def current_weixin_public_account
      @current_weixin_public_account ||= self.class.token_model_class.where("#{DEFAULT_WEIXIN_SECRET_KEY}" => weixin_secret_key).first
      @current_weixin_public_account.instance_eval do
        def aes_key
          WexinAdapter.decode64(encoding_aes_key)
        end
      end
      @current_weixin_public_account
    end
def current_weixin_public_account
      @current_weixin_public_account ||= self.class.token_model_class.where("#{DEFAULT_WEIXIN_SECRET_KEY}" => weixin_secret_key).first
      @current_weixin_public_account.instance_eval do
        def aes_key
          WexinAdapter.decode64(encoding_aes_key)
        end
      end
      @current_weixin_public_account
    end
TODO: handle Exception