[Question] uamethod no parent

[AiyionPrime]

Good afternoon everyone;
I came across uamethod these days and wanted to know whether it would be possible to use it as decorator for functions whose signature does not have "parent" as first attribute?

opcua-asyncio/asyncua/common/methods.py

Lines 73 to 90 in e9978c1

	def uamethod(func):
	"""
	Method decorator to automatically convert
	arguments and output to and from variants
	"""
	if iscoroutinefunction(func):
	async def wrapper(parent, *args):
	func_args = _format_call_inputs(parent, *args)
	result = await func(*func_args)
	return _format_call_outputs(result)
	else:
	def wrapper(parent, *args):
	func_args = _format_call_inputs(parent, *args)
	result = func(*func_args)
	return _format_call_outputs(result)
	return wrapper

When the fuction decorated with it is actually a method and the class is already the parent of the "function" I see little use in having it being part of every of our server methods?

If I understand it correctly a method currently can't look like this, if I want to decorate it with uamethod, even if it' not making use of 'parent'?

from asyncua.common import uamethod
from asyncua.sync import Server

class PinController:

    def __init__(self, some_server: Server):
        self.server = some_server
        server.link_method(
            server.get_node(ua.NodeId.from_string("ns=1;i=42")), uamethod(self.on_set_output)
        )

    def on_set_output(self, pin: ua.UInt32, value: ua.Boolean) -> None:
        # set the pin to something useful
        pass

[AndreasHeine]

ua methods are always part of an opc ua objecttype so the always have a parent!

[AndreasHeine]

you probably need to create a own Pincontrollertype, instantiate a instance of that type and bind the instances methods to class functions

[AiyionPrime]

Maybe my example was misleading. If I were to implement an OPC UA Server based on PinController, and wanted the method on_set_output to be the OPC UA "function" that handles the request, then it is nice, that the server gives a parent attribute in it's direction, but I don't want it.

Lets see. The Class above could have a reference to a server like this and link methods accordingly.

I've updated the example above; maybe my case became somewhat clearer. Sorry for the confusion.

[schroeder-]

Just make a wrapper function

 def remove_parent(func):
     def wrap(parent, *args):
          return func(*args)
     return wrap

class PinController:

    def __init__(self, some_server: Server):
        self.server = some_server
        server.link_method(
            server.get_node(ua.NodeId.from_string("ns=1;i=42")), uamethod(remove_parent(self.on_set_output))
        )

    def on_set_output(self, pin: ua.UInt32, value: ua.Boolean) -> None:
        # set the pin to something useful
        pass

[AiyionPrime]

I did so; just wondered whether this was unidiomatic. Thanks :)