PHP for cleaning a string from SQL injection

function clean_string($string) {
  $string = strip_tags($string);
  $string = htmlspecialchars($string);
  $string = mysqli_real_escape_string($string);
  return $string;
}

Explanation:

The above function takes a string as input and performs a series of operations to clean it from SQL injection.

• strip_tags() removes any HTML tags from the string. This is useful to prevent attackers from embedding malicious code in your application.
• htmlspecialchars() converts special characters (such as "<", ">", and "&") into their HTML entities. This is useful to prevent attackers from injecting HTML code into your application.
• mysqli_real_escape_string() adds slashes to any characters that are considered special characters in SQL. This is useful to prevent attackers from injecting SQL code into your application.

How to implement:

To use the above function, you can simply call it with the string that you want to clean as the argument. For example:

$clean_string = clean_string($_GET['username']);

This will clean the string in the $_GET['username'] variable and assign the cleaned string to the $clean_string variable.

Additional notes:

In addition to the above function, there are a few other things that you can do to help prevent SQL injection attacks.

• Use prepared statements. Prepared statements are a more secure way to execute SQL queries because they prevent attackers from injecting malicious code into your queries.
• Use a web application firewall. A web application firewall can help to protect your application from SQL injection attacks and other types of attacks.
• Keep your software up to date. Software updates often include security patches that can help to protect your application from vulnerabilities.