SSH ChannelReceiveUntilMatchN (Match Any of Several Prompts)

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Demonstrates ChannelReceiveUntilMatchN, which receives until any one of several patterns is matched. This is useful when driving an interactive session where the shell prompt differs from device to device.

Note: This example deliberately requests a PTY. Matching a shell prompt only works in an interactive session — without a PTY the shell runs non-interactively and never prints a prompt at all. For scripted use, omit the PTY and match on a marker your own command echoes.

Dim success As Long
success = 0

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

'  Demonstrates ChannelReceiveUntilMatchN, which receives until ANY one of several patterns is
'  matched.  This is useful when driving an interactive session where the shell prompt varies
'  from device to device.
'  
'  Note: This example deliberately DOES request a PTY.  Matching a shell prompt only works in an
'  interactive session -- without a PTY the shell runs non-interactively and never prints a
'  prompt at all.  For scripted use where no prompt is needed, omit the PTY and match on a
'  marker your own command echoes instead.

Dim ssh As New ChilkatSsh

'  The remote shell prompt may be any of these, depending on the device.
Dim saPrompts As New CkStringArray
success = saPrompts.Append("~$")
success = saPrompts.Append("mars#")
success = saPrompts.Append("jupiter%")
success = saPrompts.Append("chilkat$")
success = saPrompts.Append("admin>")

Dim hostname As String
hostname = "ssh.example.com"
Dim port As Long
port = 22
success = ssh.Connect(hostname,port)
If (success = 0) Then
    Debug.Print 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
password = "mySshPassword"

success = ssh.AuthenticatePw("mySshLogin",password)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Dim channelNum As Long
channelNum = ssh.OpenSessionChannel()
If (channelNum < 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

'  Request a pseudo-terminal so the shell runs interactively and prints prompts.  A "dumb"
'  terminal is used so that ANSI escape sequences are not mixed into the output.
Dim termType As String
termType = "dumb"
Dim widthInChars As Long
widthInChars = 120
Dim heightInChars As Long
heightInChars = 40
Dim pixWidth As Long
pixWidth = 0
Dim pixHeight As Long
pixHeight = 0
success = ssh.SendReqPty(channelNum,termType,widthInChars,heightInChars,pixWidth,pixHeight)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

success = ssh.SendReqShell(channelNum)
If (success = 0) Then
    Debug.Print 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 Long
caseSensitive = 1

'  Read the initial login text up to the first prompt.
success = ssh.ChannelReceiveUntilMatchN(channelNum,saPrompts,"utf-8",caseSensitive)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Dim cmdOutput As String
cmdOutput = ssh.GetReceivedText(channelNum,"utf-8")
If (ssh.LastMethodSuccess = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Debug.Print cmdOutput

'  ---- 1st command ----
success = ssh.ChannelSendString(channelNum,"cd /tmp" & vbLf,"utf-8")
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

success = ssh.ChannelReceiveUntilMatchN(channelNum,saPrompts,"utf-8",caseSensitive)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

'  Retrieving the text also clears the receive buffer, which matters: if a prompt were left
'  buffered, the next receive would match it immediately and return the wrong output.
cmdOutput = ssh.GetReceivedText(channelNum,"utf-8")
If (ssh.LastMethodSuccess = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Debug.Print cmdOutput

'  ---- 2nd command ----
success = ssh.ChannelSendString(channelNum,"ls" & vbLf,"utf-8")
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

success = ssh.ChannelReceiveUntilMatchN(channelNum,saPrompts,"utf-8",caseSensitive)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

cmdOutput = ssh.GetReceivedText(channelNum,"utf-8")
If (ssh.LastMethodSuccess = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Debug.Print cmdOutput

'  Finish the session.
success = ssh.ChannelSendEof(channelNum)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

success = ssh.ChannelReceiveToClose(channelNum)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

cmdOutput = ssh.GetReceivedText(channelNum,"utf-8")
If (ssh.LastMethodSuccess = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Debug.Print cmdOutput

ssh.Disconnect