PHP parameter filtering, data filtering class

Introducing php parameter filtering and php data filtering, including the basic principles of php submitted data filtering, php simple data filtering

Basic principles of php submission data filtering

1) When submitting variables into the database, we must use addslashes() for filtering. For example, our injection problem can be solved with just one addslashes(). In fact, when it comes to variable values, the intval() function is also a good choice for filtering strings.
2) Enable magic_quotes_gpc and magic_quotes_runtime in php.ini. magic_quotes_gpc can change the quotation marks in get, post, and cookie into slashes. magic_quotes_runtime can play a formatting role in data entering and exiting the database. In fact, this parameter was very popular back in the old days when injection was crazy.
3) When using system functions, you must use escapeshellarg(), escapeshellcmd() parameters to filter, so that you can use system functions with confidence.
4) For cross-site, both parameters of strip_tags() and htmlspecialchars() are good. All tags with html and php submitted by users will be converted. For example, angle brackets "<" will be converted into harmless characters such as "<".
$new = htmlspecialchars("Test", ENT_QUOTES);
strip_tags($text,);
5) For the filtering of related functions, just like the previous include(), unlink, fopen(), etc., as long as you specify the variables you want to perform the operation or filter the related characters strictly