MVC - 一步一步

Question

我尝试使用 ChatGPT 深入了解 MVC 设计各个步骤的核心。我特别尝试了解哪个实例在何时何地执行什么操作。我最终列出了 13 个基本点。

我很清楚该列表没有考虑到无数的中间步骤。

虽然ChatGPT很有趣，但我想向一些在世的专家询问一下这个列表： 该列表是否包含根本性错误？是否包含所有基本步骤？有什么意见欢迎留言！

这是列表和一些 PHP 代码：

1. 前端控制器收到请求。
2. 前端控制器实例化路由器。
3. 前端控制器将请求传递给路由器。
4. 路由器接收请求并从中提取控制器名称、操作和 ID。
5. 路由器决定使用哪个控制器来处理请求。
6. 路由器实例化所选控制器。
7. 路由器在控制器上调用适当的操作。
8. 控制器实例化模型。
9. 控制器在模型上调用适当的操作来获取用户数据。
10. 模型从数据库中检索数据，然后将其返回给控制器。
11. 控制器实例化视图。
12. Controller将处理后的数据传递给View。
13. View 根据从 Controller 接收到的数据为用户呈现页面。

## Step 1: The Front Controller receives the request.
$request = $_SERVER['REQUEST_URI']; // "/index.php/user/read/42"

## Step 2: The Front Controller instantiates the Router.
$router = new Router();

## Step 3: The Front Controller passes the request to the Router.
$router->dispatch($request);


class Router {
    private $controller = "UserController";
    private $action = "read";
    private $id = 42;

    public function getController() {
        return $this->controller;
    }

    public function getAction() {
        return $this->action;
    }

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

    public function dispatch($request) {
        ## Step 4: The Router recieves the request and extracts controller name, action, and id from it.
        // logic to set $this->controller, $this->action, and $this->id based on $request
        $tmp = explode('/', $request);
        $this->controller = ucfirst($tmp[2]).'Controller';
        $this->action = $tmp[3];
        $this->id = $tmp[4];

        ## Step 5: The Router determines which Controller to use to handle the request.
        $controllerName = $this->getController(); // returns "UserController"

        ## Step 6: The Router instantiates the chosen Controller.
        $controller = new $controllerName(); // instantiates the UserController

        ## Step 7: The Router calls the appropriate action on the Controller.
        $action = $this->getAction(); // returns "read"
        $userId = $this->getId(); // returns 42
        $controller->$action($userId); // calls UserController->read(42)
    }
}

class UserController {
    public function read($id) {
        ## Step 8: The Controller instantiates the Model.
        $model = new UserModel();

        ## Step 9: The Controller calls the appropriate action on the Model to get user data.
        $userData = $model->readUser($id);
        // logic to process $data

        ## Step 11: The Controller instantiates the View.
        $view = new UserView();

        ## Step 12: The Controller passes the processed data to the View.
        $view->render($userData);
    }

    public function update($id) {
        $model = new UserModel();
        $userData = $model->updateUser($id);
        $view = new UserView();
        $view->render($userData);
    }
}

class UserModel {
    public function readUser($id) {
        ## Step 10: The Model retrieves data from the database, then returns it to the Controller.
        // database logic to get user
        $userData = ['id' => 42, 'given_name' => 'John', 'family_name' => 'Dow']; // placeholder
        return $userData;
    }

    public function updateUser($id) {
        // database logic to update user
        $updatedUserData = ['id' => 42, 'given_name' => 'John', 'family_name' => 'Dow']; // placeholder
        return $updatedUserData;
    }
}

class UserView {
    public function render($userData) {
        ## Step 13: The View renders the page for the user based on the data received from the Controller.
        // display logic using $userData
        echo implode('<br>', $userData);
    }
}