public static string GetIPAddress(RequestContext context)
        {
            string ipAddress = context.HttpContext.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

            if (!string.IsNullOrEmpty(ipAddress))
            {
                string[] addresses = ipAddress.Split(',');
                if (addresses.Length != 0)
                    return addresses[0];
            }
            return context.HttpContext.Request.ServerVariables["HTTP_CLIENT_IP"] ?? context.HttpContext.Request.ServerVariables["REMOTE_ADDR"];
        }