Detailed explanation of filter functions for PHP security processing

In PHP, some very useful functions are open sourced and are very convenient to prevent your website from various attacks, such as SQL injection attacks, XSS (Cross Site Scripting: Cross-site scripting) attacks, etc. This article mainly shares with you the detailed explanation of the filter function of PHP security processing. I hope it can help you.

1.mysql_real_escape_string()

This function prevents in PHP SQLVery useful during injection attacks. This function adds a backslash to special characters such as single quotes, double quotes, backslashes, etc. to ensure that the input provided by the user is clean before querying this data. But please note that you are using this function under the premise of connecting to the database. But using mysql_real_escape_string() is no longer recommended. All new applications should use function libraries like PDO to perform database operations. , that is, we can use ready-made statements to prevent SQL injection attacks.

2. htmlentities()

htmlentities() function converts characters into HTML entities.

3. strip_tags()

This function can remove all HTML, JavaScript and PHP tags in the string , of course you can also make some specific labels appear by setting the second parameter of the function.

strip_tags("Hello<b><i>world!</i></b>","<b>");

4. md5()

is used for database password encryption, etc.

5. intval()

The intval() function converts variables into integer types. You can use this function to make your PHP code safer , especially when you are parsing data such as id and age.

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