DeleteDirectory(IEasyUAFileTransfer,UAEndpointDescriptor,UANodeDescriptor,String) Method

Deletes an existing OPC UA directory.

Syntax

[Extension()]
public static void DeleteDirectory( 
   IEasyUAFileTransfer fileTransfer,
   UAEndpointDescriptor endpointDescriptor,
   UANodeDescriptor directoryNodeDescriptor,
   string existingDirectoryName
)

[Extension()]
public:
static void DeleteDirectory( 
   IEasyUAFileTransfer^ fileTransfer,
   UAEndpointDescriptor^ endpointDescriptor,
   UANodeDescriptor^ directoryNodeDescriptor,
   String^ existingDirectoryName
)

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Sub DeleteDirectory( _
   ByVal fileTransfer As IEasyUAFileTransfer, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal directoryNodeDescriptor As UANodeDescriptor, _
   ByVal existingDirectoryName As String _
)

'Usage
 
Dim fileTransfer As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim directoryNodeDescriptor As UANodeDescriptor
Dim existingDirectoryName As String
 
IEasyUAFileTransferExtension.DeleteDirectory(fileTransfer, endpointDescriptor, directoryNodeDescriptor, existingDirectoryName)

Parameters

fileTransfer: The OPC UA file transfer object that will perform the operation.
endpointDescriptor: Endpoint descriptor. Identifies the OPC-UA server.
directoryNodeDescriptor: Node descriptor of the OPC UA directory.
existingDirectoryName: A name of the OPC UA directory to delete.

Exceptions

Exception Description

Exception	Description
System.ArgumentNullException	A `null` reference (`Nothing` in Visual Basic) is passed to a method that does not accept it as a valid argument. This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.
OpcLabs.EasyOpc.UA.OperationModel.UAException	The OPC UA operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause. This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

System.ArgumentNullException

A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

OpcLabs.EasyOpc.UA.OperationModel.UAException

The OPC UA operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause.

This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

Remarks

The directoryNodeDescriptor must be an existing node in the server, of object type OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAObjectTypeIds.FileDirectoryType.

The directoryNodeDescriptor is a parent directory of the directory to be deleted.

This method throws a OpcLabs.EasyOpc.UA.OperationModel.UAException exception if the directory does not exist.

Recommendation: Whenever possible, do not use this method directly, and use a higher-level abstraction instead. See e.g. the GetWritableDirectoryContents(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) method, which allows you to obtain an object that can be used to manage directories, in a way that is generic and not tied to OPC UA specifics.

Example

.NET

// Shows how to create and delete OPC UA directories, using the file transfer client.
// Note: Consider using a higher-level abstraction, OPC UA file provider, instead.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.AddressSpace;
using OpcLabs.EasyOpc.UA.Extensions;
using OpcLabs.EasyOpc.UA.FileTransfer;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples.FileTransfer._EasyUAFileTransferClient
{
    class CreateDirectoryAndDelete
    {
        public static void Main1()
        {
            // Unified Automation .NET based demo server (UaNETServer/UaServerNET.exe)
            var endpointDescriptor = new UAEndpointDescriptor("opc.tcp://localhost:48030")
                .WithUserNameIdentity("john", "master");

            // An object that aggregates an OPC UA file system.
            UANodeDescriptor objectDescriptor = "nsu=http://www.unifiedautomation.com/DemoServer/ ;s=Demo.Files";

            // Create a random number generator - will be used for file/directory names.
            var random = new Random();
            
            // Instantiate the file transfer client object
            var fileTransferClient = new EasyUAFileTransferClient();

            // Create two directories, and one nested directory, and delete the first one.
            try
            {
                // The file system node is a root directory of the file system.
                Console.WriteLine("Getting file system...");
                UANodeDescriptor fileSystemNodeDescriptor = fileTransferClient.GetFileSystem(endpointDescriptor, objectDescriptor);

                string directoryName1 = "MyDirectory1-" + random.Next();
                Console.WriteLine($"Creating first directory, '{directoryName1}'...");
                UANodeId directoryNodeId1 = fileTransferClient.CreateDirectory(endpointDescriptor, fileSystemNodeDescriptor, directoryName1);
                Console.WriteLine($"Node Id of the first directory: {directoryNodeId1}");

                string directoryName2 = "MyDirectory2-" + random.Next();
                Console.WriteLine($"Creating second directory, '{directoryName2}'...");
                UANodeId directoryNodeId2 = fileTransferClient.CreateDirectory(endpointDescriptor, fileSystemNodeDescriptor, directoryName2);
                Console.WriteLine($"Node Id of the second directory: {directoryNodeId2}");

                string nestedDirectoryName = "MyDirectory3-" + random.Next();
                Console.WriteLine($"Creating nested directory, '{nestedDirectoryName}'...");
                // Note how directoryNodeId2 (a parent directory) is passed as the 2nd argument to the CreateDirectory method.
                UANodeId nestedDirectoryNodeId = fileTransferClient.CreateDirectory(endpointDescriptor, directoryNodeId2, nestedDirectoryName);
                Console.WriteLine($"Node Id of the nested directory: {nestedDirectoryNodeId}");

                // At this moment, the directory structure we have created looks like this:
                // * MyDirectory1
                // * MyDirectory2
                // * * MyDirectory3

                Console.WriteLine("Deleting the first directory...");
                fileTransferClient.DeleteDirectory(endpointDescriptor, fileSystemNodeDescriptor, directoryName1);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            Console.WriteLine("Finished...");
        }
    }
}

# Shows how to create and delete OPC UA directories, using the file transfer client.
# Note: Consider using a higher-level abstraction, OPC UA file provider, instead.
#
# 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 random

# Import .NET namespaces.
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.Extensions import *
from OpcLabs.EasyOpc.UA.FileTransfer import *
from OpcLabs.EasyOpc.UA.OperationModel import *


# Unified Automation .NET based demo server (UaNETServer/UaServerNET.exe).
endpointDescriptor = UAEndpointDescriptor('opc.tcp://localhost:48030')
endpointDescriptor = UAEndpointDescriptorExtension.WithUserNameIdentity(endpointDescriptor,'john', 'master')

# An object that aggregates an OPC UA file system.
objectDescriptor = UANodeDescriptor('nsu=http://www.unifiedautomation.com/DemoServer/ ;s=Demo.Files')

# Create a random number generator - will be used for file/directory names.
random = random.Random()

# Instantiate the file transfer client object.
fileTransferClient = EasyUAFileTransferClient()

# Prevent prompt to trust the server certificate (INSECURE, used just for smooth example flow).
EasyUAClient.SharedParameters.EngineParameters.CertificateAcceptancePolicy.TrustEndpointUrlString(
    endpointDescriptor.UrlString)

# Create two directories, and one nested directory, and delete the first one.
try:
    # The file system node is a root directory of the file system.
    print('Getting file system...')
    fileSystemNodeDescriptor = IEasyUAFileTransferExtension.GetFileSystem(fileTransferClient,
                                                                          endpointDescriptor, objectDescriptor)

    directoryName1 = 'MyDirectory1-' + str(random.randint(0, 999_999_999))
    print("Creating first directory, '", directoryName1, "'...", sep='')
    directoryNodeId1 = fileTransferClient.CreateDirectory(endpointDescriptor,
                                                          fileSystemNodeDescriptor,
                                                          directoryName1)
    print('Node Id of the first directory: ', directoryNodeId1, sep='')

    directoryName2 = 'MyDirectory2-' + str(random.randint(0, 999_999_999))
    print("Creating second directory, '", directoryName2, "'...", sep='')
    directoryNodeId2 = fileTransferClient.CreateDirectory(endpointDescriptor,
                                                          fileSystemNodeDescriptor,
                                                          directoryName2)
    print('Node Id of the second directory: ', directoryNodeId1, sep='')

    nestedDirectoryName = 'MyDirectory3-' + str(random.randint(0, 999_999_999))
    print("Creating nested directory, '", nestedDirectoryName, "'...", sep='')
    # Note how directoryNodeId2 (a parent directory) is passed as the 2nd argument to the CreateDirectory method.
    nestedDirectoryNodeId = fileTransferClient.CreateDirectory(endpointDescriptor,
                                                               UANodeDescriptor(directoryNodeId2),
                                                               nestedDirectoryName)
    print('Node Id of the nested directory: ', nestedDirectoryNodeId, sep='')

    # At this moment, the directory structure we have created looks like this:
    # * MyDirectory1
    # * MyDirectory2
    # * * MyDirectory3

    print('Deleting the first directory...')
    IEasyUAFileTransferExtension.DeleteDirectory(fileTransferClient,
                                                 endpointDescriptor, fileSystemNodeDescriptor, directoryName1)

except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

print()
print('Finished.')

' Shows how to create and delete OPC UA directories, using the file transfer client.
' Note: Consider using a higher-level abstraction, OPC UA file provider, instead.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.AddressSpace
Imports OpcLabs.EasyOpc.UA.Extensions
Imports OpcLabs.EasyOpc.UA.FileTransfer
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace FileTransfer._EasyUAFileTransferClient

    Friend Class CreateDirectoryAndDelete

        Public Shared Sub Main1()

            ' Unified Automation .NET based demo server (UaNETServer/UaServerNET.exe)
            Dim endpointDescriptor As UAEndpointDescriptor =
                New UAEndpointDescriptor("opc.tcp://localhost:48030") _
                .WithUserNameIdentity("john", "master")

            ' An object that aggregates an OPC UA file system.
            Dim objectDescriptor As UANodeDescriptor = "nsu=http://www.unifiedautomation.com/DemoServer/ ;s=Demo.Files"

            ' Create a random number generator - will be used for file/directory names.
            Dim random = New Random

            ' Instantiate the file transfer client object
            Dim fileTransferClient = New EasyUAFileTransferClient

            ' Create two directories, and one nested directory, and delete the first one.
            Try
                ' The file system node is a root directory of the file system.
                Console.WriteLine("Getting file system...")
                Dim fileSystemNodeDescriptor As UANodeDescriptor = fileTransferClient.GetFileSystem(endpointDescriptor, objectDescriptor)

                Dim directoryName1 As String = "MyDirectory1-" & random.Next()
                Console.WriteLine($"Creating first directory, '{directoryName1}'...")
                Dim directoryNodeId1 As UANodeId = fileTransferClient.CreateDirectory(endpointDescriptor, fileSystemNodeDescriptor, directoryName1)
                Console.WriteLine($"Node Id of the first directory: {directoryNodeId1}")

                Dim directoryName2 As String = "MyDirectory2-" & random.Next()
                Console.WriteLine($"Creating second directory, '{directoryName2}'...")
                Dim directoryNodeId2 As UANodeId = fileTransferClient.CreateDirectory(endpointDescriptor, fileSystemNodeDescriptor, directoryName2)
                Console.WriteLine($"Node Id of the second directory: {directoryNodeId2}")

                Dim nestedDirectoryName As String = "MyDirectory3-" & random.Next()
                Console.WriteLine($"Creating nested directory, '{nestedDirectoryName}'...")
                ' Note how directoryNodeId2 (a parent directory) Is passed as the 2nd argument to the CreateDirectory method.
                Dim nestedDirectoryNodeId As UANodeId = fileTransferClient.CreateDirectory(endpointDescriptor, directoryNodeId2, nestedDirectoryName)
                Console.WriteLine($"Node Id of the nested directory: {nestedDirectoryNodeId}")

                ' At this moment, the directory structure we have created looks Like this
                ' * MyDirectory1
                ' * MyDirectory2
                ' * * MyDirectory3

                Console.WriteLine("Deleting the first directory...")
                fileTransferClient.DeleteDirectory(endpointDescriptor, fileSystemNodeDescriptor, directoryName1)
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try

            Console.WriteLine("Finished...")
        End Sub
    End Class
End Namespace

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

Reference

IEasyUAFileTransferExtension Class
IEasyUAFileTransferExtension Members
Overload List
Delete Method

Send Documentation Feedback. Resources: Knowledge Base, Product Downloads. Technical support: Online Forums, FAQ.

Missing some example? Ask us for it on our Online Forums! You do not have to own a commercial license in order to use Online Forums, and we reply to every post.