Examples - OPC UA File Providers - Browse for files and directories

The example below shows how to browse for OPC UA files and directories, using the file provider model.

// Shows how to browse for OPC UA files and directories, using the file provider model.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using OpcLabs.BaseLib.Extensions.FileProviders;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.Extensions;
using OpcLabs.EasyOpc.UA.FileTransfer;

namespace UADocExamples.FileProviders._DirectoryContents2
{
    class Enumerate
    {
        public static void Main1()
        {
            // Unified Automation .NET based demo server (UaNETServer/UaServerNET.exe)
            var endpointDescriptor = new UAEndpointDescriptor("opc.tcp://localhost:48030")
                .WithUserNameIdentity("john", "master");

            // A node that represents an OPC UA file system (a root directory).
            UANodeDescriptor fileSystemNodeDescriptor = "nsu=http://www.unifiedautomation.com/DemoServer/ ;s=Demo.Files.FileSystem";

            // 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();

            Console.WriteLine("Getting writable file provider...");
            IWritableFileProvider writableFileProvider =
                fileTransferClient.GetWritableFileProvider(endpointDescriptor, fileSystemNodeDescriptor);
            // From this point onwards, the code is independent of the concrete realization of the file provider, and would
            // be identical e.g. for files in the physical file system, if the corresponding file provider was used.

            // Create two files, and then browse the directory that contains them.
            try
            {
                string fileName1 = "MyFile1-" + random.Next();
                Console.WriteLine($"Creating first file, '{fileName1}'...");
                IWritableFileInfo writableFileInfo1 = writableFileProvider.GetWritableFileInfo(fileName1);
                writableFileInfo1.WriteAllBytes(Array.Empty<byte>());

                string fileName2 = "MyFile2-" + random.Next();
                Console.WriteLine($"Creating second file, '{fileName2}'...");
                IWritableFileInfo writableFileInfo2 = writableFileProvider.GetWritableFileInfo(fileName2);
                writableFileInfo2.WriteAllBytes(Array.Empty<byte>());

                Console.WriteLine("Browsing for files...");
                IDirectoryContents2 directoryContents2 = writableFileProvider.GetDirectoryContents2(null);
                foreach (IFileInfo2 fileInfo2 in directoryContents2)
                    Console.WriteLine(fileInfo2);
                // You can distinguish between files and directories using the IFileInfo.IsDirectory property.
            }
            // Methods in the file provider model throw IOException and other exceptions, but not UAException.
            catch (Exception exception)
            {
                Console.WriteLine($"*** Failure: {exception.GetBaseException().Message}");
                return;
            }

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

# Shows how to browse for OPC UA files and directories, using the file provider model.
#
# 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 System import *
from OpcLabs.BaseLib.Extensions.FileProviders import *
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.Extensions import *
from OpcLabs.EasyOpc.UA.FileTransfer 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 OPC UA file system (a root directory).
fileSystemNodeDescriptor = UANodeDescriptor('nsu=http://www.unifiedautomation.com/DemoServer/ ;s=Demo.Files.FileSystem')

# 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)

print('Getting writable file provider...')
writableFileProvider = IEasyUAFileTransferExtension.GetWritableFileProvider(fileTransferClient,
                                                                            endpointDescriptor,
                                                                            fileSystemNodeDescriptor)
# From this point onwards, the code is independent of the concrete realization of the file provider, and would
# be identical e.g. for files in the physical file system, if the corresponding file provider was used.

# Create two files, and then browse the directory that contains them.
try:
    fileName1 = 'MyFile1-' + str(random.randint(0, 999_999_999))
    print("Creating first file, '", fileName1, "'...", sep='')
    writableFileInfo1 = writableFileProvider.GetWritableFileInfo(fileName1)
    IWritableFileInfoExtension.WriteAllBytes(writableFileInfo1, Array.Empty[Byte]())

    fileName2 = 'MyFile2-' + str(random.randint(0, 999_999_999))
    print("Creating second file, '", fileName2, "'...", sep='')
    writableFileInfo2 = writableFileProvider.GetWritableFileInfo(fileName2)
    IWritableFileInfoExtension.WriteAllBytes(writableFileInfo2, Array.Empty[Byte]())

    print('Browsing for files...')
    directoryContents2 = writableFileProvider.GetDirectoryContents2(None)
    for fileInfo2 in directoryContents2:
        print(fileInfo2)
    # You can distinguish between files and directories using the IFileInfo.IsDirectory property.

# Methods in the file provider model throw IOException and other exceptions, but not UAException.
except Exception as exception:
    print('*** Failure: ' + exception.GetBaseException().Message)
    exit()

print()
print('Finished.')

' Shows how to browse for OPC UA files and directories, using the file provider model.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Imports OpcLabs.BaseLib.Extensions.FileProviders
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.Extensions
Imports OpcLabs.EasyOpc.UA.FileTransfer

Namespace FileProviders._DirectoryContents2

    Friend Class Enumerate

        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")

            ' A node that represents an OPC UA file system (a root directory).
            Dim fileSystemNodeDescriptor As UANodeDescriptor =
                "nsu=http://www.unifiedautomation.com/DemoServer/ ;s=Demo.Files.FileSystem"

            ' 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

            Console.WriteLine("Getting writable file provider...")
            Dim writableFileProvider As IWritableFileProvider =
                fileTransferClient.GetWritableFileProvider(endpointDescriptor, fileSystemNodeDescriptor)
            ' From this point onwards, the code is independent of the concrete realization of the file provider, and would
            ' be identical e.g. for files in the physical file system, if the corresponding file provider was used.

            ' Create two files, and then browse the directory that contains them.
            Try
                Dim fileName1 As String = "MyFile1-" & random.Next()
                Console.WriteLine($"Creating first file, '{fileName1}'...")
                Dim writableFileInfo1 As IWritableFileInfo = writableFileProvider.GetWritableFileInfo(fileName1)
                writableFileInfo1.WriteAllBytes(Array.Empty(Of Byte))

                Dim fileName2 As String = "MyFile2-" & random.Next()
                Console.WriteLine($"Creating second file, '{fileName2}'...")
                Dim writableFileInfo2 As IWritableFileInfo = writableFileProvider.GetWritableFileInfo(fileName2)
                writableFileInfo2.WriteAllBytes(Array.Empty(Of Byte))

                Console.WriteLine("Browsing for files...")
                Dim directoryContents2 As IDirectoryContents2 = writableFileProvider.GetDirectoryContents2(Nothing)

                For Each fileInfo2 As IFileInfo2 In directoryContents2
                    Console.WriteLine(fileInfo2)
                Next fileInfo2
                ' You can distinguish between files and directories using the IFileInfo.IsDirectory property.

                ' Methods in the file provider model throw IOException and other exceptions, but not UAException.
            Catch exception As Exception
                Console.WriteLine("*** Failure: {0}", exception.GetBaseException.Message)
                Exit Sub
            End Try

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

Examples - OPC UA File Transfer

Examples - OPC UA File Transfer - Browse for files

Conceptual

File Provider Model in OPC UA