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Custom objects and methods

Goal​

Extend the Function node server with custom objects and methods in the address space.

Where to add the code​

Place the following additions right after you create the namespace in your Function node. This keeps the example aligned with the basic server tutorial.

Example: add a custom object​

// Add a custom object under the Objects folder
const device = namespace.addObject({
    organizedBy: "ObjectsFolder",
    browseName: "Device001"
});

// Add a few variables to the object
const serialNumber = namespace.addVariable({
    componentOf: device,
    browseName: "SerialNumber",
    dataType: "String"
});

const temperature = namespace.addVariable({
    componentOf: device,
    browseName: "Temperature",
    dataType: "Double"
});

// Set initial values (and update later with new messages)
serialNumber.setValueFromSource({ dataType: opcua.DataType.String, value: "SN-001" });
temperature.setValueFromSource({ dataType: opcua.DataType.Double, value: msg.value || 20.0 });

Example: add a method​

const method = namespace.addMethod(device, {
    browseName: "Reset",
    inputArguments: [],
    outputArguments: []
});

method.bindMethod((inputArguments, context, callback) => {
    // Do your reset logic here
    const callMethodResult = {
        statusCode: opcua.StatusCodes.Good,
        outputArguments: []
    };
    callback(null, callMethodResult);
});

Test the method​

Use any OPC UA client to call Device001.Reset. You should receive a Good status code.

Next step​

Continue with user authentication.

Further reading​

For more tips and examples, see the Sterfive book node-opcua by example.