public static void RequestProcessing(HttpContext httpContext)
{
if (!Configurationed)
{
return;
}
// check if rate limiting is enabled
if (Options == null)
{
return;
}
// compute identity from request
var identity = SetIdentity(httpContext);
// check white list
if (Processor.IsWhitelisted(identity))
{
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
ReturnQuotaExceededResponse(httpContext, rule, retryAfter);
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);
httpContext.Response.Headers["X-Rate-Limit-Limit"] = headers.Limit;
httpContext.Response.Headers["X-Rate-Limit-Remaining"] = headers.Remaining;
httpContext.Response.Headers["X-Rate-Limit-Reset"] = headers.Reset;
}
}
