check if user has liked the page

fbcheck.php

//
// via https://twitter.com/#!/wesbos/status/143765415502413824
// check if user has liked the page
function has_liked()
{
	 if (!isset($_REQUEST["signed_request"])) {  
	 	return 2;
	 }
    $signed_request = $_REQUEST["signed_request"];
    list($encoded_sig, $payload) = explode('.', $signed_request, 2);
    $data = json_decode(base64_decode(strtr($payload, '-_', '+/')), true);
    
    if (($data["page"]["liked"]) == 1) {
        return 1;
    } else {
        return 0;
    }
}