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import asyncio
import logging
import re
from dataclasses import dataclass
from typing import Any, Dict, List, Optional
from aioice import Candidate, Connection, ConnectionClosed
from pyee.asyncio import AsyncIOEventEmitter
from .exceptions import InvalidStateError
from .rtcconfiguration import RTCIceServer
STUN_REGEX = re.compile(
r"(?P<scheme>stun|stuns)\:(?P<host>[^?:]+)(\:(?P<port>[0-9]+?))?"
# RFC 7064 does not define a "transport" option but some providers
# include it, so just ignore it
r"(\?transport=.*)?"
)
TURN_REGEX = re.compile(
r"(?P<scheme>turn|turns)\:(?P<host>[^?:]+)(\:(?P<port>[0-9]+?))?"
r"(\?transport=(?P<transport>.*))?"
)
logger = logging.getLogger(__name__)
@dataclass
class RTCIceCandidate:
"""
The :class:`RTCIceCandidate` interface represents a candidate Interactive
Connectivity Establishment (ICE) configuration which may be used to
establish an RTCPeerConnection.
"""
component: int
foundation: str
ip: str
port: int
priority: int
protocol: str
type: str
relatedAddress: Optional[str] = None
relatedPort: Optional[int] = None
sdpMid: Optional[str] = None
sdpMLineIndex: Optional[int] = None
tcpType: Optional[str] = None
@dataclass
class RTCIceParameters:
"""
The :class:`RTCIceParameters` dictionary includes the ICE username
fragment and password and other ICE-related parameters.
"""
usernameFragment: Optional[str] = None
"ICE username fragment."
password: Optional[str] = None
"ICE password."
iceLite: bool = False
def candidate_from_aioice(x: Candidate) -> RTCIceCandidate:
return RTCIceCandidate(
component=x.component,
foundation=x.foundation,
ip=x.host,
port=x.port,
priority=x.priority,
protocol=x.transport,
relatedAddress=x.related_address,
relatedPort=x.related_port,
tcpType=x.tcptype,
type=x.type,
)
def candidate_to_aioice(x: RTCIceCandidate) -> Candidate:
return Candidate(
component=x.component,
foundation=x.foundation,
host=x.ip,
port=x.port,
priority=x.priority,
related_address=x.relatedAddress,
related_port=x.relatedPort,
transport=x.protocol,
tcptype=x.tcpType,
type=x.type,
)
def connection_kwargs(servers: List[RTCIceServer]) -> Dict[str, Any]:
kwargs: Dict[str, Any] = {}
for server in servers:
if isinstance(server.urls, list):
uris = server.urls
else:
uris = [server.urls]
for uri in uris:
parsed = parse_stun_turn_uri(uri)
if parsed["scheme"] == "stun":
# only a single STUN server is supported
if "stun_server" in kwargs:
continue
kwargs["stun_server"] = (parsed["host"], parsed["port"])
elif parsed["scheme"] in ["turn", "turns"]:
# only a single TURN server is supported
if "turn_server" in kwargs:
continue
# only 'udp' and 'tcp' transports are supported
if parsed["scheme"] == "turn" and parsed["transport"] not in [
"udp",
"tcp",
]:
continue
elif parsed["scheme"] == "turns" and parsed["transport"] != "tcp":
continue
# only 'password' credentialType is supported
if server.credentialType != "password":
continue
kwargs["turn_server"] = (parsed["host"], parsed["port"])
kwargs["turn_ssl"] = parsed["scheme"] == "turns"
kwargs["turn_transport"] = parsed["transport"]
kwargs["turn_username"] = server.username
kwargs["turn_password"] = server.credential
return kwargs
def parse_stun_turn_uri(uri: str) -> Dict[str, Any]:
if uri.startswith("stun"):
match = STUN_REGEX.fullmatch(uri)
elif uri.startswith("turn"):
match = TURN_REGEX.fullmatch(uri)
else:
raise ValueError("malformed uri: invalid scheme")
if not match:
raise ValueError("malformed uri")
# set port
parsed: Dict[str, Any] = match.groupdict()
if parsed["port"]:
parsed["port"] = int(parsed["port"])
elif parsed["scheme"] in ["stuns", "turns"]:
parsed["port"] = 5349
else:
parsed["port"] = 3478
# set transport
if parsed["scheme"] == "turn" and not parsed["transport"]:
parsed["transport"] = "udp"
elif parsed["scheme"] == "turns" and not parsed["transport"]:
parsed["transport"] = "tcp"
return parsed
class RTCIceGatherer(AsyncIOEventEmitter):
"""
The :class:`RTCIceGatherer` interface gathers local host, server reflexive
and relay candidates, as well as enabling the retrieval of local
Interactive Connectivity Establishment (ICE) parameters which can be
exchanged in signaling.
"""
def __init__(self, iceServers: Optional[List[RTCIceServer]] = None) -> None:
super().__init__()
if iceServers is None:
iceServers = self.getDefaultIceServers()
ice_kwargs = connection_kwargs(iceServers)
self._connection = Connection(ice_controlling=False, **ice_kwargs)
self._remote_candidates_end = False
self.__state = "new"
@property
def state(self) -> str:
"""
The current state of the ICE gatherer.
"""
return self.__state
async def gather(self) -> None:
"""
Gather ICE candidates.
"""
if self.__state == "new":
self.__setState("gathering")
await self._connection.gather_candidates()
self.__setState("completed")
@classmethod
def getDefaultIceServers(cls) -> List[RTCIceServer]:
"""
Return the list of default :class:`RTCIceServer`.
"""
return [RTCIceServer("stun:stun.l.google.com:19302")]
def getLocalCandidates(self) -> List[RTCIceCandidate]:
"""
Retrieve the list of valid local candidates associated with the ICE
gatherer.
"""
return [candidate_from_aioice(x) for x in self._connection.local_candidates]
def getLocalParameters(self) -> RTCIceParameters:
"""
Retrieve the ICE parameters of the ICE gatherer.
:rtype: RTCIceParameters
"""
return RTCIceParameters(
usernameFragment=self._connection.local_username,
password=self._connection.local_password,
)
def __setState(self, state: str) -> None:
self.__state = state
self.emit("statechange")
class RTCIceTransport(AsyncIOEventEmitter):
"""
The :class:`RTCIceTransport` interface allows an application access to
information about the Interactive Connectivity Establishment (ICE)
transport over which packets are sent and received.
:param gatherer: An :class:`RTCIceGatherer`.
"""
def __init__(self, gatherer: RTCIceGatherer) -> None:
super().__init__()
self.__iceGatherer = gatherer
self.__monitor_task: Optional[asyncio.Future[None]] = None
self.__start: Optional[asyncio.Event] = None
self.__state = "new"
self._connection = gatherer._connection
self._role_set = False
# expose recv / send methods
self._recv = self._connection.recv
self._send = self._connection.send
@property
def iceGatherer(self) -> RTCIceGatherer:
"""
The ICE gatherer passed in the constructor.
"""
return self.__iceGatherer
@property
def role(self) -> str:
"""
The current role of the ICE transport.
Either `'controlling'` or `'controlled'`.
"""
if self._connection.ice_controlling:
return "controlling"
else:
return "controlled"
@property
def state(self) -> str:
"""
The current state of the ICE transport.
"""
return self.__state
async def addRemoteCandidate(self, candidate: Optional[RTCIceCandidate]) -> None:
"""
Add a remote candidate.
:param candidate: The new candidate or `None` to signal end of candidates.
"""
if not self.__iceGatherer._remote_candidates_end:
if candidate is None:
self.__iceGatherer._remote_candidates_end = True
await self._connection.add_remote_candidate(None)
else:
await self._connection.add_remote_candidate(
candidate_to_aioice(candidate)
)
def getRemoteCandidates(self) -> List[RTCIceCandidate]:
"""
Retrieve the list of candidates associated with the remote
:class:`RTCIceTransport`.
"""
return [candidate_from_aioice(x) for x in self._connection.remote_candidates]
async def start(self, remoteParameters: RTCIceParameters) -> None:
"""
Initiate connectivity checks.
:param remoteParameters: The :class:`RTCIceParameters` associated with
the remote :class:`RTCIceTransport`.
"""
if self.state == "closed":
raise InvalidStateError("RTCIceTransport is closed")
# handle the case where start is already in progress
if self.__start is not None:
await self.__start.wait()
return
self.__start = asyncio.Event()
self.__monitor_task = asyncio.ensure_future(self._monitor())
self.__setState("checking")
self._connection.remote_is_lite = remoteParameters.iceLite
self._connection.remote_username = remoteParameters.usernameFragment
self._connection.remote_password = remoteParameters.password
try:
await self._connection.connect()
except ConnectionError:
self.__setState("failed")
else:
self.__setState("completed")
self.__start.set()
async def stop(self) -> None:
"""
Irreversibly stop the :class:`RTCIceTransport`.
"""
if self.state != "closed":
self.__setState("closed")
await self._connection.close()
if self.__monitor_task is not None:
await self.__monitor_task
self.__monitor_task = None
async def _monitor(self) -> None:
while True:
event = await self._connection.get_event()
if isinstance(event, ConnectionClosed):
if self.state == "completed":
self.__setState("failed")
return
def __log_debug(self, msg: str, *args) -> None:
logger.debug(f"RTCIceTransport(%s) {msg}", self.role, *args)
def __setState(self, state: str) -> None:
if state != self.__state:
self.__log_debug("- %s -> %s", self.__state, state)
self.__state = state
self.emit("statechange")
# no more events will be emitted, so remove all event listeners
# to facilitate garbage collection.
if state == "closed":
self.iceGatherer.remove_all_listeners()
self.remove_all_listeners()
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