WriteAllBytes(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor,Byte[]) Method

Writes binary data to an OPC UA file. Not appending.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Sub WriteAllBytes( _
   ByVal fileTransfer As IEasyUAFileTransfer, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal fileNamedNodeDescriptor As UANamedNodeDescriptor, _
   ByVal data() As Byte _
)

'Usage
 
Dim fileTransfer As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim fileNamedNodeDescriptor As UANamedNodeDescriptor
Dim data() As Byte
 
IEasyUAFileTransferExtension2.WriteAllBytes(fileTransfer, endpointDescriptor, fileNamedNodeDescriptor, data)

[Extension()]
public static void WriteAllBytes( 
   IEasyUAFileTransfer fileTransfer,
   UAEndpointDescriptor endpointDescriptor,
   UANamedNodeDescriptor fileNamedNodeDescriptor,
   byte[] data
)

[Extension()]
public:
static void WriteAllBytes( 
   IEasyUAFileTransfer^ fileTransfer,
   UAEndpointDescriptor^ endpointDescriptor,
   UANamedNodeDescriptor^ fileNamedNodeDescriptor,
   array<byte>^ data
)

Parameters

fileTransfer

The OPC UA file transfer object that will perform the operation.

This is typically the OpcLabs.EasyOpc.UA.FileTransfer.EasyUAFileTransferClient object.

The value of this parameter cannot be null (Nothing in Visual Basic).

endpointDescriptor

Endpoint descriptor. Identifies the OPC-UA server.

Because the OpcLabs.EasyOpc.UA.UAEndpointDescriptor has implicit conversions from System.String and System.Uri, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a string (representing the endpoint URL, or a so-called OPC UA endpoint descriptor string), or a System.Uri object, in place of this parameter, and the corresponding endpoint descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the OpcLabs.EasyOpc.UA.UAEndpointDescriptor.FromString or OpcLabs.EasyOpc.UA.UAEndpointDescriptor.FromUri static method instead.

If you are using OPC Wizard (for server development), an implicit conversion from OpcLabs.EasyOpc.UA.EasyUAServerCore can be used in the same way to simply pass the server object in place of this parameter, which will use its OpcLabs.EasyOpc.UA.EasyUAServerCore.EffectiveServerDescriptor property for the connection.

The value of this parameter cannot be null (Nothing in Visual Basic).

fileNamedNodeDescriptor

The named node descriptor of the file to which the data should be written.

Because the OpcLabs.EasyOpc.UA.Navigation.UANamedNodeDescriptor has an implicit conversion from OpcLabs.EasyOpc.UA.UANodeDescriptor, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a OpcLabs.EasyOpc.UA.UANodeDescriptor (containing the final node descriptor) in place of this parameter, and the corresponding OPC UA named node descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the OpcLabs.EasyOpc.UA.Navigation.UANamedNodeDescriptor.FromUANodeDescriptor static method instead.

The value of this parameter cannot be null (Nothing in Visual Basic).

data

Data to be written to the file.

The value of this parameter cannot be null (Nothing in Visual Basic).

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.
System.IO.IOException	An I/O error has occurred. 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.

System.IO.IOException

An I/O error has occurred.

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

If the OPC UA file does not already exist, the method creates it.

This method is similar to FileSystem.WriteAllBytes Method for normal (operating system) files.

CAUTION: This method does not throw the usual OpcLabs.EasyOpc.UA.OperationModel.UAException. Instead, an System.IO.IOException is thrown in case of an error during the operation.

This method overload overwrites the file contents (does not append to it).

For this method to succeed if it is creating a new file, the fileNamedNodeDescriptor must contain both the named node path (of the parent directory) in the OpcLabs.EasyOpc.UA.Navigation.UANamedNodeDescriptor.NamedNodePath property, and the node name (name of the file) in the OpcLabs.EasyOpc.UA.Navigation.UANamedNodeDescriptor.NodeName property. If this method is opening an existing stream, the file can also be specified using just the final node descriptor (node of the file object) in the OpcLabs.EasyOpc.UA.Navigation.UANamedNodeDescriptor.FinalNodeDescriptor property.

Note: This method opens a file, writes to it, and then closes it. Code that uses this method is simpler than code that uses a System.IO.BinaryWriter object with a System.IO.Stream. However, if you are adding data to a file using a loop, a System.IO.BinaryWriter object can provide better performance because you only have to open and close the file once.

See OPC UA File Transfer internals for information about Stream buffering.

Recommendation: Whenever possible, do not use this method directly, and use a higher-level abstraction instead. You can obtain a writable file provider (using GetWritableFileProvider), and make use of its methods, and methods available on the writable directory contents (obtained using OpcLabs.BaseLib.Extensions.FileProviders.IWritableDirectory.GetWritableDirectoryContents) or writable file info (obtained using OpcLabs.BaseLib.Extensions.FileProviders.IWritableDirectory.GetWritableFileInfo).

This is an extension method (info: C#, VB.NET). In languages that have support for extensions methods (such as C# and VB.NET), you can use the extension method as if it were a regular method on the object that is its first parameter. In other languages (such as with Python.NET), you will call the extension as a static method, and pass it the object on which it acts as its first parameter.

Example

CSharp
VB.NET
Python

// Shows how to write the full contents of an OPC UA file at once, 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 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 System.IO;
using System.Text;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.FileTransfer;
using OpcLabs.EasyOpc.UA.IO.Extensions;

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

            // A node that represents an instance of OPC UA FileType object.
            UANodeDescriptor fileNodeDescriptor = "nsu=http://www.unifiedautomation.com/DemoServer/ ;s=Demo.Files.TextFile";
            
            // Instantiate the file transfer client object
            var fileTransferClient = new EasyUAFileTransferClient();

            // Write all contents into a specified file node.
            byte[] bytes = Encoding.UTF8.GetBytes("TEXT FROM FILE TRANSFER CLIENT EXAMPLE. Demonstrates writing the whole contents of a file at once.");
            try
            {
                Console.WriteLine("Writing the whole file...");
                fileTransferClient.WriteAllBytes(endpointDescriptor, fileNodeDescriptor, bytes);

                // Due to an issue in the server, the file might not be readable now, without server restart.
                //Console.WriteLine("Reading the data back...");
                //byte[] data = fileTransferClient.ReadAllFileBytes(endpointDescriptor, fileNodeDescriptor);
                //Console.WriteLine(Encoding.UTF8.GetString(data));
            }
            // Beware that WriteAllFileBytes throws IOException and not UAException.
            catch (IOException ioException)
            {
                Console.WriteLine("*** Failure: {0}", ioException.GetBaseException().Message);
                return;
            }

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

' Shows how to write the full contents of an OPC UA file at once, 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 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 System.IO
Imports System.Text
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.FileTransfer
Imports OpcLabs.EasyOpc.UA.IO.Extensions

Namespace FileTransfer._EasyUAFileTransferClient

    Friend Class WriteAllBytes

        Public Shared Sub Main1()

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

            ' A node that represents an instance of OPC UA FileType object.
            Dim fileNodeDescriptor As UANodeDescriptor = "nsu=http://www.unifiedautomation.com/DemoServer/ ;s=Demo.Files.TextFile"

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

            ' Write all contents into a specified file node.
            Dim bytes As Byte() = Encoding.UTF8.GetBytes("TEXT FROM FILE TRANSFER CLIENT EXAMPLE. Demonstrates writing the whole contents of a file at once.")
            Try
                Console.WriteLine("Writing the whole file...")
                fileTransferClient.WriteAllBytes(endpointDescriptor, fileNodeDescriptor, bytes)

                ' Due to an issue in the server, the file might Not be readable now, without server restart.
                'Console.WriteLine("Reading the data back...")
                'Dim data As Byte() = fileTransferClient.ReadAllFileBytes(endpointDescriptor, fileNodeDescriptor)
                'Console.WriteLine(Encoding.UTF8.GetString(data))

                ' Beware that WriteAllFileBytes throws IOException And Not UAException.
            Catch ioException As IOException
                Console.WriteLine("*** Failure: {0}", ioException.GetBaseException.Message)
                Exit Sub
            End Try

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

# Shows how to write the full contents of an OPC UA file at once, 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 .
# 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 System.Text import *
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.Extensions import *
from OpcLabs.EasyOpc.UA.FileTransfer import *
from OpcLabs.EasyOpc.UA.IO.Extensions import *
from OpcLabs.EasyOpc.UA.Navigation import *


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

# A node that represents an instance of OPC UA FileType object.
fileNodeDescriptor = UANodeDescriptor('nsu=http://www.unifiedautomation.com/DemoServer/ ;s=Demo.Files.TextFile')

# 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)

# Write all contents into a specified file node.
bytes = Encoding.UTF8.GetBytes('TEXT FROM FILE TRANSFER CLIENT EXAMPLE. Demonstrates writing the whole contents of a '
                               'file at once.')
try:
    print('Writing the whole file...')
    IEasyUAFileTransferExtension2.WriteAllBytes(fileTransferClient,
                                                endpointDescriptor,
                                                UANamedNodeDescriptor(fileNodeDescriptor),
                                                bytes)

    # Due to an issue in the server, the file might not be readable now, without server restart.
    print('Reading the data back...')
    data = IEasyUAFileTransferExtension2.ReadAllBytes(fileTransferClient,
                                                       endpointDescriptor,
                                                       UANamedNodeDescriptor(fileNodeDescriptor))
    print(Encoding.UTF8.GetString(data))

# Beware that ReadAllFileBytes throws IOException and not UAException.
except IOException as ioException:
    print('*** Failure: ' + ioException.GetBaseException().Message)
    exit()

print()
print('Finished.')

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

IEasyUAFileTransferExtension2 Class
IEasyUAFileTransferExtension2 Members
Overload List
WriteAllBytes(IWritableFileInfo,Byte[]) Method
ReadAllBytes(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) Method

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