subscribing to events with custom data type definitions

[ThomasSindlinger]

Hello together,

The main question: How do I get access on the data type from the server?

I'm new in this opc-ua-game and I wanted to subscribe an event on a OPC-UA-Server.
The event (CycleDoneEventType) is called about every 60 seconds and outputs the following data:

The important data for me are the "Curves" which are an extension Object with this Structure:

To get the data I use this code:

from asyncua import ua
from asyncua import Client
import asyncio

logging.basicConfig(level=logging.INFO)
_logger = logging.getLogger(__name__)

class SubHandler:
    def event_notification(self, event):
        _logger.info("New event received: %r", event.CycleNumber)
        for idx,extensionObject in  enumerate(event.Curves):
            _logger.info("CURVE: %r", CurveDataType(extensionObject.body))
            # _logger.info("CURVE: %r", extensionObject.body)

async def main():
    url = "opc.tcp://192.168.2.131:4840/comoneo/server/"
    async with Client(url=url) as client:
        try:
            obj = await client.nodes.root.get_child(["0:Objects", "0:Server"])
            await client.load_data_type_definitions()
            myevent = await client.nodes.root.get_child(["0:Types", "0:EventTypes", "0:BaseEventType", "2:CycleDoneEventType"])
            handler = SubHandler()
            sub = await client.create_subscription(100, handler)
            handle = await sub.subscribe_events(obj, myevent)

            await asyncio.sleep(100)
            await sub.unsubscribe(handle)
            await sub.delete()

        except Exception as msg:
            print("ERROR:", msg)


if __name__ == "__main__":
    asyncio.run(main())

I get data back but as "ExtensionObject". Which is still somehow binary encrypted.
It looks something like this:

b'\x01\x00\x00\x00\x00\x00\x02\x00\x00\x00X\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00@\xb2\xd0D@\x00\x00\x00 V\x0e\xa1?\x00\x00\x00\x00\x17\xd0D@\x00\x00\x00\xa0n\x12\xb1?\x00\x00\x00\xc0L\xd0D@\x00\x00\x00@\xb2\x9d\xb9?\x00\x00\x00 \xf9\xcfD@\x00\x00\x00\xe0z\x14\xc1?\x00\x00\x00\xc0\x7f\xcfD@\x00\x00\x00\xc0\x1cZ\xc5?\x00\x00\x00\x80\xb1\xcfD@\x00\x00\x00\x80\xbe\x9f\xc9?\x00\x00\x00`\xc7\xcfD@\x00\x00\x00``\xe5\xcd?\x00\x00\x00`\xc4\xcfD@\x00\x00\x00 \x81\x15\xd1?\x00\x00\x00\xe0W\xcfD@\x00\x00\x00\x00R8\xd3?\x00\x00\x00`\xbc\xcfD@\x00\x00\x00\xe0"[\xd5?\x00\x00\x00\x80\xa6\xcfD@\x00\x00\x00\xc0\xf3}\xd7?\x00\x00\x00 \xce\xd0D@\x00\x00\x00\xc0\xc4\xa0\xd9?\x00\x0 [...]'

The logger returns the following information, which leads me to conclude that the data types have been loaded:

INFO:asyncua.common.structures104:Registring Enum NodeId(Identifier=3005, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) ChannelType OptionSet=False
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3005, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='ChannelType')
INFO:asyncua.common.structures104:Registring Enum NodeId(Identifier=3003, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) InputSignalCategory OptionSet=False
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3003, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='InputSignalCategory')
INFO:asyncua.common.structures104:Registring Enum NodeId(Identifier=3010, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) MoldTypeEnumeration OptionSet=False
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3010, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='MoldTypeEnumeration')
INFO:asyncua.common.structures104:Registring Enum NodeId(Identifier=3012, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) SetupChangeType OptionSet=False
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3012, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='SetupChangeType')
INFO:asyncua.common.structures104:Registring Enum NodeId(Identifier=3011, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) StopConditionType OptionSet=False
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3011, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='StopConditionType')
INFO:asyncua.client.ua_client.UaClient:browse
INFO:asyncua.client.ua_client.UaClient:browse
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3004, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='ChannelIdDataType')
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3009, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='CurveDataType')
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3006, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='CurvePointDataType')
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3008, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='DigitalSignalChangeDataType')
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3007, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='InputSignalIdDataType')
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=5, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='ProcessValueType')
INFO:asyncua.common.structures104:Registering data type NodeId(Identifier=3002, NamespaceIndex=2, NodeIdType=<NodeIdType.FourByte: 1>) QualifiedName(NamespaceIndex=2, Name='SignalSubIdDataType')

Now my question is:
How do I get the correct data? Or how do I use the data type from the server?

I am in despair :D
So I am grateful for any help!

[schroeder-]

I tested with a simple testcase all structs should be converted to a dataclass, in this case CurveDataType. Can you read a CurveDataType from any variable? Your diagram looks a bit complex are there any subtyping structs or anything more than basic structs? Maybe there is a nodeset2.xml for the datatypes?

[schroeder-]

Ok the problem is getting the datatype from the server. Because if don't have a CurveDataType in "ua" then a ExtensionObject can't be decoded.
If you can get the datatype, then you should get a CurveDataType instead of ExtensionObject.
Which Server are you targeting?
Do you use load_data_type_definitions or load_type_definitions?

[ThomasSindlinger]

What du you mean with which Server? the version?
I tried it with both.

[schroeder-]

Which Server Product/SDK you are connecting to with your client?

[ThomasSindlinger]

It is a Molding-Measurement-Tool "Kistler-ComoNeo. It serves a normal opc-ua-server.
DOC:
OPCUA-Interface-Neo-3.1.pdf

[ThomasSindlinger]

BTW.: I also often get this error:

AttributeError: module 'asyncua.ua' has no attribute 'Bit'
ERROR loading GEN module 'asyncua.ua' has no attribute 'Bit'

[oroulet]

after calling load_data_types_definitions() then all server custom classes should be registered locally on your client. (For example newCurve = ua.CurveDataType()should work fine
If you receive an ExtensionObejct instead of the expected class then somehow the data type has not been registered. but I have no ideas why...
looks like the ID of you class is ns=2,i=5011. Do you see that ID beeing registered when calling load_data_type_definitoins? maybe it prints some errror?

[schroeder-]

Did you remove ua.Bit = ua.Boolean monkey patch?

[ThomasSindlinger]

Yes. Do you mean for the load_type_definitions() solution?!

[schroeder-]

Sry my bad, missed a bit in the optionset encoding, while porting the patch. Will update the pr soon.

[schroeder-]

Should be correct now

[ThomasSindlinger]

Thanks for patching. I will test it next monday.