Examples - OPC XML-DA - Browse nodes recursively

.NET

// This example shows how to recursively browse the nodes in the OPC XML-DA address space.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using System.Diagnostics;
using OpcLabs.EasyOpc;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.AddressSpace;
using OpcLabs.EasyOpc.OperationModel;

namespace DocExamples.DataAccess.Xml
{
    class BrowseNodes
    {
        public static void RecursiveXml()
        {
            var stopwatch = new Stopwatch();
            stopwatch.Start();

            // Instantiate the client object.
            var client = new EasyDAClient();

            _branchCount = 0;
            _leafCount = 0;

            try
            {
                BrowseFromNode(client, "http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx", "");
            }
            catch (OpcException opcException)
            {
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
                return;
            }

            stopwatch.Stop();
            Console.WriteLine("Browsing has taken (milliseconds): {0}", stopwatch.ElapsedMilliseconds);
            Console.WriteLine("Branch count: {0}", _branchCount);
            Console.WriteLine("Leaf count: {0}", _leafCount);
        }

        private static void BrowseFromNode(
            EasyDAClient client,
            ServerDescriptor serverDescriptor,
            DANodeDescriptor parentNodeDescriptor)
        {
            Debug.Assert(client != null);
            Debug.Assert(serverDescriptor != null);
            Debug.Assert(parentNodeDescriptor != null);

            // Obtain all node elements under parentNodeDescriptor
            var browseParameters = new DABrowseParameters();    // no filtering whatsoever
            DANodeElementCollection nodeElementCollection =
                client.BrowseNodes(serverDescriptor, parentNodeDescriptor, browseParameters);
            // Remark: that BrowseNodes(...) may also throw OpcException; a production code should contain handling for 
            // it, here omitted for brevity.

            foreach (DANodeElement nodeElement in nodeElementCollection)
            {
                Debug.Assert(nodeElement != null);

                Console.WriteLine(nodeElement);

                // If the node is a branch, browse recursively into it.
                if (nodeElement.IsBranch)
                {
                    _branchCount++;
                    BrowseFromNode(client, serverDescriptor, nodeElement);
                }
                else
                {
                    _leafCount++;
                }
            }
        }

        private static int _branchCount;
        private static int _leafCount;
    }
}

# This example shows how to recursively browse the nodes in the OPC XML-DA address space.
#
# 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 .
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
import timeit

# Import .NET namespaces.
from OpcLabs.EasyOpc import *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.OperationModel import *


def browseFromNode(client, serverDescriptor, parentNodeDescriptor):
    global branchCount
    global leafCount

    assert client is not None
    assert serverDescriptor is not None
    assert parentNodeDescriptor is not None

    # Obtain all node elements under parentNodeDescriptor.
    browseParameters = DABrowseParameters() # no filtering whatsoever
    nodeElementCollection = client.BrowseNodes(serverDescriptor, parentNodeDescriptor, browseParameters)
    # BrowseNodes(...) may also throw OpcException; here it is handled by the caller.

    for nodeElement in nodeElementCollection:
        assert nodeElement is not None
        print(nodeElement)

        # If the node is a branch, browse recursively into it.
        if nodeElement.IsBranch:
            branchCount = branchCount + 1
            browseFromNode(client, serverDescriptor, DANodeDescriptor(nodeElement))
        else:
            leafCount = leafCount + 1


beginTime = timeit.default_timer()

# Instantiate the client object.
client = EasyDAClient()
branchCount = 0
leafCount = 0

try:
    browseFromNode(client,
                   ServerDescriptor('http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx'),
                   DANodeDescriptor(''))
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message)
    exit()

endTime = timeit.default_timer()
print()
print('Browsing has taken (milliseconds): ',(endTime - beginTime)*1000)
print('Branch count: ', branchCount);
print('Leaf count: ', leafCount);

' This example shows how to recursively browse the nodes in the OPC XML-DA address space.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Imports OpcLabs.EasyOpc
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.AddressSpace
Imports OpcLabs.EasyOpc.OperationModel

Namespace DataAccess.Xml
    Partial Friend Class BrowseNodes

        Shared Sub RecursiveXml()
            Dim stopwatch = New Stopwatch()
            stopwatch.Start()

            Dim client = New EasyDAClient()
            _branchCount = 0
            _leafCount = 0

            Try
                BrowseFromNode(client, "http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx", "")
            Catch opcException As OpcException
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
                Exit Sub
            End Try

            stopwatch.Stop()
            Console.WriteLine("Browsing has taken (milliseconds): {0}", stopwatch.ElapsedMilliseconds)
            Console.WriteLine("Branch count: {0}", _branchCount)
            Console.WriteLine("Leaf count: {0}", _leafCount)
        End Sub

        Private Shared Sub BrowseFromNode( _
            client As EasyDAClient,
            serverDescriptor As ServerDescriptor,
            parentNodeDescriptor As DANodeDescriptor)

            Debug.Assert(client IsNot Nothing)
            Debug.Assert(serverDescriptor IsNot Nothing)
            Debug.Assert(parentNodeDescriptor IsNot Nothing)

            ' Obtain all node elements under parentNodeDescriptor
            Dim browseParameters = New DABrowseParameters() ' no filtering whatsoever
            Dim nodeElementCollection As DANodeElementCollection =
                client.BrowseNodes(serverDescriptor, parentNodeDescriptor, browseParameters)
            ' Remark: that BrowseNodes(...) may also throw OpcException; a production code should contain handling for 
            ' it, here omitted for brevity.

            For Each nodeElement As DANodeElement In nodeElementCollection
                Debug.Assert(nodeElement IsNot Nothing)

                Console.WriteLine(nodeElement)

                ' If the node is a branch, browse recursively into it.
                If nodeElement.IsBranch Then
                    _branchCount += 1
                    BrowseFromNode(client, serverDescriptor, nodeElement)
                Else
                    _leafCount += 1
                End If
            Next nodeElement
        End Sub

        Private Shared _branchCount As Integer
        Private Shared _leafCount As Integer
    End Class
End Namespace

COM

// This example shows how to recursively browse the nodes in the OPC XML-DA address space.
//
// Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

type
  TBrowseNodes = class
    BranchCount: Integer;
    LeafCount: Integer;
    procedure BrowseFromNode(
      Client: OpcLabs_EasyOpcClassic_TLB._EasyDAClient;
      ServerDescriptor: _ServerDescriptor;
      ParentNodeDescriptor:  _DANodeDescriptor);
  end;

procedure TBrowseNodes.BrowseFromNode(
      Client: OpcLabs_EasyOpcClassic_TLB._EasyDAClient;
      ServerDescriptor: _ServerDescriptor;
      ParentNodeDescriptor: _DANodeDescriptor);
var
  BrowseParameters: _DABrowseParameters;
  Count: Cardinal;
  Element: OleVariant;
  NodeElement: _DANodeElement;
  NodeElementEnumerator: IEnumVariant;
  NodeElements: _DANodeElementCollection;
begin
  // Obtain all node elements under ParentNodeDescriptor
  BrowseParameters := CoDABrowseParameters.Create;  // no filtering whatsover
  NodeElements := Client.BrowseNodes(
    ServerDescriptor,
    ParentNodeDescriptor,
    BrowseParameters);
  // Remark: that BrowseNodes(...) may also throw OpcException; a production code should contain handling for 
  // it, here omitted for brevity.

  NodeElementEnumerator := NodeElements.GetEnumerator;
  while (NodeElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    NodeElement := IUnknown(Element) as _DANodeElement;
    WriteLn(NodeElement.ToString);

    // If the node is a branch, browse recursively into it.
    if NodeElement.IsBranch then
    begin
      BranchCount := BranchCount + 1;
      BrowseFromNode(Client, ServerDescriptor, NodeElement.ToDANodeDescriptor);
    end
    else
      LeafCount := LeafCount + 1;
  end;
end;

class procedure BrowseNodes.RecursiveXml;
var
  BeginTime: Cardinal;
  BrowseNodes: TBrowseNodes;
  Client: OpcLabs_EasyOpcClassic_TLB._EasyDAClient;
  EndTime: Cardinal;
  ServerDescriptor: _ServerDescriptor;
  NodeDescriptor: _DANodeDescriptor;
begin
  BrowseNodes := TBrowseNodes.Create;
  BrowseNodes.BranchCount := 0;
  BrowseNodes.LeafCount := 0;

  BeginTime := Ticks;

  ServerDescriptor := CoServerDescriptor.Create;
  ServerDescriptor.UrlString := 'http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx';

  NodeDescriptor := CoDANodeDescriptor.Create;
  NodeDescriptor.ItemId := '';

  // Instantiate the client object
  Client := CoEasyDAClient.Create;

  try
    BrowseNodes.BrowseFromNode(
      Client,
      ServerDescriptor,
      NodeDescriptor);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

  EndTime := Ticks;

  WriteLn;
  WriteLn('Browsing has taken (milliseconds): ', (endTime - beginTime) * 1000);
  WriteLn('Branch count: ', BrowseNodes.BranchCount);
  WriteLn('Leaf count: ', BrowseNodes.LeafCount);
end;

// This example shows how to recursively browse the nodes in the OPC XML-DA address space.
//
// Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

$beginTime = microtime(true);
$branchCount = 0;
$leafCount = 0;

$ServerDescriptor = new COM("OpcLabs.EasyOpc.ServerDescriptor");
$ServerDescriptor->UrlString = "http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx";

$NodeDescriptor = new COM("OpcLabs.EasyOpc.DataAccess.DANodeDescriptor");
$NodeDescriptor->ItemID = "";

// Instantiate the client object.
$Client = new COM("OpcLabs.EasyOpc.DataAccess.EasyDAClient");

try
{
    BrowseFromNode($Client, $ServerDescriptor, $NodeDescriptor);
}
catch (com_exception $e)
{
    printf("*** Failure: %s\n", $e->getMessage());
    Exit();
}

$endTime = microtime(true);

printf("\n");
printf("Browsing has taken (milliseconds): : %f\n", ($endTime - $beginTime) * 1000);
printf("Branch count: %d\n", $branchCount);
printf("Leaf count: %d\n", $leafCount);


function BrowseFromNode($Client, $ServerDescriptor, $ParentNodeDescriptor) : void
{
    global $branchCount, $leafCount;

    // Obtain all node elements under ParentNodeDescriptor
    $BrowseParameters = new COM("OpcLabs.EasyOpc.DataAccess.DABrowseParameters"); // no filtering whatsoever
    $NodeElementCollection = $Client->BrowseNodes($ServerDescriptor, $ParentNodeDescriptor,$BrowseParameters);
    // Remark: that BrowseNodes(...) may also throw OpcException; a production code should contain handling for 
    //it, here omitted for brevity.

    foreach ($NodeElementCollection as $NodeElement)
    {
        printf("%s\n", $NodeElement);

        // If the node is a branch, browse recursively into it.
        if ($NodeElement->IsBranch)
        {
            $branchCount = $branchCount + 1;
            BrowseFromNode($Client, $ServerDescriptor, $NodeElement->ToDANodeDescriptor());
        }
        else
        {
            $leafCount = $leafCount + 1;
        }
    }
}

Rem This example shows how to recursively browse the nodes in the OPC XML-DA address space.
Rem
Rem Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

'Public branchCount As Integer
'Public leafCount As Integer

Private Sub BrowseNodes_RecursiveXml_Command_Click()
    OutputText = ""
    branchCount = 0
    leafCount = 0
    Dim beginTime: beginTime = Timer
        
    Dim serverDescriptor As New serverDescriptor
    serverDescriptor.UrlString = "http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx"
    
    Dim NodeDescriptor As New DANodeDescriptor
    NodeDescriptor.ItemId = ""
    
    ' Instantiate the client object
    Dim client As New EasyDAClient

    On Error Resume Next
        BrowseFromNode client, serverDescriptor, NodeDescriptor
    If Err.Number <> 0 Then
        OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
        Exit Sub
    End If
    On Error GoTo 0

    Dim endTime: endTime = Timer
    
    OutputText = OutputText & vbCrLf
    OutputText = OutputText & "Browsing has taken (milliseconds): " & (endTime - beginTime) * 1000 & vbCrLf
    OutputText = OutputText & "Branch count: " & branchCount & vbCrLf
    OutputText = OutputText & "Leaf count: " & leafCount & vbCrLf
End Sub

Public Sub BrowseFromNode(client, serverDescriptor, ParentNodeDescriptor)
    ' Obtain all node elements under ParentNodeDescriptor
    Dim BrowseParameters As New DABrowseParameters
    Dim NodeElementCollection As DANodeElementCollection
    Set NodeElementCollection = client.BrowseNodes(serverDescriptor, ParentNodeDescriptor, BrowseParameters)
    ' Remark: that BrowseNodes(...) may also throw OpcException; a production code should contain handling for
    ' it, here omitted for brevity.

    Dim NodeElement: For Each NodeElement In NodeElementCollection
        OutputText = OutputText & NodeElement & vbCrLf
        
        ' If the node is a branch, browse recursively into it.
        If NodeElement.IsBranch Then
            branchCount = branchCount + 1
            BrowseFromNode client, serverDescriptor, NodeElement.ToDANodeDescriptor
        Else
            leafCount = leafCount + 1
        End If
    Next
End Sub

Rem This example shows how to recursively browse the nodes in the OPC XML-DA address space.
Rem
Rem Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Option Explicit

Dim beginTime: beginTime = Timer
Dim branchCount: branchCount = 0
Dim leafCount: leafCount = 0

Dim ServerDescriptor: Set ServerDescriptor = CreateObject("OpcLabs.EasyOpc.ServerDescriptor")
ServerDescriptor.UrlString = "http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx"

Dim NodeDescriptor: Set NodeDescriptor = CreateObject("OpcLabs.EasyOpc.DataAccess.DANodeDescriptor")
NodeDescriptor.ItemID = ""

Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient")
On Error Resume Next
BrowseFromNode Client, ServerDescriptor, NodeDescriptor
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

Dim endTime: endTime = Timer

WScript.Echo ""
WScript.Echo "Browsing has taken (milliseconds): " & (endTime - beginTime) * 1000
WScript.Echo "Branch count: " & branchCount
WScript.Echo "Leaf count: " & leafCount


Sub BrowseFromNode(Client, ServerDescriptor, ParentNodeDescriptor)
    ' Obtain all node elements under ParentNodeDescriptor
    Dim BrowseParameters: Set BrowseParameters = CreateObject("OpcLabs.EasyOpc.DataAccess.DABrowseParameters")
    Dim NodeElementCollection: Set NodeElementCollection = Client.BrowseNodes(serverDescriptor, parentNodeDescriptor, browseParameters)
    ' Remark: that BrowseNodes(...) may also throw OpcException; a production code should contain handling for 
    ' it, here omitted for brevity.

    Dim NodeElement: For Each NodeElement In NodeElementCollection
        WScript.Echo NodeElement
        
        ' If the node is a branch, browse recursively into it.
        If NodeElement.IsBranch Then
            branchCount = branchCount + 1
            BrowseFromNode Client, ServerDescriptor, NodeElement.ToDANodeDescriptor
        Else
            leafCount = leafCount + 1
        End If
    Next

End Sub

QuickOPC supports OPC XML-DA also on Linux and macOS.

Examples - OPC Data Access

Examples - OPC Data Access - Browse nodes recursively

Conceptual

Browsing for OPC Classic Nodes (Branches and Leaves)