import logging from typing import TYPE_CHECKING, List, Sequence import multiaddr from libp2p.crypto.keys import PrivateKey, PublicKey from libp2p.host.defaults import get_default_protocols from libp2p.host.exceptions import StreamFailure from libp2p.network.network_interface import INetwork from libp2p.network.stream.net_stream_interface import INetStream from libp2p.peer.id import ID from libp2p.peer.peerinfo import PeerInfo from libp2p.peer.peerstore_interface import IPeerStore from libp2p.protocol_muxer.exceptions import MultiselectClientError, MultiselectError from libp2p.protocol_muxer.multiselect import Multiselect from libp2p.protocol_muxer.multiselect_client import MultiselectClient from libp2p.protocol_muxer.multiselect_communicator import MultiselectCommunicator from libp2p.typing import StreamHandlerFn, TProtocol from .host_interface import IHost if TYPE_CHECKING: from collections import OrderedDict # Upon host creation, host takes in options, # including the list of addresses on which to listen. # Host then parses these options and delegates to its Network instance, # telling it to listen on the given listen addresses. logger = logging.getLogger("libp2p.network.basic_host") class BasicHost(IHost): """ BasicHost is a wrapper of a `INetwork` implementation. It performs protocol negotiation on a stream with multistream-select right after a stream is initialized. """ _network: INetwork peerstore: IPeerStore multiselect: Multiselect multiselect_client: MultiselectClient def __init__( self, network: INetwork, default_protocols: "OrderedDict[TProtocol, StreamHandlerFn]" = None, ) -> None: self._network = network self._network.set_stream_handler(self._swarm_stream_handler) self.peerstore = self._network.peerstore # Protocol muxing default_protocols = default_protocols or get_default_protocols(self) self.multiselect = Multiselect(default_protocols) self.multiselect_client = MultiselectClient() def get_id(self) -> ID: """ :return: peer_id of host """ return self._network.get_peer_id() def get_public_key(self) -> PublicKey: return self.peerstore.pubkey(self.get_id()) def get_private_key(self) -> PrivateKey: return self.peerstore.privkey(self.get_id()) def get_network(self) -> INetwork: """ :return: network instance of host """ return self._network def get_peerstore(self) -> IPeerStore: """ :return: peerstore of the host (same one as in its network instance) """ return self.peerstore def get_mux(self) -> Multiselect: """ :return: mux instance of host """ return self.multiselect def get_addrs(self) -> List[multiaddr.Multiaddr]: """ :return: all the multiaddr addresses this host is listening to """ # TODO: We don't need "/p2p/{peer_id}" postfix actually. p2p_part = multiaddr.Multiaddr("/p2p/{}".format(self.get_id().pretty())) addrs: List[multiaddr.Multiaddr] = [] for transport in self._network.listeners.values(): for addr in transport.get_addrs(): addrs.append(addr.encapsulate(p2p_part)) return addrs def set_stream_handler( self, protocol_id: TProtocol, stream_handler: StreamHandlerFn ) -> None: """ set stream handler for given `protocol_id` :param protocol_id: protocol id used on stream :param stream_handler: a stream handler function """ self.multiselect.add_handler(protocol_id, stream_handler) async def new_stream( self, peer_id: ID, protocol_ids: Sequence[TProtocol] ) -> INetStream: """ :param peer_id: peer_id that host is connecting :param protocol_ids: available protocol ids to use for stream :return: stream: new stream created """ net_stream = await self._network.new_stream(peer_id) # Perform protocol muxing to determine protocol to use try: selected_protocol = await self.multiselect_client.select_one_of( list(protocol_ids), MultiselectCommunicator(net_stream) ) except MultiselectClientError as error: logger.debug("fail to open a stream to peer %s, error=%s", peer_id, error) await net_stream.reset() raise StreamFailure("failt to open a stream to peer %s", peer_id) from error net_stream.set_protocol(selected_protocol) return net_stream async def connect(self, peer_info: PeerInfo) -> None: """ connect ensures there is a connection between this host and the peer with given `peer_info.peer_id`. connect will absorb the addresses in peer_info into its internal peerstore. If there is not an active connection, connect will issue a dial, and block until a connection is opened, or an error is returned. :param peer_info: peer_info of the peer we want to connect to :type peer_info: peer.peerinfo.PeerInfo """ self.peerstore.add_addrs(peer_info.peer_id, peer_info.addrs, 10) # there is already a connection to this peer if peer_info.peer_id in self._network.connections: return await self._network.dial_peer(peer_info.peer_id) async def disconnect(self, peer_id: ID) -> None: await self._network.close_peer(peer_id) async def close(self) -> None: await self._network.close() # Reference: `BasicHost.newStreamHandler` in Go. async def _swarm_stream_handler(self, net_stream: INetStream) -> None: # Perform protocol muxing to determine protocol to use try: protocol, handler = await self.multiselect.negotiate( MultiselectCommunicator(net_stream) ) except MultiselectError as error: peer_id = net_stream.muxed_conn.peer_id logger.debug( "failed to accept a stream from peer %s, error=%s", peer_id, error ) await net_stream.reset() return net_stream.set_protocol(protocol) await handler(net_stream)