Read Unix file from VB.Net?

[John Howard]

How can I read a text file that is on a UNIX server in VB.Net?

Please keep it simple.

Thanks,
John

 

[Herfried K. Wagner [MVP]]

How can I read a text file that is on a UNIX server in VB.Net?

What's the exact problem? Accessing the server? Provide more information
about the server and the connection to the server/network if you want to do
this. Or do you have problems to read the file using the right encoding?

 

[John Howard]

I don't know how to build the connection string. What provider should I
use? How do I build a data source when the file does not have a local drive
letter?

Thanks,
John

 

[Cor Ligthert]

John,

Because of your answer I thought that Herfried was again showing his
connection string message in the wrong place, however he asked you in my
opinion the right questions.

But in the first place is this not a VBNet question, more a networking
question.

You should make a drive accesable, and than you can do it with VBNet. Or you
should talk about by instance an Oracle (or whatever) database on Unix



Cor.

 

[John Howard]

My mistake. I was thinking about DB access instead of file access. Please
disregard my preveious reply.

I am attempting to access the UNIX file "xyz.txt" in directory "usercount"
on server "dev1". When I go to Windows Explorer and click on dev1,
"ftp://dev1/usercount/" appears on the address line. If I try to read file
"ftp://dev1/usercount/xyz.txt" in my program, I get "The given path's format
is not supported.". Any ideas?
Thanks again,
John

 

[Zeno Lee]

You need to understand what is going on when you put that ftp:// address in
Windows Explorer. It's not just "Accessing a file from UNIX". You are not
accessing a local or "mounted" file system.

In the background, Windows Explorer is using an FTP client to connect to
your server's FTP server, which means logging in, listing files, doing a GET
or PUT on the file, etc.

You need to build an FTP client that will go and fetch the document. It's
not a matter of simple file access.

 

[Lucas Tam]

If I try to read file
"ftp://dev1/usercount/xyz.txt" in my program, I get "The given path's
format is not supported.". Any ideas?

You need an FTP client to access the server.

http://www.xceedsoft.com/ has a good FTP component (not free though).

 

[Lucas Tam]

How can I read a text file that is on a UNIX server in VB.Net?

Depends on what method of access you have to the Unix server.

 

[Herfried K. Wagner [MVP]]

You need an FTP client to access the server.

http://www.xceedsoft.com/ has a good FTP component (not free though).

Accessing FTP servers in .NET applications
<URL:http://dotnet.mvps.org/dotnet/faqs/?id=ftp&lang=en>

 

[Tom Shelton]

How can I read a text file that is on a UNIX server in VB.Net?

Please keep it simple.

Thanks,
John

// SimpleFtp.cs
using System;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Text;

namespace FireAnt.Net.Ftp
{
[Flags()]
public enum AccessMode
{
Read = WinInet.GENERIC_READ,
Write = WinInet.GENERIC_WRITE,
}

public enum TransferMode
{
Ascii = WinInet.FTP_TRANSFER_TYPE_ASCII,
Binary = WinInet.FTP_TRANSFER_TYPE_BINARY,
}

/// <summary>
/// Summary description for SimpleFTP.
/// </summary>
public sealed class SimpleFtp : IDisposable
{
private IntPtr internet;
private IntPtr connection;
private IntPtr fileHandle;
private int context;

private const int BUFFER_SIZE = 2048;

public SimpleFtp(string host, string userName, string password)
{
internet = WinInet.InternetOpen(
null,
WinInet.INTERNET_OPEN_TYPE_DIRECT,
null,
null,
0);

if (internet == IntPtr.Zero)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}

connection = WinInet.InternetConnect(
this.internet,
host,
WinInet.INTERNET_DEFAULT_FTP_PORT,
userName,
password,
WinInet.INTERNET_SERVICE_FTP,
0,
ref this.context);

if (connection == IntPtr.Zero)
{
WinInet.InternetCloseHandle(this.internet);
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}

~SimpleFtp()
{
this.CleanUp();
}

void IDisposable.Dispose()
{
this.CleanUp();
GC.SuppressFinalize(this);
}

public string CurrentDirectory
{
get
{
StringBuilder path = new StringBuilder(260);
int bufferSize = path.Capacity;

if (!WinInet.FtpGetCurrentDirectory(this.connection,
path, ref bufferSize))
{
throw new
Win32Exception(Marshal.GetLastWin32Error());
}
return path.ToString();
}
set
{
if (!WinInet.FtpSetCurrentDirectory(this.connection,
value))
{
throw new
Win32Exception(Marshal.GetLastWin32Error());
}
}
}

public void Close()
{
((IDisposable)this).Dispose();
}

public void OpenFile(string fileName, AccessMode access,
TransferMode mode)
{
this.fileHandle = WinInet.FtpOpenFile(this.connection,
fileName, (int) access, (int) mode, out this.context);
if (this.fileHandle == IntPtr.Zero)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}

public void CloseFile()
{
if (this.fileHandle != IntPtr.Zero)
{
if (WinInet.InternetCloseHandle(this.fileHandle))
{
this.fileHandle = IntPtr.Zero;
}
else
{
throw new
Win32Exception(Marshal.GetLastWin32Error());
}
}
}

public int WriteFile(string buffer)
{
byte[] bytes = new ASCIIEncoding().GetBytes(buffer);
return this.WriteFile(bytes);
}

public int WriteFile(byte[] buffer)
{
int byteCount;
if (!WinInet.InternetWriteFile(this.fileHandle, buffer,
buffer.Length, out byteCount))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
return byteCount;
}

public bool ReadFile(out string buffer)
{
// clear the buffer...
buffer = string.Empty;

// read from the file
int bytesRead;
byte[] readBuffer = new byte[SimpleFtp.BUFFER_SIZE];
bool success = WinInet.InternetReadFile(this.fileHandle,
readBuffer, readBuffer.Length, out bytesRead);

// the call failed!
if (!success)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}

// we got some data, so convert it for the return...
if (bytesRead != 0)
{
buffer = Encoding.ASCII.GetString(readBuffer, 0,
bytesRead);
}

return (bytesRead != 0) ? true : false;
}

public bool ReadFile(byte[] buffer)
{
int bytesRead;
bool success = WinInet.InternetReadFile(this.fileHandle,
buffer, buffer.Length, out bytesRead);
if (!success)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
return (bytesRead != 0) ? true : false;
}

public void GetFile(string localFile, string remoteFile, bool
fail)
{
GetFile(localFile, remoteFile, TransferMode.Ascii, fail);
}

public void GetFile(string localFile, string remoteFile,
TransferMode mode, bool fail)
{
if(!WinInet.FtpGetFile(connection, remoteFile, localFile,
fail, 0, (int)mode, out context))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}

public void PutFile(string localFile, string remoteFile)
{
this.PutFile(localFile, remoteFile, TransferMode.Ascii);
}

public void PutFile(string localFile, string remoteFile,
TransferMode mode)
{
if (!WinInet.FtpPutFile(this.connection, localFile,
remoteFile, (int) mode, out this.context))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}

private void CleanUp()
{
if (this.fileHandle != IntPtr.Zero)
{
WinInet.InternetCloseHandle(this.fileHandle);
}

if (this.connection != IntPtr.Zero)
{
WinInet.InternetCloseHandle(this.connection);
}

if (this.internet != IntPtr.Zero)
{
WinInet.InternetCloseHandle(this.internet);
}
}
}
}

// Wininet.cs
using System;
using System.Text;
using System.Runtime.InteropServices;

namespace FireAnt.Net.Ftp
{
/// <summary>
/// Summary description for WinInet.
/// </summary>
internal sealed class WinInet
{
public const int INTERNET_OPEN_TYPE_PRECONFIG = 0;
public const int INTERNET_OPEN_TYPE_DIRECT = 1;
public const int INTERNET_OPEN_TYPE_PROXY = 3;
public const short INTERNET_DEFAULT_FTP_PORT = 21;
public const int INTERNET_SERVICE_FTP = 1;
public const int FTP_TRANSFER_TYPE_ASCII = 0x01;
public const int FTP_TRANSFER_TYPE_BINARY = 0x02;
public const int GENERIC_WRITE = 0x40000000;
public const int GENERIC_READ = unchecked((int)0x80000000);
public const int MAX_PATH = 260;

[DllImport("wininet.dll", CharSet=CharSet.Auto,
SetLastError=true)]
public static extern IntPtr InternetOpen(
string lpszAgent,
int dwAcessType,
string lpszProxyName,
string lpszProxyBypass,
int dwFlags);

[DllImport("wininet.dll", CharSet=CharSet.Auto,
SetLastError=true)]
public static extern IntPtr InternetConnect(
IntPtr hInternet,
string lpszServerName,
short nServerPort,
string lpszUserName,
string lpszPassword,
int dwService,
int dwFlags,
ref int dwContext);

[DllImport("wininet.dll", CharSet=CharSet.Auto,
SetLastError=true)]
public static extern bool FtpGetCurrentDirectory(
IntPtr hConnect,
StringBuilder lpszCurrentDirectory,
ref int lpdwCurrentDirectory);

[DllImport("wininet.dll", CharSet=CharSet.Auto,
SetLastError=true)]
public static extern bool FtpSetCurrentDirectory(
IntPtr hConnect,
string lpszCurrentDirectory);

[DllImport("wininet.dll", CharSet=CharSet.Auto,
SetLastError=true)]
public static extern IntPtr FtpOpenFile(
IntPtr hConnect,
string lpszFileName,
int dwAccess,
int dwFlags,
out int dwContext);

[DllImport("wininet.dll", SetLastError=true)]
public static extern bool InternetWriteFile(
IntPtr hFile,
[MarshalAs(UnmanagedType.LPArray)] byte[] lpBuffer,
int dwNumberOfBytesToWrite,
out int lpdwNumberOfBytesWritten);

[DllImport("wininet.dll", SetLastError=true)]
public static extern bool InternetReadFile(
IntPtr hFile,
[MarshalAs(UnmanagedType.LPArray)] byte[] lpBuffer,
int dwNumberOfBytesToRead,
out int lpdwNumberOfBytesRead
);

[DllImport("wininet.dll", CharSet=CharSet.Auto,
SetLastError=true)]
public static extern bool InternetCloseHandle(IntPtr hInternet);

[DllImport("wininet.dll", CharSet=CharSet.Auto,
SetLastError=true)]
public static extern bool FtpPutFile (
IntPtr hConnect,
string lpszLocalFile,
string lpszNewRemoteFile,
int dwFlags,
out int dwContext);

[DllImport("wininet.dll", CharSet=CharSet.Auto,
SetLastError=true)]
public static extern bool FtpGetFile (
IntPtr hConnect,
string lpszRemoteFile,
string lpszLocalFile,
bool failIfExists,
int dwFlagsAttributes,
int dwFlags,
out int dwContext);

private WinInet()
{
}
}
}

This is some code I wrote a while back, which I have used with great
success for exactly what your asking... I know it's C#, but if you
compile it into it's own dll, then you should be able to use it from
VB.NET...

Dim ftp As New SimpleFtp ("yourhost", "youruser", "yourpassword")
Dim buffer As String

ftp.OpenFile ("YourFile.Txt", AccessMode.Read, TransferMode.Ascii)

Do while (ftp.ReadFile (buffer))
' Do stuff with the buffer
loop

ftp.CloseFile ()
ftp.Close ()