private static ActionResult ResolveInternal(ErrorContext errorContext, HttpContextBase httpContext)
        {
            if (!errorContext.IsHandled)
            {
                return null;
            }

            var urlHelper = new UrlHelper(httpContext.Request.RequestContext);

            if (errorContext.IsExceptionOfType<ArticleAccessException>() && !httpContext.User.Identity.IsAuthenticated)
            {
                var returnUrl = httpContext.Request.Url.ToRelativePathAndQuery();

                string loginUrl = urlHelper.AccountsLogin(returnUrl);
                return new RedirectResult(loginUrl);
            }

            return null;
        }