Determine if bearer token has expired or is just authorized - angularjs

Question

My angular application is making use of bearer tokens as outlined in the article series http://bitoftech.net/2014/06/01/token-based-authentication-asp-net-web-api-2-owin-asp-net-identity/. I have followed the forked example to seamlessly refresh tokens when the access token has expired (via 401 http code).
My question is how can I determine if the bearer token is expired or just plain unauthorized based on the role determined?
For example, my web api method has the attribute [Authorize(Roles="Admin")]. When I make a call to that, I get back my 401 error, which is expected. However, when my access token expires and I make another web api method call, it also returns a 401 error. Heres my responseError handler in my interceptor:
responseError: function (rejection) {
var deferred = q.defer();
if (rejection.status === 401) {
var authService = $injector.get('authService');
authService.refreshToken().then(function (response) {
_retryHttpRequest(rejection.config, deferred);
}, function () {
authService.logOut();
$location.path('/dashboard');
deferred.reject(rejection);
});
} else {
deferred.reject(rejection);
}
return deferred.promise;
}
I was playing around with different things but basically, I'd like to refresh my token and resend my request when the access token has expired; however, I don't want to refresh my token if it truly is a denied request due to the role specified.
Any thoughts?

Answer 1

As noted in my response to Cory Silva's comment, the Web API Authorize attribute will always return 401 unauthorized for both authentication AND authorization.
See article and thread below:
http://leastprivilege.com/2014/10/02/401-vs-403/
Why does AuthorizeAttribute redirect to the login page for authentication and authorization failures?
It looks like there are two options:
When I store the token retrieved from my authorization server in localStorage, I also store the token's expiration. In the interceptor responseError function, I compare the stored token expiration with the current datetime. If it's determined to be expired, refresh the token and resend the request.
responseError: function (rejection) {
var deferred = q.defer();
if (rejection.status === 401) {
var tokenExpired = false;
var authData = localStorage.get('authorizationData');
if (authData) {
tokenExpired = moment().isAfter(authData.expiration);
}
if (tokenExpired) {
var authService = auth;//$injector.get('authService');
authService.refreshToken().then(function (response) {
_retryHttpRequest(rejection.config, deferred);
}, function () {
authService.logOut();
$state.go('error');
deferred.reject(rejection);
});
}
else {
$state.go('error');
deferred.reject(rejection);
}
} else {
$state.go('error');
deferred.reject(rejection);
}
return deferred.promise;
}
Use the accepted answer in the stackoverflow thread I referenced above and create my own AuthorizeAttribute to determine token expiration vs. unauthorized access.
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = true)]
public class AuthorizeAttribute : System.Web.Http.AuthorizeAttribute
{
protected override void HandleUnauthorizedRequest(HttpActionContext actionContext)
{
if (actionContext.RequestContext.Principal.Identity.IsAuthenticated)
{
actionContext.Response = actionContext.Request.CreateResponse(HttpStatusCode.Forbidden);
}
else
{
base.HandleUnauthorizedRequest(actionContext);
}
}
}
I think I'm going to use option 2 so that the error codes a little clearer to the client.