Question

我正在使用ADAL（Azure目录身份验证库）与Office 365 API进行通信。我知道我需要保留Serialize()的字节数组。在记忆中一切正常。

我试图将其保留在SQL服务器中varchar，其中.net c＃代码基本上是字符串。

如何将字节数组保存到数据库中并将其读回。我不知道用什么编码来获取字节数组。我尝试过ASCII，当然它不起作用。那里有专家吗？

Answer 1

如果要将字节存储到varchar字段，则需要先对其进行编码。例如，您可以使用base64编码将字节编码为字符串。

但是没有必要对字节进行编码，我们可以直接使用varbinary字段将其存储到SQL中。以下是使用数据库存储此code sample：

中的令牌的一段代码

public class ADALTokenCache : TokenCache
{
        private ApplicationDbContext db = new ApplicationDbContext();
        string User;
        UserTokenCache Cache;

        // 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.UserTokenCacheList.FirstOrDefault(c => c.webUserUniqueId == User);
            // place the entry in memory
            this.Deserialize((Cache == null) ? null : Cache.cacheBits);
        }

        // clean up the DB
        public override void Clear()
        {
            base.Clear();
            foreach (var cacheEntry in db.UserTokenCacheList)
                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 == User);
            }
            else
            {   // retrieve last write from the DB
                var status = from e in db.UserTokenCacheList
                             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.UserTokenCacheList.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)
            {
                Cache = new UserTokenCache
                {
                    webUserUniqueId = User,
                    cacheBits = this.Serialize(),
                    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 class ApplicationDbContext : DbContext
{
    public ApplicationDbContext()
        : base("DefaultConnection")
    {
    }

    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; }
}

ADAL令牌在数据库中保留

1 个答案: