PHP form protection tips: Use protection output scripts

PHP form protection skills: Use protective output scripts

With the development of the Internet, the user interface of web applications has gradually become the main channel for various interactions and interactions. However, these user interfaces are often vulnerable to attack and spoofing. Among them, form attacks are a common attack method. Attackers use form vulnerabilities to send illegal data to the server and steal or destroy data.

In order to protect form data in web applications, developers need to adopt some effective protection techniques. Among them, using protective output scripts is one of the most effective techniques. Below, we will introduce the protection output script in PHP form protection techniques and explain how to use it to protect against form attacks.

1. What is a protection output script?
   The guard output script is a special program used to preprocess and filter form data. It identifies and removes illegal characters and codes from form data to prevent malicious users from sending arbitrary data and codes to the server. Usually, the protection output script will check the HTML, Javascript, CSS, SQL and other codes in the form data, and delete illegal characters and comments to ensure the integrity and security of the data.
2. How to use protection output script?
   In the PHP language, common protective output scripts include the htmlspecialchars() function and the mysqli_real_escape_string() function. Below, we will introduce their usage and functions one by one.

(1) htmlspecialchars() function
htmlspecialchars() function is a PHP function that converts special characters into HTML entity characters. It can convert all HTML tags and codes in form data into corresponding entity characters, thereby preventing attackers from injecting HTML and Javascript code. For example, the following is an example of protecting the content of a form text box:

In the above code, we use the htmlspecialchars() function to protect the $_POST['username'] data and convert illegal characters into corresponding HTML entities character. In this way, when the form data is submitted to the server, the original HTML and Javascript codes are filtered out, thus ensuring data security.

(2) mysqli_real_escape_string() function
The mysqli_real_escape_string() function is a PHP function that converts special characters into SQL escape characters. It can convert all SQL keywords and characters in form data into corresponding escape characters, thereby preventing attackers from using SQL injection attacks to steal or destroy data in the database. For example, the following is an example of protecting the content of a form text box:

$username = mysqli_real_escape_string($conn, $_POST['username']);

In the above code, We used the mysqli_real_escape_string() function to protect the $_POST['username'] data and convert illegal characters into corresponding SQL escape characters. In this way, when storing data into the database, the original SQL statements are filtered out, thus ensuring the integrity and security of the data.

3. How to comprehensively use the protection output script?
   In order to better protect against form attacks, we can use the htmlspecialchars() function and the mysqli_real_escape_string() function in combination. For example, the following is an example of comprehensive protection processing for a form submission data:

$username = mysqli_real_escape_string($conn, htmlspecialchars($_POST['username']));

In the above code, we first use the htmlspecialchars() function to convert HTML and Javascript codes into entity characters, and then use the mysqli_real_escape_string() function to convert SQL keywords and characters into escape characters. In this way, you can effectively protect against form attacks and ensure data integrity and security.

In short, using protective output scripts is a very effective technique to protect against form attacks. By properly using guard output scripts, developers can effectively protect form data in web applications and prevent malicious users from stealing or destroying data. At the same time, developers should continue to improve their security awareness and skills, and update protection technologies in a timely manner to ensure the security and stability of web applications.

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