DeleteFile(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) Method

Deletes an existing OPC UA file.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Sub DeleteFile( _
   ByVal fileTransfer As IEasyUAFileTransfer, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal existingFileNamedNodeDescriptor As UANamedNodeDescriptor _
)

'Usage
 
Dim fileTransfer As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim existingFileNamedNodeDescriptor As UANamedNodeDescriptor
 
IEasyUAFileTransferExtension.DeleteFile(fileTransfer, endpointDescriptor, existingFileNamedNodeDescriptor)

[Extension()]
public static void DeleteFile( 
   IEasyUAFileTransfer fileTransfer,
   UAEndpointDescriptor endpointDescriptor,
   UANamedNodeDescriptor existingFileNamedNodeDescriptor
)

[Extension()]
public:
static void DeleteFile( 
   IEasyUAFileTransfer^ fileTransfer,
   UAEndpointDescriptor^ endpointDescriptor,
   UANamedNodeDescriptor^ existingFileNamedNodeDescriptor
)

Parameters

fileTransfer: The OPC UA file transfer object that will perform the operation.
endpointDescriptor: Endpoint descriptor. Identifies the OPC-UA server.
existingFileNamedNodeDescriptor: The named node descriptor of the file 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 existingFileNamedNodeDescriptor must refer to an existing node in the server, of object type OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAObjectTypeIds.FileType.

This methods throws a OpcLabs.EasyOpc.UA.OperationModel.UAException exception if the file does not exist.

The existingFileNamedNodeDescriptor must refer to an existing node in the server, of object type OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAObjectTypeIds.FileType.

For this method to succeed, the existingFileNamedNodeDescriptor must contain the named node path and the node name.

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

Example

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

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 CreateFileAndDelete
    {
        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 files, 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 fileName1 = "MyFile1-" + random.Next();
                Console.WriteLine($"Creating first file, '{fileName1}'...");
                UANodeId fileNodeId1 = fileTransferClient.CreateFile(endpointDescriptor, fileSystemNodeDescriptor, fileName1);
                Console.WriteLine($"Node Id of the first file: {fileNodeId1}");

                string fileName2 = "MyFile2-" + random.Next();
                Console.WriteLine($"Creating second file, '{fileName2}'...");
                UANodeId fileNodeId2 = fileTransferClient.CreateFile(endpointDescriptor, fileSystemNodeDescriptor, fileName2);
                Console.WriteLine($"Node Id of the second file: {fileNodeId2}");

                Console.WriteLine("Deleting the first file...");
                fileTransferClient.DeleteFile(endpointDescriptor, fileSystemNodeDescriptor, fileName1);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

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

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

# 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 files, 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)

    fileName1 = 'MyFile1-' + str(random.randint(0, 999_999_999))
    print("Creating first file, '", fileName1, "'...", sep='')
    fileNodeId1 = IEasyUAFileTransferExtension.CreateFile(fileTransferClient,
                                                          endpointDescriptor, fileSystemNodeDescriptor, fileName1)
    print('Node Id of the first file: ', fileNodeId1, sep='')

    fileName2 = 'MyFile2-' + str(random.randint(0, 999_999_999))
    print("Creating second file, '", fileName2, "'...", sep='')
    fileNodeId2 = IEasyUAFileTransferExtension.CreateFile(fileTransferClient,
                                                          endpointDescriptor, fileSystemNodeDescriptor, fileName2)
    print('Node Id of the second file: ', fileNodeId2, sep='')

    print('Deleting the first file...')
    IEasyUAFileTransferExtension.DeleteFile(fileTransferClient,
                                            endpointDescriptor, fileSystemNodeDescriptor, fileName1)

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

print()
print('Finished.')

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

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 CreateFileAndDelete

        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 files, 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 fileName1 As String = "MyFile1-" & random.Next()
                Console.WriteLine($"Creating first file, '{fileName1}'...")
                Dim fileNodeId1 As UANodeId = fileTransferClient.CreateFile(endpointDescriptor, fileSystemNodeDescriptor, fileName1)
                Console.WriteLine($"Node Id of the first file: {fileNodeId1}")

                Dim fileName2 As String = "MyFile2-" & random.Next()
                Console.WriteLine($"Creating second file, '{fileName2}'...")
                Dim fileNodeId2 As UANodeId = fileTransferClient.CreateFile(endpointDescriptor, fileSystemNodeDescriptor, fileName2)
                Console.WriteLine($"Node Id of the second file: {fileNodeId2}")

                Console.WriteLine("Deleting the first file...")
                fileTransferClient.DeleteFile(endpointDescriptor, fileSystemNodeDescriptor, fileName1)
            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

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