If you would like to know from which page the request has come from using post Method then there is a simple PHP script can solve your issue.

Get Current Page URL Using PHP

Check below script to Get Current page using PHP

function getCurrentURLPage()
{

	$s = empty($_SERVER["HTTPS"]) ? '': ($_SERVER["HTTPS"] == "on") ? "s" : "";

	$protocol = strleft(strtolower($_SERVER["SERVER_PROTOCOL"]), "/").$s;

	$port = ($_SERVER["SERVER_PORT"] == "80") ? "" : (":".$_SERVER["SERVER_PORT"]);

	return $protocol."://".$_SERVER['SERVER_NAME'].$port.$_SERVER['REQUEST_URI'];

}
echo getCurrentURLPage();