OPC Studio User's Guide and Reference
Examples - OPC Unified Architecture - Discover servers from GDS, hierarchical

.NET

// This example shows how to obtain information about OPC UA servers from the Global Discovery Server (GDS).
// The result is hierarchical, i.e. each server is returned in one element, and the element contains all its discovery URLs.
//
// 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.OperationModel;

namespace UADocExamples._EasyUAClient
{
    partial class DiscoverGlobalServers
    {
        public static void Hierarchical()
        {
            // Instantiate the client object
            var client = new EasyUAClient();

            // Obtain collection of application elements
            UADiscoveryElementCollection discoveryElementCollection;
            try
            {
                discoveryElementCollection = client.DiscoverGlobalServers(
                    "opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer", 
                    flat:false);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            // Display results
            foreach (UADiscoveryElement discoveryElement in discoveryElementCollection)
            {
                Console.WriteLine();
                Console.WriteLine("Server name: {0}", discoveryElement.ServerName);
                Console.WriteLine("Discovery URI strings:");
                foreach (string discoveryUriString in discoveryElement.DiscoveryUriStrings)
                    Console.WriteLine("  {0}", discoveryUriString);
                Console.WriteLine("Server capabilities: {0}", discoveryElement.ServerCapabilities);
                Console.WriteLine("Application URI string: {0}", discoveryElement.ApplicationUriString);
                Console.WriteLine("Product URI string: {0}", discoveryElement.ProductUriString);
            }
        }
    }
}
' This example shows how to obtain information about OPC UA servers from the Global Discovery Server (GDS).
' The result is hierarchical, i.e. each server is returned in one element, and the element contains all its discovery URLs.
'
' 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.OperationModel

Namespace _EasyUAClient
    Partial Friend Class DiscoverGlobalServers
        Public Shared Sub Hierarchical()
            ' Instantiate the client object
            Dim client = New EasyUAClient()

            ' Obtain collection of application elements
            Dim discoveryElementCollection As UADiscoveryElementCollection
            Try
                discoveryElementCollection = client.DiscoverGlobalServers( _
                    "opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer",
                    flat:=False)
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try

            ' Display results
            For Each discoveryElement As UADiscoveryElement In discoveryElementCollection
                Console.WriteLine()
                Console.WriteLine("Server name: {0}", discoveryElement.ServerName)
                Console.WriteLine("Discovery URI strings:")
                For Each discoveryUriString As String In discoveryElement.DiscoveryUriStrings
                    Console.WriteLine("  {0}", discoveryUriString)
                Next discoveryUriString
                Console.WriteLine("Server capabilities: {0}", discoveryElement.ServerCapabilities)
                Console.WriteLine("Application URI string: {0}", discoveryElement.ApplicationUriString)
                Console.WriteLine("Product URI string: {0}", discoveryElement.ProductUriString)
            Next discoveryElement
        End Sub
    End Class
End Namespace

Python

# This example shows how to obtain information about OPC UA servers from the Global Discovery Server (GDS).
# The result is hierarchical, i.e. each server is returned in one element, and the element contains all its discovery
# URLs.
#
# 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.Discovery import *
from OpcLabs.EasyOpc.UA.OperationModel import *


# Instantiate the client object.
client = EasyUAClient()

# Obtain collection of application elements.
try:
    discoveryElementCollection = IEasyUAClientExtension.DiscoverGlobalServers(client,
        UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer'),
        False) # flat=False
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

# Display results.
for discoveryElement in discoveryElementCollection:
    print()
    print('Server name: ', discoveryElement.ServerName, sep='')
    print('Discovery URI strings:')
    for discoveryUriString in discoveryElement.DiscoveryUriStrings:
        print('  ', discoveryUriString, sep='')
    print('Server capabilities: ', discoveryElement.ServerCapabilities, sep='')
    print('Application URI string: ', discoveryElement.ApplicationUriString, sep='')
    print('Product URI string: ', discoveryElement.ProductUriString, sep='')

print()
print('Finished.')
See Also

Concepts