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);
}
async Task <IRequestTrackerResult> PreEvaluateRateLimitRules(IdentityServerRequestRecord requestRecord)
{
// ONLY CHECK THE COUNT and Deny. DO NOT MUTATE any data
var identity = new ClientRequestIdentity()
{
ClientId = requestRecord.Client.ClientId,
EndpointKey = requestRecord.EndpointKey
};
var rateLimitClientsRule = _processor.GetRateLimitClientsRule(identity);
if (rateLimitClientsRule == null)
{
// no rules for us to evaluate
return(null);
}
var result = _serviceProvider.GetService <ClientRateLimiterRequestTrackerResult>();
result.RateLimitClientsRule = rateLimitClientsRule;
result.IdentityServerRequestRecord = requestRecord;
result.Directive = RequestTrackerEvaluatorDirective.AllowRequest;
foreach (var rule in rateLimitClientsRule.Settings.RateLimitRules)
{
if (rule.Limit > 0)
{
// get the current counter
var counter = _processor.GetCurrentRateLimitCounter(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(requestRecord.HttpContext, identity, counter, rule);
// break execution
result.Directive = RequestTrackerEvaluatorDirective.DenyRequest;
result.Rule = rule;
result.RetryAfter = retryAfter;
return(result);
}
}
else
{
// process request count
var counter = _processor.GetCurrentRateLimitCounter(identity, rule);
// log blocked request
LogBlockedRequest(requestRecord.HttpContext, identity, counter, rule);
// break execution (Int32 max used to represent infinity)
// break execution
result.Directive = RequestTrackerEvaluatorDirective.DenyRequest;
result.Rule = rule;
result.RetryAfter = Int32.MaxValue.ToString(System.Globalization.CultureInfo.InvariantCulture);
return(result);
}
}
result.Rule = rateLimitClientsRule.Settings.RateLimitRules
.OrderByDescending(x => x.PeriodTimespan.Value).First();
return(result);
}
