Unknown datatype when calling load_data_type_definitions

[tomj-99]

When I connect to an OPC UA server as a client and call await client.load_data_type_definitions(), I get this error:

error: Unknown datatype for field: StructureField(Name='ProposedRigParameters', Description=LocalizedText(Locale=None, Text=None), DataType=NodeId(Identifier=3008, NamespaceIndex=3, NodeIdType=<NodeIdType.FourByte: 1>), ValueRank=1, ArrayDimensions=[0], MaxStringLength=0, IsOptional=False) in structure:ActivityDataDataType, please report

When calling await client.load_type_definitions() instead, it works fine but gives a warning Deprecated since spec 1.04, call load_data_type_definitions.

The field 'MyCustomTypeArrayField' is an array of a custom data type (ns=3 i=3008, with only basic opc ua data types as fields) with an array size of 0 that is set dynamically at runtime.

The server that I connect to uses the .NET SDK v3.3.0 from UnifiedAutomation which should actually support spec 1.05.

versions: Python 3.11.0 ayncua 1.0.2

[schroeder-]

Does the Datatype ns=3 i=3008 exist on the server, if you check it with ua expert?

[tomj-99]

@schroeder- yes, that exists. I just had a closer look at the log and found this:

Structure type StructureDefinition(DefaultEncodingId=NodeId(Identifier=5018, NamespaceIndex=3, NodeIdType=<NodeIdType.FourByte: 1>), BaseDataType=NodeId(Identifier=22, NamespaceIndex=0, NodeIdType=<NodeIdType.TwoByte: 0>), StructureType_=<StructureType.StructureWithSubtypedValues: 3>, Fields=[...]) not implemented

I shortened it a little bit, the important part seems to be StructureType_=<StructureType.StructureWithSubtypedValues: 3>, I just went through the code of load_data_type_definitions and found in structures104.py in the function make_structure_code these lines:

if sdef.StructureType not in (ua.StructureType.Structure, ua.StructureType.StructureWithOptionalFields, ua.StructureType.Union):
        raise NotImplementedError(f"Only StructureType implemented, not {ua.StructureType(sdef.StructureType).name} for node {struct_name} with DataTypdeDefinition {sdef}")

so StructureWithSubtypedValues does not seem to be supported

[schroeder-]

StructureWithSubtypedValues is supported in the encoding layer. Should be easy to add, only structures104.py needs to bechange. Why are you using StructureWithSubtypedValues? Is there a particular reason, to do this? This is a exotic feature and can make problems with a lot of clients.

[tomj-99]

@schroeder- actually one of the StructureFields was of Type Number (dynamically resolved to Double at runtime) which made it a StructureWithSubtypedValues. We will change it to Double and expect it to work with these changes. Nevertheless it might be a good idea to support StructureWithSubtypedValues.

[schroeder-]

I will add StructureWithSubtypedValues if i find the time. I add i to my backlog.

[tomj-99]

After changing the data type of the field from Number to Double, calling await client.load_data_type_definitions() works fine 👍

[mous16]

I follow this thread, because I've also the same need. Yes, I know, it's an exotic feature, but I cannot control the custom types required by the server I'm connecting to.

[Scheibengraber]

Dear @schroeder- and @AndreasHeine I also follow this thread. Do you have already some estimation when you can implement this enhancement? I am also interested in the enhancement.