从其他类访问登录用户对象的最佳实践[关闭]

Question

This is a question regarding best practice for storing and accessing an object from another class.

I'm using a simple homemade MVC paradigm in PHP, the class is called User and has its own methods and vars that essentially works as a database abstraction layer.

This class is instantiated by calling newUser($userID) which retrieves the data from a database given $userID or throws an exception if there is no user with that ID.

Every page has its own WebViewController class governing the content of the page, and in some instances the page needs to call $loggedInUser dependent functions such as WebViewController->displayUserFriends(), which might look like this:

<?php
class WebViewController extends WVCTemplate
{
    // Class vars and methods
    // ...

    public function displayUserFriends()
    {
        foreach($loggedInUser->getFriends() as $friend) {
            // Do something
            // ...
        }
    }
}
?>

Is there a (best practice compliant) way to store LoggedInUser as a sort of global object, so it could be accessed inside of any class or WebViewController without instantiating it inside every class it's used?

Answer 1

The most elegant solution to your problem is to use dependency injection. As you may need the current user in multiple controllers it would be best to create an AuthenticationService (or similar) that provides methods to check whether a user is logged in and to get the currently logged in user and encapsulates that common functionality. You can then inject the service instance in all the controllers where you need it.

There are several standalone PHP dependency injection libraries out there:

• PHP-DI
• Pimple
• Aura.DI
• Dice