// constructor
public ADALTokenCache(string user)
{
// associate the cache to the current user of the web app
User = user;
this.AfterAccess = AfterAccessNotification;
this.BeforeAccess = BeforeAccessNotification;
this.BeforeWrite = BeforeWriteNotification;
// look up the entry in the DB
Cache = db.PerUserTokenCacheList.FirstOrDefault(c => c.webUserUniqueId == User);
// place the entry in memory
this.Deserialize((Cache == null) ? null : Cache.cacheBits);
}
// 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.PerUserTokenCacheList.FirstOrDefault(c => c.webUserUniqueId == User);
}
else
{ // retrieve last write from the DB
var status = from e in db.PerUserTokenCacheList
where (e.webUserUniqueId == User)
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.PerUserTokenCacheList.FirstOrDefault(c => c.webUserUniqueId == User);
}
}
this.Deserialize((Cache == null) ? null : Cache.cacheBits);
}
// 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)
{
// check for an existing entry
Cache = db.PerUserTokenCacheList.FirstOrDefault(c => c.webUserUniqueId == User);
if (Cache == null)
{
// if no existing entry for that user, create a new one
Cache = new PerUserTokenCache
{
webUserUniqueId = User,
};
}
// update the cache contents and the last write timestamp
Cache.cacheBits = this.Serialize();
Cache.LastWrite = DateTime.Now;
// update the DB with modification or new entry
db.Entry(Cache).State = Cache.Id == 0 ? EntityState.Added : EntityState.Modified;
db.SaveChanges();
this.HasStateChanged = false;
}
}
