(PowerBuilder) TLS Connection within SSH Tunnel (Port Forwarding)

Demonstrates using Chilkat Socket to communicate to a TLS service through an SSH tunnel. This example will connect (through a port-forwarded SSH tunnel) to the GMAIL IMAP server via TLS and will receive the greeting.

Note: The Chilkat IMAP API provides direct support for using SSH tunneling with the IMAP protocol. This example serves only to demonstrate that, in general, TLS connections can be tunneled through SSH.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

integer li_rc
oleobject loo_Tunnel
string ls_SshHostname
integer li_SshPort
integer li_Success
oleobject loo_Channel
integer li_MaxWaitMs
integer li_UseTls
string ls_ImapGreeting

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

loo_Tunnel = create oleobject
// Use "Chilkat_9_5_0.Socket" for versions of Chilkat < 10.0.0
li_rc = loo_Tunnel.ConnectToNewObject("Chilkat.Socket")
if li_rc < 0 then
    destroy loo_Tunnel
    MessageBox("Error","Connecting to COM object failed")
    return
end if

ls_SshHostname = "sftp.example.com"
li_SshPort = 22

// Connect to an SSH server and establish the SSH tunnel:
li_Success = loo_Tunnel.SshOpenTunnel(ls_SshHostname,li_SshPort)
if li_Success <> 1 then
    Write-Debug loo_Tunnel.LastErrorText
    destroy loo_Tunnel
    return
end if

// Authenticate with the SSH server via a login/password
// or with a public key.
// This example demonstrates SSH password authentication.
li_Success = loo_Tunnel.SshAuthenticatePw("mySshLogin","mySshPassword")
if li_Success <> 1 then
    Write-Debug loo_Tunnel.LastErrorText
    destroy loo_Tunnel
    return
end if

//  OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
//  Once the channel is obtained, the Socket API may
//  be used exactly the same as usual, except all communications
//  are sent through the channel in the SSH tunnel.
//  Any number of channels may be created from the same SSH tunnel.
//  Multiple channels may coexist at the same time.

// Connect to the GMAIL IMAP server via TLS (through the port-forwarded SSH tunnel)

li_MaxWaitMs = 4000
li_UseTls = 1
loo_Channel = loo_Tunnel.SshOpenChannel("imap.gmail.com",993,li_UseTls,li_MaxWaitMs)
if loo_Tunnel.LastMethodSuccess = 0 then
    Write-Debug loo_Tunnel.LastErrorText
    destroy loo_Tunnel
    return
end if

// If desired, visually inspect the LastErrorText to see that indeed the TLS
// protocol was run inside the SSH tunnel:
Write-Debug loo_Tunnel.LastErrorText

// The first thing an IMAP server does is to send a greeting terminated with a CRLF.
ls_ImapGreeting = loo_Channel.ReceiveToCRLF()
if loo_Channel.LastMethodSuccess <> 1 then
    Write-Debug loo_Channel.LastErrorText
    destroy loo_Channel
    destroy loo_Tunnel
    return
end if

Write-Debug ls_ImapGreeting

// Close the connection to imap.gmail.com.  This is actually closing our channel
// within the SSH tunnel, but keeps the tunnel open for the next port-forwarded connection.
li_Success = loo_Channel.Close(li_MaxWaitMs)
if li_Success <> 1 then
    Write-Debug loo_Channel.LastErrorText
    destroy loo_Tunnel
    return
end if

destroy loo_Channel

// Finally, close the SSH tunnel.
li_Success = loo_Tunnel.SshCloseTunnel()
if li_Success <> 1 then
    Write-Debug loo_Tunnel.LastErrorText
    destroy loo_Tunnel
    return
end if

Write-Debug "TLS SSH tunneling example completed."


destroy loo_Tunnel