Ruby

POP3 SSH Tunneling (Port Forwarding)

Demonstrates how to connect to a POP3 server through an SSH tunnel. Reads a POP3 mailbox and display the FROM and SUBJECT header fields of each email. Ruby

require 'chilkat'

success = false

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

# The mailman object is used for receiving (POP3) 
# and sending (SMTP) email.
mailman = Chilkat::CkMailMan.new()

# The SSH hostname may be a hostname or an 
# IP address, such as "192.168.1.108".
# The port is typically 22 (the standard port for SSH).
sshHostname = "sftp.example.com"
sshPort = 22

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

# Authenticate with the SSH server via a login/password
# or with a public key.
# This example demonstrates SSH password authentication.
# Note: This is not authenticating with the POP3 server, it is
# for authenticating with the SSH server, which is separate.
success = mailman.SshAuthenticatePw("ssh_login","ssh_password")
if (success == false)
    print mailman.lastErrorText() + "\n";
    exit
end

# OK, the SSH tunnel is setup.  The mailman may
# be used exactly the same as usual, except all communications
# are now sent through the SSH tunnel.

# The SSH tunnel may be kept open for any number of 
# POP3 connections.  

# Set the POP3 server's hostname
mailman.put_MailHost("mail.my-pop3-server.com")

# Set the POP3 settings for your POP3 server:
mailman.put_PopUsername("pop3_login")
mailman.put_PopPassword("pop3_password")
mailman.put_MailPort(995)
mailman.put_PopSsl(true)

# Connect to the POP3 server through the already-established SSH tunnel:
success = mailman.Pop3BeginSession()
if (success == false)
    print mailman.lastErrorText() + "\n";
    exit
end

# A visual inspection of the LastErrorText after
# a successful POP3 connection will confirm the SSH tunneling.
# Note: If the POP3 connection uses SSL/TLS, then the SSL/TLS 
# secure channel will be wrapped within the SSH tunnel.
print mailman.lastErrorText() + "\n";

# How many messages are in the POP3 inbox?
numToDownload = mailman.GetMailboxCount()
if (numToDownload > 5)
    numToDownload = 5
end

if (numToDownload == 0)
    print "No messages in the POP3 inbox." + "\n";
    exit
end

# Download a max of 5 messages

email = Chilkat::CkEmail.new()
for i in 1 .. numToDownload
    success = mailman.FetchOne(false,0,i,email)
    if (success == false)
        print mailman.lastErrorText() + "\n";
        exit
    end

    print email.ck_from() + "\n";
    print email.subject() + "\n";
    print "----" + "\n";
end

# Close the connection with the POP3 server, leaving the SSH tunnel open for subsequent POP3 connections.
success = mailman.Pop3EndSession()
if (success == false)
    print mailman.lastErrorText() + "\n";
    exit
end

# Try connecting to a different POP3 server through the same aleady setup SSH tunnel:
# Set the POP3 server's hostname
mailman.put_MailHost("mail.my-pop3-server2.com")

# Set the POP3 settings for your POP3 server:
mailman.put_PopUsername("pop3_login2")
mailman.put_PopPassword("pop3_password2")
mailman.put_MailPort(110)
mailman.put_PopSsl(false)

success = mailman.Pop3BeginSession()
if (success == false)
    print mailman.lastErrorText() + "\n";
    exit
end

# Review the LastErrorText to see that the connection was made via the SSH tunnel:
print mailman.lastErrorText() + "\n";

success = mailman.Pop3EndSession()
if (success == false)
    print mailman.lastErrorText() + "\n";
    exit
end

# Close the SSH tunnel.
success = mailman.SshCloseTunnel()
if (success == false)
    print mailman.lastErrorText() + "\n";
    exit
end