code: func (service *Service) GetLoggedInUser(request *http.Request, w http.ResponseWriter) (username string, err error) {
  	authenticatedSession, err := service.GetSession(request, SessionInteractive, "authenticatedsession")
  	if err != nil {
  		log.Error(err)
  		return
  	}
  	err = authenticatedSession.Save(request, w)
  	if err != nil {
  		log.Error(err)
  		return
  	}
  	savedusername := authenticatedSession.Values["username"]
  	if savedusername != nil {
  		username, _ = savedusername.(string)
  	}
  	return
  }
docs: //GetLoggedInUser returns an authenticated user, or an empty string if there is none