一段基于Redis-SortedSet的限流代码

[HttpGet]
      public async Task<ActionResult<string>> Get()
      {
          //限流周期：5秒
          int period = 5;
          //周期内请求数限制：5次，即限制每五秒只能请求五次
          int maxCount = 5;
          long uid = 123456;
          string action = "login";
          string key = string.Format("hist:{0}{1}", uid, action);
          long current = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
 
          var batch = db.CreateBatch();
          var tasks = new List<Task>();
          //加入SortedSet
          tasks.Add(batch.SortedSetAddAsync(key, current, current));
          //移除五秒之前的记录
          tasks.Add(batch.SortedSetRemoveRangeByScoreAsync(key, 0, current - period * 1000));
          //重置过期时间
          tasks.Add(batch.KeyExpireAsync(key, TimeSpan.FromSeconds(period + 1)));
          batch.Execute();
 
          //获取请求的次数
          long currentCount = await db.SortedSetLengthAsync(key);
          //返回是否大于限制次数
          bool res = currentCount <= maxCount;
 
          return res ? "未被限流，正常请求" : "超过请求频次，限制请求";
      }