py-libp2p/libp2p/stream_muxer/muxer_multistream.py

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from collections import OrderedDict
from libp2p.network.connection.raw_connection_interface import IRawConnection
from libp2p.peer.id import ID
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.security.secure_conn_interface import ISecureConn
from libp2p.transport.typing import TMuxerClass, TMuxerOptions
from libp2p.typing import TProtocol
from .abc import IMuxedConn
# FIXME: add negotiate timeout to `MuxerMultistream`
DEFAULT_NEGOTIATE_TIMEOUT = 60
class MuxerMultistream:
"""
MuxerMultistream is a multistream stream muxed transport multiplexer.
go implementation: github.com/libp2p/go-stream-muxer-multistream/multistream.go
"""
# NOTE: Can be changed to `typing.OrderedDict` since Python 3.7.2.
transports: "OrderedDict[TProtocol, TMuxerClass]"
multiselect: Multiselect
multiselect_client: MultiselectClient
def __init__(self, muxer_transports_by_protocol: TMuxerOptions) -> None:
self.transports = OrderedDict()
self.multiselect = Multiselect()
self.multiselect_client = MultiselectClient()
for protocol, transport in muxer_transports_by_protocol.items():
self.add_transport(protocol, transport)
def add_transport(self, protocol: TProtocol, transport: TMuxerClass) -> None:
"""
Add a protocol and its corresponding transport to multistream-
select(multiselect). The order that a protocol is added is exactly the
precedence it is negotiated in multiselect.
:param protocol: the protocol name, which is negotiated in multiselect.
:param transport: the corresponding transportation to the ``protocol``.
"""
# If protocol is already added before, remove it and add it again.
self.transports.pop(protocol, None)
self.transports[protocol] = transport
self.multiselect.add_handler(protocol, None)
async def select_transport(self, conn: IRawConnection) -> TMuxerClass:
"""
Select a transport that both us and the node on the other end of conn
support and agree on.
:param conn: conn to choose a transport over
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:return: selected muxer transport
"""
protocol: TProtocol
communicator = MultiselectCommunicator(conn)
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if conn.is_initiator:
protocol = await self.multiselect_client.select_one_of(
tuple(self.transports.keys()), communicator
)
else:
protocol, _ = await self.multiselect.negotiate(communicator)
return self.transports[protocol]
async def new_conn(self, conn: ISecureConn, peer_id: ID) -> IMuxedConn:
transport_class = await self.select_transport(conn)
return transport_class(conn, peer_id)