IdentityServer Hybrid Flow - Access Token is null after user successful login - asp.net

Question

I'm having problems in retrieving access token of an authenticated user. below is my configuration
ASP.NET MVC 5 Client:
OpenIdConnect
IdentityServer3 libraries
ResponseType = "code id_token"
ASP.NET Core Identity Server:
IdentityServer4 libraries
Client Config: AllowedGrantTypes =
GrantTypes.HybridAndClientCredentials,
I'm trying to get the access token in my client using this:
AuthorizationCodeReceived = async n =>
{
// use the code to get the access and refresh token
var tokenClient = new TokenClient(TokenEndpoint, "clientid", "secret");
var response = await tokenClient.RequestAuthorizationCodeAsync(n.Code, n.RedirectUri);
},
I used this reference for above implementation - https://github.com/IdentityServer/IdentityServer3/issues/2457
but the properties in the response has null values. I need the access token so that the user logged in the client can access the api. Below is another way that i'm trying to retrieve the access token:
public async Task<ActionResult> CallApiUsingUserAccessToken()
{
var user = User as ClaimsPrincipal;
var accessToken = user.FindFirst("access_token").Value;
var client = new HttpClient();
client.SetBearerToken(accessToken);
var content = await client.GetStringAsync("http://localhost:6001/api/values");
ViewBag.Json = JArray.Parse(content).ToString();
return View("json");
}
however, user.FindFirst("access_token").Value; is null. I'm thinking of migrating my MVC client to Core because I've tried the IdentityServer4 version in an asp.net core but that seems to be a big migration to my part. Thank you.
[updated]
It never occured to me that the endpoints in the IdentityServer3 differs from IDS4. I did have to change var tokenClient = new TokenClient(TokenEndpoint, "client", "secret"); to var tokenClient = new TokenClient("http://localhost:9000/connect/token", "client", "secret") since TokenEndpoint in IDS3 is http://localhost:9000/core/connect/token which the endpoint "core" does not exist in IDS4. I'm able to get the access token in this line var tokenResponse = await tokenClient.RequestAuthorizationCodeAsync(n.Code, n.RedirectUri); but after authorization, i'm still getting nullreference exception to this var accessToken = user.FindFirst("access_token").Value; line of code.

Answer 1

Given the IdentityServer 4 documentation on
Switching to Hybrid Flow and adding API Access back
and an example client from IdentityServer3.Samples
MVC OWIN Client (Hybrid)
you should be able to setup a working environment.
To support debugging you should always do proper response handling as shown in example below and copied from example client. Add any response errors to your question.
Notifications = new OpenIdConnectAuthenticationNotifications
{
AuthorizationCodeReceived = async n =>
{
// use the code to get the access and refresh token
var tokenClient = new TokenClient(
Constants.TokenEndpoint,
"mvc.owin.hybrid",
"secret");
var tokenResponse = await tokenClient.RequestAuthorizationCodeAsync(
n.Code, n.RedirectUri);
if (tokenResponse.IsError)
{
throw new Exception(tokenResponse.Error);
}
Finally I recommend to add code for all important parts of an IdentityServer3/4 based setup - because the truth is usually burried in the details.

Answer 2

According to these posts, https://github.com/IdentityServer/IdentityServer3/issues/2457 & https://github.com/IdentityServer/IdentityServer3/issues/2015#issuecomment-172623173, it is a good practice to not include the access token in the claims. Hence, I followed his example, https://github.com/Mich-b/IdentityServerTMLClient/blob/master/IdentityServerTMLClient/Startup.cs, in which the access token is added in the Http Session storage.