public ThrottleProcessResult Process(RequestIdentity identity, IEnableThrottlingAttribute attrPolicy = null)
{
Identity = identity;
Policy = PolicyRepo.FirstOrDefault(ThrottleManager.GetPolicyKey());
if (Policy != null)
{
Checking(attrPolicy);
}
return(processResult);
}
public ThrottleLogEntry ComputeLogEntry(
string requestId,
RequestIdentity identity,
ThrottleCounter throttleCounter,
string rateLimitPeriod,
long rateLimit)
{
return(new ThrottleLogEntry
{
ClientIp = identity.ClientIp,
ClientKey = identity.ClientKey,
Endpoint = identity.Endpoint,
LogDate = DateTime.UtcNow,
RateLimit = rateLimit,
RateLimitPeriod = rateLimitPeriod,
RequestId = requestId,
StartPeriod = throttleCounter.Timestamp,
TotalRequests = throttleCounter.TotalRequests
});
}
public void ApplyRules(RequestIdentity identity, TimeSpan timeSpan, RateLimitPeriod rateLimitPeriod, ref long rateLimit)
{
// apply endpoint rate limits
if (Policy.EndpointRules != null)
{
var rules = Policy.EndpointRules.Where(x => identity.Endpoint.Contains(x.Key.ToLowerInvariant())).ToList();
if (rules.Any())
{
// get the lower limit from all applying rules
var customRate = (from r in rules let rateValue = r.Value.GetLimit(rateLimitPeriod) select rateValue).Min();
if (customRate > 0)
{
rateLimit = customRate;
}
}
}
// apply custom rate limit for clients that will override endpoint limits
if (Policy.ClientRules != null && Policy.ClientRules.Keys.Contains(identity.ClientKey))
{
var limit = Policy.ClientRules[identity.ClientKey].GetLimit(rateLimitPeriod);
if (limit > 0)
{
rateLimit = limit;
}
}
// enforce ip rate limit as is most specific
string ipRule = null;
if (Policy.IpRules != null && ContainsIp(Policy.IpRules.Keys.ToList(), identity.ClientIp, out ipRule))
{
var limit = Policy.IpRules[ipRule].GetLimit(rateLimitPeriod);
if (limit > 0)
{
rateLimit = limit;
}
}
}
public string ComputeThrottleKey(RequestIdentity requestIdentity, RateLimitPeriod period)
{
var keyValues = new List <string>()
{
ThrottleManager.GetThrottleKey()
};
if (Policy.IpThrottling)
{
keyValues.Add(requestIdentity.ClientIp);
}
if (Policy.ClientThrottling)
{
keyValues.Add(requestIdentity.ClientKey);
}
if (Policy.EndpointThrottling)
{
keyValues.Add(requestIdentity.Endpoint);
}
keyValues.Add(period.ToString());
var id = string.Join("_", keyValues);
var idBytes = Encoding.UTF8.GetBytes(id);
byte[] hashBytes;
using (var algorithm = System.Security.Cryptography.HashAlgorithm.Create("SHA1"))
{
hashBytes = algorithm.ComputeHash(idBytes);
}
var hex = BitConverter.ToString(hashBytes).Replace("-", string.Empty);
return(hex);
}
public ThrottleCounter ProcessRequest(RequestIdentity requestIdentity, TimeSpan timeSpan, RateLimitPeriod period, out string id)
{
var throttleCounter = new ThrottleCounter()
{
Timestamp = DateTime.UtcNow,
TotalRequests = 1
};
id = ComputeThrottleKey(requestIdentity, period);
// serial reads and writes
lock (ProcessLocker)
{
var entry = ThrottleRepo.FirstOrDefault(id);
if (entry.HasValue)
{
// entry has not expired
if (entry.Value.Timestamp + timeSpan >= DateTime.UtcNow)
{
// increment request count
var totalRequests = entry.Value.TotalRequests + 1;
// deep copy
throttleCounter = new ThrottleCounter
{
Timestamp = entry.Value.Timestamp,
TotalRequests = totalRequests
};
}
}
// stores: id (string) - timestamp (datetime) - total (long)
ThrottleRepo.Save(id, throttleCounter, timeSpan);
}
return(throttleCounter);
}
