HowTo: ADB2C User Groups in Token - azure-ad-b2c

Question

I am running a ADB2C tenant and would like to know how to configure and retrieve user groups within a auth token in the ADB2C auth flow.
I am able to configure and receive the custom attribute in my token but I am unable to configure groups claim that can potentially list user membership to a certain group(s).
expected is a groups:{}

Answer 1

In the B2C, there is no group claim that will returns in the token, so you cannot follow the same way in the Azure AD.
You could try to let the application manually retrieve these claims the group claims and inject them into the token.
For this way, you could refer to the method in Azure AD:
var authority = $"https://login.microsoftonline.com/{Tenant}";
var graphCca = new ConfidentialClientApplication(GraphClientId, authority, GraphRedirectUri, new ClientCredential(GraphClientSecret), userTokenCache, null);
string[] scopes = new string[] { "https://graph.microsoft.com/.default" };
try
{
AuthenticationResult authenticationResult = await graphCca.AcquireTokenForClientAsync(scopes);
string token = authenticationResult.AccessToken;
using (var client = new HttpClient())
{
string requestUrl = $"https://graph.microsoft.com/v1.0/users/{signedInUserID}/memberOf?$select=displayName";
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, requestUrl);
request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
HttpResponseMessage response = await client.SendAsync(request);
var responseString = await response.Content.ReadAsStringAsync();
var json = JObject.Parse(responseString);
foreach (var group in json["value"])
notification.AuthenticationTicket.Identity.AddClaim(new System.Security.Claims.Claim(System.Security.Claims.ClaimTypes.Role, group["displayName"].ToString(), System.Security.Claims.ClaimValueTypes.String, "Graph"));
//TODO: Handle paging.
// https://developer.microsoft.com/en-us/graph/docs/concepts/paging
// If the user is a member of more than 100 groups,
// you'll need to retrieve the next page of results.
}
} catch (Exception ex)
{
//TODO: Handle
throw;
}