Node Opcua / QtOpcUa - Method Calls - opc-ua

Question

I have a Node OPC Server which I connect to with a Qt application using the QtOpcUa client library.
On my server I define a method that's basically a crude historic access request as HDA support is not yet available, it takes in a start_date and end_date then queries a database for the relevant values which it returns in an array.
It looks a bit like this:
const deviceTrends = namespace.addObject({
organizedBy: deviceObject,
browseName: strings.TREND_NODE
})
const method = namespace.addMethod(deviceTrends,{
nodeId: strings.NSI + part.name + "-Trend",
browseName: part.name + "-Trend",
inputArguments: [
{
name:"start_date",
description: { text: "Trend Start Date" },
dataType: opcua.DataType.DateTime
},{
name:"end_date",
description: { text: "Trend End Date" },
dataType: opcua.DataType.DateTime
}
],
outputArguments: [{
name:"Trend",
description:{ text: "Trend Data from start_date to end_date" },
dataType: opcua.DataType.String ,
valueRank: 1
}]});
method.bindMethod(function(inputArguments,context,callback) {
console.log("called")
const start = inputArguments[0].value;
const end = inputArguments[1].value;
console.log("Start: ", start);
console.log("End: ", end);
let sql = `SELECT Date date,
Name name,
Value value
FROM Trends
WHERE DateTime >= ? AND DateTime <= ?`;
var result = []
db.each(sql, [start, end], (err, row) =>
{
result.push(`${row.date}: ${row.name} - ${row.value}`)
})
console.log(result)
const callMethodResult = {
statusCode: opcua.StatusCodes.Good,
outputArguments: [{
dataType: opcua.DataType.String,
arrayType: opcua.VariantArrayType.Array,
value :result
}]
};
callback(null,callMethodResult);});}
I can see this in a client such as Prosys and call the method which works okay:
However I can't seem to call this method from Qt, I've cut out the packaging of arguments and the result handler (it just lists out the received params):
QOpcUaNode* n = devices[deviceName].client->node("ns=1;s=Speed-Trend");
connect(n, &QOpcUaNode::methodCallFinished, [this, deviceName](QString methodNodeId, QVariant result, QOpcUa::UaStatusCode status)
{
qDebug() << " Response received ";
this->handleNodeTrendResponse(deviceName, methodNodeId, result, status);
});
n->callMethod(n->nodeId(), args);
Trace:
Requesting Trend: From QDateTime(2018-10-07 13:13:56.766 BST Qt::TimeSpec(LocalTime)) TO QDateTime(2018-10-07 13:14:05.390 BST Qt::TimeSpec(LocalTime))
qt.opcua.plugins.open62541: Could not call method: BadNodeIdInvalid
Response received [Output from method result handler]
Device Name: "speed-device"
Method Node Id: "ns=1;s=Speed-Trend"
Result: QVariant(Invalid)
Result to List: << ()
Status: QOpcUa::UaStatusCode(BadNodeIdInvalid)
I also can't seem to find the method on other clients too, this is from an OPC UA Client application on my phone which shows nothing under the Trends object:
Everything else seems accessible, I can request variables, setup monitoring all fine.
Is there something I'm just missing here or is it an issue with QtOpcUa and other clients?
I can work around this by creating variables instead to capture input and output arguments and a boolean to represent a method call but it's a lot neater to tie everything up in a single method.
Thanks