PHP MVC 最佳实践 - 将会话变量从控制器传递到模型类或直接在模型中访问

发布于 2024-10-08 08:46:24 字数 686 浏览 3 评论 0原文

我们的开发团队正在讨论一般最佳实践：是直接从模型类中的函数访问会话变量更好，还是将会话变量从控制器作为参数传递给模型类中的函数更好。看下面的两个例子：

直接从模型类访问会话变量以在查询中使用：

class MyModel {
    public function getUserPrefs($userID) {
        $this->query("SELECT * FROM my_table WHERE id=$_SESSION['userID']");
    }
}

或者将会话变量作为函数参数从控制器传递到模型类中的函数：

class MyController {
    public function displayUsers() {
        $this->model->getUserPrefs($_SESSION['userID']);
    }
}

class MyModel {
    public function getUserPrefs($userID) {
        $this->query("SELECT * FROM my_table WHERE id=$userID");
    }
}

将其传递到模型的原因控制器是这样的，所以引用的所有数据都来自一个入口点，即控制器。

什么被认为是更好的做法？

原文

Our development team is debating a general best practice:
Is it better to access a session variable directly from a function in a model class or pass the session variable from the controller as an argument to a function in the model class. Look at the two examples below:

Accessing session variable directly from the model class to use in a query:

class MyModel {
    public function getUserPrefs($userID) {
        $this->query("SELECT * FROM my_table WHERE id=$_SESSION['userID']");
    }
}

Or pass the session variable from the controller to a function in the model class as a function argument:

class MyController {
    public function displayUsers() {
        $this->model->getUserPrefs($_SESSION['userID']);
    }
}

class MyModel {
    public function getUserPrefs($userID) {
        $this->query("SELECT * FROM my_table WHERE id=$userID");
    }
}

The reasoning for passing it to the model from the controller is so all data that is referenced is coming from one point of entry, that being the controller.

What is recognized as a better practice?

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誰ツ都不明白 2024-10-15 08:46:24

第二个版本（将 $_SESSION['userId'] 作为参数传递给方法）会产生更加解耦的类，因此更加灵活。随它去吧。

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复古式 2024-10-15 08:46:24

您永远不想在模型中包含会话变量。您应该始终将这些变量作为参数传递给模型中的函数。这也使您的代码更具可扩展性和灵活性。考虑一个通过 ID 获取用户的模型。您可以编写如下函数：

function find_by_id() {
  // SELECT * FROM Users WHERE user_id = $_SESSION['user_id'];
}

但是，如果您现在要构建具有用户查找功能的管理功能怎么办？您的模型被硬编码为使用会话的 user_id，但您希望能够传递您自己的 id。你会更好：

function find_by_id($id) {
  // SELECT * FROM Users WHERE user_id = $id
}

并且在你的控制器中

$user = Model::find_by_id(1);
//or
$user = Model::find_by_id($_SESSION['user_id']);
//etc

但是，在这种情况下，我真的会考虑让你的代码更加灵活：

function find($ids) {
  // this is pseudo code, but you get the idea
  if(is_array($ids))
    $ids = implode(',', $ids); // if an array of ids was passed, implode them with commas
  SELECT * FROM Users WHERE user_id IN ($ids);
}

这允许你在一个查询中获得多个用户！这更有效率。那么，在您看来：

foreach($users as $user){
  // iterate over each user and do stuff
}

您还应该考虑为 User 使用 singleton 类来限制数据库负载。创建一个名为 CurrentUser 的不变实例类（例如），如下所示：

class CurrentUser {

  private static $user;

  // we never instantiate it -its singleton
  private function __construct() {}

  public function user() {
    return self::$user;
  }

}

这是单例类的一个非常基本的示例，并且缺少很多内容。如果您想了解有关单例类的更多信息，请发布另一个问题。

You NEVER want to have session variables in your model. You should always pass these variables as parameters to the function in the model. This also makes your code more expandable and flexible. Consider a model that gets a user by their id. You may write a function like:

function find_by_id() {
  // SELECT * FROM Users WHERE user_id = $_SESSION['user_id'];
}

However, what if you now what to build an admin functionality with a user lookup feature? Your model is hardcoded to use the session's user_id, but you want to be able to pass your own id. You would be better off:

function find_by_id($id) {
  // SELECT * FROM Users WHERE user_id = $id
}

and in your controller

$user = Model::find_by_id(1);
//or
$user = Model::find_by_id($_SESSION['user_id']);
//etc

In this case, however, I would really consider making your code even MORE flexible:

function find($ids) {
  // this is pseudo code, but you get the idea
  if(is_array($ids))
    $ids = implode(',', $ids); // if an array of ids was passed, implode them with commas
  SELECT * FROM Users WHERE user_id IN ($ids);
}

This allows you to get multiple users in ONE query! Which is way more efficient. Then, in your view:

foreach($users as $user){
  // iterate over each user and do stuff
}

You should also consider using a singelton class for a User to limit database load. Create a non-changing instance class called CurrentUser (for example) like:

class CurrentUser {

  private static $user;

  // we never instantiate it -its singleton
  private function __construct() {}

  public function user() {
    return self::$user;
  }

}

This is a really basic example of a singleton class and is missing a lot of stuff. If you want to know more about singleton classes, post another question.

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