function queryURL($xri, $service_type = null)
{
// trim off the xri:// prefix
$qxri = substr(Auth_Yadis_toURINormal($xri), 6);
$hxri = $this->proxy_url . $qxri;
$args = array('_xrd_r' => 'application/xrds+xml');
if ($service_type) {
$args['_xrd_t'] = $service_type;
} else {
// Don't perform service endpoint selection.
$args['_xrd_r'] .= ';sep=false';
}
$query = Auth_Yadis_XRIAppendArgs($hxri, $args);
return $query;
}