In This Topic

Parsing

QuickOPC-UA uses the relative browse path string format recommended by the OPC specification, but extends it by an ability to specify the starting node ID (and therefore introducing the absolute browse paths), and by an ability to specify the namespaces not by an index into a namespace table, but by a namespace URI. The precise syntax of these extensions is beyond the current scope of this document, and the description below is just a close approximation.

An OPC-UA browse path can be represented by a string; in such case, it can express either a relative or absolute browse path (the UABrowsePath object cannot hold relative browse paths).

As mentioned above, the format of the browse path string is such that the individual elements (usually, node names) are separated by delimiters. In OPC-UA, the delimiter actually precedes every element, i.e. there is a delimiter also at the beginning of the relative browse path. Different delimiters are available for specifying various reference types. Following delimiters are available:

Delimiter	Description
/	Follow any subtype of HierarchicalReferences (technically, numerical node Id 44 in namespace 0).
.	Follow any subtype of Aggregates reference type (technically, numerical node Id 33 in namespace 0). This is stricter than '/'.
*<referenceSpecifier>*	Follow the specified reference type. A ‘#’ placed in front of the reference type name indicates that subtypes should not be followed. A ‘!’ in front of the reference type name is used to indicate that the inverse reference should be followed.

If the OPC-UA browse path does not start with any of the above delimiters, it denotes an absolute path that starts from the node specified at the beginning of the string. For example, “[Objects]/Boilers” is an example of such absolute OPC-UA browse path, whereas “/Boilers” in OPC-UA is a relative browse path.

The string form of an OPC-UA browse path is a concept on the client side (QuickOPC), and the browse paths strings are not directly processed by OPC-UA servers.

Because the node names can contain any characters, we need to consider situations in which the node name itself contains a slash (‘/’) or a dot (‘.’). In such case, in the string format of browse paths, these characters are escaped by preceding them with an ampersand (‘&’). An ampersand itself needs to be escaped, too.

Parsing

Parsing an absolute browse path:

.NET

// Parses an absolute  OPC-UA browse path and displays its starting node and elements.

using System;
using OpcLabs.EasyOpc.UA.Navigation;
using OpcLabs.EasyOpc.UA.Navigation.Parsing;

namespace UADocExamples._UABrowsePathParser
{
    class Parse
    {
        public static void Main1()
        {
            var browsePathParser = new UABrowsePathParser();
            UABrowsePath browsePath;
            try
            {
                browsePath = browsePathParser.Parse("[ObjectsFolder]/Data/Static/UserScalar");
            }
            catch (UABrowsePathFormatException browsePathFormatException)
            {
                Console.WriteLine("*** Failure: {0}", browsePathFormatException.GetBaseException().Message);
                return;
            }

            // Display results
            Console.WriteLine("StartingNodeId: {0}", browsePath.StartingNodeId);

            foreach (UABrowsePathElement browsePathElement in browsePath.Elements)
                Console.WriteLine(browsePathElement);

            // Example output:
            // StartingNodeId: ObjectsFolder
            // /Data
            // /Static
            // /UserScalar
        }
    }
}

# Parses an absolute  OPC-UA browse path and displays its starting node and elements.

# 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.Navigation import *
from OpcLabs.EasyOpc.UA.Navigation.Parsing import *


browsePathParser = UABrowsePathParser()
try:
    browsePath = browsePathParser.Parse('[ObjectsFolder]/Data/Static/UserScalar')
except UABrowsePathFormatException as browsePathFormatException:
    print('*** Failure: ' + browsePathFormatException.GetBaseException().Message)
    exit()

# Display results.
print('StartingNodeId: ', browsePath.StartingNodeId, sep='')

print()
for browsePathElement in browsePath.Elements:
    print(browsePathElement)

print()
print('Finished.')

' Parses an absolute  OPC-UA browse path and displays its starting node and elements.

Imports OpcLabs.EasyOpc.UA.Navigation
Imports OpcLabs.EasyOpc.UA.Navigation.Parsing

Namespace _UABrowsePathParser
    Friend Class Parse
        Public Shared Sub Main1()
            Dim browsePathParser = New UABrowsePathParser()
            Dim browsePath As UABrowsePath
            Try
                browsePath = browsePathParser.Parse("[ObjectsFolder]/Data/Static/UserScalar")
            Catch browsePathFormatException As UABrowsePathFormatException
                Console.WriteLine("*** Failure: {0}", browsePathFormatException.GetBaseException.Message)
                Exit Sub
            End Try

            ' Display results
            Console.WriteLine("StartingNodeId: {0}", browsePath.StartingNodeId)

            For Each browsePathElement As UABrowsePathElement In browsePath.Elements
                Console.WriteLine(browsePathElement)
            Next browsePathElement

            ' Example output:
            ' StartingNodeId: ObjectsFolder
            ' /Data
            ' /Static
            ' /UserScalar
        End Sub
    End Class
End Namespace

COM

// Parses an absolute  OPC-UA browse path and displays its starting node and elements.

class procedure Parse.Main;
var
  BrowsePath: _UABrowsePath;
  BrowsePathElement: _UABrowsePathElement;
  BrowsePathParser: OpcLabs_EasyOpcUA_TLB._UABrowsePathParser;
  Count: Cardinal;
  Element: OleVariant;
  ElementEnumerator: IEnumVariant;
begin
  BrowsePathParser := CoUABrowsePathParser.Create;

  try
    BrowsePath := BrowsePathParser.Parse('[ObjectsFolder]/Data/Static/UserScalar');
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

  // Display results
  WriteLn('StartingNodeId: ', BrowsePath.StartingNodeId.ToString);

  WriteLn('Elements:');
  ElementEnumerator := BrowsePath.Elements.GetEnumerator;
  while (ElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    BrowsePathElement := IUnknown(Element) as _UABrowsePathElement;
    WriteLn(BrowsePathElement.ToString);
  end;

  // Example output:
  // StartingNodeId: ObjectsFolder
  // Elements:
  // /Data
  // /Static
  // /UserScalar

end;

// Parses an absolute  OPC-UA browse path and displays its starting node and elements.


$BrowsePathParser = new COM("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser");

try
{
    $BrowsePath = $BrowsePathParser->Parse("[ObjectsFolder]/Data/Static/UserScalar");
}
catch (com_exception $e)
{
    printf("*** Failure: %s\n", $e->getMessage());
    exit();
}

// Display results
printf("StartingNodeId: %s\n", $BrowsePath->StartingNodeId);

printf("Elements:\n");

for ($i = 0; $i < $BrowsePath->Elements->Count; $i++)
{
    printf("%s\n", $BrowsePath->Elements[$i]);
}

// Example output:
// StartingNodeId: ObjectsFolder
// Elements:
// /Data
// /Static
// /UserScalar

Rem Parses an absolute  OPC-UA browse path and displays its starting node and elements.

Private Sub Parse_Main_Command_Click()
    OutputText = ""
    
    Dim BrowsePathParser As New UABrowsePathParser

    On Error Resume Next
    Dim browsePath As UABrowsePath
    Set browsePath = BrowsePathParser.Parse("[ObjectsFolder]/Data/Static/UserScalar")
    If Err.Number <> 0 Then
        OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
        Exit Sub
    End If
    On Error GoTo 0
    
    ' Display results
    OutputText = OutputText & "StartingNodeId: " & browsePath.StartingNodeId & vbCrLf
    
    OutputText = OutputText & "Elements:" & vbCrLf
    Dim BrowsePathElement: For Each BrowsePathElement In browsePath.Elements
        OutputText = OutputText & BrowsePathElement & vbCrLf
    Next

    ' Example output:
    'StartingNodeId: ObjectsFolder
    'Elements:
    '/Data
    '/Static
    '/UserScalar
End Sub

Rem Parses an absolute  OPC-UA browse path and displays its starting node and elements.

Option Explicit

Dim BrowsePathParser: Set BrowsePathParser = CreateObject("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser")
On Error Resume Next
Dim BrowsePath: Set BrowsePath = BrowsePathParser.Parse("[ObjectsFolder]/Data/Static/UserScalar")
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

' Display results
WScript.Echo "StartingNodeId: " & BrowsePath.StartingNodeId

WScript.Echo "Elements:"
Dim BrowsePathElement: For Each BrowsePathElement In BrowsePath.Elements
    WScript.Echo BrowsePathElement
Next

Attempting to parse an absolute browse path:

.NET

// Attempts to parse an absolute OPC-UA browse path and displays its starting node and elements.

using System;
using OpcLabs.BaseLib;
using OpcLabs.EasyOpc.UA.Navigation;
using OpcLabs.EasyOpc.UA.Navigation.Parsing;

namespace UADocExamples._UABrowsePathParser
{
    class TryParse
    {
        public static void Main1()
        {
            var browsePathParser = new UABrowsePathParser();

            IStringParsingError stringParsingError = browsePathParser.TryParse(
                "[ObjectsFolder]/Data/Static/UserScalar", 
                out UABrowsePath browsePath);

            // Display results
            if (!(stringParsingError is null))
            {
                Console.WriteLine("*** Error: {0}", stringParsingError);
                return;
            }

            Console.WriteLine("StartingNodeId: {0}", browsePath.StartingNodeId);

            foreach (UABrowsePathElement browsePathElement in browsePath.Elements)
                Console.WriteLine(browsePathElement);

            // Example output:
            // StartingNodeId: ObjectsFolder
            // /Data
            // /Static
            // /UserScalar
        }
    }
}

# Attempts to parse an absolute OPC-UA browse path and displays its starting node and elements.

# 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.Navigation import *
from OpcLabs.EasyOpc.UA.Navigation.Parsing import *


browsePathParser = UABrowsePathParser()

stringParsingError, browsePath = browsePathParser.TryParse('[ObjectsFolder]/Data/Static/UserScalar', None)

# Display results.
if stringParsingError is not None:
    print('*** Error: ', stringParsingError, sep='')
    exit()

print('StartingNodeId: ', browsePath.StartingNodeId, sep='')

print()
for browsePathElement in browsePath.Elements:
    print(browsePathElement)

print()
print('Finished.')

' Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

Imports System
Imports OpcLabs.BaseLib
Imports OpcLabs.EasyOpc.UA.Navigation
Imports OpcLabs.EasyOpc.UA.Navigation.Parsing

Namespace _UABrowsePathParser
    Friend Class TryParse
        Public Shared Sub Main1()
            Dim browsePathParser = New UABrowsePathParser()

            Dim browsePath As UABrowsePath = Nothing
            Dim stringParsingError As IStringParsingError = browsePathParser.TryParse("[ObjectsFolder]/Data/Static/UserScalar", browsePath)

            ' Display results
            If Not stringParsingError Is Nothing Then
                Console.WriteLine("*** Error: {0}", stringParsingError)
                Exit Sub
            End If

            Console.WriteLine("StartingNodeId: {0}", browsePath.StartingNodeId)

            For Each browsePathElement As UABrowsePathElement In browsePath.Elements
                Console.WriteLine(browsePathElement)
            Next browsePathElement

            ' Example output:
            ' StartingNodeId: ObjectsFolder
            ' /Data
            ' /Static
            ' /UserScalar
        End Sub
    End Class
End Namespace

COM

// Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

class procedure TryParse.Main;
var
  BrowsePath: _UABrowsePath;
  BrowsePathElement: _UABrowsePathElement;
  BrowsePathParser: OpcLabs_EasyOpcUA_TLB._UABrowsePathParser;
  BrowsePathResult: OleVariant;
  Count: Cardinal;
  Element: OleVariant;
  ElementEnumerator: IEnumVariant;
  StringParsingError: _StringParsingError;
begin
  BrowsePathParser := CoUABrowsePathParser.Create;

  StringParsingError := BrowsePathParser.TryParse('[ObjectsFolder]/Data/Static/UserScalar', BrowsePathResult);

  // Display results
  if StringParsingError <> nil then
  begin
    WriteLn('*** Error: ', StringParsingError.ToString);
    Exit;
  end;

  BrowsePath := IUnknown(BrowsePathResult) as _UABrowsePath;
  WriteLn('StartingNodeId: ', BrowsePath.StartingNodeId.ToString);

  WriteLn('Elements:');
  ElementEnumerator := BrowsePath.Elements.GetEnumerator;
  while (ElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    BrowsePathElement := IUnknown(Element) as _UABrowsePathElement;
    WriteLn(BrowsePathElement.ToString);
  end;

  // Example output:
  // StartingNodeId: ObjectsFolder
  // Elements:
  // /Data
  // /Static
  // /UserScalar

end;

// Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

$BrowsePath = new COM("OpcLabs.EasyOpc.UA.Navigation.UABrowsePath");

$BrowsePathParser = new COM("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser");

$StringParsingError = $BrowsePathParser->TryParse("[ObjectsFolder]/Data/Static/UserScalar", $BrowsePath);

// Display results
if (!is_null($StringParsingError)) {
    printf("*** Error: %s\n", $StringParsingError);
    exit();
}

printf("StartingNodeId: %s\n", $BrowsePath->StartingNodeId);

printf("Elements:\n");

for ($i = 0; $i < $BrowsePath->Elements->Count; $i++)
{
    printf("%s\n", $BrowsePath->Elements[$i]);
}

// Example output:
// StartingNodeId: ObjectsFolder
// Elements:
// /Data
// /Static
// /UserScalar

Rem Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

Private Sub TryParse_Main_Command_Click()
    OutputText = ""
    
    Dim BrowsePathParser As New UABrowsePathParser

    Dim stringParsingError As stringParsingError
    Dim browsePath As Variant
    Set stringParsingError = BrowsePathParser.TryParse("[ObjectsFolder]/Data/Static/UserScalar", browsePath)
    
    ' Display results
    If Not stringParsingError Is Nothing Then
        OutputText = OutputText & "*** Error: " & stringParsingError & vbCrLf
        Exit Sub
    End If
    
    OutputText = OutputText & "StartingNodeId: " & browsePath.StartingNodeId & vbCrLf
    
    OutputText = OutputText & "Elements:" & vbCrLf
    Dim BrowsePathElement: For Each BrowsePathElement In browsePath.Elements
        OutputText = OutputText & BrowsePathElement & vbCrLf
    Next

    ' Example output:
    'StartingNodeId: ObjectsFolder
    'Elements:
    '/Data
    '/Static
    '/UserScalar
End Sub

Rem Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

Option Explicit

Dim BrowsePathParser: Set BrowsePathParser = CreateObject("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser")
Dim BrowsePath
Dim StringParsingError: Set StringParsingError = BrowsePathParser.TryParse("[ObjectsFolder]/Data/Static/UserScalar", BrowsePath)

' Display results
If Not (StringParsingError Is Nothing) Then
    WScript.Echo "*** Error: " & StringParsingError
    WScript.Quit
End If

WScript.Echo "StartingNodeId: " & BrowsePath.StartingNodeId

WScript.Echo "Elements:"
Dim BrowsePathElement: For Each BrowsePathElement In BrowsePath.Elements
    WScript.Echo BrowsePathElement
Next

Parsing a relative browse path:

.NET

// Parses a relative OPC-UA browse path and displays its elements.

using System;
using OpcLabs.EasyOpc.UA.Navigation;
using OpcLabs.EasyOpc.UA.Navigation.Parsing;

namespace UADocExamples._UABrowsePathParser
{
    class ParseRelative
    {
        public static void Main1()
        {
            var browsePathParser = new UABrowsePathParser();
            UABrowsePathElementCollection browsePathElements;
            try
            {
                browsePathElements = browsePathParser.ParseRelative("/Data.Dynamic.Scalar.CycleComplete");
            }
            catch (UABrowsePathFormatException browsePathFormatException)
            {
                Console.WriteLine("*** Failure: {0}", browsePathFormatException.GetBaseException().Message);
                return;
            }

            // Display results
            foreach (UABrowsePathElement browsePathElement in browsePathElements)
                Console.WriteLine(browsePathElement);

            // Example output:
            // /Data
            // .Dynamic
            // .Scalar
            // .CycleComplete        
        }
    }
}

# Parses a relative OPC-UA browse path and displays its elements.

# 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.Navigation import *
from OpcLabs.EasyOpc.UA.Navigation.Parsing import *


browsePathParser = UABrowsePathParser()
try:
    browsePathElements = browsePathParser.ParseRelative('/Data.Dynamic.Scalar.CycleComplete')
except UABrowsePathFormatException as browsePathFormatException:
    print('*** Failure: ' + browsePathFormatException.GetBaseException().Message)
    exit()

# Display results.
for browsePathElement in browsePathElements:
    print(browsePathElement)

print()
print('Finished.')

' Parses a relative OPC-UA browse path and displays its elements.

Imports OpcLabs.EasyOpc.UA.Navigation
Imports OpcLabs.EasyOpc.UA.Navigation.Parsing

Namespace _UABrowsePathParser
    Friend Class ParseRelative
        Public Shared Sub Main1()
            Dim browsePathParser = New UABrowsePathParser()
            Dim browsePathElements As UABrowsePathElementCollection
            Try
                browsePathElements = browsePathParser.ParseRelative("/Data.Dynamic.Scalar.CycleComplete")
            Catch browsePathFormatException As UABrowsePathFormatException
                Console.WriteLine("*** Failure: {0}", browsePathFormatException.GetBaseException.Message)
                Exit Sub
            End Try

            ' Display results
            For Each browsePathElement As UABrowsePathElement In browsePathElements
                Console.WriteLine(browsePathElement)
            Next browsePathElement

            ' Example output:
            ' /Data
            ' .Dynamic
            ' .Scalar
            ' .CycleComplete
        End Sub
    End Class
End Namespace

COM

// Parses a relative OPC-UA browse path and displays its elements.

class procedure ParseRelative.Main;
var
  BrowsePathElement: _UABrowsePathElement;
  BrowsePathElements: _UABrowsePathElementCollection;
  BrowsePathParser: OpcLabs_EasyOpcUA_TLB._UABrowsePathParser;
  Count: Cardinal;
  Element: OleVariant;
  ElementEnumerator: IEnumVariant;
begin
  BrowsePathParser := CoUABrowsePathParser.Create;

  try
    BrowsePathElements := BrowsePathParser.ParseRelative('/Data.Dynamic.Scalar.CycleComplete');
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

  // Display results
  ElementEnumerator := BrowsePathElements.GetEnumerator;
  while (ElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    BrowsePathElement := IUnknown(Element) as _UABrowsePathElement;
    WriteLn(BrowsePathElement.ToString);
  end;

  // Example output:
  // /Data
  // .Dynamic
  // .Scalar
  // .CycleComplete

end;

// Parses a relative OPC-UA browse path and displays its elements.


$BrowsePathParser = new COM("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser");

try
{
    $BrowsePathElements = $BrowsePathParser->ParseRelative("/Data.Dynamic.Scalar.CycleComplete");
}
catch (com_exception $e)
{
    printf("*** Failure: %s\n", $e->getMessage());
    exit();
}

// Display results
for ($i = 0; $i < $BrowsePathElements->Count; $i++)
{
    printf("%s\n", $BrowsePathElements[$i]);
}

// Example output:
// /Data
// .Dynamic
// .Scalar
// .CycleComplete

Rem Parses a relative OPC-UA browse path and displays its elements.

Private Sub ParseRelative_Main_Command_Click()
    OutputText = ""
    Dim BrowsePathParser As New UABrowsePathParser

    On Error Resume Next
    Dim BrowsePathElements As UABrowsePathElementCollection
    Set BrowsePathElements = BrowsePathParser.ParseRelative("/Data.Dynamic.Scalar.CycleComplete")
    If Err.Number <> 0 Then
        OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
        Exit Sub
    End If
    On Error GoTo 0
    
    ' Display results
    Dim BrowsePathElement: For Each BrowsePathElement In BrowsePathElements
        OutputText = OutputText & BrowsePathElement & vbCrLf
    Next

    ' Example output:
    '/Data
    '.Dynamic
    '.Scalar
    '.CycleComplete
End Sub

Rem Parses a relative OPC-UA browse path and displays its elements.

Option Explicit

Dim BrowsePathParser: Set BrowsePathParser = CreateObject("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser")
On Error Resume Next
Dim BrowsePathElements: Set BrowsePathElements = BrowsePathParser.ParseRelative("/Data.Dynamic.Scalar.CycleComplete")
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

' Display results
Dim BrowsePathElement: For Each BrowsePathElement In BrowsePathElements
    WScript.Echo BrowsePathElement
Next

Attempting to parse a relative browse path:

.NET

// Attempts to parse a relative OPC-UA browse path and displays its elements.

using System;
using OpcLabs.BaseLib;
using OpcLabs.EasyOpc.UA.Navigation;
using OpcLabs.EasyOpc.UA.Navigation.Parsing;

namespace UADocExamples._UABrowsePathParser
{
    class TryParseRelative
    {
        public static void Main1()
        {
            var browsePathElements = new UABrowsePathElementCollection();

            var browsePathParser = new UABrowsePathParser();
            IStringParsingError stringParsingError = browsePathParser.TryParseRelative("/Data.Dynamic.Scalar.CycleComplete", browsePathElements);

            // Display results
            if (!(stringParsingError is null))
            {
                Console.WriteLine("*** Error: {0}", stringParsingError);
                return;
            }

            foreach (UABrowsePathElement browsePathElement in browsePathElements)
                Console.WriteLine(browsePathElement);

            // Example output:
            // /Data
            // .Dynamic
            // .Scalar
            // .CycleComplete        
        }
    }
}

# Attempts to parse a relative OPC-UA browse path and displays its elements.

# 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.Navigation import *
from OpcLabs.EasyOpc.UA.Navigation.Parsing import *


browsePathElements = UABrowsePathElementCollection()

browsePathParser = UABrowsePathParser()
stringParsingError = browsePathParser.TryParseRelative('/Data.Dynamic.Scalar.CycleComplete', browsePathElements)

# Display results.
if stringParsingError is not None:
    print('*** Error: ', stringParsingError, sep='')
    exit()

for browsePathElement in browsePathElements:
    print(browsePathElement)

print()
print('Finished.')

' Attempts to parse a relative OPC-UA browse path and displays its elements.

Imports System
Imports OpcLabs.BaseLib
Imports OpcLabs.EasyOpc.UA.Navigation
Imports OpcLabs.EasyOpc.UA.Navigation.Parsing

Namespace _UABrowsePathParser
    Friend Class TryParseRelative
        Public Shared Sub Main1()
            Dim browsePathElements = New UABrowsePathElementCollection()

            Dim browsePathParser = New UABrowsePathParser()
            Dim stringParsingError As IStringParsingError = browsePathParser.TryParseRelative("/Data.Dynamic.Scalar.CycleComplete", browsePathElements)

            ' Display results
            If Not stringParsingError Is Nothing Then
                Console.WriteLine("*** Error: {0}", stringParsingError)
                Exit Sub
            End If

            For Each browsePathElement As UABrowsePathElement In browsePathElements
                Console.WriteLine(browsePathElement)
            Next browsePathElement

            ' Example output:
            ' /Data
            ' .Dynamic
            ' .Scalar
            ' .CycleComplete
        End Sub
    End Class
End Namespace

COM

// Attempts to parse a relative OPC-UA browse path and displays its elements.

class procedure TryParseRelative.Main;
var
  BrowsePathElement: _UABrowsePathElement;
  BrowsePathElements: _UABrowsePathElementCollection;
  BrowsePathParser: OpcLabs_EasyOpcUA_TLB._UABrowsePathParser;
  Count: Cardinal;
  Element: OleVariant;
  ElementEnumerator: IEnumVariant;
  StringParsingError: _StringParsingError;
begin
  BrowsePathElements := CoUABrowsePathElementCollection.Create;

  BrowsePathParser := CoUABrowsePathParser.Create;
  StringParsingError := BrowsePathParser.TryParseRelative('/Data.Dynamic.Scalar.CycleComplete', BrowsePathElements);

  // Display results
  if StringParsingError <> nil then
  begin
    WriteLn('*** Error: ', StringParsingError.ToString);
    Exit;
  end;

  ElementEnumerator := BrowsePathElements.GetEnumerator;
  while (ElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    BrowsePathElement := IUnknown(Element) as _UABrowsePathElement;
    WriteLn(BrowsePathElement.ToString);
  end;

  // Example output:
  // /Data
  // .Dynamic
  // .Scalar
  // .CycleComplete

end;

// Attempts to parse a relative OPC-UA browse path and displays its elements.

$BrowsePathElements = new COM("OpcLabs.EasyOpc.UA.Navigation.UABrowsePathElementCollection");

$BrowsePathParser = new COM("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser");

$StringParsingError = $BrowsePathParser->TryParseRelative("/Data.Dynamic.Scalar.CycleComplete", $BrowsePathElements);

// Display results
if (!is_null($StringParsingError)) {
    printf("*** Error: %s\n", $StringParsingError);
    exit();
}

printf("StartingNodeId: %s\n", $BrowsePath->StartingNodeId);

printf("Elements:\n");

for ($i = 0; $i < $BrowsePathElements->Count; $i++)
{
    printf("%s\n", $BrowsePathElements[$i]);
}

// Example output:
// /Data
// .Dynamic
// .Scalar
// .CycleComplete

Rem Attempts to parse a relative OPC-UA browse path and displays its elements.

Private Sub TryParseRelative_Main_Command_Click()
    OutputText = ""
    
    Dim BrowsePathElements As New UABrowsePathElementCollection
    
    Dim BrowsePathParser As New UABrowsePathParser

    Dim stringParsingError As stringParsingError
    Set stringParsingError = BrowsePathParser.TryParseRelative("/Data.Dynamic.Scalar.CycleComplete", BrowsePathElements)
    
    ' Display results
    If Not stringParsingError Is Nothing Then
        OutputText = OutputText & "*** Error: " & stringParsingError & vbCrLf
        Exit Sub
    End If
    
    Dim BrowsePathElement: For Each BrowsePathElement In BrowsePathElements
        OutputText = OutputText & BrowsePathElement & vbCrLf
    Next

    ' Example output:
    '/Data
    '.Dynamic
    '.Scalar
    '.CycleComplete
End Sub

Rem Attempts to parse a relative OPC-UA browse path and displays its elements.

Option Explicit

Dim BrowsePathElements: Set BrowsePathElements = CreateObject("OpcLabs.EasyOpc.UA.Navigation.UABrowsePathElementCollection")

Dim BrowsePathParser: Set BrowsePathParser = CreateObject("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser")
Dim StringParsingError: Set StringParsingError = BrowsePathParser.TryParseRelative("/Data.Dynamic.Scalar.CycleComplete", BrowsePathElements)

' Display results
If Not (StringParsingError Is Nothing) Then
    WScript.Echo "*** Error: " & StringParsingError
    WScript.Quit
End If

Dim BrowsePathElement: For Each BrowsePathElement In BrowsePathElements
    WScript.Echo BrowsePathElement
Next

Examples - OPC Unified Architecture

Examples - OPC Unified Architecture - Read nodes specified by browse paths