PowerBuilder
PowerBuilder
SSH Commands to a Cisco Switch
See more SSH Examples
Demonstrates establishing an SSH session with a Cisco switch (or similar device) and sending commands in a device console session. Each command is sent, and its output is read up to the device's next prompt.
Note: QuickShell allocates a PTY, which is what a network device console expects. The device presents an interactive prompt, and each command's output is read up to the next prompt.
Background: Network devices differ from general-purpose servers in that they expose a menu- or prompt-driven console rather than a Unix shell, so
exec requests are usually unavailable and driving the interactive console is the only option. That makes prompt matching the synchronization mechanism, and it is why a PTY is appropriate here despite the general advice to avoid one. Retrieving the received text between commands is essential: a prompt left in the buffer would make the next receive return immediately with the wrong output.Chilkat PowerBuilder Downloads
integer li_rc
integer li_Success
oleobject loo_Ssh
integer li_Port
string ls_Password
integer li_ChannelNum
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 establishing an SSH session with a Cisco switch (or similar device) and sending
// commands in a device console session.
//
// Note: QuickShell allocates a PTY, which is what a network device console expects. The device
// presents an interactive prompt, and each command's output is read up to the next prompt.
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
li_Port = 22
li_Success = loo_Ssh.Connect("172.16.16.100",li_Port)
if li_Success = 0 then
Write-Debug loo_Ssh.LastErrorText
destroy loo_Ssh
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
return
end if
// Start a shell session.
li_ChannelNum = loo_Ssh.QuickShell()
if li_ChannelNum < 0 then
Write-Debug loo_Ssh.LastErrorText
destroy loo_Ssh
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
// The switch presents a prompt ending in "#". Reading up to it confirms the session is ready.
li_Success = loo_Ssh.ChannelReceiveUntilMatch(li_ChannelNum,"#","utf-8",li_CaseSensitive)
if li_Success = 0 then
Write-Debug loo_Ssh.LastErrorText
destroy loo_Ssh
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
return
end if
Write-Debug ls_CmdOutput
// Send a command and read its output up to the next prompt.
li_Success = loo_Ssh.ChannelSendString(li_ChannelNum,"show clock~n","utf-8")
if li_Success = 0 then
Write-Debug loo_Ssh.LastErrorText
destroy loo_Ssh
return
end if
li_Success = loo_Ssh.ChannelReceiveUntilMatch(li_ChannelNum,"#","utf-8",li_CaseSensitive)
if li_Success = 0 then
Write-Debug loo_Ssh.LastErrorText
destroy loo_Ssh
return
end if
// Retrieving the text also clears the receive buffer, which matters: if the 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
return
end if
Write-Debug ls_CmdOutput
// Additional commands follow the same send / read-to-prompt / retrieve pattern.
li_Success = loo_Ssh.ChannelSendString(li_ChannelNum,"show version~n","utf-8")
if li_Success = 0 then
Write-Debug loo_Ssh.LastErrorText
destroy loo_Ssh
return
end if
li_Success = loo_Ssh.ChannelReceiveUntilMatch(li_ChannelNum,"#","utf-8",li_CaseSensitive)
if li_Success = 0 then
Write-Debug loo_Ssh.LastErrorText
destroy loo_Ssh
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
return
end if
Write-Debug ls_CmdOutput
loo_Ssh.Disconnect()
destroy loo_Ssh