py-libp2p/libp2p/routing/kademlia/kademlia_peer_router.py

import json

import multiaddr

from libp2p.kademlia.network import KademliaServer
from libp2p.peer.id import ID
from libp2p.peer.peerinfo import PeerInfo
from libp2p.routing.interfaces import IPeerRouting


class KadmeliaPeerRouter(IPeerRouting):
    server: KademliaServer

    def __init__(self, dht_server: KademliaServer) -> None:
        self.server = dht_server

    async def find_peer(self, peer_id: ID) -> PeerInfo:
        """Find a specific peer.

        :param peer_id: peer to search for
        :return: PeerInfo of specified peer
        """
        # switching peer_id to xor_id used by kademlia as node_id
        xor_id = peer_id.xor_id
        # ignore type for kad
        value = await self.server.get(xor_id)  # type: ignore
        return (
            peer_info_from_str(value) if value else None
        )  # TODO: should raise error if None?


def peer_info_to_str(peer_info: PeerInfo) -> str:
    return json.dumps(
        [peer_info.peer_id.to_string(), list(map(lambda a: str(a), peer_info.addrs))]
    )


def peer_info_from_str(string: str) -> PeerInfo:
    peer_id, raw_addrs = json.loads(string)
    return PeerInfo(
        ID.from_base58(peer_id), list(map(lambda a: multiaddr.Multiaddr(a), raw_addrs))
    )