The example below shows how to read different sections from an OPC UA file stream.
// Shows how to read different sections from an OPC UA file stream. // 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 OpcLabs.EasyOpc.UA; using OpcLabs.EasyOpc.UA.FileTransfer; using OpcLabs.EasyOpc.UA.IO.Extensions; namespace UADocExamples.FileTransfer._UAFileStream { 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(); try { // Get a stream object that corresponds to an OPC UA file. Console.WriteLine("Opening the file for reading..."); using (Stream stream = fileTransferClient.OpenStream(endpointDescriptor, fileNodeDescriptor)) { // The OPC UA file stream object behaves like any other stream in .NET. 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)}"); } } // OPC UA errors encountered during opening of a UA file stream and operations on such stream are transformed // to IOException-s. catch (IOException ioException) { Console.WriteLine("*** Failure: {0}", ioException.GetBaseException().Message); return; } Console.WriteLine(); Console.WriteLine("Finished..."); } } }
' Shows how to read different sections from an OPC UA file stream. ' 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 OpcLabs.EasyOpc.UA Imports OpcLabs.EasyOpc.UA.FileTransfer Imports OpcLabs.EasyOpc.UA.IO.Extensions Namespace FileTransfer._UAFileStream 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 Try ' Get a stream object that corresponds to an OPC UA file. Console.WriteLine("Opening the file for reading...") Using stream As Stream = fileTransferClient.OpenStream(endpointDescriptor, fileNodeDescriptor) ' Get a stream object that corresponds to an OPC UA file. 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 ' OPC UA errors encountered during opening of an UA file stream And operations on such stream are transformed ' to IOException-s. 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 read different sections from an OPC UA file stream. # 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 import * from System.IO import * from OpcLabs.EasyOpc.UA 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') # 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() stream = None try: # Get a stream object that corresponds to an OPC UA file. print('Opening the file for reading...') stream = IEasyUAFileTransferExtension2.OpenStream(fileTransferClient, endpointDescriptor, UANamedNodeDescriptor(fileNodeDescriptor)) # The OPC UA file stream object behaves like any other stream in .NET. 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='') # OPC UA errors encountered during opening of a UA file stream and operations on such stream are transformed # to IOException-s. except IOException as ioException: print('*** Failure: ' + ioException.GetBaseException().Message) exit() finally: stream and stream.Dispose() print() print('Finished.')
Copyright © 2004-2024 CODE Consulting and Development, s.r.o., Plzen. All rights reserved. Web page: www.opclabs.com
Documentation Home, Send 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.