protected virtual bool IsAuthorized(HttpActionContext actionContext)
        {
            if (actionContext == null)
            {
                throw Error.ArgumentNull("actionContext");
            }

            IPrincipal user = actionContext.ControllerContext.RequestContext.Principal;
            if (user == null || user.Identity == null || !user.Identity.IsAuthenticated)
            {
                return false;
            }

            if (_usersSplit.Length > 0 && !_usersSplit.Contains(user.Identity.Name, StringComparer.OrdinalIgnoreCase))
            {
                return false;
            }

            if (_rolesSplit.Length > 0 && !_rolesSplit.Any(user.IsInRole))
            {
                return false;
            }

            return true;
        }

    public class MyAuthorizeAttribute : AuthorizeAttribute
    {
        protected override bool AuthorizeCore(HttpContextBase httpContext)
        {
            if (httpContext == null)
            {
                throw new ArgumentNullException("httpContext");
            }

            IPrincipal user = httpContext.User;
            if (!user.Identity.IsAuthenticated)
            {
                return false;
            }

            var usersSplit = SplitString(Users);
            var rolesSplit = SplitString(Roles);

            if (usersSplit.Length == 0 && rolesSplit.Length == 0)
            {
                return true;
            }

            if (usersSplit.Contains(user.Identity.Name, StringComparer.OrdinalIgnoreCase))
            {
                return true;
            }

            if (rolesSplit.Any(user.IsInRole))
            {
                return true;
            }

            return false;
        }

        internal static string[] SplitString(string original)
        {
            if (String.IsNullOrEmpty(original))
            {
                return new string[0];
            }
            var split = from piece in original.Split(',')
                        let trimmed = piece.Trim()
                        where !String.IsNullOrEmpty(trimmed)
                        select trimmed;
            return split.ToArray();
        }
    }