/// <summary> /// Raised AFTER MSAL added the new token in its in-memory copy of the cache. /// This notification is called every time MSAL accessed the cache, not just when a write took place: /// If MSAL's current operation resulted in a cache change, the property TokenCacheNotificationArgs.HasStateChanged will be set to true. /// If that is the case, we call the TokenCache.Serialize() to get a binary blob representing the latest cache content – and persist it. /// </summary> /// <param name="args">Contains parameters used by the MSAL call accessing the cache.</param> private void AppTokenCacheAfterAccessNotification(TokenCacheNotificationArgs args) { // if state changed, i.e. new token obtained if (args.HasStateChanged && !string.IsNullOrWhiteSpace(_activeClientId)) { if (_inMemoryCache == null) { _inMemoryCache = new AppTokenCache { ClientID = _activeClientId }; } _inMemoryCache.CacheBits = _dataProtector.Protect(_apptokenCache.SerializeMsalV3()); _inMemoryCache.LastWrite = DateTime.Now; try { // Update the DB and the lastwrite _tokenCacheDb.Entry(_inMemoryCache).State = _inMemoryCache.AppTokenCacheId == 0 ? EntityState.Added : EntityState.Modified; _tokenCacheDb.SaveChanges(); } catch (DbUpdateConcurrencyException) { // Record already updated on a different thread, so just read the updated record ReadCacheForSignedInApp(); } } }
/// <summary> /// Reads the cache data from the backend database. /// </summary> private void ReadCacheForSignedInApp() { if (_inMemoryCache == null) // first time access { _inMemoryCache = GetLatestAppRecordQuery().FirstOrDefault(); } else { // retrieve last written record from the DB var lastwriteInDb = GetLatestAppRecordQuery().Select(n => n.LastWrite).FirstOrDefault(); // if the persisted copy is newer than the in-memory copy if (lastwriteInDb > _inMemoryCache.LastWrite) { // read from from storage, update in-memory copy _inMemoryCache = GetLatestAppRecordQuery().FirstOrDefault(); } } // Send data to the TokenCache instance _apptokenCache.DeserializeMsalV3((_inMemoryCache == null) ? null : _dataProtector.Unprotect(_inMemoryCache.CacheBits)); }