OPC Studio User's Guide and Reference
OpcLabs.EasyOpc.UA.Gds Namespace (OpcLabs.EasyOpcUA)
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OpcLabs.EasyOpcUA Assembly : OpcLabs.EasyOpc.UA.Gds Namespace
This namespace contains classes for dealing with OPC UA Global Discovery Server (GDS).
Classes
 ClassDescription
ClassEasyUACertificateManagementClientCore The core part of the EasyUACertificateManagementClient object.
ClassEasyUAGlobalDiscoveryClientCore The core part of the EasyUAGlobalDiscoveryClient object.
ClassUAApplicationRecordDataType Represents a record in the GDS (OPC UA Global Discovery Server).
ClassUACertificateGroupElement Represents a certificate group element in the Certificate Management information model.
ClassUACertificateGroupElementCollection A collection of OPC-UA certificate groups.
Interfaces
 InterfaceDescription
InterfaceIEasyUACertificateManagement Provides access to certificate management (CM) information model of an OPC UA Global Discovery Server (GDS).
InterfaceIEasyUACertificateManagementClient Provides access to certificate management (CM) information model of an OPC UA Global Discovery Server (GDS).
InterfaceIEasyUAGlobalDiscoveryClient Provides access to information model of an OPC UA Global Discovery Server (GDS).
Enumerations
 EnumerationDescription
EnumerationUATrustListMasks Defines which trusted lists are specified.
Remarks

Global Discovery

The OPC UA Global Discovery Client is a specialized OPC UA client object for global discovery. In the OPC UA specifications, the functionality covered by this type is described in Part 12: Discovery and Global Services, in the Global Discovery Server section.

This specialized client object can be derived from IEasyUAClient Interface using the AsGlobalDiscoveryClient Extension Method, or it can be created standalone as EasyUAGlobalDiscoveryClient Component.

This interface contains methods to communicate with the OPC UA Global Discovery Server (GDS) using its information model for global discovery, making the work of assembling the proper OPC UA method parameters and retrieving the results. The methods allow querying for applications and/or servers, and registering, un-registering or updating application registrations in the GDS. Only the global discovery aspect of the GDS information is covered by this interface. Certificate management (CM), key credential management, and authorization services are treated separately.

Before deciding to use methods provided by this specialized client, it is recommended that you have a look at the IEasyUAClientServerApplication service (see OPC UA Client-Server Application Service), available from IServiceProvider.GetService method from the IEasyUAClient interface. The client application service works on higher level, and conveniently combines several methods together to achieve the typically needed functionality related to GDS and certificate management in OPC UA.

Available methods are:

The features discussed here, or some of them, may not be available in all editions of the product. Check the QuickOPC Product Editions page for differences between the editions. The trial license has all features enabled (and is limited in period for which it provides valid data), but licenses for specific commercial editions may have functionality limitations.

Example

.NET

// Shows how to check if an application needs to update its 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.AddressSpace;
using OpcLabs.EasyOpc.UA.Application;
using OpcLabs.EasyOpc.UA.Extensions;
using OpcLabs.EasyOpc.UA.Gds;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples.Gds._EasyUACertificateManagementClient
{
    class GetCertificateStatus
    {
        public static void Main1()
        {
            // Define which GDS we will work with.
            UAEndpointDescriptor gdsEndpointDescriptor = 
                ((UAEndpointDescriptor)"opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer")
                .WithUserNameIdentity("appadmin", "demo");

            // Register our client application with the GDS, so that we obtain an application ID that we need later.
            // Obtain the application interface.
            EasyUAApplication application = EasyUAApplication.Instance;
            UANodeId applicationId;
            try
            {
                applicationId = application.RegisterToGds(gdsEndpointDescriptor);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }
            Console.WriteLine("Application ID: {0}", applicationId);

            // Instantiate the certificate management client object
            var certificateManagementClient = new EasyUACertificateManagementClient();

            // Check if the application needs to update its certificate.
            bool updateRequired;
            try
            {
                updateRequired = certificateManagementClient.GetCertificateStatus(gdsEndpointDescriptor, applicationId,
                    UANodeId.Null, UANodeId.Null);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            // Display results
            Console.WriteLine("Update required: {0}", updateRequired);
        }


        // Example output:
        //Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=aec94459-f513-4979-8619-8383555fca61
        //Update required: False
    }
}

COM

// Shows how to check if an application needs to update its 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 GetCertificateStatus.Main;
var
  Application: TEasyUAApplication;
  ApplicationId: _UANodeId;
  CertificateManagementClient: OpcLabs_EasyOpcUA_TLB._EasyUACertificateManagementClient;
  GdsEndpointDescriptor: _UAEndpointDescriptor;
  NullNodeId: _UANodeId;
  UpdateRequired: boolean;
begin
  // Define which GDS we will work with.
  GdsEndpointDescriptor := CoUAEndpointDescriptor.Create;
  GdsEndpointDescriptor.UrlString := 'opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer';
  GdsEndpointDescriptor.UserIdentity.UserNameTokenInfo.UserName := 'appadmin';
  GdsEndpointDescriptor.UserIdentity.UserNameTokenInfo.Password := 'demo';

  // Register our client application with the GDS, so that we obtain an application ID that we need later.
  // Obtain the application interface.
  Application := TEasyUAApplication.Create(nil);

  // Create an application registration in the GDS, assigning it a new application ID.
  try
    ApplicationId := Application.RegisterToGds(GdsEndpointDescriptor);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
    end;
  end;

  WriteLn('Application ID: ', ApplicationId.ToString);

  // Instantiate the certificate management client object
  CertificateManagementClient := CoEasyUACertificateManagementClient.Create;

  // Check if the application needs to update its certificate.
  NullNodeId := CoUANodeId.Create;
  UpdateRequired := false;
  try
    UpdateRequired := CertificateManagementClient.GetCertificateStatus(GdsEndpointDescriptor, ApplicationId, NullNodeId, NullNodeId);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
    end;
  end;

  // Display results
  WriteLn('Update required: ', UpdateRequired);

  // Example output:
  //Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=aec94459-f513-4979-8619-8383555fca61
  //Update required: FALSE

end;

Python

# Shows how to check if an application needs to update its 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.AddressSpace import *
from OpcLabs.EasyOpc.UA.Application import *
from OpcLabs.EasyOpc.UA.Extensions import *
from OpcLabs.EasyOpc.UA.Gds import *
from OpcLabs.EasyOpc.UA.OperationModel import *


# Define which GDS we will work with.
gdsEndpointDescriptor = UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer')
gdsEndpointDescriptor = UAEndpointDescriptorExtension.WithUserNameIdentity(gdsEndpointDescriptor,
                                                                           'appadmin', 'demo')

# Register our client application with the GDS, so that we obtain an application ID that we need later.
# Obtain the application interface.
application = EasyUAApplication.Instance
try:
    print('Registering to GDS...')
    applicationId = application.RegisterToGds(gdsEndpointDescriptor)
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()
print('Application ID: ', applicationId, sep='')

# Instantiate the certificate management client object.
certificateManagementClient = EasyUACertificateManagementClient()

# Check if the application needs to update its certificate.
try:
    updateRequired = certificateManagementClient.GetCertificateStatus(gdsEndpointDescriptor,
                                                                      applicationId,
                                                                      UANodeId.Null,    # certificateGroupId
                                                                      UANodeId.Null)    # certificateTypeId
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

# Display results.
print('Update required: ', updateRequired, sep='')

print()
print('Finished.')

Certificate Management

The OPC UA Certificate Management Client is a specialized OPC UA client object providing access to certificate management (CM) information model of an OPC UA Global Discovery Server (GDS). In the OPC UA specifications, the functionality covered by this type is described in Part 12: Discovery and Global Services, in the section Certificate Management Overview.

This specialized client object can be derived from IEasyUAClient Interface using the AsCertificateManagementClient Extension Method, or it can be created standalone as EasyUACertificateManagementClient Component.

This interface contains methods to communicate with the OPC UA Global Discovery Server (GDS) using its information model for certificate management, making the work of assembling the proper OPC UA method parameters and retrieving the results. The methods allow getting certificate groups, requesting key pairs or certificate signing and obtaining the results, retrieving trust lists, and more.

Before deciding to use methods provided by this specialized client, it is recommended that you have a look at the IEasyUAClientServerApplication service (see OPC UA Client-Server Application Service), available from IServiceProvider.GetService method from the IEasyUAClient interface. The client application service works on even a higher level, and conveniently combines several methods together to achieve the typically needed functionality related to GDS and certificate management in OPC UA.

Available methods are:

There are also helper classes are available that relate to certificate management:

 

The features discussed here, or some of them, may not be available in all editions of the product. Check the QuickOPC Product Editions page for differences between the editions. The trial license has all features enabled (and is limited in period for which it provides valid data), but licenses for specific commercial editions may have functionality limitations.

 

See Also

Reference

OpcLabs.EasyOpcUA Assembly

 

 

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Missing some example? Ask us for it on our Online Forums! You do not have to own a commercial license in order to use Online Forums, and we reply to every post.