python-kasa/kasa/discover.py

"""Discovery module for TP-Link Smart Home devices."""
import asyncio
import binascii
import ipaddress
import logging
import socket
from typing import Awaitable, Callable, Dict, Optional, Type, cast

# When support for cpython older than 3.11 is dropped
# async_timeout can be replaced with asyncio.timeout
from async_timeout import timeout as asyncio_timeout

from kasa.credentials import Credentials
from kasa.exceptions import UnsupportedDeviceException
from kasa.json import dumps as json_dumps
from kasa.json import loads as json_loads
from kasa.protocol import TPLinkSmartHomeProtocol
from kasa.smartbulb import SmartBulb
from kasa.smartdevice import SmartDevice, SmartDeviceException
from kasa.smartdimmer import SmartDimmer
from kasa.smartlightstrip import SmartLightStrip
from kasa.smartplug import SmartPlug
from kasa.smartstrip import SmartStrip

_LOGGER = logging.getLogger(__name__)


OnDiscoveredCallable = Callable[[SmartDevice], Awaitable[None]]
DeviceDict = Dict[str, SmartDevice]


class _DiscoverProtocol(asyncio.DatagramProtocol):
    """Implementation of the discovery protocol handler.

    This is internal class, use :func:`Discover.discover`: instead.
    """

    discovered_devices: DeviceDict

    def __init__(
        self,
        *,
        on_discovered: Optional[OnDiscoveredCallable] = None,
        target: str = "255.255.255.255",
        discovery_packets: int = 3,
        interface: Optional[str] = None,
        on_unsupported: Optional[Callable[[Dict], Awaitable[None]]] = None,
        port: Optional[int] = None,
        discovered_event: Optional[asyncio.Event] = None,
        credentials: Optional[Credentials] = None,
        timeout: Optional[int] = None,
    ) -> None:
        self.transport = None
        self.discovery_packets = discovery_packets
        self.interface = interface
        self.on_discovered = on_discovered
        self.discovery_port = port or Discover.DISCOVERY_PORT
        self.target = (target, self.discovery_port)
        self.target_2 = (target, Discover.DISCOVERY_PORT_2)
        self.discovered_devices = {}
        self.unsupported_devices: Dict = {}
        self.invalid_device_exceptions: Dict = {}
        self.on_unsupported = on_unsupported
        self.discovered_event = discovered_event
        self.credentials = credentials
        self.timeout = timeout

    def connection_made(self, transport) -> None:
        """Set socket options for broadcasting."""
        self.transport = transport

        sock = transport.get_extra_info("socket")
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
        try:
            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        except OSError as ex:  # WSL does not support SO_REUSEADDR, see #246
            _LOGGER.debug("Unable to set SO_REUSEADDR: %s", ex)

        if self.interface is not None:
            sock.setsockopt(
                socket.SOL_SOCKET, socket.SO_BINDTODEVICE, self.interface.encode()
            )

        self.do_discover()

    def do_discover(self) -> None:
        """Send number of discovery datagrams."""
        req = json_dumps(Discover.DISCOVERY_QUERY)
        _LOGGER.debug("[DISCOVERY] %s >> %s", self.target, Discover.DISCOVERY_QUERY)
        encrypted_req = TPLinkSmartHomeProtocol.encrypt(req)
        for _i in range(self.discovery_packets):
            self.transport.sendto(encrypted_req[4:], self.target)  # type: ignore
            self.transport.sendto(Discover.DISCOVERY_QUERY_2, self.target_2)  # type: ignore

    def datagram_received(self, data, addr) -> None:
        """Handle discovery responses."""
        ip, port = addr
        if (
            ip in self.discovered_devices
            or ip in self.unsupported_devices
            or ip in self.invalid_device_exceptions
        ):
            return

        if port == self.discovery_port:
            info = json_loads(TPLinkSmartHomeProtocol.decrypt(data))
            _LOGGER.debug("[DISCOVERY] %s << %s", ip, info)

        elif port == Discover.DISCOVERY_PORT_2:
            info = json_loads(data[16:])
            self.unsupported_devices[ip] = info
            if self.on_unsupported is not None:
                asyncio.ensure_future(self.on_unsupported(info))
            _LOGGER.debug("[DISCOVERY] Unsupported device found at %s << %s", ip, info)
            if self.discovered_event is not None:
                self.discovered_event.set()
            return

        try:
            device_class = Discover._get_device_class(info)
        except SmartDeviceException as ex:
            _LOGGER.debug(
                "[DISCOVERY] Unable to find device type from %s: %s", info, ex
            )
            self.invalid_device_exceptions[ip] = ex
            if self.discovered_event is not None:
                self.discovered_event.set()
            return

        device = device_class(
            ip, port=port, credentials=self.credentials, timeout=self.timeout
        )
        device.update_from_discover_info(info)

        self.discovered_devices[ip] = device

        if self.on_discovered is not None:
            asyncio.ensure_future(self.on_discovered(device))

        if self.discovered_event is not None:
            self.discovered_event.set()

    def error_received(self, ex):
        """Handle asyncio.Protocol errors."""
        _LOGGER.error("Got error: %s", ex)

    def connection_lost(self, ex):
        """NOP implementation of connection lost."""


class Discover:
    """Discover TPLink Smart Home devices.

    The main entry point for this library is :func:`Discover.discover()`,
    which returns a dictionary of the found devices. The key is the IP address
    of the device and the value contains ready-to-use, SmartDevice-derived
    device object.

    :func:`discover_single()` can be used to initialize a single device given its
    IP address. If the type of the device and its IP address is already known,
    you can initialize the corresponding device class directly without this.

    The protocol uses UDP broadcast datagrams on port 9999 for discovery.

    Examples:
        Discovery returns a list of discovered devices:

        >>> import asyncio
        >>> found_devices = asyncio.run(Discover.discover())
        >>> [dev.alias for dev in found_devices]
        ['TP-LINK_Power Strip_CF69']

        Discovery can also be targeted to a specific broadcast address instead of
        the default 255.255.255.255:

        >>> asyncio.run(Discover.discover(target="192.168.8.255"))

        It is also possible to pass a coroutine to be executed for each found device:

        >>> async def print_alias(dev):
        >>>    print(f"Discovered {dev.alias}")
        >>> devices = asyncio.run(Discover.discover(on_discovered=print_alias))


    """

    DISCOVERY_PORT = 9999

    DISCOVERY_QUERY = {
        "system": {"get_sysinfo": None},
    }

    DISCOVERY_PORT_2 = 20002
    DISCOVERY_QUERY_2 = binascii.unhexlify("020000010000000000000000463cb5d3")

    @staticmethod
    async def discover(
        *,
        target="255.255.255.255",
        on_discovered=None,
        timeout=5,
        discovery_packets=3,
        interface=None,
        on_unsupported=None,
        credentials=None,
    ) -> DeviceDict:
        """Discover supported devices.

        Sends discovery message to 255.255.255.255:9999 in order
        to detect available supported devices in the local network,
        and waits for given timeout for answers from devices.
        If you have multiple interfaces,
        you can use *target* parameter to specify the network for discovery.

        If given, `on_discovered` coroutine will get awaited with
        a :class:`SmartDevice`-derived object as parameter.

        The results of the discovery are returned as a dict of
        :class:`SmartDevice`-derived objects keyed with IP addresses.
        The devices are already initialized and all but emeter-related properties
        can be accessed directly.

        :param target: The target address where to send the broadcast discovery
         queries if multi-homing (e.g. 192.168.xxx.255).
        :param on_discovered: coroutine to execute on discovery
        :param timeout: How long to wait for responses, defaults to 5
        :param discovery_packets: Number of discovery packets to broadcast
        :param interface: Bind to specific interface
        :return: dictionary with discovered devices
        """
        loop = asyncio.get_event_loop()
        transport, protocol = await loop.create_datagram_endpoint(
            lambda: _DiscoverProtocol(
                target=target,
                on_discovered=on_discovered,
                discovery_packets=discovery_packets,
                interface=interface,
                on_unsupported=on_unsupported,
                credentials=credentials,
                timeout=timeout,
            ),
            local_addr=("0.0.0.0", 0),  # noqa: S104
        )
        protocol = cast(_DiscoverProtocol, protocol)

        try:
            _LOGGER.debug("Waiting %s seconds for responses...", timeout)
            await asyncio.sleep(timeout)
        finally:
            transport.close()

        _LOGGER.debug("Discovered %s devices", len(protocol.discovered_devices))

        return protocol.discovered_devices

    @staticmethod
    async def discover_single(
        host: str,
        *,
        port: Optional[int] = None,
        timeout=5,
        credentials: Optional[Credentials] = None,
    ) -> SmartDevice:
        """Discover a single device by the given IP address.

        It is generally preferred to avoid :func:`discover_single()` and
        use :func:`connect_single()` instead as it should perform better when
        the WiFi network is congested or the device is not responding
        to discovery requests.

        :param host: Hostname of device to query
        :rtype: SmartDevice
        :return: Object for querying/controlling found device.
        """
        loop = asyncio.get_event_loop()
        event = asyncio.Event()

        try:
            ipaddress.ip_address(host)
            ip = host
        except ValueError:
            try:
                adrrinfo = await loop.getaddrinfo(
                    host,
                    0,
                    type=socket.SOCK_DGRAM,
                    family=socket.AF_INET,
                )
                # getaddrinfo returns a list of 5 tuples with the following structure:
                # (family, type, proto, canonname, sockaddr)
                # where sockaddr is 2 tuple (ip, port).
                # hence [0][4][0] is a stable array access because if no socket
                # address matches the host for SOCK_DGRAM AF_INET the gaierror
                # would be raised.
                # https://docs.python.org/3/library/socket.html#socket.getaddrinfo
                ip = adrrinfo[0][4][0]
            except socket.gaierror as gex:
                raise SmartDeviceException(
                    f"Could not resolve hostname {host}"
                ) from gex

        transport, protocol = await loop.create_datagram_endpoint(
            lambda: _DiscoverProtocol(
                target=ip,
                port=port,
                discovered_event=event,
                credentials=credentials,
                timeout=timeout,
            ),
            local_addr=("0.0.0.0", 0),  # noqa: S104
        )
        protocol = cast(_DiscoverProtocol, protocol)

        try:
            _LOGGER.debug("Waiting a total of %s seconds for responses...", timeout)

            async with asyncio_timeout(timeout):
                await event.wait()
        except asyncio.TimeoutError as ex:
            raise SmartDeviceException(
                f"Timed out getting discovery response for {host}"
            ) from ex
        finally:
            transport.close()

        if ip in protocol.discovered_devices:
            dev = protocol.discovered_devices[ip]
            dev.host = host
            await dev.update()
            return dev
        elif ip in protocol.unsupported_devices:
            raise UnsupportedDeviceException(
                f"Unsupported device {host}: {protocol.unsupported_devices[ip]}"
            )
        elif ip in protocol.invalid_device_exceptions:
            raise protocol.invalid_device_exceptions[ip]
        else:
            raise SmartDeviceException(f"Unable to get discovery response for {host}")

    @staticmethod
    async def connect_single(
        host: str,
        *,
        port: Optional[int] = None,
        timeout=5,
        credentials: Optional[Credentials] = None,
    ) -> SmartDevice:
        """Connect to a single device by the given IP address.

        This method avoids the UDP based discovery process and
        will connect directly to the device to query its type.

        It is generally preferred to avoid :func:`discover_single()` and
        use this function instead as it should perform better when
        the WiFi network is congested or the device is not responding
        to discovery requests.

        The device type is discovered by querying the device.

        :param host: Hostname of device to query
        :rtype: SmartDevice
        :return: Object for querying/controlling found device.
        """
        unknown_dev = SmartDevice(
            host=host, port=port, credentials=credentials, timeout=timeout
        )
        await unknown_dev.update()
        device_class = Discover._get_device_class(unknown_dev.internal_state)
        dev = device_class(
            host=host, port=port, credentials=credentials, timeout=timeout
        )
        # Reuse the connection from the unknown device
        # so we don't have to reconnect
        dev.protocol = unknown_dev.protocol
        return dev

    @staticmethod
    def _get_device_class(info: dict) -> Type[SmartDevice]:
        """Find SmartDevice subclass for device described by passed data."""
        if "system" not in info or "get_sysinfo" not in info["system"]:
            raise SmartDeviceException("No 'system' or 'get_sysinfo' in response")

        sysinfo = info["system"]["get_sysinfo"]
        type_ = sysinfo.get("type", sysinfo.get("mic_type"))
        if type_ is None:
            raise SmartDeviceException("Unable to find the device type field!")

        if "dev_name" in sysinfo and "Dimmer" in sysinfo["dev_name"]:
            return SmartDimmer

        if "smartplug" in type_.lower():
            if "children" in sysinfo:
                return SmartStrip

            return SmartPlug

        if "smartbulb" in type_.lower():
            if "length" in sysinfo:  # strips have length
                return SmartLightStrip

            return SmartBulb

        raise SmartDeviceException("Unknown device type: %s" % type_)