Let's talk about how to prevent entry without logging in in php

PHP is prohibited from entering without logging in

With the popularity of Internet applications, more and more websites require users to log in to use or view some specific content. However, unauthorized access can cause security issues such as hacking, data breaches, and more. Therefore, from a security perspective, we must restrict access to non-logged-in users to ensure the security of the website. This article mainly introduces how to use PHP to achieve this goal.

1: session mechanism

We can use the session mechanism in PHP to prohibit access for non-logged-in users. The session mechanism is a technology that saves information on the server side. When a user accesses the website, the server assigns a unique session ID to each user and creates a corresponding session file on the server. The session ID is then sent to the user's browser so that the user can be identified the next time he or she accesses the server.

Next, we can operate the session on the backend and control whether the user can access the specified page by determining whether the user is logged in. The specific implementation is to add the following code to each page that requires login to access:

session_start();
if(!isset($_SESSION['username'])){
   header("Location:login.php"); 
   exit();
}

From the above code, we can see that first open the session, and then determine whether the username identifier exists in the session. If it does not exist, Then jump to the login page.

2: Cookie Mechanism

In addition to using the session mechanism to control the access of non-logged-in users, we can also use cookies in the browser to achieve this. Cookie is a technology that saves information on the browser side. Similar to session, it can be used to identify the user. Compared with sessions, the advantage of cookies is that the user's authentication information is stored in the browser, which allows the user to remain logged in in multiple browsers, not just limited to one browser.

The specific method is that when the user logs in successfully, the user's login credentials are recorded in the cookie. When the user visits other pages that require login, the legality of the login information in the cookie is judged to determine whether Allow user access.

In addition, we can also use PHP's setcookie function to set cookies. The syntax format is as follows:

setcookie(name,value,expire,path,domain,secure,httponly);

Among them:

• name: required, the name of the cookie.
• value: required, the value of the cookie.
• expire: Optional, cookie expiration time. Set a timestamp to indicate the expiration time of the cookie. The expiration time is the number of seconds after the current time.
• path: Optional, the valid path of the cookie.
• domain: Optional, set the domain name to which the cookie belongs.
• secure: Optional, is a Boolean value indicating whether the cookie is only transmitted over HTTPS.
• httponly: Optional, is a Boolean value indicating whether cookies can only be sent through the HTTP protocol.

3: Use the framework

If the project is more complex, you can use the framework to improve development efficiency. Using the framework can easily implement functions such as user authentication and permission control, allowing developers to focus more on the implementation of business logic.

Common PHP frameworks include: Laravel, Yii, ThinkPHP, etc. These frameworks have good protection mechanisms, including preventing CSRF attacks, preventing XSS injection attacks, etc. Using a framework can help us quickly build a secure WEB application, allowing developers to focus more on the implementation of business logic.

Summary

Unauthorized access may bring huge security risks. In order to ensure the security of the website, we must restrict access to non-logged-in users. PHP provides two technologies, session and cookie, which can be used to save user identity information and verify identity on the backend. In actual development, we can also use frameworks to improve development efficiency and quickly build a secure WEB application.

Finally, I would like to emphasize that ensuring the security of a website cannot be solved overnight. It requires continuous security testing and timely patching of loopholes to make the website truly safe.

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