(Ruby) 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 Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

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

tunnel = Chilkat::CkSocket.new()

sshHostname = "www.my-ssh-server.com"
sshPort = 22

# Connect to an SSH server and establish the SSH tunnel:
success = tunnel.SshOpenTunnel(sshHostname,sshPort)
if (success != true)
    print tunnel.lastErrorText() + "\n";
    exit
end

# Authenticate with the SSH server via a login/password
# or with a public key.
# This example demonstrates SSH password authentication.
success = tunnel.SshAuthenticatePw("mySshLogin","mySshPassword")
if (success != true)
    print tunnel.lastErrorText() + "\n";
    exit
end

#  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)

maxWaitMs = 4000
useTls = true
# channel is a CkSocket
channel = tunnel.SshOpenChannel("imap.gmail.com",993,useTls,maxWaitMs)
if (tunnel.get_LastMethodSuccess() == false)
    print tunnel.lastErrorText() + "\n";
    exit
end

# If desired, visually inspect the LastErrorText to see that indeed the TLS
# protocol was run inside the SSH tunnel:
print tunnel.lastErrorText() + "\n";

# The first thing an IMAP server does is to send a greeting terminated with a CRLF.
imapGreeting = channel.receiveToCRLF()
if (channel.get_LastMethodSuccess() != true)
    print channel.lastErrorText() + "\n";

    exit
end

print imapGreeting + "\n";

# 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.
success = channel.Close(maxWaitMs)
if (success != true)
    print channel.lastErrorText() + "\n";
    exit
end

# Finally, close the SSH tunnel.
success = tunnel.SshCloseTunnel()
if (success != true)
    print tunnel.lastErrorText() + "\n";
    exit
end

print "TLS SSH tunneling example completed." + "\n";