* background worker

  for OPC UA client is
  difficult ..

src/AasxPluginAssetInterfaceDesc/AasOpcUaClient.cs

@@ -0,0 +1,324 @@
+/*
+Copyright (c) 2018-2023 Festo SE & Co. KG <https://www.festo.com/net/de_de/Forms/web/contact_international>
+Author: Michael Hoffmeister
+
+This source code is licensed under the Apache License 2.0 (see LICENSE.txt).
+
+This source code may use other Open Source software components (see LICENSE.txt).
+*/
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Opc.Ua;
+using Opc.Ua.Client;
+using Opc.Ua.Configuration;
+
+// Note: this is a DUPLICATE from WpfMtpControl
+
+namespace AasxPluginAssetInterfaceDescription
+{
+    public enum AasOpcUaClientStatus
+    {
+        ErrorCreateApplication = 0x11,
+        ErrorDiscoverEndpoints = 0x12,
+        ErrorCreateSession = 0x13,
+        ErrorBrowseNamespace = 0x14,
+        ErrorCreateSubscription = 0x15,
+        ErrorMonitoredItem = 0x16,
+        ErrorAddSubscription = 0x17,
+        ErrorRunning = 0x18,
+        ErrorReadConfigFile = 0x19,
+        ErrorNoKeepAlive = 0x30,
+        ErrorInvalidCommandLine = 0x100,
+        Running = 0x1000,
+        Quitting = 0x8000,
+        Quitted = 0x8001
+    };
+
+    public class AasOpcUaClient
+    {
+        const int ReconnectPeriod = 10;
+        Session session;
+        SessionReconnectHandler reconnectHandler;
+        string endpointURL;
+        static bool autoAccept = true;
+        static AasOpcUaClientStatus ClientStatus;
+        string userName;
+        string password;
+
+        public AasOpcUaClient(string _endpointURL, bool _autoAccept, 
+            string _userName, string _password)
+        {
+            endpointURL = _endpointURL;
+            autoAccept = _autoAccept;
+            userName = _userName;
+            password = _password;
+        }
+
+        private BackgroundWorker worker = null;
+
+        public void Run()
+        {
+            // start server as a worker (will start in the background)
+            // ReSharper disable once LocalVariableHidesMember
+            var worker = new BackgroundWorker();
+            worker.WorkerSupportsCancellation = true;
+            worker.DoWork += (s1, e1) =>
+            {
+                try
+                {
+                    while (true)
+                    {
+                        StartClientAsync().Wait();
+
+                        // keep running
+                        if (ClientStatus == AasOpcUaClientStatus.Running)
+                            while (true)
+                                Thread.Sleep(200);
+
+                        // restart
+                        Thread.Sleep(200);
+                    }
+                }
+                catch (Exception ex)
+                {
+                    AdminShellNS.LogInternally.That.SilentlyIgnoredError(ex);
+                }
+            };
+            worker.RunWorkerCompleted += (s1, e1) =>
+            {
+                ;
+            };
+            worker.RunWorkerAsync();
+        }
+
+        public void Cancel()
+        {
+            if (worker != null && worker.IsBusy)
+                try
+                {
+                    worker.CancelAsync();
+                    worker.Dispose();
+                }
+                catch (Exception ex)
+                {
+                    AdminShellNS.LogInternally.That.SilentlyIgnoredError(ex);
+                }
+        }
+
+        public void Close()
+        {
+            if (session == null)
+                return;
+            session.Close(1);
+            session = null;
+        }
+
+        public AasOpcUaClientStatus StatusCode { get => ClientStatus; }
+
+        public async Task StartClientAsync()
+        {
+            Console.WriteLine("1 - Create an Application Configuration.");
+            ClientStatus = AasOpcUaClientStatus.ErrorCreateApplication;
+
+            ApplicationInstance application = new ApplicationInstance
+            {
+                ApplicationName = "UA Core Sample Client",
+                ApplicationType = ApplicationType.Client,
+                ConfigSectionName = Utils.IsRunningOnMono() ? "Opc.Ua.MonoSampleClient" : "Opc.Ua.SampleClient"
+            };
+
+            // load the application configuration.
+            ApplicationConfiguration config = null;
+            try
+            {
+                config = await application.LoadApplicationConfiguration(false);
+            }
+            catch (Exception ex)
+            {
+                AdminShellNS.LogInternally.That.Error(ex, "Error reading the config file");
+                ClientStatus = AasOpcUaClientStatus.ErrorReadConfigFile;
+                return;
+            }
+
+            // check the application certificate.
+            bool haveAppCertificate = await application.CheckApplicationInstanceCertificate(false, 0);
+            if (!haveAppCertificate)
+            {
+                throw new Exception("Application instance certificate invalid!");
+            }
+
+            // ReSharper disable HeuristicUnreachableCode
+            // ReSharper disable once ConditionIsAlwaysTrueOrFalse
+            if (haveAppCertificate)
+            {
+                config.ApplicationUri = X509Utils.GetApplicationUriFromCertificate(
+                    config.SecurityConfiguration.ApplicationCertificate.Certificate);
+
+                if (config.SecurityConfiguration.AutoAcceptUntrustedCertificates)
+                {
+                    autoAccept = true;
+                }
+                // ReSharper disable once RedundantDelegateCreation
+                config.CertificateValidator.CertificateValidation += new CertificateValidationEventHandler(
+                    CertificateValidator_CertificateValidation);
+            }
+            else
+            {
+                Console.WriteLine("    WARN: missing application certificate, using unsecure connection.");
+            }
+            // ReSharper enable HeuristicUnreachableCode
+
+            Console.WriteLine("2 - Discover endpoints of {0}.", endpointURL);
+            ClientStatus = AasOpcUaClientStatus.ErrorDiscoverEndpoints;
+            // ReSharper disable once ConditionIsAlwaysTrueOrFalse
+            var selectedEndpoint = CoreClientUtils.SelectEndpoint(endpointURL, haveAppCertificate, 15000);
+            Console.WriteLine("    Selected endpoint uses: {0}",
+                selectedEndpoint.SecurityPolicyUri.Substring(selectedEndpoint.SecurityPolicyUri.LastIndexOf('#') + 1));
+
+            Console.WriteLine("3 - Create a session with OPC UA server.");
+            ClientStatus = AasOpcUaClientStatus.ErrorCreateSession;
+            var endpointConfiguration = EndpointConfiguration.Create(config);
+            var endpoint = new ConfiguredEndpoint(null, selectedEndpoint, endpointConfiguration);
+
+            session = await Session.Create(config, endpoint, false, "OPC UA Console Client", 60000,
+                new UserIdentity(userName, password), null);
+
+            // register keep alive handler
+            session.KeepAlive += Client_KeepAlive;
+
+            // ok
+            ClientStatus = AasOpcUaClientStatus.Running;
+        }
+
+        private void Client_KeepAlive(Session sender, KeepAliveEventArgs e)
+        {
+            if (e.Status != null && ServiceResult.IsNotGood(e.Status))
+            {
+                Console.WriteLine("{0} {1}/{2}", e.Status, sender.OutstandingRequestCount, sender.DefunctRequestCount);
+
+                if (reconnectHandler == null)
+                {
+                    Console.WriteLine("--- RECONNECTING ---");
+                    reconnectHandler = new SessionReconnectHandler();
+                    reconnectHandler.BeginReconnect(sender, ReconnectPeriod * 1000, Client_ReconnectComplete);
+                }
+            }
+        }
+
+        private void Client_ReconnectComplete(object sender, EventArgs e)
+        {
+            // ignore callbacks from discarded objects.
+            if (!Object.ReferenceEquals(sender, reconnectHandler))
+            {
+                return;
+            }
+
+            if (reconnectHandler != null)
+            {
+                session = reconnectHandler.Session;
+                reconnectHandler.Dispose();
+            }
+
+            reconnectHandler = null;
+
+            Console.WriteLine("--- RECONNECTED ---");
+        }
+
+        private static void OnNotification(MonitoredItem item, MonitoredItemNotificationEventArgs e)
+        {
+            // ReSharper disable once UnusedVariable
+            foreach (var value in item.DequeueValues())
+            {
+                //// Console.WriteLine("{0}: {1}, {2}, {3}", item.DisplayName, value.Value, 
+                //// value.SourceTimestamp, value.StatusCode);
+            }
+        }
+
+        private static void CertificateValidator_CertificateValidation(
+            CertificateValidator validator, CertificateValidationEventArgs e)
+        {
+            if (e.Error.StatusCode == StatusCodes.BadCertificateUntrusted)
+            {
+                e.Accept = autoAccept;
+                if (autoAccept)
+                {
+                    Console.WriteLine("Accepted Certificate: {0}", e.Certificate.Subject);
+                }
+                else
+                {
+                    Console.WriteLine("Rejected Certificate: {0}", e.Certificate.Subject);
+                }
+            }
+        }
+
+        public NodeId CreateNodeId(string nodeName, int index)
+        {
+            return new NodeId(nodeName, (ushort)index);
+        }
+
+        private Dictionary<string, ushort> nsDict = null;
+
+        public NodeId CreateNodeId(string nodeName, string ns)
+        {
+            if (session == null || session.NamespaceUris == null)
+                return null;
+
+            // build up?
+            if (nsDict == null)
+            {
+                nsDict = new Dictionary<string, ushort>();
+                for (ushort i = 0; i < session.NamespaceUris.Count; i++)
+                    nsDict.Add(session.NamespaceUris.GetString(i), i);
+            }
+
+            // find?
+            if (nsDict == null || !nsDict.ContainsKey(ns))
+                return null;
+
+            return new NodeId(nodeName, nsDict[ns]);
+        }
+
+        public string ReadSubmodelElementValueAsString(string nodeName, int index)
+        {
+            if (session == null)
+                return "";
+
+            NodeId node = new NodeId(nodeName, (ushort)index);
+            return (session.ReadValue(node).ToString());
+        }
+
+        public DataValue ReadNodeId(NodeId nid)
+        {
+            if (session == null || nid == null || !session.Connected)
+                return null;
+            return (session.ReadValue(nid));
+        }
+
+        public void SubscribeNodeIds(NodeId[] nids, MonitoredItemNotificationEventHandler handler,
+            int publishingInteral = 1000)
+        {
+            if (session == null || nids == null || !session.Connected || handler == null)
+                return;
+
+            var subscription = new Subscription(session.DefaultSubscription)
+            { PublishingInterval = publishingInteral };
+
+            foreach (var nid in nids)
+            {
+                var mi = new MonitoredItem(subscription.DefaultItem);
+                mi.StartNodeId = nid;
+                mi.Notification += handler;
+                subscription.AddItem(mi);
+            }
+
+            session.AddSubscription(subscription);
+            subscription.Create();
+        }
+    }
+}

src/AasxPluginAssetInterfaceDesc/AasxPluginAssetInterfaceDesc.csproj

@@ -14,6 +14,7 @@
     <None Remove="Resources\logo-http.png" />
     <None Remove="Resources\logo-modbus.png" />
     <None Remove="Resources\logo-mqtt.png" />
+    <None Remove="Resources\logo-opc-ua.png" />
   </ItemGroup>
   <ItemGroup>
     <None Update="AasxPluginAssetInterfaceDesc.options.json">
@@ -31,6 +32,7 @@
     <EmbeddedResource Include="Resources\logo-http.png" />
     <EmbeddedResource Include="Resources\logo-modbus.png" />
     <EmbeddedResource Include="Resources\logo-mqtt.png" />
+    <EmbeddedResource Include="Resources\logo-opc-ua.png" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\AasxIntegrationBaseGdi\AasxIntegrationBaseGdi.csproj" />
@@ -48,5 +50,6 @@
     <PackageReference Include="FluentModbus" Version="5.0.3" />
     <PackageReference Include="MQTTnet" Version="4.1.1.318" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+    <PackageReference Include="OPCFoundation.NetStandard.Opc.Ua" Version="1.4.370.12" />
   </ItemGroup>
 </Project>