// 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.UserTokenCaches.FirstOrDefault(c => c.webUserUniqueId == userId);
}
else
{
// retrieve last write from the DB
var status = from e in db.UserTokenCaches
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.UserTokenCaches.FirstOrDefault(c => c.webUserUniqueId == userId);
}
}
this.Deserialize((Cache == null) ? null : MachineKey.Unprotect(Cache.cacheBits, "ADALCache"));
}
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.UserTokenCaches.FirstOrDefault(c => c.webUserUniqueId == userId);
// place the entry in memory
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 (this.HasStateChanged)
{
Cache = Cache ?? new UserTokenCach();
Cache.webUserUniqueId = userId;
Cache.cacheBits = MachineKey.Protect(this.Serialize(), "ADALCache");
Cache.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;
}
}