Can I retain a Google apps session token permanently for a specific user who logs into my google application?

Question

Hi guys, is it possible to retain upon authorization a single session token for a user who signs into my gogle application. CUrrently my application seems to every now and then require the user to authenticate into google apps. I think it has to do with session dying out or so. I have the following code:

function getCurrentUrl()
{
    global $_SERVER;

    $php_request_uri = htmlentities(substr($_SERVER['REQUEST_URI'], 0,
    strcspn($_SERVER['REQUEST_URI'], "\n\r")), ENT_QUOTES);

    if (isset($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) == 'on') {
        $protocol = 'https://';
    } else {
        $protocol = 'http://';
    }
    $host = $_SERVER['HTTP_HOST'];
    if ($_SERVER['SERVER_PORT'] != '' &&
        (($protocol == 'http://' && $_SERVER['SERVER_PORT'] != '80') ||
        ($protocol == 'https://' && $_SERVER['SERVER_PORT'] != '443'))) {
            $port = ':' . $_SERVER['SERVER_PORT'];
    } else {
        $port = '';
    }
    return $protocol . $host . $port . $php_request_uri;
}




function getAuthSubUrl($n=false)
{
    $next = $n?$n:getCurrentUrl();
    $scope = 'http://docs.google.com/feeds/documents https://www.google.com/calendar/feeds/ https://spreadsheets.google.com/feeds/ https://www.google.com/m8/feeds/ https://mail.google.com/mail/feed/atom/';
    $secure = false;
    $session = true;
//echo Zend_Gdata_AuthSub::getAuthSubTokenUri($next, $scope, $secure, $session);;
    return Zend_Gdata_AuthSub::getAuthSubTokenUri($next, $scope, $secure, $session).(isset($_SESSION['domain'])?'&hd='.$_SESSION['domain']:'');
}




function _regenerate_token()
{
    global $BASE_URL;
    if(!$_SESSION['token'])
    {
        if(isset($_GET['token'])):
            $_SESSION['token'] = Zend_Gdata_AuthSub::getAuthSubSessionToken($_GET['token']);
            return;
        else:
            _regenerate_sessions();
            _redirect(getAuthSubUrl($BASE_URL . '/index.php?'.$_SERVER['QUERY_STRING']));
        endif;
    }
}

_regenerate_token();

I know I'm doing it all wrong here and I don't know why :( I have a CONSUMER SECRET code but only use it whereever I need to access a google service. However something is wrong with my authentication as the user has to periodically 'grant access to my application' and reauthorise himself... help please