I configured my MVC webapp using the built-in "Configure Azure AD Authentication" function and it provided me with the following code:
public async Task<string> GetTokenForApplication()
{
string signedInUserID = ClaimsPrincipal.Current.FindFirst(ClaimTypes.NameIdentifier).Value;
string tenantID = ClaimsPrincipal.Current.FindFirst("http://schemas.microsoft.com/identity/claims/tenantid").Value;
string userObjectID = ClaimsPrincipal.Current.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier").Value;
// get a token for the Graph without triggering any user interaction (from the cache, via multi-resource refresh token, etc)
ClientCredential clientcred = new ClientCredential(clientId, appKey);
// initialize AuthenticationContext with the token cache of the currently signed in user, as kept in the app's database
AuthenticationContext authenticationContext = new AuthenticationContext(aadInstance + tenantID, new ADALTokenCache(signedInUserID));
AuthenticationResult authenticationResult = await authenticationContext.AcquireTokenSilentAsync(graphResourceID, clientcred, new UserIdentifier(userObjectID, UserIdentifierType.UniqueId));
return authenticationResult.AccessToken;
}
And heres the model
public class ADALTokenCache : TokenCache
{
private ApplicationDbContext db = new ApplicationDbContext();
private string userId;
private UserTokenCache Cache;
public ADALTokenCache(string signedInUserId)
{
// associate the cache to the current user of the web app
userId = signedInUserId;
this.AfterAccess = AfterAccessNotification;
this.BeforeAccess = BeforeAccessNotification;
this.BeforeWrite = BeforeWriteNotification;
// look up the entry in the database
Cache = db.UserTokenCacheList.FirstOrDefault(c => c.webUserUniqueId == userId);
// place the entry in memory
this.Deserialize((Cache == null) ? null : MachineKey.Unprotect(Cache.cacheBits,"ADALCache"));
}
// clean up the database
public override void Clear()
{
base.Clear();
var cacheEntry = db.UserTokenCacheList.FirstOrDefault(c => c.webUserUniqueId == userId);
db.UserTokenCacheList.Remove(cacheEntry);
db.SaveChanges();
}
// Notification raised before ADAL accesses the cache.
// This is your chance to update the in-memory copy from the DB, if the in-memory version is stale
void BeforeAccessNotification(TokenCacheNotificationArgs args)
{
if (Cache == null)
{
// first time access
Cache = db.UserTokenCacheList.FirstOrDefault(c => c.webUserUniqueId == userId);
}
else
{
// retrieve last write from the DB
var status = from e in db.UserTokenCacheList
where (e.webUserUniqueId == userId)
select new
{
LastWrite = e.LastWrite
};
// if the in-memory copy is older than the persistent copy
if (status.First().LastWrite > Cache.LastWrite)
{
// read from from storage, update in-memory copy
Cache = db.UserTokenCacheList.FirstOrDefault(c => c.webUserUniqueId == userId);
}
}
this.Deserialize((Cache == null) ? null : MachineKey.Unprotect(Cache.cacheBits, "ADALCache"));
}
// Notification raised after ADAL accessed the cache.
// If the HasStateChanged flag is set, ADAL changed the content of the cache
void AfterAccessNotification(TokenCacheNotificationArgs args)
{
// if state changed
if (this.HasStateChanged)
{
Cache = new UserTokenCache
{
webUserUniqueId = userId,
cacheBits = MachineKey.Protect(this.Serialize(), "ADALCache"),
LastWrite = DateTime.Now
};
// update the DB and the lastwrite
db.Entry(Cache).State = Cache.UserTokenCacheId == 0 ? EntityState.Added : EntityState.Modified;
db.SaveChanges();
this.HasStateChanged = false;
}
}
void BeforeWriteNotification(TokenCacheNotificationArgs args)
{
// if you want to ensure that no concurrent write take place, use this notification to place a lock on the entry
}
public override void DeleteItem(TokenCacheItem item)
{
base.DeleteItem(item);
}
}
DBContext:
public class ApplicationDbContext : DbContext
{
public ApplicationDbContext()
: base("AzureDatabase")
{
}
public DbSet<UserTokenCache> UserTokenCacheList { get; set; }
}
public class UserTokenCache
{
[Key]
public int UserTokenCacheId { get; set; }
public string webUserUniqueId { get; set; }
public byte[] cacheBits { get; set; }
public DateTime LastWrite { get; set; }
}
At first all the token cache were stored in a local database auto configured by the function connected to a database called "defaultconnection". However as I was trying to publish my web app I was getting errors and I realised it was because all the tokens are stored locally. So I tried to migrate the DBContext to my Azure Database. After I've migrated I keep getting this exception. Is there a way to fix this??
