private static string GetAccessToken() {
// get user ID in security cookie
var signedInUserID = ClaimsPrincipal.Current.FindFirst(ClaimTypes.NameIdentifier).Value;
// get token cache for signed in user
ApplicationDbContext db = new ApplicationDbContext();
ADALTokenCache userTokenCache = new ADALTokenCache(signedInUserID);
AuthenticationContext authContext = new AuthenticationContext(Authority, userTokenCache);
// Get credentials for user
var clientCredential = new ClientCredential(clientId, clientSecret);
// Create user identifier object using User ID for Azure Active Directory account
string objectIdentifierID = "http://schemas.microsoft.com/identity/claims/objectidentifier";
var userObjectId = ClaimsPrincipal.Current.FindFirst(objectIdentifierID).Value;
var userIdentifier = new UserIdentifier(userObjectId, UserIdentifierType.UniqueId);
// call to ADAL to get access token from cache of across network
var authResult = authContext.AcquireTokenSilent(urlMicrosoftGraphApiResource, clientCredential, userIdentifier);
// obtain access token
return authResult.AccessToken;
}
private static async Task<string> GetAccessTokenAsync() {
// determine authorization URL for current tenant
string authorizationUrlRoot = ConfigurationManager.AppSettings["ida:AADInstance"];
string tenantID = ClaimsPrincipal.Current.FindFirst("http://schemas.microsoft.com/identity/claims/tenantid").Value;
string authorizationUrlTenant = authorizationUrlRoot + tenantID;
// create ADAL cache object
ApplicationDbContext db = new ApplicationDbContext();
string signedInUserID = ClaimsPrincipal.Current.FindFirst(ClaimTypes.NameIdentifier).Value;
ADALTokenCache userTokenCache = new ADALTokenCache(signedInUserID);
// create authentication context
AuthenticationContext authenticationContext = new AuthenticationContext(authorizationUrlTenant, userTokenCache);
// determine the resources to be accessed
string MicrosoftGraphApiResourceId = "https://graph.Microsoft.com";
// create client credential object using client ID and client secret
string clientId = ConfigurationManager.AppSettings["ida:ClientId"];
string clientSecret = ConfigurationManager.AppSettings["ida:ClientSecret"];
ClientCredential clientCredential = new ClientCredential(clientId, clientSecret);
// create user identifier object for logged on user
string objectIdentifierId = "http://schemas.microsoft.com/identity/claims/objectidentifier";
string userObjectID = ClaimsPrincipal.Current.FindFirst(objectIdentifierId).Value;
UserIdentifier userIdentifier = new UserIdentifier(userObjectID, UserIdentifierType.UniqueId);
// get access token for Office 365 unifed API from AAD
AuthenticationResult authenticationResult =
await authenticationContext.AcquireTokenSilentAsync(MicrosoftGraphApiResourceId, clientCredential, userIdentifier);
// return access token back to user
return authenticationResult.AccessToken;
}
