asp.net mvc 用Redis实现分布式集群共享Session。

1、这两天研究Redis搞分布式session问题，网上找的资料都是用ServiceStack.Redis来实现的，但是在做性能测试的时候发现最新的v4版本有限制每小时候最多请求6000次，因为官网开始商业化要收费了，好坑爹的说，还好我前期弄了个性能测试列子，不然上线以后出问题那就麻烦了。后面找了个NServiceKit.Redis（好像就是ServiceStack.Redis的v3版本）来替代v4的收费版。

2、解决方案是 Redis+cookie方式实现记录用户登录状态

     cookie：存放用户的ID，这个ID是经过加密的，并且后台可以通过密钥解密。

     Redis：key/value 方式存储，key存放比如：user_1。  value存放用户实体对象。

3、先安装一个Redis，windows的版本在本地进行测试，后期上线更换linux系统的Redis替换一下ip就可以了。

4、添加一个Session管理类

public class SessionHelper
    {
        private const int secondsTimeOut = 60 * 20;  //默认过期时间20分钟  单位秒


        public RedisHelper Redis = new RedisHelper(false);
        public LoginUserInfo this[string key]
        {
            get
            {
                string webCookie = WebHelper.GetCookie(key);
                if (webCookie == "")
                {
                    return null;
                }
                key = key + "_" + SecureHelper.AESDecrypt(webCookie);

                //距离过期时间还有多少秒
                long l = Redis.TTL(key);
                if (l >= 0)
                {
                    Redis.Expire(key, secondsTimeOut);
                }
                
                return Redis.Get<LoginUserInfo>(key);
            }
            set
            {
                SetSession(key, value);
            }
        }
        public void SetSession(string key, LoginUserInfo value)
        {
            if (string.IsNullOrWhiteSpace(key))
            {
                throw new Exception("Key is Null or Epmty");
            }
            WebHelper.SetCookie(key, SecureHelper.AESEncrypt(value.ID.ToString()));
            key = key + "_" + value.ID;
            Redis.Set<LoginUserInfo>(key, value, secondsTimeOut);
        }

        /// <summary>
        /// 移除Session
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public bool Remove(string key)
        {
            var rs = Redis.Remove(key + "_" + SecureHelper.AESDecrypt(WebHelper.GetCookie(key)));
            WebHelper.DeleteCookie(key);
            return rs;
        }
             
    }

5、Redis操作类

public class RedisHelper : IDisposable
    {
       private RedisClient Redis = new RedisClient("127.0.0.1", 6379);
        //缓存池
        PooledRedisClientManager prcm = new PooledRedisClientManager();

        //默认缓存过期时间单位秒
        public int secondsTimeOut = 20 * 60;

        /// <summary>
        /// 缓冲池
        /// </summary>
        /// <param name="readWriteHosts"></param>
        /// <param name="readOnlyHosts"></param>
        /// <returns></returns>
        public static PooledRedisClientManager CreateManager(string[] readWriteHosts, string[] readOnlyHosts)
        {
            return new PooledRedisClientManager(readWriteHosts, readOnlyHosts,
                new RedisClientManagerConfig
                {
                    MaxWritePoolSize = readWriteHosts.Length * 5,
                    MaxReadPoolSize = readOnlyHosts.Length * 5,
                    AutoStart = true,
                }); 
        }
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="OpenPooledRedis">是否开启缓冲池</param>
        public RedisHelper(bool OpenPooledRedis = false)
        {

            if (OpenPooledRedis)
            {
                prcm = CreateManager(new string[] { "127.0.0.1:6379" }, new string[] { "127.0.0.1:6379" });
                Redis = prcm.GetClient() as RedisClient;
            }
        }
        /// <summary>
        /// 距离过期时间还有多少秒
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public long TTL(string key)
        {
            return Redis.Ttl(key);
        }
        /// <summary>
        /// 设置过期时间
        /// </summary>
        /// <param name="key"></param>
        /// <param name="timeout"></param>
        public void Expire(string key,int timeout = 0)
        {
            if (timeout >= 0)
            {
                if (timeout > 0)
                {
                    secondsTimeOut = timeout;
                }
                Redis.Expire(key, secondsTimeOut);
            }
        }

        #region Key/Value存储
        /// <summary>
        /// 设置缓存
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="key">缓存建</param>
        /// <param name="t">缓存值</param>
        /// <param name="timeout">过期时间，单位秒,-1：不过期，0：默认过期时间</param>
        /// <returns></returns>
        public bool Set<T>(string key, T t, int timeout = 0)
        {
            Redis.Set<T>(key, t);
            if (timeout >= 0)
            {
                if (timeout > 0)
                {
                    secondsTimeOut = timeout;
                }
                Redis.Expire(key, secondsTimeOut);
            }
            return true;
            
        }
        /// <summary>
        /// 获取
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="key"></param>
        /// <returns></returns>
        public T Get<T>(string key)
        {
            return Redis.Get<T>(key);
        }
        /// <summary>
        /// 删除
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public bool Remove(string key)
        {
            return Redis.Remove(key);
        }
        #endregion

        //释放资源
        public void Dispose()
        {
            if (Redis != null)
            {
                Redis.Dispose();
                Redis = null;
            }
            GC.Collect();

        }
    }