Azure AD and OAUTH resources - asp.net-core

Question

I am writing a web application that needs to access both PowerBI and Microsoft Graph. I am new with OAUTH so I am not understanding how to request access to two different resources. This is my code to access one (PowerBI) resource. How do I modify it to also get access to Microsoft Graph?
class ConfigureAzureOptions : IConfigureNamedOptions<OpenIdConnectOptions>
{
private readonly PowerBiOptions _powerBiOptions;
private readonly IDistributedCache _distributedCache;
private readonly AzureADOptions _azureOptions;
public ConfigureAzureOptions(IOptions<AzureADOptions> azureOptions, IOptions<PowerBiOptions> powerBiOptions, IDistributedCache distributedCache)
{
_azureOptions = azureOptions.Value;
_powerBiOptions = powerBiOptions.Value;
_distributedCache = distributedCache;
}
public void Configure(string name, OpenIdConnectOptions options)
{
options.ClientId = _azureOptions.ClientId;
options.Authority = _azureOptions.Instance + "/" + _azureOptions.TenantId;
options.UseTokenLifetime = true;
options.CallbackPath = _azureOptions.CallbackPath;
options.RequireHttpsMetadata = false;
options.ClientSecret = _azureOptions.ClientSecret;
options.Resource = _powerBiOptions.Resource;
// Without overriding the response type (which by default is id_token), the OnAuthorizationCodeReceived event is not called.
// but instead OnTokenValidated event is called. Here we request both so that OnTokenValidated is called first which
// ensures that context.Principal has a non-null value when OnAuthorizeationCodeReceived is called
options.ResponseType = "id_token code";
options.Events.OnAuthorizationCodeReceived = OnAuthorizationCodeReceived;
options.Events.OnAuthenticationFailed = OnAuthenticationFailed;
}
public void Configure(OpenIdConnectOptions options)
{
Configure(Options.DefaultName, options);
}
private async Task OnAuthorizationCodeReceived(AuthorizationCodeReceivedContext context)
{
string userObjectId = context.Principal.FindFirst(AccessTokenProvider.Identifier)?.Value;
var authContext = new AuthenticationContext(context.Options.Authority, new DistributedTokenCache(_distributedCache, userObjectId));
var credential = new ClientCredential(context.Options.ClientId, context.Options.ClientSecret);
var authResult = await authContext.AcquireTokenByAuthorizationCodeAsync(context.TokenEndpointRequest.Code,
new Uri(context.TokenEndpointRequest.RedirectUri, UriKind.RelativeOrAbsolute), credential, context.Options.Resource);
context.HandleCodeRedemption(authResult.AccessToken, context.ProtocolMessage.IdToken);
}
private Task OnAuthenticationFailed(AuthenticationFailedContext context)
{
context.HandleResponse();
context.Response.Redirect("/Home/Error?message=" + context.Exception.Message);
return Task.FromResult(0);
}
}

Answer 1

You doesn't need to get each access token for different resource at the first sign-in process .
Suppose the first time you are acquiring PowerBI's access token in OnAuthorizationCodeReceived function , in controller , of course you can directly use that access token to call PowerBI's API since token is cached . Now you need to call Microsoft Graph , just try below codes :
string userObjectID = (User.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier"))?.Value;
// Using ADAL.Net, get a bearer token to access the TodoListService
AuthenticationContext authContext = new AuthenticationContext(AzureAdOptions.Settings.Authority, new NaiveSessionCache(userObjectID, HttpContext.Session));
ClientCredential credential = new ClientCredential(AzureAdOptions.Settings.ClientId, AzureAdOptions.Settings.ClientSecret);
result = await authContext.AcquireTokenSilentAsync("https://graph.microsoft.com", credential, new UserIdentifier(userObjectID, UserIdentifierType.UniqueId));
Just set the resource parameter of AcquireTokenSilentAsync function ,it will use refresh token to acquire access token for new resource .