// 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.PerUserCacheList.FirstOrDefault(c => c.WebUserUniqueId == User);
}
else // retrieve last write from the DB
{
var status = from e in db.PerUserCacheList
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.PerUserCacheList.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)
{
//for a first time person, cache is null.
if (Cache == null)
{
//created a new object
Cache = new PerUserWebCache
{
WebUserUniqueId = User,
CacheBits = this.Serialize(),
LastWrite = DateTime.Now
};
//add it to the DbContext
db.PerUserCacheList.Add(Cache);
}
else
{
//update the CacheBits and LastWrite on the existing cache object.
Cache.CacheBits = this.Serialize();
Cache.LastWrite = DateTime.Now;
db.Entry(Cache).State = EntityState.Modified;
}
//update the database
db.SaveChanges();
//reset the flag
this.HasStateChanged = false;
}
}
// constructor
public EfAdalTokenCache(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.PerUserCacheList.FirstOrDefault(c => c.WebUserUniqueId == User);
// place the entry in memory
this.Deserialize((Cache == null) ? null : Cache.CacheBits);
}