How to use session and cookie functions for user login status management in PHP?

How to use session and cookie functions in PHP to manage user login status?

In website development, user login status management is a very important function. Through user login status management, we can implement functions such as user authentication and permission control. In PHP, we can use session and cookie functions to manage user login status. This article will introduce how to use session and cookie functions in PHP to manage user login status, and provide corresponding code examples.

1. The concept and use of session

Session is a mechanism for storing user information on the server side. Sessions allow a user's login status or other relevant information to be saved server-side for sharing across multiple pages. In PHP, we can use the session_start() function to start a session, and use the $_SESSION super global variable to store and obtain session data.

1. Start the session

Before using the session, we need to call the session_start() function at the top of each page to start the session.

<?php
session_start();
?>

2. Storing session data

During the login process, user-related information can be saved in the session.

<?php
// 将用户ID保存在会话中
$_SESSION['user_id'] = $user_id;

// 将用户角色保存在会话中
$_SESSION['user_role'] = $user_role;
?>

3. Get session data

Where session data needs to be used, session data can be obtained through the $_SESSION super global variable.

<?php
// 获取用户ID
$user_id = $_SESSION['user_id'];

// 获取用户角色
$user_role = $_SESSION['user_role'];
?>

4. Destroy the session

After the user logs out or after a certain period of time, you can use the session_destroy() function to destroy the session to release server-side resources .

<?php
session_destroy();
?>

2. The concept and use of Cookie

Cookie is a mechanism for storing data on the client. When using cookies for user login status management, the user's login status is identified by storing an identifier (such as user ID or token) on the client. In PHP, we can use the setcookie() function to set Cookie, and use the $_COOKIE super global variable to obtain the value of Cookie.

1. Set Cookie

After the user successfully logs in, you can use the setcookie() function to set a Cookie.

<?php
// 设置一个名为user_id的Cookie，有效期为1小时
setcookie('user_id', $user_id, time()+3600);
?>

2. Get the value of Cookie

Where you need to use Cookie, you can get the value of Cookie through the $_COOKIE super global variable.

<?php
// 获取名为user_id的Cookie的值
$user_id = $_COOKIE['user_id'];
?>

3. Delete Cookie

After the user logs out or after a certain period of time, you can use the setcookie() function to set the cookie expiration time to one time in the past, thereby invalidating the cookie.

<?php
// 将名为user_id的Cookie的过期时间设置为一个过去的时间
setcookie('user_id', '', time()-3600);
?>

The above is an introduction to how to use session and cookie functions in PHP to manage user login status. Through sessions and cookies, we can easily manage the user's login status. I hope the introduction in this article will be helpful to everyone!

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