Difficulty with Methods

[jeff-latray]

Using milo 1.6 I have a server that is successfully publishing values. I have a client I am using to test with that can successfully read values.

I am now trying to get some methods working and am having trouble. Scaled it down to just a ping so that I can call a method on the server with out parameters.

The client can see the method nodes by browsing through the nodes but if I try to call the method I am getting this error:StatusCode[name=Bad_MethodInvalid, value=0x80750000, quality=bad]

Logging from Browsing:

16:42:25.456 [main] io.elexity.opcuaclient.EbcOpcUaClient - Connected to opc.tcp://192.168.64.6:12686/EbcRoot 16:42:25.457 [main] io.elexity.opcuaclient.EbcOpcUaClient - Found namespace 'urn:io:elexity:ebc' at index 1 16:42:25.466 [main] io.elexity.opcuaclient.EbcOpcUaClient - Top node browse name: EbcRoot 16:42:25.468 [main] io.elexity.opcuaclient.EbcOpcUaClient - Ping (Method) 16:42:25.468 [main] io.elexity.opcuaclient.EbcOpcUaClient - balanceString (Method)

This is the client code I have for calling the method:

`
NodeId objectId = new NodeId(namespaceIndex, "EbcRoot"); // parent folder of method
NodeId methodId = new NodeId(namespaceIndex, "PingMethod");
// Build the CallMethodRequest
CallMethodRequest request = new CallMethodRequest(
objectId,
methodId,
new Variant[0]
);

    // Wrap the single request in a List
    List<CallMethodRequest> requests = Collections.singletonList(request);

    // Call the method
    CallResponse response = client.call(requests);

    // Output return values
    CallMethodResult[] outputs = response.getResults();

`

This is the server side code I have for the method:

`
public class OpcUaPingCommand {
private static Logger logger = LogManager.getLogger();
private final UaNodeContext cNodeContext;
private final UaFolderNode cParentFolder;
private final int cNamespaceIndex;

public OpcUaPingCommand(UaNodeContext nodeContext, UaFolderNode parentFolder, UShort namespaceIndex) {
    this.cNodeContext = nodeContext;
    this.cParentFolder = parentFolder;
    this.cNamespaceIndex = namespaceIndex.intValue();
}

public void addPingCommandMethodNode() {
    // Method NodeId
    NodeId methodId = new NodeId(cNamespaceIndex, "PingMethod");

    UaMethodNode methodNode = UaMethodNode.builder(cNodeContext)
        .setNodeId(methodId)
        .setBrowseName(new QualifiedName(cNamespaceIndex, "Ping"))
        .setDisplayName(LocalizedText.english("Ping"))
        .setDescription(LocalizedText.english("Simple ping method with no parameters"))
        .setExecutable(true)
        .setUserExecutable(true)
        .build();

    // No arguments
    methodNode.setInputArguments(new Argument[0]);
    methodNode.setOutputArguments(new Argument[0]);

    // Register handler
    methodNode.setInvocationHandler(new PingHandler(methodNode));

    // Add node to address space
    cNodeContext.getNodeManager().addNode(methodNode);

    // Add as component so clients can browse it
    cParentFolder.addComponent(methodNode);
}

public static class PingHandler extends AbstractMethodInvocationHandler {

    public PingHandler(UaMethodNode node) {
        super(node);
    }

    @Override
    protected Variant[] invoke(InvocationContext context, Variant[] inputValues) {
        // Should be length 0
        logger.info("Ping method invoked!");

        // No output values
        return new Variant[0];
    }

    @Override
    public Argument[] getInputArguments() {
        return null;
    }

    @Override
    public Argument[] getOutputArguments() {
        return null;
    }
}

}
`

[kevinherron]

Double check your NodeIds or set a breakpoint in getInvocationHandler:

milo/opc-ua-sdk/sdk-server/src/main/java/org/eclipse/milo/opcua/sdk/server/ManagedAddressSpace.java

Lines 251 to 280 in 28563c2

	/**
	* Get the {@link MethodInvocationHandler} for the method identified by {@code methodId}.
	*
	* @param objectId the {@link NodeId} identifying the object the method will be invoked on.
	* @param methodId the {@link NodeId} identifying the method.
	* @return the {@link MethodInvocationHandler} for {@code methodId}.
	* @throws UaException a {@link UaException} containing the appropriate operation result if either
	* the object or method can't be found.
	*/
	protected MethodInvocationHandler getInvocationHandler(NodeId objectId, NodeId methodId)
	throws UaException {
	UaNode node =
	nodeManager
	.getNode(objectId)
	.orElseThrow(() -> new UaException(StatusCodes.Bad_NodeIdUnknown));
	UaMethodNode methodNode = null;
	if (node instanceof UaObjectNode objectNode) {
	methodNode = objectNode.findMethodNode(methodId);
	} else if (node instanceof UaObjectTypeNode objectTypeNode) {
	methodNode = objectTypeNode.findMethodNode(methodId);
	}
	if (methodNode != null) {
	return methodNode.getInvocationHandler();
	} else {
	throw new UaException(StatusCodes.Bad_MethodInvalid);
	}
	}

This is the only place StatusCodes.Bad_MethodInvalid is used, so it means either the UaMethodNode is not found, or its invocation handler is not found.