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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Use canopen with externally provided bus and notifier","articleBody":"I have a use-case where canopen have to live next to another protocol (using only extendedids). The (physical) can bus interface cannot have multiple instances and the same `can.Bus()` interface. It and and the `can.Notifier()` instance must be shared with both protocols. `Network.connect()` makes it a bit cumbersome to define bus and notifier from the outside.\n\nhttps://github.com/christiansandberg/canopen/blob/ae71853be7fb42870bb5763066b0c3c50d015669/canopen/network.py#L83-L112\n\nThere are several things that can be done here to make it more consistent. I'm interested in hearing what opinions there might be for how to improve this:\n\n### Option 1\n\nBe able to support a provided notifier, similar to what's done with `bus`:\n\n```py\n# L111 in network.py\nif self.notifier is None:\n    self.notifier = can.Notifier(self.bus, [], self.NOTIFIER_CYCLE, **kwargs_notifier)\nfor listener in self.listeners:\n    self.notifier.add_listener(listener)\n```\n\nTo use your own:\n\n```py\nnetwork = canopen.Network()\nnetwork.bus = mybus\nnetwork.notifier = mynotifier\nnetwork.connect()\n```\n\n### Option2 \n\nExtend arguments to `connect()`:\n\n```py\nbus = kwargs.pop(\"bus\", None)\nnotifier = kwargs.pop(\"notifier\", None)\nif self.bus is None:\n    self.bus = bus or can.Bus(*args, *kwargs)\nlogger.info(\"Connected to '%s'\", self.bus.channel_info)\nif self.notifier is None:\n    self.notifier = notifier or can.Notifier(self.bus, [], self.NOTIFIER_CYCLE)\nfor listener in self.listeners:\n    self.notifier.add_listener(listener)\n```\n\nThis allows the usage:\n\n```py\nnetwork = canopen.Network()\nnetwork.connect(bus=mybus, notifier=mynotifier)\n```\n\nPS! `Network.disconnect()` doesn't really play nice with externally provided bus and notifier either and should be looked at.\n\n### * EDIT * \n\nI think also the init of `Network` should be extended:\n\n```py\ndef __init__(self, bus: Optional[can.BusABC] = None, notifier: Optional[can.Notifier] = None):\n```","author":{"url":"https://github.com/sveinse","@type":"Person","name":"sveinse"},"datePublished":"2025-01-25T18:51:42.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":8},"url":"https://github.com/556/canopen/issues/556"}