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);
}