Function apache_request_headers supports only on Apache, how to use it on Nginx. Here is the solution:
if (!function_exists('apache_request_headers')) { function apache_request_headers() { $return = array(); foreach($_SERVER as $key=>$value) { if (substr($key,0,5)=="HTTP_") { $key=str_replace(" ","-",ucwords(strtolower(str_replace("_"," ",substr($key,5))))); $return[$key]=$value; }else{ $return[$key]=$value; } } return $return; } }