# File lib/omniauth/strategies/xauth.rb, line 40
      def callback_phase
        @access_token = consumer.get_access_token(nil, {}, session['omniauth.xauth'])
        super
        rescue ::Net::HTTPFatalError => e
          fail!(:service_unavailable, e)
        rescue ::OAuth::Unauthorized => e
          fail!(:invalid_credentials, e)
        rescue ::MultiJson::DecodeError => e
          fail!(:invalid_response, e)
      ensure
        session['omniauth.xauth'] = nil        
      end