VB.NET

Send an FTP NOOP (Keep-Alive)

Demonstrates the Chilkat Ftp2.Noop method, which sends the FTP NOOP command. It takes no arguments and succeeds only when the server returns a positive reply.

Background: NOOP asks the server to do nothing and simply reply, which makes it the standard keep-alive: sending one periodically resets the server's idle timer so a long-running job does not lose its control connection between transfers. Because it exercises a real request/reply round trip, a successful NOOP is also firmer evidence the connection is alive than CheckConnection.

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VB.NET

Dim success As Boolean = False

'  Demonstrates the Ftp2.Noop method, which sends the FTP NOOP command.  It takes no arguments.
'  The server must return a positive reply for the method to succeed.

Dim ftp As New Chilkat.Ftp2

ftp.Hostname = "ftp.example.com"
ftp.Username = "myFtpLogin"

'  Normally you would not hard-code the password in source.  You should instead obtain it
'  from an interactive prompt, environment variable, or a secrets vault.
ftp.Password = "myPassword"

'  Connect and log in (Connect performs both).
success = ftp.Connect()
If (success = False) Then
    Debug.WriteLine(ftp.LastErrorText)
    Exit Sub
End If


'  NOOP does nothing on the server, but a successful reply confirms the control connection is
'  still responsive -- useful as a keep-alive during an otherwise idle session.
success = ftp.Noop()
If (success = False) Then
    Debug.WriteLine(ftp.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("NOOP acknowledged by the server.")

success = ftp.Disconnect()
If (success = False) Then
    Debug.WriteLine(ftp.LastErrorText)
    Exit Sub
End If