OPC Studio User's Guide and Reference
User Identity in QuickOPC-UA
Concepts > QuickOPC Concepts > QuickOPC Development Models > Imperative Programming Model > Imperative Programming Model for OPC Data (Classic and UA) > Setting Parameters (OPC Data) > User Identity in QuickOPC-UA

OPC UA Servers may require that the user making a connection from the OPC UA client is authenticated, and reject the connection of the authentication fails. In addition, different users may have different permissions (authorization) for various operations on the OPC UA Server. For more information, see OPC UA User Authentication (Client).

You can specify the identity of the user making the connection using the UserIdentity property. This property is a UserIdentity object that contains following user token infos:

Note: The Kerberos token info may represent an explicitly specified user identity (if you set KerberosTokenInfo.NetworkSecurity.CustomNetworkCredential to true and specify additional parameters, such as the user name, password, and domain), or it can represent the current user running the code (if KerberosTokenInfo.NetworkSecurity.CustomNetworkCredential is set to false).

Zero, one, or more user token infos (of different types) may be specified in the UserIdentity object. By default, no user token info is specified. The user token infos are always present (i.e. non-null), but they are only used if they are filled in with data. For example, if you leave the UserName and Password in the UserNameTokenInfo empty, the user name token will not be used. If you, however, start putting values into any of the token infos, you need to fill in everything necessary in that token, otherwise an error may occur. For an AnonymousTokenInfo, the anonymous token is used when its IsConfigured property is set to true.

You can easily create a UserIdentity with certain user token by one of the following static methods:

When QuickOPC-UA makes a connection to the OPC UA server, it selects the user token according to its built-in token selection policy. The OPC UA server is interrogated for user token policies available on the endpoint, and the QuickOPC-UA selects the most appropriate one from them.

When you set the user identity in the above described way, i.e. in the session parameters object, it applies to all sessions (connections) made by that EasyUAClient object. In addition to this, it is also possible to specify the user identity directly for a specific connection, i.e. on the UAEndpointDescriptor object.

There is a UserIdentity property on the UAEndpointDescriptor as well, and the user token infos contained there are merged together with those coming from the session parameters, for each connection made on that endpoint. For details on easier handling user identities specified directly on an endpoint, see OPC UA Server Endpoints.

Example

.NET

// Shows how to find all registrations in the GDS.
//
// 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.Discovery;
using OpcLabs.EasyOpc.UA.Extensions;
using OpcLabs.EasyOpc.UA.Gds;
using OpcLabs.EasyOpc.UA.OperationModel;

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

            // Instantiate the global discovery client object
            var globalDiscoveryClient = new EasyUAGlobalDiscoveryClient();

            // Find all (client or server) applications registered in the GDS.
            UAApplicationDescription[] applicationDescriptionArray;
            try
            {
                globalDiscoveryClient.QueryApplications(
                    gdsEndpointDescriptor: gdsEndpointDescriptor,
                    startingRecordId: 0,
                    maximumRecordsToReturn: 0,
                    applicationName: "",
                    applicationUriString: "",
                    applicationTypes: UAApplicationTypes.All,
                    productUriString: "",
                    serverCapabilities: new string[0],
                    lastCounterResetTime: out _,
                    nextRecordId: out _,
                    applications: out applicationDescriptionArray);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            // For each application returned by the query, find its registrations in the GDS.
            foreach (UAApplicationDescription applicationDescription in applicationDescriptionArray)
            {
                Console.WriteLine();
                Console.WriteLine("Application URI string: {0}", applicationDescription.ApplicationUriString);

                UAApplicationRecordDataType[] applicationRecordArray;
                try
                {
                    applicationRecordArray = globalDiscoveryClient.FindApplications(
                        gdsEndpointDescriptor,
                        applicationDescription.ApplicationUriString);
                }
                catch (UAException uaException)
                {
                    Console.WriteLine("  *** Failure: {0}", uaException.GetBaseException().Message);
                    continue;
                }

                // Display results
                foreach (UAApplicationRecordDataType applicationRecord in applicationRecordArray)
                    Console.WriteLine("  Application ID: {0}", applicationRecord.ApplicationId);
            }


            // Example output:
            //
            //Application URI string: urn:sampleserver
            //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=09ecaa08-6ec6-462c-a214-1e66a3099107
            //
            //Application URI string: urn:alarmconditionserver
            //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=783e1e9a-8036-43b6-928f-97488c460266
            //
            //Application URI string: urn:PC:MultiTargetUADocExamples:5.54.1026.1:neutral:null
            //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=9e700ea5-55a6-4c3c-ba9f-b91c890dc519
            //
            //Application URI string: urn:PC:UADocExamples:5.56.0.16:neutral:null
            //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=e182e28c-086b-4fc7-82c7-70ca7cda3033
            //
            //Application URI string: urn:PC:cscript:5.812.10240.16384
            //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=aec94459-f513-4979-8619-8383555fca61
        }
    }
}

' Shows how to find all registrations in the GDS.
'
' 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.Discovery
Imports OpcLabs.EasyOpc.UA.Extensions
Imports OpcLabs.EasyOpc.UA.Gds
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace Gds._EasyUAGlobalDiscoveryClient
    Friend Class FindApplications
        Public Shared Sub Main1()

            ' Define which GDS we will work with.
            Dim gdsEndpointDescriptor As UAEndpointDescriptor =
                New UAEndpointDescriptor("opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer") _
                .WithUserNameIdentity("appuser", "demo")

            ' Instantiate the global discovery client object
            Dim globalDiscoveryClient = New EasyUAGlobalDiscoveryClient()

            ' Find all (client or server) applications registered in the GDS.
            Dim applicationDescriptionArray() As UAApplicationDescription = Nothing
            Try
                Dim lastCounterResetTime As DateTime
                Dim nextRecordId As Long
                globalDiscoveryClient.QueryApplications(
                    gdsEndpointDescriptor:=gdsEndpointDescriptor,
                    startingRecordId:=0,
                    maximumRecordsToReturn:=0,
                    applicationName:="",
                    applicationUriString:="",
                    applicationTypes:=UAApplicationTypes.All,
                    productUriString:="",
                    serverCapabilities:=New String() {},
                    lastCounterResetTime:=lastCounterResetTime,
                    nextRecordId:=nextRecordId,
                    applications:=applicationDescriptionArray)
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try

            ' For each application returned by the query, find its registrations in the GDS.
            For Each applicationDescription As UAApplicationDescription In applicationDescriptionArray
                Console.WriteLine()
                Console.WriteLine("Application URI string: {0}", applicationDescription.ApplicationUriString)

                Dim applicationRecordArray() As UAApplicationRecordDataType
                Try
                    applicationRecordArray = globalDiscoveryClient.FindApplications(
                        gdsEndpointDescriptor,
                        applicationDescription.ApplicationUriString)
                Catch uaException As UAException
                    Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                    Continue For
                End Try

                ' Display results
                For Each applicationRecord As UAApplicationRecordDataType In applicationRecordArray
                    Console.WriteLine("  Application ID: {0}", applicationRecord.ApplicationId)
                Next applicationRecord
            Next applicationDescription
        End Sub
    End Class
End Namespace

COM

// Shows how to find all registrations in the GDS.
//
// 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 FindApplications.Main;
var
  ApplicationDescription: _UAApplicationDescription;
  ApplicationDescriptionArray: OleVariant;
  ApplicationName: WideString;
  ApplicationRecord: _UAApplicationRecordDataType;
  ApplicationRecordArray: OleVariant;
  ApplicationUriString: WideString;
  GlobalDiscoveryClient: OpcLabs_EasyOpcUA_TLB._EasyUAGlobalDiscoveryClient;
  GdsEndpointDescriptor: _UAEndpointDescriptor;
  I, J: integer;
  LastCounterResetTime: TDateTime;
  MaximumRecordsToReturn: Integer;
  NextRecordId: Integer;
  ProductUriString: WideString;
  ServerCapabilities: array of string;
  StartingRecordId: Integer;
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';

  // Instantiate the global discovery client object
  GlobalDiscoveryClient := CoEasyUAGlobalDiscoveryClient.Create;

  // Find all (client or server) applications registered in the GDS.
  StartingRecordId := 0;
  MaximumRecordsToReturn := 0;
  ApplicationName := '';
  ApplicationUriString := '';
  ProductUriString := '';
  try
    GlobalDiscoveryClient.QueryApplications(
      GdsEndpointDescriptor,
      StartingRecordId,
      MaximumRecordsToReturn,
      ApplicationName,
      ApplicationUriString,
      UAApplicationTypes_All,
      ProductUriString,
      ServerCapabilities,
      LastCounterResetTime,
      NextRecordId,
      ApplicationDescriptionArray);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
    end;
  end;

  // For each application returned by the query, find its registrations in the GDS.
  for I := VarArrayLowBound(ApplicationDescriptionArray,1) to VarArrayHighBound(ApplicationDescriptionArray,1) do
  begin
    ApplicationDescription := IUnknown(ApplicationDescriptionArray[I]) as _UAApplicationDescription;
    WriteLn;
    WriteLn('Application URI string: ', ApplicationDescription.ApplicationUriString);
    try
    TVarData(ApplicationRecordArray).VType := varArray or varVariant;
    TVarData(ApplicationRecordArray).VArray := PVarArray(
      GlobalDiscoveryClient.FindApplications(
        GdsEndpointDescriptor,
        ApplicationDescription.ApplicationUriString));
    except
      on E: EOleException do
      begin
        WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
        Continue;
      end;
    end;
      for J := VarArrayLowBound(ApplicationRecordArray, 1) to VarArrayHighBound(ApplicationRecordArray, 1) do
      begin
        // Display results
        ApplicationRecord := IUnknown(ApplicationRecordArray[J]) as _UAApplicationRecordDataType;
        WriteLn('  Application ID: ', ApplicationRecord.ApplicationId.ToString);
      end;
  end;

  // Example output:
  //
  //Application URI string: urn:sampleserver
  //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=09ecaa08-6ec6-462c-a214-1e66a3099107
  //
  //Application URI string: urn:alarmconditionserver
  //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=783e1e9a-8036-43b6-928f-97488c460266
  //
  //Application URI string: urn:PC:MultiTargetUADocExamples:5.54.1026.1:neutral:null
  //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=9e700ea5-55a6-4c3c-ba9f-b91c890dc519
  //
  //Application URI string: urn:PC:UADocExamples:5.56.0.16:neutral:null
  //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=e182e28c-086b-4fc7-82c7-70ca7cda3033
  //
  //Application URI string: urn:PC:cscript:5.812.10240.16384
  //  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=aec94459-f513-4979-8619-8383555fca61

end;

Rem Shows how to find all registrations in the GDS.
Rem
Rem Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Rem OPC client and subscriber examples in VBScript on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBScript .
Rem Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
Rem a commercial license in order to use Online Forums, and we reply to every post.

Option Explicit

Const UAApplicationTypes_All = 7

' Define which GDS we will work with.
Dim GdsEndpointDescriptor: Set GdsEndpointDescriptor = CreateObject("OpcLabs.EasyOpc.UA.UAEndpointDescriptor")
GdsEndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer"
GdsEndpointDescriptor.UserIdentity.UserNameTokenInfo.UserName = "appadmin"
GdsEndpointDescriptor.UserIdentity.UserNameTokenInfo.Password = "demo"

' Instantiate the global discovery client object
Dim GlobalDiscoveryClient: Set GlobalDiscoveryClient = CreateObject("OpcLabs.EasyOpc.UA.Gds.EasyUAGlobalDiscoveryClient")

' Find all (client or server) applications registered in the GDS.
Dim startingRecordId: startingRecordId = 0
Dim maximumRecordsToReturn: maximumRecordsToReturn = 0
Dim applicationName: applicationName = ""
Dim applicationUriString: applicationUriString = ""
Dim productUriString: productUriString = ""
Dim serverCapabilities: serverCapabilities = Array()
Dim lastCounterResetTime
Dim nextRecordId
Dim applicationDescriptionArray
On Error Resume Next
GlobalDiscoveryClient.QueryApplications _
    GdsEndpointDescriptor, _
    startingRecordId, _
    maximumRecordsToReturn, _
    applicationName, _
    applicationUriString, _
    UAApplicationTypes_All, _
    productUriString, _
    serverCapabilities, _ 
    lastCounterResetTime, _
    nextRecordId, _
    applicationDescriptionArray
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

' For each application returned by the query, find its registrations in the GDS.
Dim ApplicationDescription
For Each ApplicationDescription In applicationDescriptionArray
    WScript.Echo
    WScript.Echo "Application URI string: " & ApplicationDescription.ApplicationUriString

    On Error Resume Next
    Dim applicationRecordArray: applicationRecordArray = GlobalDiscoveryClient.FindApplications( _
        gdsEndpointDescriptor, _
        ApplicationDescription.ApplicationUriString)
    If Err.Number <> 0 Then
        WScript.Echo "  *** Failure: " & Err.Source & ": " & Err.Description
    Else
        Dim ApplicationRecord
        For Each ApplicationRecord In applicationRecordArray
            ' Display results
            WScript.Echo "  Application ID: " & ApplicationRecord.ApplicationId
        Next
    End If
    On Error Goto 0
Next


' Example output:
'
'Application URI string: urn:sampleserver
'  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=09ecaa08-6ec6-462c-a214-1e66a3099107
'
'Application URI string: urn:alarmconditionserver
'  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=783e1e9a-8036-43b6-928f-97488c460266
'
'Application URI string: urn:PC:MultiTargetUADocExamples:5.54.1026.1:neutral:null
'  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=9e700ea5-55a6-4c3c-ba9f-b91c890dc519
'
'Application URI string: urn:PC:UADocExamples:5.56.0.16:neutral:null
'  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=e182e28c-086b-4fc7-82c7-70ca7cda3033
'
'Application URI string: urn:PC:cscript:5.812.10240.16384
'  Application ID: nsu=http://opcfoundation.org/UA/GDS/applications/ ;ns=2;g=aec94459-f513-4979-8619-8383555fca61

Python

# Shows how to find all registrations in the GDS.
#
# 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 System import *
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.Discovery 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')

# Instantiate the global discovery client object.
globalDiscoveryClient = EasyUAGlobalDiscoveryClient()

# Find all (client or server) applications registered in the GDS.
try:
    _, _, _, applicationDescriptionArray = globalDiscoveryClient.QueryApplications(
        gdsEndpointDescriptor,
        0,  # startingRecordId
        0,  # maximumRecordsToReturn
        '', # applicationName
        '', # applicationUriString
        UAApplicationTypes.All, # applicationTypes
        '', # productUriString
        Array.Empty[String](),  # serverCapabilities
        DateTime(), # out lastCounterResetTime
        0,  # out nextRecordId
        Array.Empty[UAApplicationDescription]()) # out applications
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

# For each application returned by the query, find its registrations in the GDS.
for applicationDescription in applicationDescriptionArray:
    print()
    print('Application URI string: ', applicationDescription.ApplicationUriString, sep='')

    try:
        applicationRecordArray = globalDiscoveryClient.FindApplications(
            gdsEndpointDescriptor,
            applicationDescription.ApplicationUriString)
    except UAException as uaException:
        print('  *** Failure: ' + uaException.GetBaseException().Message)
        continue

    # Display results.
    for applicationRecord in applicationRecordArray:
        print('  Application ID: ', applicationRecord.ApplicationId, sep='')

print()
print('Finished.')
See Also
Setting OPC-UA Parameters
Setting Parameters (OPC Data)
Imperative Programming Model for OPC Data (Classic and UA)
Imperative Programming Model

Fundamentals

OPC UA Server Endpoints
OPC UA User Authentication (Client)

Examples - OPC UA GDS and CM

Examples - OPC UA GDS and CM - Find all registrations

 

 

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