public bool ApplyRateLimit(string key, double bucketSize)
{
bool resourceConsumed = false;
var rateLimit = _instance.GetRateLimitByKey(key);
if (rateLimit != null)
{
resourceConsumed = ConsumeResource(rateLimit, out RateLimitModel updatedRateLimit);
_instance.UpdateRateLimit(updatedRateLimit);
}
else
{
DateTimeOffset currentTime = DateTimeOffset.Now;
long maxTimeWindow = currentTime.AddSeconds(_maxTimeWindow).ToUnixTimeMilliseconds();
var newrateLimit = new RateLimitModel
{
Token = key,
FillRate = bucketSize / maxTimeWindow,
CurrentBucketSize = bucketSize,
MaxBucketSize = bucketSize,
LastUpdatedTime = currentTime.ToUnixTimeMilliseconds()
};
_instance.UpdateRateLimit(newrateLimit);
resourceConsumed = true;
}
return(resourceConsumed);
}
// Update rate Limit
public void UpdateRateLimit(RateLimitModel rateLimit)
{
try
{
if (!string.IsNullOrEmpty(rateLimit.Token))
{
if (_dictionaryRateLimit.ContainsKey(rateLimit.Token))
{
_dictionaryRateLimit.Remove(rateLimit.Token);
}
_dictionaryRateLimit.Add(rateLimit.Token, rateLimit);
}
}
catch (Exception)
{
throw;
}
}
// Get rate Limit
public RateLimitModel GetRateLimitByKey(string key)
{
RateLimitModel rateLimit = null;
try
{
if (!string.IsNullOrEmpty(key) && _dictionaryRateLimit.ContainsKey(key))
{
rateLimit = _dictionaryRateLimit[key];
}
}
catch (Exception)
{
throw;
}
return(rateLimit);
}
public bool ConsumeResource(RateLimitModel rateLimit, out RateLimitModel updatedRateLimit)
{
bool resourceConsumed = false;
double currentBucket = rateLimit.CurrentBucketSize;
double maxBucket = rateLimit.MaxBucketSize;
long lastUpdatedTime = rateLimit.LastUpdatedTime;
double fillRate = rateLimit.FillRate;
updatedRateLimit = new RateLimitModel();
// check if key is suspended, if yes return false
if (lastUpdatedTime <= DateTimeOffset.Now.ToUnixTimeMilliseconds())
{
// get the time in milliseconds , since the lastupdatedtime
long timeSinceLastUpdatedTime =
DateTimeOffset.Now.ToUnixTimeMilliseconds() - lastUpdatedTime;
// get Current bucket
currentBucket = Math.Min(maxBucket,
currentBucket + timeSinceLastUpdatedTime * fillRate);
// get new lastUpdatedTime
lastUpdatedTime += timeSinceLastUpdatedTime;
// uppdate rateLimit
updatedRateLimit.Token = rateLimit.Token;
updatedRateLimit.MaxBucketSize = rateLimit.MaxBucketSize;
updatedRateLimit.FillRate = rateLimit.FillRate;
if (currentBucket >= _amount)
{
currentBucket -= _amount;
updatedRateLimit.CurrentBucketSize = currentBucket;
updatedRateLimit.MaxBucketSize = rateLimit.MaxBucketSize;
updatedRateLimit.LastUpdatedTime = lastUpdatedTime;
resourceConsumed = true;
}
}
return(resourceConsumed);
}
