/// <inheritdoc />
public Task StopAsync()
{
log.Debug("Stopping");
Swarm.ConnectionEstablished -= Swarm_ConnectionEstablished;
Swarm.PeerDisconnected -= Swarm_PeerDisconnected;
Swarm.RemoveProtocol(this);
RemoteTopics.Clear();
localTopics.Clear();
return Task.CompletedTask;
}
/// <summary>
/// Process a subscription request from another peer.
/// </summary>
/// <param name="sub">
/// The subscription request.
/// </param>
/// <param name="remote">
/// The remote <see cref="Peer"/>.
/// </param>
/// <seealso cref="RemoteTopics"/>
/// <remarks>
/// Maintains the <see cref="RemoteTopics"/>.
/// </remarks>
public void ProcessSubscription(Subscription sub, Peer remote)
{
if (sub.Subscribe)
{
log.Debug($"Subscribe '{sub.Topic}' by {remote}");
RemoteTopics.AddInterest(sub.Topic, remote);
}
else
{
log.Debug($"Unsubscribe '{sub.Topic}' by {remote}");
RemoteTopics.RemoveInterest(sub.Topic, remote);
}
}
/// <inheritdoc />
public Task PublishAsync(PublishedMessage message, CancellationToken cancel)
{
if (tracker.RecentlySeen(message.MessageId))
return Task.CompletedTask;
// Find a set of peers that are interested in the topic(s).
// Exclude author and sender
var peers = message.Topics
.SelectMany(topic => RemoteTopics.GetPeers(topic))
.Where(peer => peer != message.Sender)
.Where(peer => peer != message.Forwarder);
// Forward the message.
var forward = new PubSubMessage
{
PublishedMessages = new PublishedMessage[] { message }
};
return SendAsync(forward, peers, cancel);
}
/// <summary>
/// Raised when the peer has no more connections.
/// </summary>
/// <param name="sender"></param>
/// <param name="peer"></param>
/// <remarks>
/// Removes the <paramref name="peer"/> from the
/// <see cref="RemoteTopics"/>.
/// </remarks>
void Swarm_PeerDisconnected(object sender, Peer peer)
{
RemoteTopics.Clear(peer);
}
/// <inheritdoc />
public IEnumerable<Peer> InterestedPeers(string topic)
{
return RemoteTopics.GetPeers(topic);
}
