Adding localtuya custom component

config/custom_components/localtuya/discovery.py

@@ -0,0 +1,90 @@
+"""Discovery module for Tuya devices.
+
+Entirely based on tuya-convert.py from tuya-convert:
+
+https://github.com/ct-Open-Source/tuya-convert/blob/master/scripts/tuya-discovery.py
+"""
+import asyncio
+import json
+import logging
+from hashlib import md5
+
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+
+_LOGGER = logging.getLogger(__name__)
+
+UDP_KEY = md5(b"yGAdlopoPVldABfn").digest()
+
+DEFAULT_TIMEOUT = 6.0
+
+
+def decrypt_udp(message):
+    """Decrypt encrypted UDP broadcasts."""
+
+    def _unpad(data):
+        return data[: -ord(data[len(data) - 1 :])]
+
+    cipher = Cipher(algorithms.AES(UDP_KEY), modes.ECB(), default_backend())
+    decryptor = cipher.decryptor()
+    return _unpad(decryptor.update(message) + decryptor.finalize()).decode()
+
+
+class TuyaDiscovery(asyncio.DatagramProtocol):
+    """Datagram handler listening for Tuya broadcast messages."""
+
+    def __init__(self, callback=None):
+        """Initialize a new BaseDiscovery."""
+        self.devices = {}
+        self._listeners = []
+        self._callback = callback
+
+    async def start(self):
+        """Start discovery by listening to broadcasts."""
+        loop = asyncio.get_running_loop()
+        listener = loop.create_datagram_endpoint(
+            lambda: self, local_addr=("0.0.0.0", 6666)
+        )
+        encrypted_listener = loop.create_datagram_endpoint(
+            lambda: self, local_addr=("0.0.0.0", 6667)
+        )
+
+        self._listeners = await asyncio.gather(listener, encrypted_listener)
+        _LOGGER.debug("Listening to broadcasts on UDP port 6666 and 6667")
+
+    def close(self):
+        """Stop discovery."""
+        self._callback = None
+        for transport, _ in self._listeners:
+            transport.close()
+
+    def datagram_received(self, data, addr):
+        """Handle received broadcast message."""
+        data = data[20:-8]
+        try:
+            data = decrypt_udp(data)
+        except Exception:  # pylint: disable=broad-except
+            data = data.decode()
+
+        decoded = json.loads(data)
+        self.device_found(decoded)
+
+    def device_found(self, device):
+        """Discover a new device."""
+        if device.get("ip") not in self.devices:
+            self.devices[device.get("gwId")] = device
+            _LOGGER.debug("Discovered device: %s", device)
+
+        if self._callback:
+            self._callback(device)
+
+
+async def discover():
+    """Discover and return devices on local network."""
+    discovery = TuyaDiscovery()
+    try:
+        await discovery.start()
+        await asyncio.sleep(DEFAULT_TIMEOUT)
+    finally:
+        discovery.close()
+    return discovery.devices