Go

POP3 over Multiple Hop SSH

Demonstrates how to read POP3 email (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => POP3Server

Go

    success := false

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

    ssh1 := chilkat.NewSsh()

    // Connect directly to the 1st SSH server.
    success = ssh1.Connect("serverssh1.com",22)
    if success == false {
        fmt.Println(ssh1.LastErrorText())
        ssh1.DisposeSsh()
        return
    }

    // Authenticate using login/password:
    success = ssh1.AuthenticatePw("ssh1Login","ssh1Password")
    if success == false {
        fmt.Println(ssh1.LastErrorText())
        ssh1.DisposeSsh()
        return
    }

    // Connect through the 1st SSH connection to reach a 2nd SSH server.
    // Note: Any number of SSH connections may be simultaneously tunneled through a single
    // existing SSH connection.
    ssh2 := chilkat.NewSsh()
    success = ssh2.ConnectThroughSsh(ssh1,"serverssh2.com",22)
    if success == false {
        fmt.Println(ssh2.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        return
    }

    // Authenticate with ssh2...
    success = ssh2.AuthenticatePw("ssh2Login","ssh2Password")
    if success == false {
        fmt.Println(ssh2.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        return
    }

    mailman := chilkat.NewMailMan()

    // Tell the mailman object to connect to the POP3 server though the ssh2 tunnel (which itself is routed through ssh1).
    // The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => POP3Server
    success = mailman.UseSsh(ssh2)
    if success == false {
        fmt.Println(mailman.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        mailman.DisposeMailMan()
        return
    }

    // Set the POP3 server's hostname
    mailman.SetMailHost("pop.example.com")

    // Set the POP3 login/password.
    mailman.SetPopUsername("myLogin")
    mailman.SetPopPassword("myPassword")

    // Establish the POP3 connection through the ssh2 tunnel.
    success = mailman.Pop3BeginSession()
    if success == false {
        fmt.Println(mailman.LastErrorText())
        ssh1.DisposeSsh()
        ssh2.DisposeSsh()
        mailman.DisposeMailMan()
        return
    }

    // Get the number of messages in the mailbox.
    numMessages := mailman.GetMailboxCount()

    email := chilkat.NewEmail()
    i := 1
    for i <= numMessages {
        // Fetch by the message number (not by the UIDL)
        success = mailman.FetchOne(false,0,i,email)
        if success == false {
            fmt.Println(mailman.LastErrorText())
            ssh1.DisposeSsh()
            ssh2.DisposeSsh()
            mailman.DisposeMailMan()
            email.DisposeEmail()
            return
        }

        fmt.Println(email.From(), ": ", email.Subject(), "\n")

        i = i + 1
    }

    // Close the connection with the POP3 server.  (This closes the tunnel through ssh2)
    // The connection with ssh2 is still alive, and may be used for more connections.
    success = mailman.Pop3EndSession()

    // Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
    // The connection with ssh1 is still alive, and may be used for more connections.

    ssh2.Disconnect()

    ssh1.Disconnect()

    ssh1.DisposeSsh()
    ssh2.DisposeSsh()
    mailman.DisposeMailMan()
    email.DisposeEmail()