knxdclient 1.2.0

A pure Python async client for KNXD's (EIBD's) native Layer 4

KNXDclient

A pure Python async client for KNXD's (EIBD's) native Layer 4 KNX protocol.

EIBD is a *NIX daemon for routing EIB/KNX telegrams through various interfaces and programmatically accessing the EIB/KNX bus. It's part of the no-longer maintained BCUSDK. However, there's a fork called KNXD, which is still actively maintained.

This package reimplements small parts of the EIBD client (see BCUSDK documentation, section 7.7) in pure Python 3, based on asynchronous coroutines (asyncio). Currently, it allows to open a Group Socket for sending and receiving KNX telegrams to/for any group address via KNXD. Additionally, this package includes helper methods encode_value() and decode_value() to convert the send/received data from/to native Python types according to a known KNX Datapoint Type (DPT).

Usage example

import asyncio
import knxdclient


def handler(packet: knxdclient.ReceivedGroupAPDU) -> None:
    print("Received group telegram: {}".format(packet))

async def main() -> None:
    # Raises a TimeoutError after 30 seconds of not receiving any traffic. This argument is optional
    connection = knxdclient.KNXDConnection(timeout=30.0) 
    connection.set_group_apdu_handler(handler)
    await connection.connect()
    # Connection was successful. Start receive loop:
    run_task = asyncio.create_task(connection.run())
    # Now that the receive loop is running, we can open the KNXd Group Socket:
    await connection.open_group_socket()

    # Startup completed. Now our `handler()` will receive incoming telegrams and we can send some:
    await connection.group_write(knxdclient.GroupAddress(1,3,2),
                                 knxdclient.KNXDAPDUType.WRITE,
                                 knxdclient.encode_value(True, knxdclient.KNXDPT.BOOLEAN))
    
    await asyncio.sleep(5)
    # Let's stop the connection and wait for graceful termination of the receive loop:
    await connection.stop()
    await run_task


asyncio.run(main())

Alternatively, an async iterator can be used for receiving group telegrams:

import asyncio
import knxdclient

# KNX Datapoint Types of some known group addresses, used for decoding incoming values and encoding group RESPONSE
DPTs = {
    knxdclient.GroupAddress(1, 2, 3): knxdclient.KNXDPT.BOOLEAN,
    knxdclient.GroupAddress(4, 5, 6): knxdclient.KNXDPT.FLOAT16,
}

# Some values for responding to group READ telegrams
CURRENT_VALUE = {
    knxdclient.GroupAddress(1, 2, 3): True
}


async def main() -> None:
    connection = knxdclient.KNXDConnection()
    await connection.connect()
    try:
        # Start run task and open group socket
        run_task = asyncio.create_task(connection.run())
        await connection.open_group_socket()

        # Iterate asynchronously over incoming group telegrams
        packet: knxdclient.ReceivedGroupAPDU
        async for packet in connection.iterate_group_telegrams():
            # Respond to GROUP READ telegrams with known values from CURRENT_VALUE dict
            if packet.payload.type == knxdclient.KNXDAPDUType.READ:
                address = packet.dst
                if address in CURRENT_VALUE:
                    await connection.group_write(address,
                                                 knxdclient.KNXDAPDUType.RESPONSE,
                                                 knxdclient.encode_value(CURRENT_VALUE[address], DPTs[address]))
            # Decode and log incoming group WRITE and RESPONSE telegrams 
            else:
                if packet.dst not in DPTs:
                    # Skip telegrams with unknown datatype
                    continue
                value = knxdclient.decode_value(packet.payload.value, DPTs[packet.dst])
                print(f"Telegram from {packet.src} to GAD {packet.dst}: {value}")

    finally:
        # Let's stop the connection and wait for graceful termination of the receive loop:
        await connection.stop()
        await run_task


asyncio.run(main())

License

This package is published under the terms of the Apache License 2.0.