Pass a value into filter_input() using variable

Question

Can anyone please explain, why do I get very strange warning:

filter_input() expects parameter 1 to be long, string given

when executing the co

Answer 1

INPUT_POST and INPUT_GET are defined as follows:

/**
 * POST variables.
 * @link http://www.php.net/manual/en/filter.constants.php
 */
define ('INPUT_POST', 0);

/**
 * GET variables.
 * @link http://www.php.net/manual/en/filter.constants.php
 */
define ('INPUT_GET', 1);

Answer 2

Here the problem. When you concatenate 'INPUT_' with variable it bacame a string, see example:

echo $type = 'INPUT_' . 'POST'; // give you a string INPUT_POST

echo INPUT_POST; //give you 0

That's why :

filter_input() expects parameter 1 to be long, string given

Answer 3

What you're supposed to use there are constants. These constants have integer values. So the documentation is entirely correct, INPUT_GET is an integer. Try var_dump(INPUT_GET).

If you need to get a constant value from a string, use constant():

echo constant('INPUT_' . $type);