在控制器中使用模型和存储库

Question

据我所知，使用存储库会限制控制器访问数据库层，并且所有查询都会通过存储库。但是控制器可以使用模型（laravel 可以在控制器中注入模型而不是 ID）将其传递给存储库或服务——例如在用户之间进行交易吗？或者更好地将 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）。

还有更一般的问题，您可以使用存储库外部的模型吗，因为如果您将某些表从 postgres 或 mysql 更改为其他内容，您的模型也会更改。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

这是一个固执己见的答案，但这是我的看法。我的建议是不要为了在 Laravel 中拥有存储库而添加存储库层。无论您需要什么方法，将它们添加到模型 classes，当它们 bloated/expect 变得臃肿时，只考虑存储库（很可能您需要服务 class 或其他一些在这里抽象）。

因为所有这些 eloquent 模型 classes 都可以从容器中解析出来，所以很容易使用它们。它可以在任何地方访问，甚至可以像您提到的那样在控制器中注入，这提供了极大的便利性。

并且存储库有助于更改例如底层数据库，但是 eloquent 已经为我们提供了这种灵活性。当您计划更改数据库时，我认为这不会是一个简单的更改，所以为什么要将逻辑包装在另一层抽象中（不必要）。

至少根据我的经验，存储库模式与 Active Record 模式不太相配。 Laravel 紧随其后。存储库套件非常适合数据映射器模式（例如 Symfony 使用它）。这就是为什么在 laravel 文档中您没有看到他们采用存储库模式。你可以在 symfony 文档中看到它。

所以我建议拥抱框架而不是对抗它

Answer 2

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：

交付机制：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），控制器和视图是传递机制。他们应该与 domain model only through the service layer objects (services). Consequently, they should have no knowledge of the domain model components (entities - also known as domain objects, data mappers, repositories 等互动）。更重要的是，控制器应该只有一个职责：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，控制器不应该能够创建域模型元素的任何实例（所以你所说的实例“模型”——关于 Laravel 的 Active Record），甚至将此类对象传递给其他组件（如存储库、服务等）。相反，控制器应该只将请求的值（例如 用户 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 save/fetch to/from 数据库。

至于第二个问题（如果我理解正确的话）：存储库将被视为实体的集合——这是领域模型组件。因此，可以获取、存储、更改或删除元素（例如实体实例）to/from。因此，根据定义，entities 必须与存储库分开 defined/used。关于 Laravel，同样适用：“模型”应该 defined/used 与存储库分开。

“通用”MVC 实现（为了更清楚）：

控制器：

<?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

在控制器中使用模型和存储库

Using models in a controller alongside with repository

php

database

model-view-controller

repository

laravel