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.

integer li_rc
integer li_Success
oleobject loo_Ssh
oleobject loo_SaPrompts
string ls_Hostname
integer li_Port
string ls_Password
integer li_ChannelNum
string ls_TermType
integer li_WidthInChars
integer li_HeightInChars
integer li_PixWidth
integer li_PixHeight
integer li_CaseSensitive
string ls_CmdOutput

li_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.

loo_Ssh = create oleobject
li_rc = loo_Ssh.ConnectToNewObject("Chilkat.Ssh")
if li_rc < 0 then
    destroy loo_Ssh
    MessageBox("Error","Connecting to COM object failed")
    return
end if

//  The remote shell prompt may be any of these, depending on the device.
loo_SaPrompts = create oleobject
li_rc = loo_SaPrompts.ConnectToNewObject("Chilkat.StringArray")

loo_SaPrompts.Append("~~$")
loo_SaPrompts.Append("mars#")
loo_SaPrompts.Append("jupiter%")
loo_SaPrompts.Append("chilkat$")
loo_SaPrompts.Append("admin>")

ls_Hostname = "ssh.example.com"
li_Port = 22
li_Success = loo_Ssh.Connect(ls_Hostname,li_Port)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
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.
ls_Password = "mySshPassword"

li_Success = loo_Ssh.AuthenticatePw("mySshLogin",ls_Password)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

li_ChannelNum = loo_Ssh.OpenSessionChannel()
if li_ChannelNum < 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
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.
ls_TermType = "dumb"
li_WidthInChars = 120
li_HeightInChars = 40
li_PixWidth = 0
li_PixHeight = 0
li_Success = loo_Ssh.SendReqPty(li_ChannelNum,ls_TermType,li_WidthInChars,li_HeightInChars,li_PixWidth,li_PixHeight)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

li_Success = loo_Ssh.SendReqShell(li_ChannelNum)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
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.
loo_Ssh.ReadTimeoutMs = 15000

li_CaseSensitive = 1

//  Read the initial login text up to the first prompt.
li_Success = loo_Ssh.ChannelReceiveUntilMatchN(li_ChannelNum,loo_SaPrompts,"utf-8",li_CaseSensitive)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

ls_CmdOutput = loo_Ssh.GetReceivedText(li_ChannelNum,"utf-8")
if loo_Ssh.LastMethodSuccess = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

Write-Debug ls_CmdOutput

//  ---- 1st command ----
li_Success = loo_Ssh.ChannelSendString(li_ChannelNum,"cd /tmp~n","utf-8")
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

li_Success = loo_Ssh.ChannelReceiveUntilMatchN(li_ChannelNum,loo_SaPrompts,"utf-8",li_CaseSensitive)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
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.
ls_CmdOutput = loo_Ssh.GetReceivedText(li_ChannelNum,"utf-8")
if loo_Ssh.LastMethodSuccess = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

Write-Debug ls_CmdOutput

//  ---- 2nd command ----
li_Success = loo_Ssh.ChannelSendString(li_ChannelNum,"ls~n","utf-8")
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

li_Success = loo_Ssh.ChannelReceiveUntilMatchN(li_ChannelNum,loo_SaPrompts,"utf-8",li_CaseSensitive)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

ls_CmdOutput = loo_Ssh.GetReceivedText(li_ChannelNum,"utf-8")
if loo_Ssh.LastMethodSuccess = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

Write-Debug ls_CmdOutput

//  Finish the session.
li_Success = loo_Ssh.ChannelSendEof(li_ChannelNum)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

li_Success = loo_Ssh.ChannelReceiveToClose(li_ChannelNum)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

ls_CmdOutput = loo_Ssh.GetReceivedText(li_ChannelNum,"utf-8")
if loo_Ssh.LastMethodSuccess = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    destroy loo_SaPrompts
    return
end if

Write-Debug ls_CmdOutput

loo_Ssh.Disconnect()


destroy loo_Ssh
destroy loo_SaPrompts