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{"@context":"https://schema.org","@type":"QAPage","mainEntity":{"@type":"Question","name":"Using the __init__() method to pass objects to the server implementation of an interface?","text":"
Hi!
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When implementing the server side of an interface it seems to me to be convenient to be able to pass references etc. to an interface using the def __init__(self, ...) call.
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But I'm having trouble to get this to work, as I get the error:
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... object has no attribute '_dbus'\n
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back.
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An example:
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from sdbus import (DbusInterfaceCommonAsync, dbus_method_async,\n                   request_default_bus_name_async)\nfrom asyncio import new_event_loop\n\nclass HelloInterface(\n    DbusInterfaceCommonAsync,\n    interface_name='org.example.interface'\n):\n    def __init__(self, hello):\n        self.hello = hello\n\n    @dbus_method_async(\n        input_signature='s',\n        result_signature='s',\n    )\n    async def hello(self, string: str) -> str:\n        return self.hello.say_hello_back(str)\n\nclass Hello:\n    def say_hello_back(str):\n        return \"Hello {str}!\"\n\nhello = Hello()\ni = HelloInterface(hello)\n\nasync def startup() -> None:\n    await request_default_bus_name_async('org.example.test')\n    i.export_to_dbus('/')\n\nloop = new_event_loop()\n\nloop.run_until_complete(startup())\nloop.run_forever()\n
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This gives the error:
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Traceback (most recent call last):\n  File \"/tmp/test/hello_interface.py\", line 32, in <module>\n    loop.run_until_complete(startup())\n    ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^\n  File \"/usr/lib/python3.13/asyncio/base_events.py\", line 725, in run_until_complete\n    return future.result()\n           ~~~~~~~~~~~~~^^\n  File \"/tmp/test/hello_interface.py\", line 28, in startup\n    i.export_to_dbus('/')\n    ~~~~~~~~~~~~~~~~^^^^^\n  File \"/usr/lib/python3/dist-packages/sdbus/dbus_proxy_async_interface_base.py\", line 322, in export_to_dbus\n    local_object_meta = self._dbus\n                        ^^^^^^^^^^\nAttributeError: 'HelloInterface' object has no attribute '_dbus'\n
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Obviously something is missing in the def __init__() method, but I've not been able to find out what it could be.
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Any pointers?
","upvoteCount":1,"answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"
It is a different error caused by the fact you are using hello both as attribute and method. You have to rename one of them. For example, call attribute _hello:
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    def __init__(self, hello):\n        super().__init__()\n        self._hello = hello
","upvoteCount":0,"url":"https://github.com/python-sdbus/python-sdbus/discussions/115#discussioncomment-14910541"}}}