MVC 静态化的ActionFilter

在MVC中，需要对某些页面进行静态化，用ActionFilter来做静态化，把页面存到缓存中。如下代码所示，其中Result.RenderString是扩展方法，第一次缓存的时候，Action代码会运行两次，其中一次是RenderString这个方法重复调用Action的Render，待改善

不采用IResultFilter是因为需要跳过Action的执行过程

       /// <summary>
        /// 页面缓存
        /// </summary>
        /// <param name="expiry">缓存过期时间</param>
        /// <param name="cacheProvider">缓存器名称</param>
        public ResultCachingAttribute(int expiry = 60, string cacheProvider = "default")
        {
            _timeSpan = TimeSpan.FromSeconds(expiry);
            _cacheProvider = cacheProvider;
        }

        public void OnActionExecuting(ActionExecutingContext filterContext)
        {
            try
            {
                string key = "_page_{0}_{1}_{2}";
                string controller = filterContext.RouteData.GetRequiredString("controller");
                string action = filterContext.RouteData.GetRequiredString("action");

                string strUrl = string.Empty;
                if (filterContext.HttpContext.Request != null && filterContext.HttpContext.Request.Url != null)
                    strUrl = filterContext.HttpContext.Request.Url.Query;

                _cacheKey = string.Format(key, controller, action, strUrl);

                cache = CacheManager.GetInstance(_cacheProvider);
                string cachedPage = cache.Get<string>(_cacheKey);
                if (!string.IsNullOrWhiteSpace(cachedPage))
                {
                    filterContext.Result = new ContentResult()
                        {
                            Content = cachedPage
                        };
                }
            }
            catch (Exception exception)
            {
                Logger logger = LoggerManager.GetLogger("Common.Filter");
                logger.Error(string.Format("CachingResult Error {0},
{1}", _cacheKey, exception.Message), exception);
            }
        }

        public void OnActionExecuted(ActionExecutedContext filterContext)
        {
            try
            {
                if (!string.IsNullOrWhiteSpace(_cacheKey))
                {
                    cache = CacheManager.GetInstance(_cacheProvider);
                    string strResult = filterContext.Result.RenderString(filterContext.Controller.ControllerContext);
                    cache.Set(_cacheKey, strResult, _timeSpan);
                }
            }
            catch (Exception exception)
            {
                Logger logger = LoggerManager.GetLogger("Common.Filter");
                logger.Error(string.Format("CachingResult Error {0},
{1}", _cacheKey, exception.Message), exception);
            }
        }