(Swift 3,4,5...) 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

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 POP3 server though the ssh2 tunnel (which itself is routed through ssh1).
    // The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => POP3Server
    success = mailman.use(ssh2)
    if success != true {
        print("\(mailman.lastErrorText!)")
        return
    }

    // Set the POP3 server's hostname
    mailman.mailHost = "pop.someMailServer.com"

    // Set the POP3 login/password.
    mailman.popUsername = "myLogin"
    mailman.popPassword = "myPassword"

    // Establish the POP3 connection through the ssh2 tunnel.
    success = mailman.pop3BeginSession()
    if success != true {
        print("\(mailman.lastErrorText!)")
        return
    }

    // Get the number of messages in the mailbox.
    var numMessages: Int = mailman.getMailboxCount().intValue

    var i: Int = 1

    var email: CkoEmail?
    while i <= numMessages {

        email = mailman.fetch(byMsgnum: i)
        if mailman.lastMethodSuccess != true {
            print("\(mailman.lastErrorText!)")
            return
        }

        print("\(email!.from!): \(email!.subject!)\n")
        email = nil

        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()

}