public static function buildQS($params) 
	{
		$val;
		$ret = "";
		foreach($params->getKeys() as $key) 
		{
			$val = $params->getString($key);
			if (isset($val))
			{
				$ret .="$key=".urlencode($val);
			}
			$ret .='&';
		}

		$ret = rtrim($ret, "&");

		return $ret;
	}