ServiceStack.HttpRequestExtensions.ToStatusCode C# (CSharp) Method

        public static int ToStatusCode(this Exception ex)
        {
            var hasStatusCode = ex as IHasStatusCode;
            if (hasStatusCode != null)
                return hasStatusCode.StatusCode;

            if (HostContext.AppHost != null && HostContext.Config != null)
            {
                var exType = ex.GetType();
                foreach (var entry in HostContext.Config.MapExceptionToStatusCode)
                {
                    if (entry.Key.IsAssignableFromType(exType))
                        return entry.Value;
                }
            }

            if (ex is HttpError) return ((HttpError)ex).Status;
            if (ex is NotImplementedException || ex is NotSupportedException) return (int)HttpStatusCode.MethodNotAllowed;
            if (ex is ArgumentException || ex is SerializationException || ex is FormatException) return (int)HttpStatusCode.BadRequest;
            if (ex is AuthenticationException) return (int)HttpStatusCode.Unauthorized;
            if (ex is UnauthorizedAccessException) return (int)HttpStatusCode.Forbidden;
            if (ex is OptimisticConcurrencyException) return (int)HttpStatusCode.Conflict;
            return (int)HttpStatusCode.InternalServerError;
        }