VB.NET

Continue SFTP Keyboard-Interactive Authentication

Demonstrates the Chilkat SFtp.ContinueKeyboardAuth method, which submits a response to a keyboard-interactive prompt. The only argument is the response text; for a request with multiple prompts, an XML response is supplied instead. It returns XML indicating the next prompt or the final result.

Background: This is the second half of the exchange started by StartKeyboardAuth. A server may issue several rounds of prompts, so a robust client loops: submit answers, read the returned XML, and continue until it sees success or failure. On success, remember that InitializeSftp still must be called before any file operation.

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Dim success As Boolean = False

'  Demonstrates the SFtp.ContinueKeyboardAuth method, which submits a response to a
'  keyboard-interactive prompt.  The only argument is the response.  For multiple prompts, an
'  XML response is supplied instead.

Dim sftp As New Chilkat.SFtp

'  Step 1: Connect the SSH transport.  Port 22 is the usual port.
Dim port As Integer = 22
success = sftp.Connect("sftp.example.com",port)
If (success = False) Then
    Debug.WriteLine(sftp.LastErrorText)
    Exit Sub
End If


'  Begin keyboard-interactive authentication to receive the server's prompt(s).
Dim infoRequestXml As String = sftp.StartKeyboardAuth("mySshLogin")
If (sftp.LastMethodSuccess = False) Then
    Debug.WriteLine(sftp.LastErrorText)
    Exit Sub
End If


'  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.
Dim password As String = "mySshPassword"

'  Submit the response (typically the password).  The returned XML indicates the next prompt or
'  the final result.
Dim result As String = sftp.ContinueKeyboardAuth(password)
If (sftp.LastMethodSuccess = False) Then
    Debug.WriteLine(sftp.LastErrorText)
    Exit Sub
End If

Debug.WriteLine(result)

'  On success, initialize the SFTP subsystem.
success = sftp.InitializeSftp()
If (success = False) Then
    Debug.WriteLine(sftp.LastErrorText)
    Exit Sub
End If


sftp.Disconnect()