public class ClientErrorHandler : FilterAttribute, IExceptionFilter
    {
        public void OnException(ExceptionContext filterContext)
        {
            var response = filterContext.RequestContext.HttpContext.Response;
            response.Write(filterContext.Exception.Message);
            response.ContentType = MediaTypeNames.Text.Plain;
            filterContext.ExceptionHandled = true;
            filterContext.Result = new HttpStatusCodeResult(HttpStatusCode.BadRequest);
        }
    }