Returns the contents of a file in an abstract file provider as a byte array.
Syntax
Parameters
- fileInfo
- A file info that represents a file in the file provider.
Return Value
System.Byte array containing the contents of the file.
Exceptions
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.FileNotFoundException |
An attempt to access a file that does not exist on disk has failed.
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.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.NotSupportedException | An invoked method is not supported at all, or is not supported with the parameters used to create the object. |
System.Security.SecurityException |
A security error was detected.
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.UnauthorizedAccessException |
The operating system has denied access because of an I/O error or a specific type of security error.
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. |
Example
.NET
// Shows how to read the full contents of an OPC UA file at once, 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.Text;
using OpcLabs.BaseLib.Extensions.FileProviders;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.FileTransfer;
namespace UADocExamples.FileProviders._FileInfo2
{
class ReadAllBytes
{
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.
// Read in all contents from a specified file node.
byte[] bytes;
try
{
Console.WriteLine("Reading the whole file...");
bytes = fileInfo2.ReadAllBytes();
}
// Methods in the file provider model throw IOException and other exceptions, but not UAException.
catch (Exception exception)
{
Console.WriteLine($"*** Failure: {exception.GetBaseException().Message}");
return;
}
// Display result
Console.WriteLine();
// We know that the file contains text, so we convert the received data to a string. If the file contents was
// binary, you would process the data according to their format.
string text = Encoding.UTF8.GetString(bytes);
Console.WriteLine("File content:");
Console.WriteLine(text);
Console.WriteLine();
Console.WriteLine("Finished...");
}
}
}
# Shows how to read the full contents of an OPC UA file at once, 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.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.
# Read in all contents from a specified file node.
try:
print('Reading the whole file...')
bytes = IFileInfoExtension.ReadAllBytes(fileInfo2)
# Methods in the file provider model throw IOException and other exceptions, but not UAException.
except Exception as exception:
print('*** Failure: ' + exception.GetBaseException().Message)
exit()
# Display result.
print()
# We know that the file contains text, so we convert the received data to a string. If the file contents was
# binary, you would process the data according to their format.
text = Encoding.UTF8.GetString(bytes)
print('File content:')
print(text)
print()
print('Finished.')
' Shows how to read the full contents of an OPC UA file at once, using the file provider model.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Imports System.Text
Imports OpcLabs.BaseLib.Extensions.FileProviders
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.FileTransfer
Namespace FileProviders._FileInfo2
Friend Class ReadAllBytes
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.
' Read in all contents from a specified file node.
Dim bytes As Byte()
Try
Console.WriteLine("Reading the whole file...")
bytes = fileInfo2.ReadAllBytes()
' 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
' Display result
Console.WriteLine()
' We know that the file contains text, so we convert the received data to a string. If the file contents was
' binary, you would process the data according to their format.
Dim text As String = Encoding.UTF8.GetString(bytes)
Console.WriteLine("File content:")
Console.WriteLine(text)
Console.WriteLine()
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
See Also