php - 在 Controller 中使用模型和存储库

Question

据我了解，使用存储库会限制 Controller 访问数据库层，并且所有查询都通过存储库进行。但是 Controller 可以使用模型(laravel 可以在 Controller 中注入(inject)模型而不是 ID)将其传递给存储库或服务 - 例如在用户之间进行交易吗？或者最好将 ID 发送到存储库，以查找用户并应用业务逻辑(用户是否有钱，或者他是否被禁止)。

还有更通用的问题，你能在存储库之外使用模型吗，因为如果你将一些表从 postgres 或 mysql 更改为其他表，你的模型也会改变。这意味着您的存储库应该有 get 方法来发回一些 DTO 对象？

Answer 1

注意:这是对此事的一般看法，适用于任何基于 MVC 的应用程序，不仅适用于 Laravel。

一个基于MVC模式的应用应该由三部分组成:

• 传递机制:UI 逻辑(用户请求处理和服务器响应创建)，
• 服务层:应用逻辑，
• 领域模型:业务逻辑。

以下是一些图形表示(我自己制作的):

如上所示(并在下面的资源中详细描述)， Controller 和 View 是交付机制的一部分。他们应该与 domain model 交互。 只能通过 service layer 个对象(服务)。因此，他们不应该了解域模型组件(实体 - 也称为 域对象、data mappers、repositories 等)。更重要的是， Controller 应该只有一项职责:将用户请求的值传递给服务层，以便它更新模型。

所以，回答你的第一个问题:不， Controller 不应该能够创建域模型元素的任何实例(所以你称之为“模型”的实例 - 尊重Laravel 的 Active Record )，甚至可以将这些对象传递给其他组件(如存储库、服务等)。相反， Controller 应该只将请求的值(例如 user id)传递给相应的服务。然后，这些服务将创建适当的域模型对象并使用适当的存储库、数据映射器等，以便在数据库中保存/获取数据。

至于第二个问题(如果我理解正确的话):存储库将被视为entities 的集合——它们是域模型组件。因此，可以从元素(例如实体实例)中获取、存储、更改或删除元素。因此，根据定义，entities 必须与存储库分开定义/使用。对于 Laravel，同样适用:“模型”应该与存储库分开定义/使用。

“通用”MVC 实现(为了更清晰):

Controller :

<?php

namespace MyApp\UI\Web\Controller\Users;

use MyApp\Domain\Service\Users;
use Psr\Http\Message\ServerRequestInterface;

/**
 * Add a user.
 */
class AddUser {

    /**
     * User service.
     * 
     * @var Users
     */
    private $userService;

    /**
     * 
     * @param Users $userService User service.
     */
    public function __construct(Users $userService) {
        $this->userService = $userService;
    }

    /**
     * Invoke.
     * 
     * @param ServerRequestInterface $request Request.
     * @return void
     */
    public function __invoke(ServerRequestInterface $request) {
        // Read request values.
        $username = $request->getParsedBody()['username'];

        // Call the corresponding service.
        $this->userService->addUser($username);
    }

}

服务:

<?php

namespace MyApp\Domain\Service;

use MyApp\Domain\Model\User\User;
use MyApp\Domain\Model\User\UserCollection;
use MyApp\Domain\Service\Exception\UserExists;

/**
 * Service for handling the users.
 */
class Users {

    /**
     * User collection (a repository).
     * 
     * @var UserCollection
     */
    private $userCollection;

    /**
     * 
     * @param UserCollection $userCollection User collection.
     */
    public function __construct(UserCollection $userCollection) {
        $this->userCollection = $userCollection;
    }

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

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

    /**
     * Add a user.
     * 
     * @param string $username Username.
     * @return User User.
     */
    public function addUser(string $username) {
        $user = $this->createUser($username);

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

    /**
     * Create a user.
     * 
     * @param string $username Username.
     * @return User User.
     */
    private function createUser(string $username) {
        $user = new User();

        $user->setUsername($username);

        return $user;
    }

    /**
     * Store a user.
     * 
     * @param User $user User.
     * @return User User.
     */
    private function storeUser(User $user) {
        if ($this->userCollection->userExists($user)) {
            throw new UserExists('Username "' . $user->getUsername() . '" already used');
        }

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

}

存储库:

<?php

namespace MyApp\Domain\Infrastructure\Repository\User;

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

/**
 * User collection.
 */
class UserCollection implements UserCollectionInterface {

    /**
     * User mapper (a data mapper).
     * 
     * @var UserMapper
     */
    private $userMapper;

    /**
     * 
     * @param UserMapper $userMapper User mapper.
     */
    public function __construct(UserMapper $userMapper) {
        $this->userMapper = $userMapper;
    }

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

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

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

}

实体:

<?php

namespace MyApp\Domain\Model\User;

/**
 * User.
 */
class User {

    /**
     * Id.
     * 
     * @var int
     */
    private $id;

    /**
     * Username.
     * 
     * @var string
     */
    private $username;

    /**
     * Get id.
     * 
     * @return int
     */
    public function getId() {
        return $this->id;
    }

    /**
     * Set id.
     * 
     * @param int $id Id.
     * @return $this
     */
    public function setId(int $id) {
        $this->id = $id;
        return $this;
    }

    /**
     * Get username.
     * 
     * @return string
     */
    public function getUsername() {
        return $this->username;
    }

    /**
     * Set username.
     * 
     * @param string $username Username.
     * @return $this
     */
    public function setUsername(string $username) {
        $this->username = $username;
        return $this;
    }

}

数据映射器:

<?php

namespace MyApp\Domain\Infrastructure\Mapper\User;

use PDO;
use MyApp\Domain\Model\User\User;
use MyApp\Domain\Infrastructure\Mapper\User\UserMapper;

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

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

    /**
     * 
     * @param PDO $connection Database 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,
        ]);

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

        return ($data === false) ? null : $this->convertDataToUser($data);
    }

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

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

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

        return $this->convertDataToUserList($data);
    }

    /**
     * Check if a 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(),
        ]);

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

        return ($data['cnt'] > 0) ? true : false;
    }
    
    /**
     * Save a user.
     * 
     * @param User $user User.
     * @return User User.
     */
    public function saveUser(User $user) {
        return $this->insertUser($user);
    }
    
    /**
     * Insert a user.
     * 
     * @param User $user User.
     * @return User User.
     */
    private function insertUser(User $user) {
        $sql = 'INSERT INTO users (username) VALUES (:username)';

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

        $user->setId($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 WHERE id = :id';

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

        return $user;
    }

    /**
     * Convert the given data to a user.
     * 
     * @param array $data Data.
     * @return User User.
     */
    private function convertDataToUser(array $data) {
        $user = new User();

        $user
                ->setId($data['id'])
                ->setUsername($data['username'])
        ;

        return $user;
    }

    /**
     * Convert the given data to a list of users.
     * 
     * @param array $data Data.
     * @return User[] User list.
     */
    private function convertDataToUserList(array $data) {
        $userList = [];

        foreach ($data as $item) {
            $userList[] = $this->convertDataToUser($item);
        }

        return $userList;
    }

}

查看:

<?php

namespace MyApp\UI\Web\View\Users;

use MyApp\UI\Web\View\View;
use MyApp\Domain\Service\Users;
use MyLib\Template\TemplateInterface;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ResponseFactoryInterface;

/**
 * Add a user.
 */
class AddUser extends View {

    /**
     * User service.
     * 
     * @var Users
     */
    private $userService;

    /**
     * 
     * @param ResponseFactoryInterface $responseFactory Response factory.
     * @param TemplateInterface $template Template.
     * @param Users $userService User service.
     */
    public function __construct(ResponseFactoryInterface $responseFactory, TemplateInterface $template, Users $userService) {
        parent::__construct($responseFactory, $template);

        $this->userService = $userService;
    }
    
    /**
     * Display a form for adding a user.
     * 
     * @return ResponseInterface Response.
     */
    public function index() {
        $body = $this->template->render('@Template/Users/add-user.html.twig', [
            'activeMainMenuItem' => 'addUser',
            'action' => '',
        ]);
        
        $response = $this->responseFactory->createResponse();
        $response->getBody()->write($body);

        return $response;
    }

    /**
     * Add a user.
     * 
     * @return ResponseInterface Response.
     */
    public function addUser() {
        $body = $this->template->render('@Template/Users/add-user.html.twig', [
            'activeMainMenuItem' => 'addUser',
            'message' => 'User successfully added.',
        ]);

        $response = $this->responseFactory->createResponse();
        $response->getBody()->write($body);

        return $response;
    }

}

资源:

• How should a model be structured in MVC?
• Keynote: Architecture the Lost Years
• GeeCON 2014: Sandro Mancuso - Crafted Design