Examples - OPC UA Interaction - Accept instance certificate

The example below triggers the component to ask the user whether he/she wants to accept the server's instance certificate.

.NET

C#
VB.NET

// This example shows how in a console application, the user is asked to accept a server instance certificate.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.Engine;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples.Interaction
{
    partial class AcceptCertificate
    {
        public static void Instance()
        {
            // Do not implicitly trust any endpoint URLs. We want the user be asked explicitly.
            EasyUAClient.SharedParameters.EngineParameters.CertificateAcceptancePolicy.TrustedEndpointUrlStrings.Clear();

            // Define which server we will work with.
            UAEndpointDescriptor endpointDescriptor = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // Require secure connection, in order to enforce the certificate check.
            endpointDescriptor.EndpointSelectionPolicy = UAMessageSecurityModes.Secure;
            
            // Instantiate the client object.
            var client = new EasyUAClient();

            UAAttributeData attributeData;
            try
            {
                // Obtain attribute data.
                // The component automatically triggers the necessary user interaction during the first operation.
                attributeData = client.Read(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853");
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            // Display results.
            Console.WriteLine("Value: {0}", attributeData.Value);
            Console.WriteLine("ServerTimestamp: {0}", attributeData.ServerTimestamp);
            Console.WriteLine("SourceTimestamp: {0}", attributeData.SourceTimestamp);
            Console.WriteLine("StatusCode: {0}", attributeData.StatusCode);
        }
    }
}

' This example shows how in a console application, the user is asked to accept a server instance certificate.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET .
' Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
' a commercial license in order to use Online Forums, and we reply to every post.

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.Engine
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace Interaction
    Partial Friend Class AcceptCertificate
        Public Shared Sub Instance()

            ' Do not implicitly trust any endpoint URLs. We want the user be asked explicitly.
            EasyUAClient.SharedParameters.EngineParameters.CertificateAcceptancePolicy.TrustedEndpointUrlStrings.Clear()

            ' Define which server we will work with.
            Dim endpointDescriptor As UAEndpointDescriptor = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
            ' Require secure connection, in order to enforce the certificate check.
            endpointDescriptor.EndpointSelectionPolicy = UAMessageSecurityModes.Secure

            ' Instantiate the client object.
            Dim client = New EasyUAClient()

            Dim attributeData As UAAttributeData
            Try
                ' Obtain attribute data.
                ' The component automatically triggers the necessary user interaction during the first operation.
                attributeData = client.Read(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853")
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try

            ' Display results.
            Console.WriteLine("Value: {0}", attributeData.Value)
            Console.WriteLine("ServerTimestamp: {0}", attributeData.ServerTimestamp)
            Console.WriteLine("SourceTimestamp: {0}", attributeData.SourceTimestamp)
            Console.WriteLine("StatusCode: {0}", attributeData.StatusCode)
        End Sub
    End Class
End Namespace

COM

Object Pascal

// This example shows how in a console application, the user is asked to accept a server instance certificate.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in Object Pascal (Delphi) on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-OP .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

class procedure AcceptCertificate.Instance;
var
  Arguments: OleVariant;
  AttributeData: _UAAttributeData;
  Client: OpcLabs_EasyOpcUA_TLB._EasyUAClient;
  ClientManagement: TEasyUAClientManagement;
  EndpointSelectionPolicy: _UAEndpointSelectionPolicy;
  ReadArguments: _UAReadArguments;
  Result: _UAAttributeDataResult;
  Results: OleVariant;
begin
  // The configuration object allows access to static behavior.
  ClientManagement := TEasyUAClientManagement.Create(nil);
  ClientManagement.Connect;

  // Do not implicitly trust any endpoint URLs. We want the user be asked explicitly.
  ClientManagement.SharedParameters.EngineParameters.CertificateAcceptancePolicy.TrustedEndpointUrlStrings.Clear();

  // Define which server we will work with.
  ReadArguments := CoUAReadArguments.Create;
  ReadArguments.EndpointDescriptor.UrlString := 'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  // Require secure connection, in order to enforce the certificate check.
  EndpointSelectionPolicy := CoUAEndpointSelectionPolicy.Create;
  EndpointSelectionPolicy.AllowedMessageSecurityModes := UAMessageSecurityModes_Secure;
  ReadArguments.EndpointDescriptor.EndpointSelectionPolicy := EndpointSelectionPolicy;
  ReadArguments.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10853';

  Arguments := VarArrayCreate([0, 0], varVariant);
  Arguments[0] := ReadArguments;

  // Instantiate the client object.
  Client := CoEasyUAClient.Create;

  // Obtain attribute data.
  // The component automatically triggers the necessary user interaction during the first operation.
  TVarData(Results).VType := varArray or varVariant;
  TVarData(Results).VArray := PVarArray(Client.ReadMultiple(Arguments));

  Result := IInterface(Results[0]) as _UAAttributeDataResult;
  if Result.Succeeded then
  begin
    AttributeData := Result.AttributeData;
    // Display results.
    WriteLn('Value: ', AttributeData.Value);
    WriteLn('ServerTimestamp: ', DateTimeToStr(AttributeData.ServerTimestamp));
    WriteLn('SourceTimestamp: ', DateTimeToStr(AttributeData.SourceTimestamp));
    WriteLn('StatusCode: ', AttributeData.StatusCode.ToString);
  end
  else
    WriteLn('*** Failure: ', Result.ErrorMessageBrief);

  VarClear(Results);
  VarClear(Arguments);
  FreeAndNil(ClientManagement);
end;

Python

Python (.NET)

# This example shows how in a console application, the user is asked to accept a server instance certificate.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python .
# Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
# a commercial license in order to use Online Forums, and we reply to every post.
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.Engine import *
from OpcLabs.EasyOpc.UA.OperationModel import *


# Do not implicitly trust any endpoint URLs. We want the user be asked explicitly.
EasyUAClient.SharedParameters.EngineParameters.CertificateAcceptancePolicy.TrustedEndpointUrlStrings.Clear()

# Define which server we will work with.
endpointDescriptor = UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:51210/UA/SampleServer')
# Require secure connection, in order to enforce the certificate check.
endpointDescriptor.EndpointSelectionPolicy = UAEndpointSelectionPolicy(UAMessageSecurityModes.Secure)

# Instantiate the client object.
client = EasyUAClient()

try:
    # Obtain attribute data.
    # The component automatically triggers the necessary user interaction during the first operation.
    attributeData = IEasyUAClientExtension.Read(client,
                                                endpointDescriptor,
                                                UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10853'))
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

# Display results.
print('Value: ', attributeData.Value)
print('ServerTimestamp: ', attributeData.ServerTimestamp)
print('SourceTimestamp: ', attributeData.SourceTimestamp)
print('StatusCode: ', attributeData.StatusCode)

print()
print('Finished.')

The program output may look like this:

Console - Accept instance certificate

Examples - Client OPC Unified Architecture

Examples - OPC Unified Architecture - Read a single attribute of a single node

Concepts

Unsolicited User Interaction

Console Interaction