private async Task <RateLimiterContext> GetRateLimiterContextAsync(HttpContext context)
{
var ip = context.Connection.RemoteIpAddress?.ToString();
var rateLimiterContext = new RateLimiterContext();
rateLimiterContext.IpNumber = ip;
foreach (var rule in Settings.Rules)
{
var cacheKey = $"{rule.Name}:{ip}";
var contextString = await _cache.GetStringAsync(cacheKey);
RateLimiterRuleContext ruleContext;
if (contextString != null)
{
ruleContext = new RateLimiterRuleContext(contextString);
ruleContext.ExistsInCache = true;
ruleContext.Rule = Settings.Rules.Find(r => r.Name == rule.Name);
}
else
{
ruleContext = new RateLimiterRuleContext(rule);
}
ruleContext.Context = rateLimiterContext;
rateLimiterContext.Rules.Add(ruleContext);
}
return(rateLimiterContext);
}
private void CheckIfCallerIsBanned(RateLimiterContext context)
{
foreach (var ruleContext in context.Rules)
{
if (ruleContext.Banned)
{
throw new TooManyRequestsException("Too many requests", ruleContext.SecondsLeftOnBan);
}
}
}
private Task WriteRateLimiterContextAsync(RateLimiterContext rateLimiterContext)
{
foreach (var ruleContext in rateLimiterContext.Rules)
{
var value = ruleContext.ToString();
var cacheKey = $"{ruleContext.Name}:{rateLimiterContext.IpNumber}";
_cache.SetStringAsync(cacheKey, value, new DistributedCacheEntryOptions
{
AbsoluteExpiration = ruleContext.WindowExpiration
});
}
return(Task.FromResult(new object()));
}
