class Facebook_model extends CI_Model {

    public function get_user() {
        $config = array(
        	'appId'  => 'xxxx',
        	'secret' => 'xxxx',
        	'cookie' => true, // enable optional cookie support
		);

        $this->load->library('Facebook', $config);

		$session = $this->facebook->getSession();

        $me = null;
        $uid = null;

        // Session based API call.
        if ($session) {
            try {
                $uid = $this->facebook->getUser();
              	$me = $this->facebook->api('/me?fields=id,name,link,email,picture');
            } catch (FacebookApiException $e) {
                error_log($e);
            }
        }

        // Here you could actually use an else to redirect the user to a login page,
        // however, CI wont accept by default some URI chars and it will fail
        // Instead I recommend using the FBML or the JavaScript SDK to process login and logout

        $this->session->set_userdata('fb_me', $me);
        $this->session->set_userdata('fb_uid', $uid);
    }
}