filter_input

(PHP 5 >= 5.2.0, PHP 7)

Gets a specific external variable by name and optionally filters it

mixed filter_input ( int $type, string $variable_name [, int $filter = FILTER_DEFAULT [, mixed $options ]] )

Parameters:

type

One of INPUT_GET, INPUT_POST, INPUT_COOKIE, INPUT_SERVER, or INPUT_ENV.

variable_name

Name of a variable to get.

filter

The ID of the filter to apply. The Types of filters manual page lists the available filters.

If omitted, FILTER_DEFAULT will be used, which is equivalent to FILTER_UNSAFE_RAW. This will result in no filtering taking place by default.

options

Associative array of options or bitwise disjunction of flags. If filter accepts options, flags can be provided in "flags" field of array.

Returns:

Value of the requested variable on success, FALSE if the filter fails, or NULL if the variable_name variable is not set. If the flag FILTER_NULL_ON_FAILURE is used, it returns FALSE if the variable is not set and NULL if the filter fails.

Examples:

A filter_input() example

<?php
$search_html = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_SPECIAL_CHARS);
$search_url = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_ENCODED);
echo "You have searched for $search_html.\n";
echo "<a href='?search=$search_url'>Search again.</a>";
?>

The above example will output something similar to:

You have searched for Me &#38; son.
<a href='?search=Me%20%26%20son'>Search again.</a>