I am learning node opc-ua and have followed the example provided in the GitHub page for the sample_server.js and simple_client.js.
In the sample_server I add a variable when constructing the address space of the server such as:
//this code is in the server addressSpace.addVariable({ componentOf: device, nodeId: "ns=1;s=variable_1", browseName: "MyVariable1", dataType: "Double", value: { get: function () { return new opcua.Variant({ dataType: opcua.DataType.Double, value: variable1 }); } } }); Here is the whole server code for reference:
var opcua = require("node-opcua"); var server = new opcua.OPCUAServer({ port: 4334, // the port of the listening socket of the server resourcePath: "UA/MyLittleServer", // this path will be added to the endpoint resource name buildInfo: { productName: "MySampleServer1", buildNumber: "7658", buildDate: new Date(2014, 5, 2) } }); server.initialize(post_initialize); function post_initialize() { console.log("initialized"); construct_my_address_space(server, function () { server.start(function () { console.log("Server is now listening ... ( press CTRL+C to stop)"); console.log("port ", server.endpoints[0].port); var endpointUrl = server.endpoints[0].endpointDescriptions()[0].endpointUrl; console.log(" the primary server endpoint url is ", endpointUrl); }); }); } function construct_my_address_space(server, callback) { var addressSpace = server.engine.addressSpace; // declare a new object var device = addressSpace.addObject({ organizedBy: addressSpace.rootFolder.objects, browseName: "MyDevice" }); // add a variable named MyVariable1 to the newly created folder "MyDevice" var variable1 = 1; // emulate variable1 changing every 500 ms setInterval(function () { variable1 += 1; }, 500); addressSpace.addVariable({ componentOf: device, nodeId: "ns=1;s=variable_1", browseName: "MyVariable1", dataType: "Double", value: { get: function () { return new opcua.Variant({ dataType: opcua.DataType.Double, value: variable1 }); } } }); callback(); } Now, in the client i want to discover this variable by name or the full nodeId. I am using the sample provided to browse the session to the server but in the return i only see FolderType, Objects, Types and Views and can not locate this variable anywhere.
Here is the client code:
var opcua = require("node-opcua"); var async = require("async"); var client = new opcua.OPCUAClient(); var endpointUrl = "opc.tcp://" + require("os").hostname() + ":4334/UA/MyLittleServer"; var the_session, the_subscription; async.series([ // step 1 : connect to function (callback) { client.connect(endpointUrl, function (err) { if (err) { console.log(" cannot connect to endpoint :", endpointUrl); } else { console.log("connected !"); } callback(err); }); }, // step 2 : createSession function (callback) { client.createSession(function (err, session) { if (!err) { the_session = session; } callback(err); }); }, // step 3 : browse function (callback) { the_session.browse("RootFolder", function (err, browse_result) { if (!err) { console.log('Result of browsing: ', browse_result); browse_result[0].references.forEach(function (reference) { console.log('browsing: ', reference.browseName); console.log(reference); console.log("**************************************"); }); } callback(err); }); }, /* step 4 : read a variable with readVariableValue function (callback) { the_session.readVariableValue("ns=1;s=variable_1", function (err, dataValue) { if (!err) { console.log(" var 1 = ", dataValue.toString()); } callback(err); }); }, // step 4' : read a variable with read function (callback) { var max_age = 0; var nodes_to_read = [ { nodeId: "ns=1;s=variable_1", attributeId: opcua.AttributeIds.Value } ]; the_session.read(nodes_to_read, max_age, function (err, nodes_to_read, dataValues) { if (!err) { console.log(" variable 1 = ", dataValues[0]); } callback(err); }); }, */ // step 5: install a subscription and install a monitored item for 10 seconds function (callback) { the_subscription = new opcua.ClientSubscription(the_session, { requestedPublishingInterval: 1000, requestedLifetimeCount: 10, requestedMaxKeepAliveCount: 2, maxNotificationsPerPublish: 10, publishingEnabled: true, priority: 10 }); the_subscription.on("started", function () { console.log("subscription started for 2 seconds - subscriptionId=", the_subscription.subscriptionId); }).on("keepalive", function () { console.log("keepalive"); }).on("terminated", function () { callback(); }); setTimeout(function () { the_subscription.terminate(); }, 10000); // install monitored item var monitoredItem = the_subscription.monitor({ nodeId: opcua.resolveNodeId("ns=1;s=variable_1"), attributeId: opcua.AttributeIds.Value }, { samplingInterval: 100, discardOldest: true, queueSize: 10 }, opcua.read_service.TimestampsToReturn.Both ); console.log("-------------------------------------"); monitoredItem.on("changed", function (dataValue) { console.log("variable_1 = ", dataValue.value.value); }); }, // close session function (callback) { the_session.close(function (err) { if (err) { console.log("session closed failed ?"); } else{ console.log("session closed!"); } callback(); }); } ], function (err) { if (err) { console.log(" failure ", err); } else { console.log("done!"); } client.disconnect(function () { }); }); Thanks in advance
