return xml gz archive

function get_xml(){
    $xml_doc = new DOMDocument();
    $xml_doc->load("http://api.openweathermap.org/data/2.5/weather?q=London,uk&appid=2de143494c0b295cca9337e1e96b00e0");
    $xml_string = $xml_doc->saveXML();
    $filename = "xml_" . time();
    $gzfilename = $filename . ".gz";
    $fp = fopen($gzfilename, "w");
    fwrite($fp, $xml_string);
    fclose($fp);
    $fd = fopen ($gzfilename, "r");
    header("Content-Type: application/x-gzip");
    header("Content-Disposition: attachment; filename=\"".$gzfilename."\"");
    fpassthru($fd);
    unlink($gzfilename);
}