public static void WriteFile(HttpContext httpContext, PreProcessResponse preProcessor)
		{
			HttpResponse response = httpContext.Response;
			response.Clear();
			response.AddHeader("Content-Type", "Application/Octect-Stream");

			string fileId = httpContext.Request.QueryString["fileId"];
			string storedPath = FileStorage.FileId2FullName(fileId);
			if (File.Exists(storedPath))
			{
				string realName = FileStorage.GetRealName(fileId);
				preProcessor.Invoke(httpContext, realName);

				response.WriteFile(storedPath);
			}
			else
			{
				response.StatusCode = 404;
			}
			response.End();
		}
        public static void WriteFile(HttpContext httpContext, PreProcessResponse preProcessor)
        {
            HttpResponse response = httpContext.Response;

            response.Clear();
            response.AddHeader("Content-Type", "Application/Octect-Stream");

            string fileId     = httpContext.Request.QueryString["fileId"];
            string storedPath = FileStorage.FileId2FullName(fileId);

            if (File.Exists(storedPath))
            {
                string realName = FileStorage.GetRealName(fileId);
                preProcessor.Invoke(httpContext, realName);

                response.WriteFile(storedPath);
            }
            else
            {
                response.StatusCode = 404;
            }
            response.End();
        }