PHP Filter

A PHP filter is used to validate and filter data coming from insecure sources.
The PHP filter extension is designed to make data filtering easier and quicker. The filter extension is an extension that comes by default in PHP 5.2. It is here to help us to “validate and filter data that comes from insecure sources, such as user input”. It can validate integers, booleans, floats, regular expressions, URLs, E-Mails and IPs. It can sanitize strings, integers, floats, URLs, E-Mails…
To filter a variable, one of the following filter functions can be used:
  • filter_var() - Filters a single variable with a specified filter
  • filter_var_array() - Filter several variables with the same or different filters
  • filter_input - Get one input variable and filter it
  • filter_input_array - Get several input variables and filter them with the same or different filters