCollectionInterface {

    private $userMapper;

    public function __construct(UserMapper $userMapper) {
        $this->userMapper = $userMapper;
    }

    /**
     * Find a user by id.
     * 
     * @param int $id User id.
     * @return User|null User.
     */
    public function findById(int $id) {
        return $this->userMapper->fetchUserById($id);
    }

    /**
     * Find all users.
     * 
     * @return User[] User list.
     */
    public function findAll() {
        return $this->userMapper->fetchAllUsers();
    }

    /**
     * Check if the given user exists.
     * 
     * @param User $user User
     * @return bool True if user exists, false otherwise.
     */
    public function exists(User $user) {
        return $this->userMapper->userExists($user);
    }

    /**
     * Store a user.
     * 
     * @param User $user User
     * @return User User.
     */
    public function store(User $user) {
        return $this->userMapper->saveUser($user);
    }

}

数据映射器接口：

<?php

namespace MyApp\Domain\Infrastructure\Mapper\Users;

use MyApp\Domain\Model\Users\User;

/**
 * User mapper.
 */
interface UserMapper {

    /**
     * Fetch a user by id.
     * 
     * @param int $id User id.
     * @return User|null User.
     */
    public function fetchUserById(int $id);

    /**
     * Fetch all users.
     * 
     * @return User[] User list.
     */
    public function fetchAllUsers();

    /**
     * Check if the given user exists.
     * 
     * @param User $user User.
     * @return bool True if the user exists, false otherwise.
     */
    public function userExists(User $user);

    /**
     * Save a user.
     * 
     * @param User $user User.
     * @return User User.
     */
    public function saveUser(User $user);
}

数据映射器：

<?php

namespace MyApp\Domain\Infrastructure\Mapper\Users;

use PDO;
use MyApp\Domain\Model\Users\User;
use MyApp\Domain\Model\Users\Email;
use MyApp\Domain\Model\Users\Password;
use MyApp\Domain\Infrastructure\Mapper\Users\UserMapper;

/**
 * PDO user mapper.
 */
class PdoUserMapper implements UserMapper {

    /**
     * Database connection.
     * 
     * @var PDO
     */
    private $connection;

    public function __construct(PDO $connection) {
        $this->connection = $connection;
    }

    /**
     * Fetch a user by id.
     * 
     * Note: PDOStatement::fetch returns FALSE if no record is found.
     * 
     * @param int $id User id.
     * @return User|null User.
     */
    public function fetchUserById(int $id) {
        $sql = 'SELECT * FROM users WHERE id = :id LIMIT 1';

        $statement = $this->connection->prepare($sql);
        $statement->execute([
            'id' => $id,
        ]);

        $record = $statement->fetch(PDO::FETCH_ASSOC);

        return ($record === false) ? null : $this->convertRecordToUser($record);
    }

    /**
     * Fetch all users.
     * 
     * @return User[] User list.
     */
    public function fetchAllUsers() {
        $sql = 'SELECT * FROM users';

        $statement = $this->connection->prepare($sql);
        $statement->execute();

        $recordset = $statement->fetchAll(PDO::FETCH_ASSOC);

        return $this->convertRecordsetToUserList($recordset);
    }

    /**
     * Check if the given user exists.
     * 
     * Note: PDOStatement::fetch returns FALSE if no record is found.
     * 
     * @param User $user User.
     * @return bool True if the user exists, false otherwise.
     */
    public function userExists(User $user) {
        $sql = 'SELECT COUNT(*) as cnt FROM users WHERE username = :username';

        $statement = $this->connection->prepare($sql);
        $statement->execute([
            ':username' => $user->getUsername(),
        ]);

        $record = $statement->fetch(PDO::FETCH_ASSOC);

        return ($record['cnt'] > 0) ? true : false;
    }

    /**
     * Save a user.
     * 
     * @param User $user User.
     * @return User User.
     */
    public function saveUser(User $user) {
        $id = $user->getId();

        if (!isset($id)) {
            return $this->insertUser($user);
        }

        return $this->updateUser($user);
    }

    /**
     * Insert a user.
     * 
     * @param User $user User.
     * @return User User.
     */
    private function insertUser(User $user) {
        $sql = 'INSERT INTO users (
                    username,
                    password,
                    email
                ) VALUES (
                    :username,
                    :password,
                    :email
                )';

        $statement = $this->connection->prepare($sql);
        $statement->execute([
            ':username' => $user->getUsername(),
            ':password' => (string) $user->getPassword(),
            ':email' => (string) $user->getEmail(),
        ]);

        $user->setId($this->connection->lastInsertId());

        return $user;
    }

    /**
     * Update a user.
     * 
     * @param User $user User.
     * @return User User.
     */
    private function updateUser(User $user) {
        $sql = 'UPDATE users 
                SET 
                    username = :username,
                    password = :password,
                    email = :email 
                WHERE id = :id';

        $statement = $this->connection->prepare($sql);
        $statement->execute([
            ':id' => $user->getId(),
            ':username' => $user->getUsername(),
            ':password' => (string) $user->getPassword(),
            ':email' => (string) $user->getEmail(),
        ]);

        return $user;
    }

    /**
     * Convert a record to a user.
     * 
     * @param array $record Record data.
     * @return User User.
     */
    private function convertRecordToUser(array $record) {
        $user = $this->createUser(
                    $record['id'],
                    $record['username'],
                    $record['password'],
                    $record['email']
                );

        return $user;
    }

    /**
     * Convert a recordset to a list of users.
     * 
     * @param array $recordset Recordset data.
     * @return User[] User list.
     */
    private function convertRecordsetToUserList(array $recordset) {
        $users = [];

        foreach ($recordset as $record) {
            $users[] = $this->convertRecordToUser($record);
        }

        return $users;
    }

    /**
     * Create user.
     *
     * @param int $id User id.
     * @param string $username Username.
     * @param string $password Password.
     * @param string $email Email.
     * @return User User.
     */
    private function createUser(int $id, string $username, string $password, string $email) {
        $user = new User();

        $user
            ->setId($id)
            ->setUsername($username)
            ->setPassword(new Password($password))
            ->setEmail(new Email($email))
        ;

        return $user;
    }

}

资源：

php - 域对象和数据映射器应如何在使用 MVC 的身份验证系统的服务类中交互

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