bool CanRewriteOutput(HttpContextBase httpContext) { if (!settings.IsHtmlRewritingEnabled) return false; if (!httpContext.IsHtmlRewritingEnabled()) return false; var statusCode = httpContext.Response.StatusCode; if (300 <= statusCode && statusCode < 400) return false; if (statusCode == 401) return false; // 401 gets converted into a redirect by FormsAuthenticationModule. return IsHtmlResponse(httpContext); }