4 ways to implement safe exit in PHP

With the improvement of network security awareness, user safe exit has become one of the functions that major websites must consider. In program implementation, PHP is a popular development language, and there are many ways to implement safe exit. This article will introduce several ways to implement safe exit in PHP.

1. Use Session to achieve safe exit

Session is used to store client state on the server side, which is a common implementation method. When logging in, user information is saved in the Session. When exiting, you only need to destroy the Session. The following is the specific code implementation:

// 先启用session
session_start();

// 清空session
$_SESSION = [];

// 注销session
session_destroy();

In the above code, PHP's session function is first enabled, then the $_SESSION array is cleared, and finally the session is destroyed. Of course, the above code will only be called after the user successfully logs in.

2. Use cookies to achieve safe exit

Cookies are a way for browsers to store information. When logging in, user information is saved in cookies. When exiting, just delete the cookies. The following is the specific code implementation:

// 清空Cookie
setcookie('username', '', time() - 1);
setcookie('password', '', time() - 1);

In the above code, the username and password cookies are cleared, and their expiration time is set to the current time minus one second. In this way, the browser will think that these two cookies have expired and delete them.

3. Use redirection to achieve safe exit

Redirection is a common implementation method. On logout, simply redirect the user to the login page. The following is the specific code implementation:

// 跳转到登录页面
header('Location: login.php');
exit;

In the above code, use the header function to redirect the page to login.php, and then use the exit function to stop the execution of subsequent code. Of course, you need to ensure that login-related information has been destroyed before redirecting the user to the login page.

4. Use session to achieve single sign-on

Single sign-on means that you only need to log in once to access all systems in multiple systems. In the system, user information is saved in Session. If the user accesses other systems, the Session information is passed to that system, and the user does not need to log in again. The following is the specific code implementation:

// 负责初始化session
session_start();

// 判断是否已经登录
if (isset($_SESSION['username'])) {
    // 已经登录，不需要再次登录
    echo '欢迎回来：' . $_SESSION['username'];
} else {
    // 跳转到登录页面
    header('Location: login.php');
    exit;
}

In the above code, Session is first enabled to determine whether the user is logged in. If you are already logged in, you do not need to log in again and the welcome message will be displayed directly; otherwise, the user will be redirected to the login page.

Summary

The above are several ways to implement safe exit in PHP. Among them, using Session to exit is a common method, while Cookie and redirection are suitable for different scenarios. In addition, single sign-on is a very useful feature that improves user experience. Developers can choose the corresponding implementation method according to their own needs to improve system security and user experience.

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