public function login()
 {
     if (UserAuthController::isLogin()) {
         return Redirect::to('/welcome');
     }
     if (Request::isMethod('get')) {
         $user_id = Input::get('id', null);
         $user_info = tb_users::where('id', $user_id)->first();
         if (null == $user_info) {
             return View::make('login')->with('deny_info', '链接失效!')->with('deny_user_id', $user_id);
         }
         // 使用免登录金牌
         if (true !== UserAuthController::login($user_id, null)) {
             return Response::make(View::make('login'))->withCookie(Cookie::make('user_id', $user_id));
         }
         return Redirect::to('/welcome');
     }
     if (Request::isMethod('post')) {
         // 使用邀请码登录
         $token = Input::get('token');
         $user_id = Cookie::get('user_id');
         self::recordAccessLog(array('token' => $token, 'user_id' => $user_id));
         $error_info = UserAuthController::login($user_id, $token);
         if (true !== $error_info) {
             return Redirect::back()->with('error_info', $error_info)->withInput();
         }
         return Redirect::to('/welcome');
     }
     return Response::make('此页面只能用GET/POST方法访问!', 404);
 }