server_with_method.js

/* global console, require */
const opcua = require("node-opcua");


(async () => {

    try {
        const server = new opcua.OPCUAServer({
            port: 4334 // the port of the listening socket of the server
        });
        
        
        await server.initialize();
        
        const addressSpace = server.engine.addressSpace;
        const namespace = addressSpace.getOwnNamespace();
        
        const myDevice = namespace.addObject({
            organizedBy: addressSpace.rootFolder.objects,
            browseName: "MyDevice"
        });
        
        const method = namespace.addMethod(myDevice,{
        
            browseName: "Bark",
        
            inputArguments:  [
                {
                    name:"nbBarks",
                    description: { text: "specifies the number of time I should bark" },
                    dataType: opcua.DataType.UInt32        
                },{
                    name:"volume",
                    description: { text: "specifies the sound volume [0 = quiet ,100 = loud]" },
                    dataType: opcua.DataType.UInt32
                }
             ],
        
            outputArguments: [{
                 name:"Barks",
                 description:{ text: "the generated barks" },
                 dataType: opcua.DataType.String ,
                 valueRank: 1
            }]
        });
        
        // optionally, we can adjust userAccessLevel attribute 
        method.outputArguments.userAccessLevel = opcua.makeAccessLevelFlag("CurrentRead");
        method.inputArguments.userAccessLevel = opcua.makeAccessLevelFlag("CurrentRead");
        
        
        method.bindMethod((inputArguments,context,callback) => {
        
            const nbBarks = inputArguments[0].value;
            const volume =  inputArguments[1].value;
        
            console.log("Hello World ! I will bark ",nbBarks," times");
            console.log("the requested volume is ",volume,"");
            const sound_volume = Array(volume).join("!");
        
            const barks = [];
            for(let i=0; i < nbBarks; i++){
                barks.push("Whaff" + sound_volume);
            }
        
            const callMethodResult = {
                statusCode: opcua.StatusCodes.Good,
                outputArguments: [{
                        dataType: opcua.DataType.String,
                        arrayType: opcua.VariantArrayType.Array,
                        value :barks
                }]
            };
            callback(null,callMethodResult);
        });
        
        await server.start();
        console.log("Server is now listening ... ( press CTRL+C to stop)");
        const endpointUrl = server.endpoints[0].endpointDescriptions()[0].endpointUrl;
        console.log(" the primary server endpoint url is ", endpointUrl );
        
    }
    catch(err) {
        console.log(err);
    }
})();