This package implements ISO-TP over CAN as an asyncio transport layer, enabling simultaneous receiving and transmitting messages with any number of connections.
Raw CAN communication uses python-can which offers compatibility for many different CAN interfaces and operating systems.
If SocketCAN ISO-TP module is loaded and Python 3.7+ is used, the transport is delegated to the kernel if possible for better timing performance. Use the 'socketcan' interface. If unsuccessful, raw CAN will be used as fallback.
The isotpserver from can-utils can also be used to bridge a SocketCAN ISO-TP connection over TCP/IP. Use the 'isotpserver' interface and 'host:port' as channel.
Asynchronous programming simplifies some possible use-cases:
- Full duplex receiving and transmitting on a single connection.
- Communicate on multiple connections simultaneously.
- Functional addressing where one request is sent out and all nodes respond, then processing the responses as they arrive.
- Implementing or simulating multiple servers.
No threads need to be handled with all the locking mechanisms required by it.
Install from PyPI:
$ pip install aioisotp
A basic documentation can be built using Sphinx:
$ python setup.py build_sphinx
Here is an example of an echo server implemented using a callback based protocol and a client implemented as sequencial reader and writer streams.
import asyncio
import aioisotp
class EchoServer(asyncio.Protocol):
def connection_made(self, transport):
self.transport = transport
def data_received(self, data):
# Echo back the same data
self.transport.write(data)
async def main():
network = aioisotp.ISOTPNetwork('vcan0',
interface='virtual',
receive_own_messages=True)
with network.open():
# A server that uses a protocol
transport, protocol = await network.create_connection(
EchoServer, 0x1CDADCF9, 0x1CDAF9DC)
# A client that uses streams
reader, writer = await network.open_connection(
0x1CDAF9DC, 0x1CDADCF9)
writer.write(b'Hello world!')
response = await reader.read(4095)
assert response == b'Hello world!'
loop = asyncio.get_event_loop()
loop.run_until_complete(main())This package is meant to enable the use of other protocols that require ISO-TP. One of the most common is UDS. A third party library like udsoncan or pyvit can be used to encode and decode payloads.
import aioisotp
import udsoncan
...
reader, writer = await network.open_connection(0x1CDAF9DC, 0x1CDADCF9)
# Construct and send request
request = udsoncan.Request(
udsoncan.services.ReadDataByIdentifier, data=b'\xF1\x90')
writer.write(request.get_payload())
# Wait for response and decode the payload
payload = await reader.read(4095)
response = udsoncan.Response.from_payload(payload)
print(response)
print(response.data)