public override IResponseMessage OnEvent_SubscribeRequest(SubscribeEventMessage requestMessage)
 {
     using (var manager = new ArticleManager())
     {
         return manager.GetWelcome();
     }
 }
        public override IResponseMessage OnTextRequest(RequestMessageText requestMessage)
        {
            var content = requestMessage.Content.Trim().ToLower();
            if (content == "help")
            {
                using (var manager = new ArticleManager())
                {
                    return manager.GetHelp();
                }
            }
            if (content == "about")
            {
                using (var manager = new ArticleManager())
                {
                    return manager.GetAbout();
                }
            }
            if (content == "top")
            {
                using (var manager = new ArticleManager())
                {
                    return manager.GetTop();
                }
            }
            if (content == "next")
                return new ResponseMessageText("此命令功能尚未开发完成,请稍后再试");
            if (content == "tags")
            {
                using (var manager = new ArticleManager())
                {
                    return manager.GetAllTags();
                }
            }
            if (content.Length == 8)
            {
                long publishDate;
                if (long.TryParse(content, out publishDate))
                {
                    using (var manager = new ArticleManager())
                    {
                        return manager.GetByPublishDate(content);
                    }
                }
            }
            IResponseMessage responseForTag;
            using (var manager = new ArticleManager())
            {
                responseForTag = manager.GetByTag(content);
            }

            return responseForTag ?? new ResponseMessageText("无此命令或关键字,请发送 help 来获得帮助");
        }