public static TrackerBehavior Discover(Tracker tracker)
{
TrackerBehavior behavior = new TrackerBehavior(tracker);
behavior.SupportsScrape = tracker.SupportsScrape;
behavior.SupportsMultiScrape = false;
behavior.MultiScrapeRange = 0;
behavior.MultiScrapeThreshold = -1;
behavior.SupportsFullScrape = false;
behavior.IndicatesPasskey = false;
behavior.IndicatesPrivacy = false;
behavior.DefaultInterval = TrackerSettings.DefaultInterval;
PeerId peerId1 = CreateDiscoveryPeerId();
PeerId peerId2 = CreateDiscoveryPeerId();
InfoHash infoHash1 = CreateDiscoveryInfoHash();
InfoHash infoHash2 = CreateDiscoveryInfoHash();
if (tracker.Protocol == TrackerProtocol.HTTP || tracker.Protocol == TrackerProtocol.HTTPS)
{
string[] announcePathFragments = tracker.AnnounceUrl.LocalPath.Split('/');
string announceQueryLower = tracker.AnnounceUrl.Query.ToLower();
if (announcePathFragments.Length > 2)
{
if (Regex.IsMatch(announcePathFragments[announcePathFragments.Length - 2], @"\A[0-9a-fA-F]*\z"))
{
behavior.IndicatesPasskey = true;
behavior.IndicatesPrivacy = true;
goto EndExposureAssessment;
}
}
string passkey = HttpUtility.ParseQueryString(announceQueryLower)["passkey"];
if (!String.IsNullOrEmpty(passkey))
{
if (Regex.IsMatch(passkey, @"\A[0-9a-fA-F]*\z"))
{
behavior.IndicatesPasskey = true;
behavior.IndicatesPrivacy = true;
}
}
EndExposureAssessment: ;
}
if (behavior.SupportsScrape)
{
try
{
behavior.DefaultInterval = tracker.CreateAnnounceRequest(infoHash1, peerId1, discoveryPort, 0, 0, 0).GetTransport().GetResponse().Interval;
}
catch (TrackerFailureException tfe)
{
string messageLower = tfe.Message.ToLower();
if (messageLower.Contains("client") || messageLower.Contains("protocol"))
behavior.IndicatesClientRestriction = true;
else
behavior.IndicatesRegistration = true;
}
catch (Exception)
{
throw;
}
if (tracker.Protocol == TrackerProtocol.HTTP || tracker.Protocol == TrackerProtocol.HTTPS)
{
try
{
HttpScrapeTransport scrapeTestTransport = (HttpScrapeTransport)tracker.CreateScrapeRequest().GetTransport();
HttpWebResponse scrapeTestResponse = (HttpWebResponse)scrapeTestTransport.HttpRequest.GetResponse();
if (scrapeTestResponse.StatusCode == HttpStatusCode.OK)
{
char[] scrapeStartTestResponseBuffer = new char[httpMultiScrapeResponseStartFragment.Length];
char[] scrapeEndTestResponseBuffer = new char[httpMultiScrapeResponseEndFragment.Length];
using (StreamReader scrapeTestResponseReader = new StreamReader(scrapeTestResponse.GetResponseStream()))
{
if (
scrapeTestResponseReader.Read(scrapeStartTestResponseBuffer, 0, scrapeStartTestResponseBuffer.Length) == scrapeStartTestResponseBuffer.Length &&
scrapeTestResponseReader.Read(scrapeEndTestResponseBuffer, 0, scrapeEndTestResponseBuffer.Length) == scrapeEndTestResponseBuffer.Length
)
{
if (new string(scrapeStartTestResponseBuffer) == httpMultiScrapeResponseStartFragment)
{
if (scrapeTestResponse.ContentLength != -1 && new string(scrapeEndTestResponseBuffer) != httpMultiScrapeResponseEndFragment)
{
behavior.ScrapeThreshold = (int)Math.Ceiling((decimal)scrapeTestResponse.ContentLength / (decimal)(tracker.ScrapeUrl.ToString().Length + httpInfoHashQueryFieldSize));
behavior.MultiScrapeThreshold = (int)Math.Ceiling((decimal)scrapeTestResponse.ContentLength / (decimal)httpInfoHashQueryFieldSize);
}
else
{
behavior.ScrapeThreshold = TrackerSettings.DefaultScrapeThreshold;
behavior.MultiScrapeThreshold = TrackerSettings.DefaultMultiScrapeThreshold;
}
behavior.SupportsFullScrape = true;
}
}
}
}
}
catch (TrackerFailureException tfe)
{
if (tfe.Message.ToLower().Contains("client"))
behavior.IndicatesClientRestriction = true;
else
behavior.IndicatesPrivacy = true;
}
catch (Exception)
{
throw;
}
if (!behavior.IndicatesRegistration && !behavior.IndicatesPrivacy)
{
try
{
tracker.CreateAnnounceRequest(infoHash2, peerId2, discoveryPort, 0, 0, 0).GetResponse();
IScrapeResponse scrapeResponse = tracker.CreateScrapeRequest(new InfoHash[2] { infoHash1, infoHash2 }).GetResponse();
if (scrapeResponse.Files.ContainsKey(infoHash1) && scrapeResponse.Files.ContainsKey(infoHash2))
{
behavior.SupportsMultiScrape = true;
behavior.MultiScrapeRange = HttpScrapeTransport.MultiScrapeRange;
}
}
catch (TrackerFailureException tfe)
{
string mutliScrapeError = tfe.Message.ToLower();
if (mutliScrapeError.Contains("register") && !mutliScrapeError.Contains("pass") && !mutliScrapeError.Contains("key"))
behavior.SupportsMultiScrape = true;
}
}
else
{
// Tracker is private, but multi-scrape is probably enabled
behavior.SupportsMultiScrape = true;
}
}
else if (tracker.Protocol == TrackerProtocol.UDP)
{
behavior.SupportsMultiScrape = true;
behavior.MultiScrapeRange = UdpScrapeTransport.MultiScrapeRange;
}
}
return behavior;
}
private TrackerBehavior(Tracker tracker)
{
SupportsScrape = tracker.SupportsScrape;
SupportsFullScrape = false;
DefaultInterval = TrackerSettings.DefaultInterval;
}
public TrackerBehavior this[Tracker tracker]
{
get
{
lock (syncRoot)
{
if (tracker == null)
throw new ArgumentNullException("tracker");
if (cache.ContainsKey(tracker.AnnounceUrl))
{
BehaviorCacheItem item = cache[tracker.AnnounceUrl];
if (!item.Expired)
return item.Behavior;
}
return null;
}
}
set
{
lock (syncRoot)
{
if (tracker == null)
throw new ArgumentNullException("tracker");
if (cache.ContainsKey(tracker.AnnounceUrl))
cache[tracker.AnnounceUrl] = new BehaviorCacheItem(value, cache[tracker.AnnounceUrl].LifeTime);
else
cache.Add(tracker.AnnounceUrl, new BehaviorCacheItem(value));
}
}
}
