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""" |
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High level method related functions |
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""" |
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from asyncio import iscoroutinefunction |
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from asyncua import ua |
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async def call_method(parent, methodid, *args): |
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""" |
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Call an OPC-UA method. methodid is browse name of child method or the |
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nodeid of method as a NodeId object |
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arguments are variants or python object convertible to variants. |
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which may be of different types |
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returns a list of values or a single value depending on the output of the method |
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: param: parent `Node` |
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""" |
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result = await call_method_full(parent, methodid, *args) |
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if len(result.OutputArguments) == 0: |
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return None |
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elif len(result.OutputArguments) == 1: |
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return result.OutputArguments[0] |
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else: |
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return result.OutputArguments |
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async def call_method_full(parent, methodid, *args): |
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""" |
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Call an OPC-UA method. methodid is browse name of child method or the |
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nodeid of method as a NodeId object |
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arguments are variants or python object convertible to variants. |
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which may be of different types |
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returns a CallMethodResult object with converted OutputArguments |
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: param: parent `Node` |
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""" |
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if isinstance(methodid, (str, ua.uatypes.QualifiedName)): |
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methodid = (await parent.get_child(methodid)).nodeid |
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elif hasattr(methodid, 'nodeid'): |
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methodid = methodid.nodeid |
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result = await _call_method(parent.server, parent.nodeid, methodid, to_variant(*args)) |
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result.OutputArguments = [var.Value for var in result.OutputArguments] |
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return result |
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async def _call_method(server, parentnodeid, methodid, arguments): |
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""" |
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:param server: `UaClient` or `InternalSession` |
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:param parentnodeid: |
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:param methodid: |
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:param arguments: |
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:return: |
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""" |
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request = ua.CallMethodRequest() |
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request.ObjectId = parentnodeid |
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request.MethodId = methodid |
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request.InputArguments = arguments |
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methodstocall = [request] |
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results = await server.call(methodstocall) |
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res = results[0] |
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res.StatusCode.check() |
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return res |
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def uamethod(func): |
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""" |
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Method decorator to automatically convert |
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arguments and output to and from variants |
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""" |
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if iscoroutinefunction(func): |
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async def wrapper(parent, *args): |
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func_args = _format_call_inputs(parent, *args) |
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result = await func(*func_args) |
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return _format_call_outputs(result) |
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else: |
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def wrapper(parent, *args): |
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func_args = _format_call_inputs(parent, *args) |
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result = func(*func_args) |
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return _format_call_outputs(result) |
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return wrapper |
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def _format_call_inputs(parent, *args): |
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if isinstance(parent, ua.NodeId): |
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return (parent, *[arg.Value for arg in args]) |
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else: |
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self = parent |
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parent = args[0] |
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args = args[1:] |
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return (self, parent, *[arg.Value for arg in args]) |
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def _format_call_outputs(result): |
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if result is None: |
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return [] |
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elif isinstance(result, ua.CallMethodResult): |
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result.OutputArguments = to_variant(*result.OutputArguments) |
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return result |
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elif isinstance(result, ua.StatusCode): |
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return result |
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elif isinstance(result, tuple): |
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return to_variant(*result) |
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else: |
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return to_variant(result) |
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110
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111
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def to_variant(*args): |
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uaargs = [] |
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for arg in args: |
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if not isinstance(arg, ua.Variant): |
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arg = ua.Variant(arg) |
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uaargs.append(arg) |
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return uaargs |
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