Injecting standard companion specifications (RFID example)

Goal

Load a standard companion specification (RFID) into your scripted server and instantiate a complex object type. The pattern generalises to any OPC UA companion spec: AutoID, DI, Machinery, ISA-95, and so on.

Prerequisites

• The basic scripted server is working — see Creating an OPC UA server.
• The nodesets: field accepts the built-in names that ship with the palette — "standard", "di", "autoId", "machinery", "ia", ... — or absolute paths to your own .NodeSet2.xml files. Use the latter when you have a downloaded companion spec that isn't bundled.

The Boot Function

const sterfive = global.get("sterfive");
if (!sterfive) {
    node.error("global.get('sterfive') is not set — is the Sterfive OPC UA palette loaded?");
} else {
    const { bootstrap, opcua } = sterfive;
    const { bootstrapServer } = bootstrap;

    const cfg = msg.config || {};

    const handle = await bootstrapServer({
        port: cfg.port ?? 4840,
        endpoint: cfg.endpoint || "node-red-server",
        nodesets: ["standard", "di", "autoId"],
        onPopulate: (addressSpace, exposed) => {
            const namespace = addressSpace.getOwnNamespace();

            const nsAutoId = addressSpace.getNamespaceIndex("http://opcfoundation.org/UA/AutoID/");
            const rfidReaderDeviceType = addressSpace.findObjectType("RfidReaderDeviceType", nsAutoId);
            if (!rfidReaderDeviceType) {
                throw new Error("RfidReaderDeviceType not found — is the AutoID nodeset loaded?");
            }

            const devicesFolder = namespace.addFolder("ObjectsFolder", { browseName: "Devices" });

            const rfidDevice = rfidReaderDeviceType.instantiate({
                organizedBy: devicesFolder,
                browseName: "RFID_Reader_1",
                nodeId: "s=RFID_Reader_1",
                optionals: ["DeviceHealth", "DeviceStatus", "ScanActive", "LastScanData"],
            });

            const deviceStatus = rfidDevice.getComponentByName("DeviceStatus", nsAutoId);
            if (deviceStatus) {
                deviceStatus.writeEnumValue("Idle");
                exposed.deviceStatus = deviceStatus;
            }
            const scanActive = rfidDevice.getComponentByName("ScanActive", nsAutoId);
            if (scanActive) {
                scanActive.setValueFromSource({ dataType: opcua.DataType.Boolean, value: false });
                exposed.scanActive = scanActive;
            }
        },
    });

    flow.set("$rfid_deviceStatus", handle.exposed.deviceStatus);
    flow.set("$rfid_scanActive",   handle.exposed.scanActive);
    flow.set("$opcuaHandle",       handle);

    node.send({ payload: `OPC UA Server running at ${handle.server.getEndpointUrl()}` });
}

If you have an XML file you've downloaded yourself, mix paths and built-ins:

nodesets: [
    "standard",
    "/srv/nodesets/Opc.Ua.Di.NodeSet2.xml",
    "/srv/nodesets/Opc.Ua.AutoID.NodeSet2.xml",
],

Paths must be absolute. The bootstrap helper validates each entry up-front and throws a helpful error listing built-in names if you misspell one — that pre-empts node-opcua's [NODE-OPCUA-E02] generateAddressSpace : cannot find nodeset2 xml file crash, which would otherwise leave the server in a partially-initialized state.

caution

Nodesets are construction-time only — nodesets: is part of the config-identity hash. Adding a new nodeset to the boot Function and redeploying triggers an automatic teardown-then-rebuild.

Update values dynamically

In a separate Update Function:

const sterfive = global.get("sterfive");
if (!sterfive) {
    node.error("global.get('sterfive') is not set — is the Sterfive OPC UA palette loaded?");
} else {
    const { opcua } = sterfive;
    const scanActive = flow.get("$rfid_scanActive");

    if (!scanActive) {
        node.warn("server not booted");
    } else {
        scanActive.setValueFromSource({
            dataType: opcua.DataType.Boolean,
            value: Boolean(msg.payload),
        });
    }
}

Tips

• The companion specs define many optional components. optionals: [...] controls which ones are materialised on instantiation. Be deliberate; instantiating everything inflates the address space.
• getComponentByName(name, namespaceIndex) requires the namespace index because the same browse name might exist in several namespaces.
• For composite extension-object values (e.g., RfidScanResult), use addressSpace.constructExtensionObject(dataTypeNode, fields) to build the value, then setValueFromSource({ dataType: DataType.ExtensionObject, value: extObj }).
• Several companion specs depend on others (AutoID requires DI, MachineTool requires Machinery, etc.). Load the prerequisites in nodesets: order.

Further reading

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