// @nuget: Workstation.UaClient -version 2.4.0

using System;

using System.Threading.Tasks;

using Workstation.ServiceModel.Ua;

using Workstation.ServiceModel.Ua.Channels;

public class Program

{

    /// <summary>

    /// Connects to server and reads the current ServerState. 

    /// </summary>

    public static async Task Main()

    {

        // describe this client application.

        var clientDescription = new ApplicationDescription

        {

            ApplicationName = "Workstation.UaClient.FeatureTests",

            ApplicationUri = $"urn:{System.Net.Dns.GetHostName()}:Workstation.UaClient.FeatureTests",

            ApplicationType = ApplicationType.Client

        };

​

        // create a 'UaTcpSessionChannel', a client-side channel that opens a 'session' with the server.

        var channel = new UaTcpSessionChannel(

            clientDescription,

            null, // no x509 certificates

            new AnonymousIdentity(), // no user identity

            "opc.tcp://opcua.rocks:4840", // the public endpoint of a server at opcua.rocks.

            SecurityPolicyUris.None); // no encryption

        try

        {

            // try opening a session and reading a few nodes.

            await channel.OpenAsync();

​

            Console.WriteLine($"Opened session with endpoint '{channel.RemoteEndpoint.EndpointUrl}'.");

            Console.WriteLine($"SecurityPolicy: '{channel.RemoteEndpoint.SecurityPolicyUri}'.");

            Console.WriteLine($"SecurityMode: '{channel.RemoteEndpoint.SecurityMode}'.");

            Console.WriteLine($"UserIdentityToken: '{channel.UserIdentity}'.");

​

            // build a ReadRequest. See 'OPC UA Spec Part 4' paragraph 5.10.2

            var readRequest = new ReadRequest {

                // set the NodesToRead to an array of ReadValueIds.

                NodesToRead = new[] {

                    // construct a ReadValueId from a NodeId and AttributeId.

                    new ReadValueId {

                        // you can parse the nodeId from a string.

                        // e.g. NodeId.Parse("ns=2;s=Demo.Static.Scalar.Double")

                        NodeId = NodeId.Parse(VariableIds.Server_ServerStatus),

                        // variable class nodes have a Value attribute.

                        AttributeId = AttributeIds.Value

                    }

                }

            };

            // send the ReadRequest to the server.

            var readResult = await channel.ReadAsync(readRequest);

​

            // the result will have a array 'Results' of DataValues, one for every ReadValueId.

            // A DataValue holds the value, timestamps and status code.

            var serverStatus = readResult.Results[0].GetValueOrDefault<ServerStatusDataType>();

​

            Console.WriteLine("\nServer status:");

            Console.WriteLine("  ProductName: {0}", serverStatus.BuildInfo.ProductName);

            Console.WriteLine("  SoftwareVersion: {0}", serverStatus.BuildInfo.SoftwareVersion);

            Console.WriteLine("  ManufacturerName: {0}", serverStatus.BuildInfo.ManufacturerName);

            Console.WriteLine("  State: {0}", serverStatus.State);

            Console.WriteLine("  CurrentTime: {0}", serverStatus.CurrentTime);

​

            Console.WriteLine($"\nClosing session '{channel.SessionId}'.");

            await channel.CloseAsync();

        }

        catch(Exception ex)

        {

            await channel.AbortAsync();

            Console.WriteLine(ex.Message);

        }

    }

}

​