feat: Add a local channel, similar to the MQTT channel (#410)

* feat: Add a local channel, similar to the MQTT channel

* feat: Log a warning when transport is already closed

Author: allenporter

roborock/devices/local_channel.py

@@ -0,0 +1,146 @@
+"""Module for communicating with Roborock devices over a local network."""
+
+import asyncio
+import logging
+from collections.abc import Callable
+from dataclasses import dataclass
+from json import JSONDecodeError
+
+from roborock.exceptions import RoborockConnectionException, RoborockException
+from roborock.protocol import Decoder, Encoder, create_local_decoder, create_local_encoder
+from roborock.roborock_message import RoborockMessage
+
+_LOGGER = logging.getLogger(__name__)
+_PORT = 58867
+
+
+@dataclass
+class _LocalProtocol(asyncio.Protocol):
+    """Callbacks for the Roborock local client transport."""
+
+    messages_cb: Callable[[bytes], None]
+    connection_lost_cb: Callable[[Exception | None], None]
+
+    def data_received(self, data: bytes) -> None:
+        """Called when data is received from the transport."""
+        self.messages_cb(data)
+
+    def connection_lost(self, exc: Exception | None) -> None:
+        """Called when the transport connection is lost."""
+        self.connection_lost_cb(exc)
+
+
+class LocalChannel:
+    """Simple RPC-style channel for communicating with a device over a local network.
+
+    Handles request/response correlation and timeouts, but leaves message
+    format most parsing to higher-level components.
+    """
+
+    def __init__(self, host: str, local_key: str):
+        self._host = host
+        self._transport: asyncio.Transport | None = None
+        self._protocol: _LocalProtocol | None = None
+        self._subscribers: list[Callable[[RoborockMessage], None]] = []
+        self._is_connected = False
+
+        # RPC support
+        self._waiting_queue: dict[int, asyncio.Future[RoborockMessage]] = {}
+        self._decoder: Decoder = create_local_decoder(local_key)
+        self._encoder: Encoder = create_local_encoder(local_key)
+        self._queue_lock = asyncio.Lock()
+
+    async def connect(self) -> None:
+        """Connect to the device."""
+        if self._is_connected:
+            _LOGGER.warning("Already connected")
+            return
+        _LOGGER.debug("Connecting to %s:%s", self._host, _PORT)
+        loop = asyncio.get_running_loop()
+        protocol = _LocalProtocol(self._data_received, self._connection_lost)
+        try:
+            self._transport, self._protocol = await loop.create_connection(lambda: protocol, self._host, _PORT)
+            self._is_connected = True
+        except OSError as e:
+            raise RoborockConnectionException(f"Failed to connect to {self._host}:{_PORT}") from e
+
+    async def close(self) -> None:
+        """Disconnect from the device."""
+        if self._transport:
+            self._transport.close()
+        else:
+            _LOGGER.warning("Close called but transport is already None")
+        self._transport = None
+        self._is_connected = False
+
+    def _data_received(self, data: bytes) -> None:
+        """Handle incoming data from the transport."""
+        if not (messages := self._decoder(data)):
+            _LOGGER.warning("Failed to decode local message: %s", data)
+            return
+        for message in messages:
+            _LOGGER.debug("Received message: %s", message)
+            asyncio.create_task(self._resolve_future_with_lock(message))
+            for callback in self._subscribers:
+                try:
+                    callback(message)
+                except Exception as e:
+                    _LOGGER.exception("Uncaught error in message handler callback: %s", e)
+
+    def _connection_lost(self, exc: Exception | None) -> None:
+        """Handle connection loss."""
+        _LOGGER.warning("Connection lost to %s", self._host, exc_info=exc)
+        self._transport = None
+        self._is_connected = False
+
+    async def subscribe(self, callback: Callable[[RoborockMessage], None]) -> Callable[[], None]:
+        """Subscribe to all messages from the device."""
+        self._subscribers.append(callback)
+
+        def unsubscribe() -> None:
+            self._subscribers.remove(callback)
+
+        return unsubscribe
+
+    async def _resolve_future_with_lock(self, message: RoborockMessage) -> None:
+        """Resolve waiting future with proper locking."""
+        if (request_id := message.get_request_id()) is None:
+            _LOGGER.debug("Received message with no request_id")
+            return
+        async with self._queue_lock:
+            if (future := self._waiting_queue.pop(request_id, None)) is not None:
+                future.set_result(message)
+            else:
+                _LOGGER.debug("Received message with no waiting handler: request_id=%s", request_id)
+
+    async def send_command(self, message: RoborockMessage, timeout: float = 10.0) -> RoborockMessage:
+        """Send a command message and wait for the response message."""
+        if not self._transport or not self._is_connected:
+            raise RoborockConnectionException("Not connected to device")
+
+        try:
+            if (request_id := message.get_request_id()) is None:
+                raise RoborockException("Message must have a request_id for RPC calls")
+        except (ValueError, JSONDecodeError) as err:
+            _LOGGER.exception("Error getting request_id from message: %s", err)
+            raise RoborockException(f"Invalid message format, Message must have a request_id: {err}") from err
+
+        future: asyncio.Future[RoborockMessage] = asyncio.Future()
+        async with self._queue_lock:
+            if request_id in self._waiting_queue:
+                raise RoborockException(f"Request ID {request_id} already pending, cannot send command")
+            self._waiting_queue[request_id] = future
+
+        try:
+            encoded_msg = self._encoder(message)
+            self._transport.write(encoded_msg)
+            return await asyncio.wait_for(future, timeout=timeout)
+        except asyncio.TimeoutError as ex:
+            async with self._queue_lock:
+                self._waiting_queue.pop(request_id, None)
+            raise RoborockException(f"Command timed out after {timeout}s") from ex
+        except Exception:
+            logging.exception("Uncaught error sending command")
+            async with self._queue_lock:
+                self._waiting_queue.pop(request_id, None)
+            raise