public RateLimitCounter ProcessRequest(ClientRequestIdentity requestIdentity, RateLimitRule rule)
{
var counter = new RateLimitCounter
{
Timestamp = DateTime.UtcNow,
TotalRequests = 1
};
var counterId = ComputeCounterKey(requestIdentity, rule);
// serial reads and writes
lock (_processLocker)
{
var entry = _counterStore.Get(counterId);
if (entry.HasValue)
{
// entry has not expired
if (entry.Value.Timestamp + rule.PeriodTimespan.Value >= DateTime.UtcNow)
{
// increment request count
var totalRequests = entry.Value.TotalRequests + 1;
// deep copy
counter = new RateLimitCounter
{
Timestamp = entry.Value.Timestamp,
TotalRequests = totalRequests
};
}
}
// stores: id (string) - timestamp (datetime) - total_requests (long)
_counterStore.Set(counterId, counter, rule.PeriodTimespan.Value);
}
return(counter);
}
public RateLimitHeaders GetRateLimitHeaders(ClientRequestIdentity requestIdentity, RateLimitRule rule)
{
var headers = new RateLimitHeaders();
var counterId = ComputeCounterKey(requestIdentity, rule);
var entry = _counterStore.Get(counterId);
if (entry.HasValue)
{
headers.Reset = (entry.Value.Timestamp + ConvertToTimeSpan(rule.Period)).ToUniversalTime().ToString("o", DateTimeFormatInfo.InvariantInfo);
headers.Limit = rule.Period;
headers.Remaining = (rule.Limit - entry.Value.TotalRequests).ToString();
}
else
{
headers.Reset = (DateTime.UtcNow + ConvertToTimeSpan(rule.Period)).ToUniversalTime().ToString("o", DateTimeFormatInfo.InvariantInfo);
headers.Limit = rule.Period;
headers.Remaining = rule.Limit.ToString();
}
return(headers);
}
public virtual void LogBlockedRequest(Microsoft.AspNetCore.Http.HttpContext httpContext, ClientRequestIdentity identity, RateLimitCounter counter, RateLimitRule rule)
{
_logger.LogInformation($"Request {identity.HttpVerb}:{identity.Path} from ClientId {identity.ClientId} has been blocked, quota {rule.Limit}/{rule.Period} exceeded by {counter.TotalRequests}. Blocked by rule {rule.Endpoint}, TraceIdentifier {httpContext.TraceIdentifier}.");
}
public virtual Task ReturnQuotaExceededResponse(Microsoft.AspNetCore.Http.HttpContext httpContext, RateLimitRule rule, string retryAfter)
{
var message = string.IsNullOrEmpty(_options.QuotaExceededMessage) ? $"API calls quota exceeded! maximum admitted {rule.Limit} per {rule.Period}." : _options.QuotaExceededMessage;
if (!_options.DisableRateLimitHeaders)
{
httpContext.Response.Headers["Retry-After"] = retryAfter;
}
httpContext.Response.StatusCode = _options.HttpStatusCode;
return(httpContext.Response.WriteAsync(message));
}
public string RetryAfterFrom(DateTime timestamp, RateLimitRule rule)
{
return(_core.RetryAfterFrom(timestamp, rule));
}
public RateLimitHeaders GetRateLimitHeaders(ClientRequestIdentity requestIdentity, RateLimitRule rule)
{
return(_core.GetRateLimitHeaders(requestIdentity, rule));
}
public RateLimitCounter ProcessRequest(ClientRequestIdentity requestIdentity, RateLimitRule rule)
{
return(_core.ProcessRequest(requestIdentity, rule));
}