Examples - Sparkplug Consumer - Subscribe to metrics, identify subscriptions using an integer

.NET

C#
VB.NET

// This example shows how to subscribe to changes of multiple metrics and display each change, identifying the different
// subscriptions by an integer.
//
// In order to publish or observe messages for this example, start the SparkplugEdgeNodeConsoleDemo program first.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
// Sparkplug examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-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.EasySparkplug;
using OpcLabs.EasySparkplug.OperationModel;

namespace SparkplugDocExamples.Consumer._EasySparkplugConsumer
{
    class SubscribeMetric
    {
        public static void StateAsInteger()
        {
            // Note that the default port for the "mqtt" scheme is 1883.
            var hostDescriptor = new SparkplugHostDescriptor("mqtt://localhost");

            // Instantiate the consumer object and hook events.
            var consumer = new EasySparkplugConsumer();
            consumer.MetricNotification += consumer_StateAsInteger_MetricNotification;

            Console.WriteLine("Subscribing...");
            consumer.SubscribeMetric(
                new EasySparkplugMetricSubscriptionArguments(SparkplugComponentTypes.EdgeNode, hostDescriptor, 
                    "easyGroup", "easySparkplugDemo", "", "Random", null)
                    { State = 1 });    // An integer we have chosen to identify the subscription
            consumer.SubscribeMetric(
                new EasySparkplugMetricSubscriptionArguments(SparkplugComponentTypes.EdgeNode, hostDescriptor,
                        "easyGroup", "easySparkplugDemo", "", "Simple", null)
                    { State = 2 });    // An integer we have chosen to identify the subscription
            consumer.SubscribeMetric(
                new EasySparkplugMetricSubscriptionArguments(SparkplugComponentTypes.EdgeNode, hostDescriptor,
                        "easyGroup", "easySparkplugDemo", "", "Ramp", null)
                    { State = 3 });    // An integer we have chosen to identify the subscription

            Console.WriteLine("Processing notifications for 20 seconds...");
            System.Threading.Thread.Sleep(20 * 1000);

            Console.WriteLine("Unsubscribing...");
            consumer.UnsubscribeAllMetrics();

            Console.WriteLine("Waiting for 5 seconds...");
            System.Threading.Thread.Sleep(5 * 1000);

            Console.WriteLine("Finished.");
        }


        static void consumer_StateAsInteger_MetricNotification(object sender, EasySparkplugMetricNotificationEventArgs eventArgs)
        {
            // Obtain the integer state we have passed in.
            // Note that the metric name also comes with the notification and can be used to determine which metric the
            // notification relates to. The reason we are using the state is that it allows to pass in the information that
            // your application understands immediately, and is thus more efficient.
            var stateAsInteger = (int)eventArgs.Arguments.State;

            // Display the data.
            if (eventArgs.Succeeded)
            {
                if (eventArgs.HasData)
                    Console.WriteLine($"{stateAsInteger}: {eventArgs.MetricData}");
            }
            else
                Console.WriteLine($"{stateAsInteger} *** Failure: {eventArgs.ErrorMessageBrief}");
        }
    }
}

' This example shows how to subscribe to changes of multiple metrics and display each change, identifying the different
' subscriptions by an integer.
'
' In order to publish or observe messages for this example, start the SparkplugEdgeNodeConsoleDemo program first.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
' Sparkplug examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-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.

Imports OpcLabs.EasySparkplug
Imports OpcLabs.EasySparkplug.OperationModel

Namespace Global.SparkplugDocExamples.Consumer._EasySparkplugConsumer
    Class SubscribeMetric
        Public Shared Sub StateAsInteger()
            ' Note that the default port for the "mqtt" scheme is 1883.
            Dim hostDescriptor = New SparkplugHostDescriptor("mqtt://localhost")

            ' Instantiate the consumer object and hook events.
            Dim consumer = New EasySparkplugConsumer()
            AddHandler consumer.MetricNotification, AddressOf consumer_StateAsInteger_MetricNotification

            Console.WriteLine("Subscribing...")
            consumer.SubscribeMetric(
                New EasySparkplugMetricSubscriptionArguments(SparkplugComponentTypes.EdgeNode, hostDescriptor,
                    "easyGroup", "easySparkplugDemo", "", "Random", Nothing) With
                    {.State = 1}) ' An integer we have chosen to identify the subscription
            consumer.SubscribeMetric(
                New EasySparkplugMetricSubscriptionArguments(SparkplugComponentTypes.EdgeNode, hostDescriptor,
                    "easyGroup", "easySparkplugDemo", "", "Simple", Nothing) With
                    {.State = 2}) ' An integer we have chosen to identify the subscription
            consumer.SubscribeMetric(
                New EasySparkplugMetricSubscriptionArguments(SparkplugComponentTypes.EdgeNode, hostDescriptor,
                    "easyGroup", "easySparkplugDemo", "", "Ramp", Nothing) With
                    {.State = 3}) ' An integer we have chosen to identify the subscription

            Console.WriteLine("Processing notifications for 20 seconds...")
            Threading.Thread.Sleep(20 * 1000)

            Console.WriteLine("Unsubscribing...")
            consumer.UnsubscribeAllMetrics()

            Console.WriteLine("Waiting for 5 seconds...")
            Threading.Thread.Sleep(5 * 1000)

            Console.WriteLine("Finished.")
        End Sub

        Private Shared Sub consumer_StateAsInteger_MetricNotification(ByVal sender As Object, ByVal eventArgs As EasySparkplugMetricNotificationEventArgs)
            ' Obtain the integer state we have passed in.
            ' Note that the metric name also comes with the notification and can be used to determine which metric the
            ' notification relates to. The reason we are using the state is that it allows to pass in the information that
            ' your application understands immediately, and is thus more efficient.
            Dim stateAsInteger = CInt(eventArgs.Arguments.State)

            ' Display the data.
            If (eventArgs.Succeeded) Then
                If (eventArgs.HasData) Then
                    Console.WriteLine($"{stateAsInteger}: {eventArgs.MetricData}")
                End If
            Else
                Console.WriteLine($"{stateAsInteger} *** Failure: {eventArgs.ErrorMessageBrief}")
            End If
        End Sub
    End Class
End Namespace

Reference

EasySparkplugMetricNotificationEventArgs Class

Arguments Property

State Property

Rapid Toolkit for Sparkplug

Subscribing to Data in Sparkplug Consumer