コード例 #1
0
        public virtual async Task <RateLimitCounter> ProcessRequestAsync(ClientRequestIdentity requestIdentity, RateLimitRule rule, CancellationToken cancellationToken = default)
        {
            var counter = new RateLimitCounter
            {
                Timestamp = DateTime.UtcNow,
                Count     = 1
            };

            var counterId = BuildCounterKey(requestIdentity, rule);

            // serial reads and writes on same key
            using (await AsyncKeyLock.WriterLockAsync(counterId).ConfigureAwait(false))
            {
                var entry = await _counterStore.GetAsync(counterId, cancellationToken);

                // entry has not expired
                if (entry.HasValue && entry.Value.Timestamp + rule.PeriodTimespan.Value >= DateTime.UtcNow)
                {
                    // increment request count
                    var totalCount = entry.Value.Count + _config.RateIncrementer?.Invoke() ?? 1;

                    // deep copy
                    counter = new RateLimitCounter
                    {
                        Timestamp = entry.Value.Timestamp,
                        Count     = totalCount
                    };
                }

                // stores: id (string) - timestamp (datetime) - total_requests (long)
                await _counterStore.SetAsync(counterId, counter, rule.PeriodTimespan.Value, cancellationToken);
            }

            return(counter);
        }