// Shows how to read different sections from an OPC UA file, 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 System.IO;
using OpcLabs.BaseLib.Extensions.FileProviders;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.FileTransfer;
namespace UADocExamples.FileProviders._FileInfo2
{
class ReadAndSeek
{
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();
Console.WriteLine("Getting file info...");
IFileInfo2 fileInfo2 = fileTransferClient.GetFileInfo2(endpointDescriptor, fileNodeDescriptor);
// 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.
// Open the file, read two separate sections of it, and close it.
try
{
Console.WriteLine("Opening file...");
using (Stream stream = fileInfo2.CreateReadStream())
{
Console.WriteLine("Reading first section of a stream...");
var buffer1 = new byte[16];
int bytesRead1 = stream.Read(buffer1, 0, buffer1.Length);
Console.WriteLine($"{bytesRead1} bytes read, buffer: {BitConverter.ToString(buffer1)}");
Console.WriteLine("Reading second section of a stream...");
var buffer2 = new byte[10];
int bytesRead2 = stream.Read(buffer2, 0, buffer2.Length);
Console.WriteLine($"{bytesRead2} bytes read, buffer: {BitConverter.ToString(buffer2)}");
Console.WriteLine("Seeking...");
stream.Seek(100, SeekOrigin.Begin);
Console.WriteLine("Reading third section of a stream...");
var buffer3 = new byte[20];
int bytesRead3 = stream.Read(buffer3, 0, buffer3.Length);
Console.WriteLine($"{bytesRead3} bytes read, buffer: {BitConverter.ToString(buffer3)}");
}
}
// Methods in the file provider model throw IOException and other exceptions, but not UAException.
catch (Exception exception)
{
Console.WriteLine($"*** Failure: {exception.GetBaseException().Message}");
return;
}
Console.WriteLine("Finished...");
}
}
}
# Shows how to read different sections from an OPC UA file, 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 .NET namespaces.
from System import *
from System.IO import *
from System.Text import *
from OpcLabs.BaseLib.Extensions.FileProviders import *
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.FileTransfer import *
from OpcLabs.EasyOpc.UA.Navigation import *
# Unified Automation .NET based demo server (UaNETServer/UaServerNET.exe).
endpointDescriptor = UAEndpointDescriptor('opc.tcp://localhost:48030')
# 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()
print('Getting file info......')
fileInfo2 = IEasyUAFileTransferExtension.GetFileInfo2(fileTransferClient,
endpointDescriptor,
UANamedNodeDescriptor(fileNodeDescriptor))
# 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.
# Open the file, read two separate sections of it, and close it.
stream = None
try:
print('Opening file...')
stream = fileInfo2.CreateReadStream()
print('Reading first section of a stream...')
buffer1 = Array.CreateInstance(Byte, 16)
bytesRead1, _ = stream.Read(buffer1, 0, buffer1.Length)
print(bytesRead1, ' bytes read, buffer: ', BitConverter.ToString(buffer1), sep='')
print('Reading second section of a stream...')
buffer2 = Array.CreateInstance(Byte, 10)
bytesRead2, _ = stream.Read(buffer2, 0, buffer2.Length)
print(bytesRead2, ' bytes read, buffer: ', BitConverter.ToString(buffer2), sep='')
print('Seeking...')
stream.Seek(100, SeekOrigin.Begin)
print('Reading third section of a stream...')
buffer3 = Array.CreateInstance(Byte, 20)
bytesRead3, _ = stream.Read(buffer3, 0, buffer3.Length)
print(bytesRead3, ' bytes read, buffer: ', BitConverter.ToString(buffer3), sep='')
# Methods in the file provider model throw IOException and other exceptions, but not UAException.
except Exception as exception:
print('*** Failure: ' + exception.GetBaseException().Message)
exit()
finally:
stream and stream.Dispose()
print()
print('Finished.')
' Shows how to read different sections from an OPC UA file, using the file provider model.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Imports System.IO
Imports OpcLabs.BaseLib.Extensions.FileProviders
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.FileTransfer
Namespace FileProviders._FileInfo2
Friend Class ReadAndSeek
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
Console.WriteLine("Getting file info...")
Dim fileInfo2 As IFileInfo2 =
fileTransferClient.GetFileInfo2(endpointDescriptor, fileNodeDescriptor)
' 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.
' Open the file, read two separate sections of it, and close it.
Try
Console.WriteLine("Opening file...")
Using stream As Stream = fileInfo2.CreateReadStream()
Console.WriteLine("Reading first section of a stream...")
Dim buffer1(16 - 1) As Byte
Dim bytesRead1 As Integer = stream.Read(buffer1, 0, buffer1.Length)
Console.WriteLine($"{bytesRead1} bytes read, buffer: {BitConverter.ToString(buffer1)}")
Console.WriteLine("Reading second section of a stream...")
Dim buffer2(10 - 1) As Byte
Dim bytesRead2 As Integer = stream.Read(buffer2, 0, buffer2.Length)
Console.WriteLine($"{bytesRead2} bytes read, buffer: {BitConverter.ToString(buffer2)}")
Console.WriteLine("Seeking...")
stream.Seek(100, SeekOrigin.Begin)
Console.WriteLine("Reading third section of a stream...")
Dim buffer3(20 - 1) As Byte
Dim bytesRead3 As Integer = stream.Read(buffer3, 0, buffer3.Length)
Console.WriteLine($"{bytesRead3} bytes read, buffer: {BitConverter.ToString(buffer3)}")
End Using
' 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