(Swift 3,4,5...) SMTP over Multiple Hop SSH

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

Application => ServerSSH1 => ServerSSH2 => SmtpServer

The ConnectThroughSsh and UseSsh methods are added in Chilkat version 9.5.0.55 to accomplish this task.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

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

    let ssh1 = CkoSsh()!

    // Connect directly to the 1st SSH server.
    var success: Bool = ssh1.connect("serverssh1.com", port: 22)
    if success != true {
        print("\(ssh1.lastErrorText!)")
        return
    }

    // Authenticate using login/password:
    success = ssh1.authenticatePw("ssh1Login", password: "ssh1Password")
    if success != true {
        print("\(ssh1.lastErrorText!)")
        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.
    let ssh2 = CkoSsh()!
    success = ssh2.connectThroughSsh(ssh1, hostname: "serverssh2.com", port: 22)
    if success != true {
        print("\(ssh2.lastErrorText!)")
        return
    }

    // Authenticate with ssh2...
    success = ssh2.authenticatePw("ssh2Login", password: "ssh2Password")
    if success != true {
        print("\(ssh2.lastErrorText!)")
        return
    }

    let mailman = CkoMailMan()!

    // Tell the mailman object to connect to the SMTP server though the ssh2 tunnel (which itself is routed through ssh1).
    // The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => SMTPServer
    success = mailman.use(ssh2)
    if success != true {
        print("\(mailman.lastErrorText!)")
        return
    }

    // Set the SMTP server.
    mailman.smtpHost = "smtp.someserver.com"

    // Set the SMTP login/password (if required)
    mailman.smtpUsername = "myUsername"
    mailman.smtpPassword = "myPassword"

    // Create a new email object
    let email = CkoEmail()!

    email.subject = "This is a test"
    email.body = "This is a test"
    email.from = "Chilkat Support <support@chilkatsoft.com>"
    success = email.add(to: "Chilkat Admin", emailAddress: "admin@chilkatsoft.com")

    success = mailman.send(email)
    if success != true {
        print("\(mailman.lastErrorText!)")
        return
    }

    // Close the connection with the server.  This closes the tunnel through ssh2.
    success = mailman.closeSmtpConnection()
    if success != true {
        print("Connection to SMTP server not closed cleanly.")
    }

    print("Mail Sent!")

    // 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()

}