SSH Quick/Simple Shell Session

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Demonstrates the simplified way to run multiple commands in a shell session using QuickShell, which combines OpenSessionChannel, SendReqPty, and SendReqShell into one call. The commands are built in a StringBuilder, sent together, and the output is read up to a marker echoed by the final command.

Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  Demonstrates the simplified way to run multiple commands in a shell session using QuickShell.
'  
'  Note: QuickShell internally does OpenSessionChannel, SendReqPty, and SendReqShell, so it DOES
'  allocate a pseudo-terminal.  The remote shell therefore runs interactively: it prints a
'  command prompt and echoes back the commands that are sent to it.  Both the echoed input and
'  the real output appear in what is received.

Dim ssh As New Chilkat.Ssh

Dim port As Integer = 22
success = ssh.Connect("ssh.example.com",port)
If (success = False) Then
    Debug.WriteLine(ssh.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"

success = ssh.AuthenticatePw("mySshLogin",password)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  Start the shell session.  A negative return value indicates failure.
Dim channelNum As Integer = ssh.QuickShell()
If (channelNum < 0) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  Build the commands, one per line.  Line endings matter: Unix/Linux servers typically expect
'  a bare LF, while Windows servers may require CRLF.
Dim sbCommands As New Chilkat.StringBuilder
sbCommands.Append("echo hello world" & vbLf)
sbCommands.Append("date" & vbLf)
sbCommands.Append("df" & vbLf)

'  The final command echoes a marker used to detect the end of the output.  The single quotes
'  around 'IS' are a trick: the terminal echo of the typed command includes the quotes, while
'  the command's actual output does not.  Matching the unquoted form therefore matches the real
'  output rather than the echo.
sbCommands.Append("echo THIS 'IS' THE END OF THE SCRIPT" & vbLf)

Dim commands As String = sbCommands.GetAsString()
success = ssh.ChannelSendString(channelNum,commands,"utf-8")
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
'  which means no limit -- without it, this call waits forever if the received data never
'  contains a match.
ssh.ReadTimeoutMs = 15000

Dim caseSensitive As Boolean = True
success = ssh.ChannelReceiveUntilMatch(channelNum,"THIS IS THE END OF THE SCRIPT","utf-8",caseSensitive)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  Indicate that no more commands will be sent, then close the channel.  Close only after the
'  desired output has been received.
success = ssh.ChannelSendEof(channelNum)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


success = ssh.ChannelSendClose(channelNum)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  Collect any remaining output.
success = ssh.ChannelReceiveToClose(channelNum)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


Dim sessionOutput As String = ssh.GetReceivedText(channelNum,"utf-8")
If (ssh.LastMethodSuccess = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("--- output ----")
Debug.WriteLine(sessionOutput)

ssh.Disconnect()