/// <inheritdoc />
public async Task <Peer> FindPeerAsync(MultiHash id, CancellationToken cancel = default)
{
// Can always find self.
if (SwarmService.LocalPeer.Id == id)
{
return(SwarmService.LocalPeer);
}
// Maybe the swarm knows about it.
var found = SwarmService.KnownPeers.FirstOrDefault(p => p.Id == id);
if (found != null && found.Addresses.Any())
{
return(found);
}
// Ask our peers for information on the requested peer.
var dQuery = new DistributedQuery <Peer>
{
QueryType = MessageType.FindNode,
QueryKey = id,
Dht = this,
AnswersNeeded = 1
};
await dQuery.RunAsync(cancel).ConfigureAwait(false);
// If not found, return the closest peer.
return(!dQuery.Answers.Any() ? RoutingTable.NearestPeers(id).FirstOrDefault() : dQuery.Answers.First());
}
/// <inheritdoc />
public async Task <IEnumerable <Peer> > FindProvidersAsync(Cid id,
int limit = 20,
Action <Peer> action = null,
CancellationToken cancel = default)
{
var dQuery = new DistributedQuery <Peer>
{
QueryType = MessageType.GetProviders,
QueryKey = id.Hash,
Dht = this,
AnswersNeeded = limit,
};
if (action != null)
{
dQuery.AnswerObtained += (s, e) => action.Invoke(e);
}
// Add any providers that we already know about.
var providers = ContentRouter
.Get(id)
.Select(pid => pid == SwarmService.LocalPeer.Id
? SwarmService.LocalPeer
: SwarmService.RegisterPeer(new Peer {
Id = pid
}));
foreach (var provider in providers)
{
dQuery.AddAnswer(provider);
}
// Ask our peers for more providers.
if (limit > dQuery.Answers.Count())
{
await dQuery.RunAsync(cancel).ConfigureAwait(false);
}
return(dQuery.Answers.Take(limit));
}
