public async Task <IEnumerable <RateLimitCounterRecord> > GetRateLimitCounterRecordsAsync(ClientRequestIdentity identity)
{
var rules = _processor.GetMatchingRules(identity);
List <RateLimitCounterRecord> rateLimitCounterRecords = new List <RateLimitCounterRecord>();
foreach (var rule in rules)
{
RateLimitCounter?counter = _core.GetStoredRateLimitCounter(identity, rule);
var record = new RateLimitCounterRecord
{
RateLimitCounter = counter,
RateLimitRule = rule
};
rateLimitCounterRecords.Add(record);
}
return(rateLimitCounterRecords);
}
public async Task Invoke(HttpContext httpContext)
{
// check if rate limiting is enabled
if (_options == null)
{
await _next.Invoke(httpContext);
return;
}
// compute identity from request
var identity = await _clientRequestStore.GetClientRequestIdentityAsync(httpContext);
if (identity == null)
{
await _next.Invoke(httpContext);
return;
}
// check white list
if (_processor.IsWhitelisted(identity))
{
await _next.Invoke(httpContext);
return;
}
var rules = _processor.GetMatchingRules(identity);
foreach (var rule in rules)
{
if(rule.Limit > 0)
{
// increment counter
var counter = _processor.ProcessRequest(identity, rule);
// check if key expired
if (counter.Timestamp + rule.PeriodTimespan.Value < DateTime.UtcNow)
{
continue;
}
// check if limit is reached
if (counter.TotalRequests > rule.Limit)
{
//compute retry after value
var retryAfter = _processor.RetryAfterFrom(counter.Timestamp, rule);
// log blocked request
LogBlockedRequest(httpContext, identity, counter, rule);
// break execution
await ReturnQuotaExceededResponse(httpContext, rule, retryAfter);
return;
}
}
// if limit is zero or less, block the request.
else
{
// process request count
var counter = _processor.ProcessRequest(identity, rule);
// log blocked request
LogBlockedRequest(httpContext, identity, counter, rule);
// break execution (Int32 max used to represent infinity)
await ReturnQuotaExceededResponse(httpContext, rule, Int32.MaxValue.ToString(System.Globalization.CultureInfo.InvariantCulture));
return;
}
}
//set X-Rate-Limit headers for the longest period
if(rules.Any() && !_options.DisableRateLimitHeaders)
{
var rule = rules.OrderByDescending(x => x.PeriodTimespan.Value).First();
var headers = _processor.GetRateLimitHeaders(identity, rule);
headers.Context = httpContext;
httpContext.Response.OnStarting(SetRateLimitHeaders, state: headers);
}
await _next.Invoke(httpContext);
}