C# 基於StackExchange.Redis.dll利用Redis實現分散式Session
阿新 • • 發佈：2019-01-24
最近在研發一款O2O產品，考慮到分散式架構的需要，以前那一套.NET的Session管理方式已經不合用了。遂研究了一下Redis，發現基於這種Key-Value的記憶體資料庫很適合來做分散式Session。本示例將基於StackExchange.Redis.dll進行實現，序列化使用的是Newtonsoft.json.dll。
為了避免APP等客戶端重複登入導致同一個使用者出現重複的Session，將以ServerID（可以是資料庫主鍵）為服務端令牌，並生成一個新的GUID作為其客戶端令牌，客戶端令牌將返回給客戶端。
兩個令牌都將儲存在Redis中，形成2個鍵值對，在服務端令牌中儲存了其對應的客戶端令牌ID。當同一使用者再次登入時，將首先檢查是否有基於其ServerID的服務端令牌存在，如果存在，則直接取其值（客戶端令牌）返回給客戶端，以此避免重複的Session浪費。
Web.config:
<!--Redis資料庫編號（範圍：0~15）-->
<add key="SessionRedisDBIndex" value="0"/>
<!--主Redis連線串-->
<add key="SessionRedisMaster" value="pass:192.168.1.236:6379"/>
<!--Session有效時長，單位：分鐘-->
<add key="SessionTimeOut" value="120"/>public abstract class BaseSession { DateTime mExpiresTime = DateTime.Now; [JsonConverter(typeof(TimestampConverter))] public DateTime ExpiresTime { get { return mExpiresTime; } } /// <summary> /// 設定Session過期時間 /// </summary> /// <param name="aExpiresTime"></param> internal void SetExpiresTime(DateTime aExpiresTime) { mExpiresTime = aExpiresTime; } [JsonIgnore] /// <summary> /// 獲取服務端ID /// </summary> public abstract string ServerID { get; } }
public static class SessionService { /// <summary> /// Session有效時長,預設120分鐘 /// </summary> static int TimeOutMinutes=120; /// <summary> /// Redis快取訪問物件 /// </summary> static ConnectionMultiplexer mRedisSession; /// <summary> /// Session管理 /// </summary> static SessionService() { try { TimeOutMinutes = int.Parse(ConfigurationManager.AppSettings["SessionTimeOut"]); string[] redisMaster = ConfigurationManager.AppSettings["SessionRedisMaster"].Split(':'); ConfigurationOptions fRedisConfig = new ConfigurationOptions() { Password = redisMaster[0], EndPoints ={ { redisMaster[1], int.Parse(redisMaster[2]) } }, KeepAlive = 180, DefaultDatabase = int.Parse(ConfigurationManager.AppSettings["SessionRedisDBIndex"]) }; mRedisSession = ConnectionMultiplexer.Connect(fRedisConfig); } catch (Exception ex) { Lib.LocalLog.Append("Session Error(SessionService):" + ex.Message, "", "SessionError", "SessionError"); throw ex; } } /// <summary> /// 新增Session /// </summary> /// <typeparam name="T">Session物件型別</typeparam> /// <param name="aSession">要存為Session的物件</param> /// <param name="aPrefix">字首</param> /// <returns>令牌</returns> public static string Add<T>(T aSession,string aPrefix="") where T:BaseSession { try { IDatabase client = mRedisSession.GetDatabase(); aSession.SetExpiresTime(DateTime.Now.AddMinutes(TimeOutMinutes)); string fExistToken = client.StringGet(aSession.ServerID);//獲取服務端唯一碼當前對應的客戶端令牌 if (fExistToken != null) {//存在客戶端令牌 //更新客戶端令牌 if (client.StringSet(fExistToken, JsonConvert.SerializeObject(aSession), aSession.ExpiresTime.Subtract(DateTime.Now))) { return fExistToken; } } else { string token = aPrefix + Guid.NewGuid().ToString("N"); if(client.StringSet(token, JsonConvert.SerializeObject(aSession), aSession.ExpiresTime.Subtract(DateTime.Now)) &&//新增Session client.StringSet(aSession.ServerID, token, aSession.ExpiresTime.AddSeconds(-5).Subtract(DateTime.Now)))//繫結服務端唯一碼與客戶端令牌（將比Session早5秒失效） { return token; } } } catch (Exception ex) { Lib.LocalLog.Append("Session Error(Add<T>):" + ex.Message, "", "SessionError", "SessionError"); } return null; } /// <summary> /// 獲取Session /// </summary> /// <typeparam name="T">Session物件型別</typeparam> /// <param name="aToken">令牌</param> /// <returns>令牌對應的Session物件</returns> public static T Get<T>(string aToken) where T : BaseSession { try { IDatabase client = mRedisSession.GetDatabase(); T fEntity = null; string fSessionValue = client.StringGet(aToken); if (!string.IsNullOrEmpty(fSessionValue)) { fEntity = JsonConvert.DeserializeObject<T>(fSessionValue); CheckExpireTime<T>(aToken, fEntity, client); } return fEntity; } catch (Exception ex) { Lib.LocalLog.Append("Session Error(Get<T>):" + ex.Message, "", "SessionError", "SessionError"); } return default(T); } /// <summary> /// 獲取Session 字串值 /// </summary> /// <param name="aToken">令牌</param> /// <returns>令牌對應的Session 字串值</returns> public static string GetValue<T>(string aToken) where T : BaseSession { try { IDatabase client = mRedisSession.GetDatabase(); string fSessionValue = client.StringGet(aToken); if (fSessionValue != null) { CheckExpireTime<T>(aToken, JsonConvert.DeserializeObject<T>(fSessionValue), client); } return fSessionValue; } catch (Exception ex) { Lib.LocalLog.Append("Session Error(GetValue<T>):" + ex.Message, "", "SessionError", "SessionError"); } return null; } /// <summary> /// 刪除Session /// </summary> /// <param name="aToken">令牌</param> public static void Remove<T>(string aToken) where T : BaseSession { try { IDatabase client = mRedisSession.GetDatabase(); T fEntity = null; string fSessionValue = client.StringGet(aToken); if (!string.IsNullOrEmpty(fSessionValue)) { fEntity = JsonConvert.DeserializeObject<T>(fSessionValue); client.KeyDelete(fEntity.ServerID); client.KeyDelete(aToken); } } catch (Exception ex) { Lib.LocalLog.Append("Session Error(Remove):" + ex.Message, "", "SessionError", "SessionError"); } } /// <summary> /// 令牌有效時間檢查 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="aToken">令牌</param> /// <param name="aSession"></param> static void CheckExpireTime<T>(string aToken, T aSession, IDatabase client) where T : BaseSession { if (aSession.ExpiresTime.Subtract(DateTime.Now).TotalMinutes < 10) {//離Session過期時間小於10分鐘，延長Session有效期 try { aSession.SetExpiresTime(DateTime.Now.AddMinutes(TimeOutMinutes)); client.StringSet(aToken, JsonConvert.SerializeObject(aSession), aSession.ExpiresTime.Subtract(DateTime.Now)); client.KeyExpire(aSession.ServerID, aSession.ExpiresTime.AddSeconds(-5).Subtract(DateTime.Now)); } catch (Exception ex) { Lib.LocalLog.Append("Session Error(6):" + ex.Message, "", "SessionError", "SessionError"); } } } }