public void RequiresThrottling(
IPipelines pipelines,
ThrottlingProperties propertiesSet,
ThrottlingPeriod period,
int requestCountLimit,
Func <NancyContext, bool> checkIf = null,
Func <NancyContext, bool> skipIf = null,
params string[] requestKeys)
{
pipelines.BeforeRequest.AddItemToStartOfPipeline(
ctx => CheckThrottlingLimitHook(ctx, propertiesSet, period, requestCountLimit,
checkIf: checkIf,
skipIf: skipIf,
requestKeys: requestKeys));
}
public void RequiresThrottling(
INancyModule module,
ThrottlingProperties propertiesSet,
ThrottlingPeriod period,
int requestCountLimit,
Func <NancyContext, bool> checkIf = null,
Func <NancyContext, bool> skipIf = null,
params string[] requestKeys)
{
module.AddBeforeHookOrExecute(
ctx => CheckThrottlingLimitHook(ctx, propertiesSet, period, requestCountLimit,
checkIf: checkIf,
skipIf: skipIf,
requestKeys: requestKeys),
"RequiresThrottling");
}
private static string BuildRequestKey(
ThrottlingProperties propertiesSet,
ThrottlingPeriod period,
NancyContext context,
params string[] requestKeys)
{
using (var ms = new MemoryStream())
using (var sw = new StreamWriter(ms, Encoding.UTF8))
{
if (propertiesSet.HasFlag(ThrottlingProperties.RemoteIp))
{
sw.Write(context.GetClientHost());
}
if (propertiesSet.HasFlag(ThrottlingProperties.Method))
{
sw.Write(context.Request.Method);
}
if (propertiesSet.HasFlag(ThrottlingProperties.Path))
{
sw.Write(context.Request.Path);
}
sw.Write(period);
if (requestKeys != null)
{
foreach (var key in requestKeys)
{
sw.Write(key);
}
}
sw.Flush();
ms.Position = 0;
using (var algorithm = new SHA1Managed())
{
var hash = algorithm.ComputeHash(ms);
return(Convert.ToBase64String(hash));
}
}
}
private Response CheckThrottlingLimitHook(
NancyContext context,
ThrottlingProperties propertiesSet,
ThrottlingPeriod period,
int requestCountLimit,
Func <NancyContext, bool> checkIf = null,
Func <NancyContext, bool> skipIf = null,
params string[] requestKeys)
{
if (checkIf != null && !checkIf(context))
{
return(null);
}
if (skipIf != null && skipIf(context))
{
return(null);
}
var key = BuildRequestKey(propertiesSet, period, context, requestKeys);
var expirationTime = CalculateExpirationTime(period);
var counterValue = IncrementCounter(key, expirationTime);
if (IsLimitExceeded(requestCountLimit, counterValue))
{
if (IsNeedToLog(requestCountLimit, counterValue))
{
logger.Error($"Flood detected ({counterValue} in {period.ToString()} allowed {requestCountLimit})" +
$" on path: {context?.Request?.Path}" +
$" ip: {context?.GetClientHost()}");
}
return(new Response
{
StatusCode = HttpStatusCode.TooManyRequests
});
}
return(null);
}
