VB.NET

Check if the FTP Control Connection is Open

Demonstrates the Chilkat Ftp2.CheckConnection method, which returns whether Chilkat currently considers the FTP control connection to be open. It takes no arguments and does not require the session to be authenticated.

Background: This reports the object's view of the control-connection state, which is distinct from being logged in — it can return true after ConnectOnly and before authentication. For a stronger liveness check that the server is actually responding, send a Noop, which requires a positive reply. FTP servers commonly drop idle control connections after a timeout, so long-lived sessions should verify before assuming the connection is still usable.

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Dim success As Boolean = False

'  Demonstrates the Ftp2.CheckConnection method, which returns whether Chilkat currently considers
'  the FTP control connection to be open.  It takes no arguments and does not require the session
'  to be authenticated.

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


'  Check whether the control connection is still open.
If (ftp.CheckConnection()) Then
    Debug.WriteLine("The control connection is open.")
Else
    Debug.WriteLine("The control connection is not open.")
End If


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