QuickOPC User's Guide and Reference
Subscriber Communication Parameters (OPC UA PubSub)
Development Models > Imperative Programming Model > Imperative Programming Model for OPC UA PubSub > Subscribing to Information (OPC UA PubSub) > Subscriber Communication Parameters (OPC UA PubSub)
In This Topic

The subscriber communication parameters specify details of how the OPC UA PubSub communication is performed. As opposed to the PubSub connection descriptor, which contains parameters needed to establish and maintain the connection to the message-oriented middleware, the subscriber communication parameters are more concerned with the actual communication that takes place after the PubSub connection is established.

The subscriber communication parameters are represented by the UASubscriberCommunicationParameters Class.

There are various communication parameters that can be set, and whether some of them are used also depends on whether broker-based middleware, or broker-less model is in use. PubSub security is also configured using communication parameters.

The most important part of the communication parameters is the

Communication parameters with broker-based middleware

With broker-based middleware, you will typically need to set the broker queue name in the subscriber communication parameters (unless the logical resolution process provides this information for you). This is done inside the BrokerDataSetReaderTransportParameters Property, which contains sub-parameters used with broker-based middleware. The QueueName Property could be the name of a queue or topic defined in the broker (depending on the terminology used by the protocol in use).

The setting of the broker queue name is illustrated in the example below.

// This example shows how to subscribe to all dataset messages on an OPC-UA PubSub connection with MQTT UADP mapping using
// TCP.
//
// The OpcLabs.MqttNet assembly needs to be referenced in your project (or otherwise made available, together with its
// dependencies) for the MQTT transport to work. Refer to the documentation for more information.

using System;
using System.Collections.Generic;
using System.Threading;
using OpcLabs.EasyOpc.UA.PubSub;
using OpcLabs.EasyOpc.UA.PubSub.Engine;
using OpcLabs.EasyOpc.UA.PubSub.OperationModel;

namespace UADocExamples.PubSub._EasyUASubscriber
{
    partial class SubscribeDataSet
    {
        public static void MqttUadpTcp()
        {
            // Define the PubSub connection we will work with. Uses implicit conversion from a string.
            // Default port with MQTT is 1883.
            UAPubSubConnectionDescriptor pubSubConnectionDescriptor = "mqtt://opcua-pubsub.demo-this.com";
            // Specify the transport protocol mapping.
            // The statement below isn't actually necessary, due to automatic message mapping recognition feature; see
            // https://kb.opclabs.com/OPC_UA_PubSub_Automatic_Message_Mapping_Recognition for more details.
            pubSubConnectionDescriptor.TransportProfileUriString = UAPubSubTransportProfileUriStrings.MqttUadp;

            // Define the arguments for subscribing to the dataset, specifying the MQTT topic name.
            var subscribeDataSetArguments = new UASubscribeDataSetArguments(pubSubConnectionDescriptor)
            {
                DataSetSubscriptionDescriptor = {CommunicationParameters = {BrokerDataSetReaderTransportParameters =
                {
                    QueueName = "opcuademo/uadp/none"
                }}}
            };

            // Instantiate the subscriber object and hook events.
            var subscriber = new EasyUASubscriber();
            subscriber.DataSetMessage += subscriber_DataSetMessage_MqttUadpTcp;

            Console.WriteLine("Subscribing...");
            subscriber.SubscribeDataSet(subscribeDataSetArguments);

            Console.WriteLine("Processing dataset message events for 20 seconds...");
            Thread.Sleep(20 * 1000);

            Console.WriteLine("Unsubscribing...");
            subscriber.UnsubscribeAllDataSets();

            Console.WriteLine("Waiting for 1 second...");
            // Unsubscribe operation is asynchronous, messages may still come for a short while.
            Thread.Sleep(1 * 1000);

            Console.WriteLine("Finished.");
        }

        static void subscriber_DataSetMessage_MqttUadpTcp(object sender, EasyUADataSetMessageEventArgs e)
        {
            // Display the dataset.
            if (e.Succeeded)
            {
                // An event with null DataSetData just indicates a successful connection.
                if (!(e.DataSetData is null))
                {
                    Console.WriteLine();
                    Console.WriteLine($"Dataset data: {e.DataSetData}");
                    foreach (KeyValuePair<string, UADataSetFieldData> pair in e.DataSetData.FieldDataDictionary)
                        Console.WriteLine(pair);
                }
            }
            else
            {
                Console.WriteLine();
                Console.WriteLine($"*** Failure: {e.ErrorMessage}");
            }
        }

        // Example output:
        //
        //Subscribing...
        //Processing dataset message events for 20 seconds...
        //
        //Dataset data: Good; Data; publisher="32", writer=1, class=eae79794-1af7-4f96-8401-4096cd1d8908, fields: 4
        //[#0, False {System.Boolean}; Good]
        //[#1, 6685 {System.Int32}; Good]
        //[#2, 1444 {System.Int32}; Good]
        //[#3, 1/4/2020 6:06:20 PM {System.DateTime}; Good]
        //
        //Dataset data: Good; Data; publisher="32", writer=3, class=96976b7b-0db7-46c3-a715-0979884b55ae, fields: 100
        //[#0, 85 {System.Int64}; Good]
        //[#1, 185 {System.Int64}; Good]
        //[#2, 285 {System.Int64}; Good]
        //[#3, 385 {System.Int64}; Good]
        //[#4, 485 {System.Int64}; Good]
        //[#5, 585 {System.Int64}; Good]
        //[#6, 685 {System.Int64}; Good]
        //[#7, 785 {System.Int64}; Good]
        //[#8, 885 {System.Int64}; Good]
        //[#9, 985 {System.Int64}; Good]
        //[#10, 1085 {System.Int64}; Good]
        //...
    }
}

# This example shows how to subscribe to all dataset messages on an OPC-UA PubSub connection with MQTT UADP mapping
# using TCP.
#
# The following package needs to be referenced in your project (or otherwise made available) for the MQTT transport to
# work.
# - OpcLabs.MqttNet
# Refer to the documentation for more information.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
import time

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


def dataSetMessage(sender, e):
    # Display the dataset.
    if e.Succeeded:
        # An event with null DataSetData just indicates a successful connection.
        if e.DataSetData is not None:
            print('')
            print('Dataset data: ', e.DataSetData, sep='')
            for pair in e.DataSetData.FieldDataDictionary:
                print(pair)
    else:
        print('')
        print('*** Failure: ', e.ErrorMessageBrief, sep='')


# Define the PubSub connection we will work with. Uses implicit conversion from a string.
# Default port with MQTT is 1883.
pubSubConnectionDescriptor = UAPubSubConnectionDescriptor.op_Implicit('mqtt://opcua-pubsub.demo-this.com')
# Specify the transport protocol mapping.
# The statement below isn't actually necessary, due to automatic message mapping recognition feature; see
# https://kb.opclabs.com/OPC_UA_PubSub_Automatic_Message_Mapping_Recognition for more details.
pubSubConnectionDescriptor.TransportProfileUriString = UAPubSubTransportProfileUriStrings.MqttUadp

# Define the arguments for subscribing to the dataset, specifying the MQTT topic name.
subscribeDataSetArguments = UASubscribeDataSetArguments(pubSubConnectionDescriptor)
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.BrokerDataSetReaderTransportParameters.\
    QueueName = 'opcuademo/uadp/none'

# Instantiate the subscriber object and hook events.
subscriber = EasyUASubscriber()
subscriber.DataSetMessage += dataSetMessage

print('Subscribing...')
IEasyUASubscriberExtension.SubscribeDataSet(subscriber, subscribeDataSetArguments)

print('Processing dataset message events for 20 seconds...')
time.sleep(20)

print('Unsubscribing...')
subscriber.UnsubscribeAllDataSets()

print('Waiting for 1 second...')
# Unsubscribe operation is asynchronous, messages may still come for a short while.
time.sleep(1)

subscriber.DataSetMessage -= dataSetMessage

print('Finished.')

Manually configuring format of JSON messages

In some situations, more communication parameters need to be set - for example, when JSON message mapping is used, and the automatic format recognition provided by QuickOPC is turned off, such as in the example below.

// This example shows how to set parameters specific to JSON message mapping.
//
// The following package needs to be referenced in your project (or otherwise made available) for the MQTT transport to 
// work.
// - OpcLabs.MqttNet
// Refer to the documentation for more information.

using System;
using System.Collections.Generic;
using System.Threading;
using OpcLabs.EasyOpc.UA.AddressSpace;
using OpcLabs.EasyOpc.UA.PubSub;
using OpcLabs.EasyOpc.UA.PubSub.Configuration;
using OpcLabs.EasyOpc.UA.PubSub.Engine;
using OpcLabs.EasyOpc.UA.PubSub.OperationModel;

namespace UADocExamples.PubSub._EasyUASubscriber
{
    partial class SubscribeDataSet
    {
        public static void MappingParameters()
        {
            // Define the PubSub connection we will work with. Uses implicit conversion from a string.
            // Default port with MQTT is 1883.
            UAPubSubConnectionDescriptor pubSubConnectionDescriptor = "mqtt://opcua-pubsub.demo-this.com";
            // Specify the transport protocol mapping.
            // The statement below isn't actually necessary, due to automatic message mapping recognition feature; see
            // https://kb.opclabs.com/OPC_UA_PubSub_Automatic_Message_Mapping_Recognition for more details.
            pubSubConnectionDescriptor.TransportProfileUriString = UAPubSubTransportProfileUriStrings.MqttJson;

            // Set a custom property on the PubSub connection that influences how the JSON parsing works. 
            // We are instructing the message parser to turn off the automatic recognition of message format.
            // For more details, see https://kb.opclabs.com/OPC_UA_PubSub_JSON_mapping_component .
            pubSubConnectionDescriptor.CustomPropertyValueDictionary[new UAQualifiedName("{OpcLabs}",
                "OpcLabs.EasyOpc.UA.Toolkit.PubSub.Sdk.JsonReceiveMessageMapping.MessageParsingParameters.AutoRecognizeMessageFormat")] =
                false;

            // Define the arguments for subscribing to the dataset.
            var subscribeDataSetArguments = new UASubscribeDataSetArguments(pubSubConnectionDescriptor)
            {
                DataSetSubscriptionDescriptor =
                {
                    CommunicationParameters =
                    {
                        BrokerDataSetReaderTransportParameters = {QueueName = "opcuademo/json"},
                        // We must set the DataSetFieldContentMask when the format auto-recognition is turned off.
                        DataSetFieldContentMask = UADataSetFieldContentMask.RawData,
                        JsonDataSetReaderMessageParameters =
                        {
                            // We must set the DataSetMessageContentMask when the format auto-recognition is turned off.
                            DataSetMessageContentMask =
                                UAJsonDataSetMessageContentMask.DataSetWriterId |
                                UAJsonDataSetMessageContentMask.SequenceNumber |
                                UAJsonDataSetMessageContentMask.Status,
                            // We must set the NetworkMessageContentMask when the format auto-recognition is turned off.
                            NetworkMessageContentMask =
                                UAJsonNetworkMessageContentMask.NetworkMessageHeader |
                                UAJsonNetworkMessageContentMask.DataSetMessageHeader |
                                UAJsonNetworkMessageContentMask.PublisherId
                        }
                    },
                    Filter =
                    {
                        DataSetWriterDescriptor = 1,
                    }
                }
            };

            // Instantiate the subscriber object and hook events.
            var subscriber = new EasyUASubscriber();
            subscriber.DataSetMessage += subscriber_DataSetMessage_MappingParameters;

            Console.WriteLine("Subscribing...");
            subscriber.SubscribeDataSet(subscribeDataSetArguments);

            Console.WriteLine("Processing dataset message events for 20 seconds...");
            Thread.Sleep(20 * 1000);

            Console.WriteLine("Unsubscribing...");
            subscriber.UnsubscribeAllDataSets();

            Console.WriteLine("Waiting for 1 second...");
            // Unsubscribe operation is asynchronous, messages may still come for a short while.
            Thread.Sleep(1 * 1000);

            Console.WriteLine("Finished.");
        }

        static void subscriber_DataSetMessage_MappingParameters(object sender, EasyUADataSetMessageEventArgs e)
        {
            // Display the dataset.
            if (e.Succeeded)
            {
                // An event with null DataSetData just indicates a successful connection.
                if (!(e.DataSetData is null))
                {
                    Console.WriteLine();
                    Console.WriteLine($"Dataset data: {e.DataSetData}");
                    foreach (KeyValuePair<string, UADataSetFieldData> pair in e.DataSetData.FieldDataDictionary)
                        Console.WriteLine(pair);
                }
            }
            else
            {
                Console.WriteLine();
                Console.WriteLine($"*** Failure: {e.ErrorMessage}");
            }
        }

        // Example output:
        //
        //Subscribing...
        //Processing dataset message events for 20 seconds...
        //
        //Dataset data: Good; Data; publisher=[String]30, writer=1, fields: 4
        //[BoolToggle, True {System.Boolean}; Good]
        //[Int32, 9034 {System.Int64}; Good]
        //[Int32Fast, 1751 {System.Int64}; Good]
        //[DateTime, 1/30/2020 5:23:11 PM {System.DateTime}; Good]
        //
        //Dataset data: Good; Data; publisher=[String]30, writer=1, fields: 4
        //[BoolToggle, True {System.Boolean}; Good]
        //[Int32, 9036 {System.Int64}; Good]
        //[Int32Fast, 2526 {System.Int64}; Good]
        //[DateTime, 1/30/2020 5:23:13 PM {System.DateTime}; Good]
        //...
    }
}

# This example shows how to set parameters specific to JSON message mapping.
#
# The following package needs to be referenced in your project (or otherwise made available) for the MQTT transport to
# work.
# - OpcLabs.MqttNet
# Refer to the documentation for more information.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
import opclabs_mqttnet
import time

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


def dataSetMessage(sender, e):
    # Display the dataset.
    if e.Succeeded:
        # An event with null DataSetData just indicates a successful connection.
        if e.DataSetData is not None:
            print('')
            print('Dataset data: ', e.DataSetData, sep='')
            for pair in e.DataSetData.FieldDataDictionary:
                print(pair)
    else:
        print('')
        print('*** Failure: ', e.ErrorMessageBrief, sep='')


# Define the PubSub connection we will work with. Uses implicit conversion from a string.
# Default port with MQTT is 1883.
pubSubConnectionDescriptor = UAPubSubConnectionDescriptor.op_Implicit('mqtt://opcua-pubsub.demo-this.com')
# Specify the transport protocol mapping.
# The statement below isn't actually necessary, due to automatic message mapping recognition feature; see
# https://kb.opclabs.com/OPC_UA_PubSub_Automatic_Message_Mapping_Recognition for more details.
pubSubConnectionDescriptor.TransportProfileUriString = UAPubSubTransportProfileUriStrings.MqttJson

# Set a custom property on the PubSub connection that influences how the JSON parsing works.
# We are instructing the message parser to turn off the automatic recognition of message format.
# For more details, see https://kb.opclabs.com/OPC_UA_PubSub_JSON_mapping_component .
pubSubConnectionDescriptor.CustomPropertyValueDictionary.set_Item(
    UAQualifiedName(
        '{OpcLabs}',
        'OpcLabs.EasyOpc.UA.Toolkit.PubSub.Sdk.JsonReceiveMessageMapping.MessageParsingParameters.AutoRecognizeMessageFormat'), False)

# Define the arguments for subscribing to the dataset.
subscribeDataSetArguments = UASubscribeDataSetArguments(pubSubConnectionDescriptor)
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.BrokerDataSetReaderTransportParameters.\
    QueueName = 'opcuademo/json'
# We must set the DataSetFieldContentMask when the format auto-recognition is turned off.
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.\
    DataSetFieldContentMask = UADataSetFieldContentMask.RawData
# We must set the DataSetMessageContentMask when the format auto-recognition is turned off.
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.JsonDataSetReaderMessageParameters.\
    DataSetMessageContentMask =\
        UAJsonDataSetMessageContentMask.DataSetWriterId |\
        UAJsonDataSetMessageContentMask.SequenceNumber |\
        UAJsonDataSetMessageContentMask.Status
# We must set the NetworkMessageContentMask when the format auto-recognition is turned off.
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.JsonDataSetReaderMessageParameters.\
    NetworkMessageContentMask =\
        UAJsonNetworkMessageContentMask.NetworkMessageHeader |\
        UAJsonNetworkMessageContentMask.DataSetMessageHeader |\
        UAJsonNetworkMessageContentMask.PublisherId
subscribeDataSetArguments.DataSetSubscriptionDescriptor.Filter.DataSetWriterDescriptor = UADataSetWriterDescriptor(1)

# Instantiate the subscriber object and hook events.
subscriber = EasyUASubscriber()
subscriber.DataSetMessage += dataSetMessage

print('Subscribing...')
IEasyUASubscriberExtension.SubscribeDataSet(subscriber, subscribeDataSetArguments)

print('Processing dataset message events for 20 seconds...')
time.sleep(20)

print('Unsubscribing...')
subscriber.UnsubscribeAllDataSets()

print('Waiting for 1 second...')
# Unsubscribe operation is asynchronous, messages may still come for a short while.
time.sleep(1)

subscriber.DataSetMessage -= dataSetMessage

print('Finished.')

In order to explore the various options that control the format of JSON messages, you can use the OPC UA PubSub Formatter tool.

Secure PubSub communication

For concepts around secure OPC UA PubSub communication, see OPC UA PubSub Security . There are three main parameters that need to be configured:

The example below configures the necessary parameters and then subscribes with them to secure dataset messages.

.NET

// This example shows how to securely subscribe to signed and encrypted dataset messages.
// An external Security Key Service (SKS) is needed (not a part of QuickOPC).
//
// The network messages for this example can be published e.g. using the UADemoPublisher tool - see
// https://kb.opclabs.com/How_to_publish_or_subscribe_to_secure_OPC_UA_PubSub_messages .

using System;
using System.Collections.Generic;
using System.Threading;
using OpcLabs.EasyOpc.UA.Engine;
using OpcLabs.EasyOpc.UA.PubSub;
using OpcLabs.EasyOpc.UA.PubSub.OperationModel;

namespace UADocExamples.PubSub._EasyUASubscriber
{
    partial class SubscribeDataSet
    {
        public static void Secure()
        {
            // Define the PubSub connection we will work with. Uses implicit conversion from a string.
            UAPubSubConnectionDescriptor pubSubConnectionDescriptor = "opc.udp://239.0.0.1";
            // In some cases you may have to set the interface (network adapter) name that needs to be used, similarly to
            // the statement below. Your actual interface name may differ, of course.
            //pubSubConnectionDescriptor.ResourceAddress.InterfaceName = "Ethernet";

            // Define the arguments for subscribing to the dataset.
            var subscribeDataSetArguments = new UASubscribeDataSetArguments(pubSubConnectionDescriptor)
            {
                DataSetSubscriptionDescriptor =
                {
                    CommunicationParameters =
                    {
                        // Specifies the security mode for the PubSub network messages received. This is a minimum security
                        // mode that you want to accept.
                        SecurityMode = UAMessageSecurityModes.SecuritySignAndEncrypt,
                        SecurityKeyServiceTemplate =
                        {
                            // Specifies the URL of the SKS (Security Key Service) endpoint.
                            UrlString = "opc.tcp://localhost:48010", 
                            // Specifies the security mode that will be used to connect to the SKS.
                            EndpointSelectionPolicy = UAMessageSecurityModes.SecuritySignAndEncrypt,
                            // Specifies the user name and password used for "logging in" to the SKS.
                            UserIdentity = { UserNameTokenInfo = { UserName = "root", Password = "secret" }}
                        },
                        // Specifies the Id of the security group in the SKS that will be used (the security group in the
                        // SKS is configured to use certain security policy, and has other parameters detailing how the
                        // security keys are generated).
                        SecurityGroupId = "TestGroup"
                    }
                }
            };

            // Instantiate the subscriber object and hook events.
            var subscriber = new EasyUASubscriber();
            subscriber.DataSetMessage += subscriber_DataSetMessage_Secure;

            Console.WriteLine("Subscribing...");
            subscriber.SubscribeDataSet(subscribeDataSetArguments);

            Console.WriteLine("Processing dataset message events for 20 seconds...");
            Thread.Sleep(20 * 1000);

            Console.WriteLine("Unsubscribing...");
            subscriber.UnsubscribeAllDataSets();

            Console.WriteLine("Waiting for 1 second...");
            // Unsubscribe operation is asynchronous, messages may still come for a short while.
            Thread.Sleep(1 * 1000);

            Console.WriteLine("Finished.");
        }

        static void subscriber_DataSetMessage_Secure(object sender, EasyUADataSetMessageEventArgs e)
        {
            // Display the dataset.
            if (e.Succeeded)
            {
                // An event with null DataSetData just indicates a successful connection.
                if (!(e.DataSetData is null))
                {
                    Console.WriteLine();
                    Console.WriteLine($"Dataset data: {e.DataSetData}");
                    foreach (KeyValuePair<string, UADataSetFieldData> pair in e.DataSetData.FieldDataDictionary)
                        Console.WriteLine(pair);
                }
            }
            else
            {
                Console.WriteLine();
                Console.WriteLine($"*** Failure: {e.ErrorMessageBrief}");
            }
        }
    }
}

# This example shows how to securely subscribe to signed and encrypted dataset messages.
# An external Security Key Service (SKS) is needed (not a part of QuickOPC).
#
# In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
# http://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
import time

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


def dataSetMessage(sender, e):
    # Display the dataset.
    if e.Succeeded:
        # An event with null DataSetData just indicates a successful connection.
        if e.DataSetData is not None:
            print('')
            print('Dataset data: ', e.DataSetData, sep='')
            for pair in e.DataSetData.FieldDataDictionary:
                print(pair)
    else:
        print('')
        print('*** Failure: ', e.ErrorMessageBrief, sep='')


# Define the PubSub connection we will work with. Uses implicit conversion from a string.
pubSubConnectionDescriptor = UAPubSubConnectionDescriptor.op_Implicit('opc.udp://239.0.0.1')
# In some cases you may have to set the interface (network adapter) name that needs to be used, similarly to
# the statement below. Your actual interface name may differ, of course.
#pubSubConnectionDescriptor.ResourceAddress.InterfaceName = 'Ethernet'

# Define the arguments for subscribing to the dataset.
subscribeDataSetArguments = UASubscribeDataSetArguments(pubSubConnectionDescriptor)
# Specifies the security mode for the PubSub network messages received. This is a minimum security
# mode that you want to accept.
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.\
    SecurityMode = UAMessageSecurityModes.SecuritySignAndEncrypt
# Specifies the URL of the SKS (Security Key Service) endpoint.
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.SecurityKeyServiceTemplate.\
    UrlString = 'opc.tcp://localhost:48010'
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.SecurityKeyServiceTemplate.\
    EndpointSelectionPolicy = UAEndpointSelectionPolicy.FromUAMessageSecurityModes(UAMessageSecurityModes.SecuritySignAndEncrypt)
# Specifies the user name and password used for "logging in" to the SKS.
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.SecurityKeyServiceTemplate.\
    UserIdentity.UserNameTokenInfo.UserName = 'root'
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.SecurityKeyServiceTemplate.\
    UserIdentity.UserNameTokenInfo.Password = 'secret'
# Specifies the Id of the security group in the SKS that will be used (the security group in the
# SKS is configured to use certain security policy, and has other parameters detailing how the
# security keys are generated).
subscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.SecurityGroupId = 'TestGroup'

# Instantiate the subscriber object and hook events.
subscriber = EasyUASubscriber()
subscriber.DataSetMessage += dataSetMessage

print('Subscribing...')
IEasyUASubscriberExtension.SubscribeDataSet(subscriber, subscribeDataSetArguments)

print('Processing dataset message events for 20 seconds...')
time.sleep(20)

print('Unsubscribing...')
subscriber.UnsubscribeAllDataSets()

print('Waiting for 1 second...')
# Unsubscribe operation is asynchronous, messages may still come for a short while.
time.sleep(1)

subscriber.DataSetMessage -= dataSetMessage

print('Finished.')

COM

Rem This example shows how to securely subscribe to signed and encrypted dataset messages.
Rem An external Security Key Service (SKS) is needed (not a part of QuickOPC).
Rem
Rem The network messages for this example can be published e.g. using the UADemoPublisher tool - see
Rem https://kb.opclabs.com/How_to_publish_or_subscribe_to_secure_OPC_UA_PubSub_messages .

' The subscriber object, with events
'Public WithEvents Subscriber6 As EasyUASubscriber

Private Sub EasyUASubscriber_SubscribeDataSet_Secure_Command_Click()
    OutputText = ""
    
    ' Define the PubSub connection we will work with.
    Dim subscribeDataSetArguments As New EasyUASubscribeDataSetArguments
    Dim ConnectionDescriptor As UAPubSubConnectionDescriptor
    Set ConnectionDescriptor = subscribeDataSetArguments.dataSetSubscriptionDescriptor.ConnectionDescriptor
    ConnectionDescriptor.ResourceAddress.ResourceDescriptor.UrlString = "opc.udp://239.0.0.1"
    ' In some cases you may have to set the interface (network adapter) name that needs to be used, similarly to
    ' the statement below. Your actual interface name may differ, of course.
    'ConnectionDescriptor.ResourceAddress.InterfaceName := 'Ethernet';

    ' Define the arguments for subscribing to the dataset.
    Dim comunicationParameters As New UASubscriberCommunicationParameters
    ' Specifies the security mode for the PubSub network messages received. This is a minimum security
    ' mode that you want to accept.
    comunicationParameters.SecurityMode = UAMessageSecurityModes_SecuritySignAndEncrypt
    ' Specifies the URL of the SKS (Security Key Service) endpoint.
    comunicationParameters.SecurityKeyServiceTemplate.UrlString = "opc.tcp://localhost:48010"
    ' Specifies the security mode that will be used to connect to the SKS.
    Dim endpointSelectionPolicy As New UAEndpointSelectionPolicy
    endpointSelectionPolicy.AllowedMessageSecurityModes = UAMessageSecurityModes_SecuritySignAndEncrypt
    Set comunicationParameters.SecurityKeyServiceTemplate.endpointSelectionPolicy = endpointSelectionPolicy ' UAMessageSecurityModes_SecuritySignAndEncrypt
    ' Specifies the user name and password used for "logging in" to the SKS.
    comunicationParameters.SecurityKeyServiceTemplate.UserIdentity.UserNameTokenInfo.UserName = "root"
    comunicationParameters.SecurityKeyServiceTemplate.UserIdentity.UserNameTokenInfo.Password = "secret"
    ' Specifies the Id of the security group in the SKS that will be used (the security group in the
    ' SKS is configured to use certain security policy, and has other parameters detailing how the
    ' security keys are generated).
    comunicationParameters.securityGroupId = "TestGroup"
    
    Set subscribeDataSetArguments.dataSetSubscriptionDescriptor.CommunicationParameters = comunicationParameters
    
    ' Instantiate the subscriber object and hook events.
    Set Subscriber6 = New EasyUASubscriber
        
    OutputText = OutputText & "Subscribing..." & vbCrLf
    Call Subscriber6.SubscribeDataSet(subscribeDataSetArguments)

    OutputText = OutputText & "Processing dataset message for 20 seconds..." & vbCrLf
    Pause 20000

    OutputText = OutputText & "Unsubscribing..." & vbCrLf
    Subscriber6.UnsubscribeAllDataSets

    OutputText = OutputText & "Waiting for 1 second..." & vbCrLf
    ' Unsubscribe operation is asynchronous, messages may still come for a short while.
    Pause 1000

    Set Subscriber6 = Nothing

    OutputText = OutputText & "Finished." & vbCrLf
End Sub

Private Sub Subscriber6_DataSetMessage(ByVal sender As Variant, ByVal eventArgs As EasyUADataSetMessageEventArgs)
    ' Display the dataset
    If eventArgs.Succeeded Then
        ' An event with null DataSetData just indicates a successful connection.
        If Not eventArgs.DataSetData Is Nothing Then
            OutputText = OutputText & vbCrLf
            OutputText = OutputText & "Dataset data: " & eventArgs.DataSetData & vbCrLf
            Dim dictionaryEntry2: For Each dictionaryEntry2 In eventArgs.DataSetData.FieldDataDictionary
                OutputText = OutputText & dictionaryEntry2 & vbCrLf
            Next
        End If
    Else
        OutputText = OutputText & vbCrLf
        OutputText = OutputText & eventArgs.ErrorMessageBrief & vbCrLf
    End If
End Sub

 

 

See Also
Subscribing to Information (OPC UA PubSub)
Imperative Programming Model for OPC UA PubSub
OPC UA PubSub Security

Reference

UASubscriberCommunicationParameters Class

Examples - OPC UA PubSub

Examples - OPC UA PubSub - MQTT JSON mapping using TCP
Examples - OPC UA PubSub - MQTT UADP mapping using TCP
Examples - OPC UA PubSub - Set message mapping parameters

Knowledge Base

How to publish or subscribe to secure OPC UA PubSub messages

 

 

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