Swift

IMAP Use Existing SSH Tunnel

Demonstrates how to connect to an IMAP server using an existing SSH tunnel. This creates a new channel within the SSH tunnel, which can be a TCP or TLS connection, and is connected to a remote IMAP server through port forwarding. Swift

func chilkatTest() {
    var success: Bool = false

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

    let tunnel = CkoSocket()!

    var sshHostname: String? = "sftp.example.com"
    var sshPort: Int = 22

    // Connect to an SSH server and establish the SSH tunnel:
    success = tunnel.sshOpenTunnel(sshHostname: sshHostname, sshPort: sshPort)
    if success == false {
        print("\(tunnel.lastErrorText!)")
        return
    }

    // 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 IMAP server, it is
    // for authenticating with the SSH server, which is separate.
    success = tunnel.sshAuthenticatePw(sshLogin: "mySshLogin", sshPassword: "mySshPassword")
    if success == false {
        print("\(tunnel.lastErrorText!)")
        return
    }

    // 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.

    let imap = CkoImap()!

    // Let the IMAP object also use the SSH tunnel
    success = imap.useSshTunnel(tunnel: tunnel)
    if success == false {
        print("\(imap.lastErrorText!)")
        return
    }

    // Connect to an IMAP server via the already established SSH tunnel.
    // Because the SSH tunnel has been previously setup,
    // this does not establish a direct connection with the IMAP
    // server.  It directs the SSH server to establish the connection.

    // In this example, the IMAP server requires SSL/TLS.  The TLS connection
    // will be enclosed within the SSH tunnel.
    imap.ssl = true
    imap.port = 993
    success = imap.connect(hostname: "imap.my-imap-server.com")
    if success == false {
        print("\(imap.lastErrorText!)")
        return
    }

    // Authenticate with the IMAP server via the SSH tunnel.
    success = imap.login(login: "myLogin", password: "myPassword")
    if success == false {
        print("\(imap.lastErrorText!)")
        return
    }

    // Select an IMAP mailbox
    success = imap.selectMailbox(mailbox: "Inbox")
    if success == false {
        print("\(imap.lastErrorText!)")
        return
    }

    // How many messages in Inbox?
    var msgCount: Int = imap.numMessages.intValue
    if msgCount == 0 {
        print("No messages found.")
        return
    }

    var upperBound: Int = 10
    if msgCount < upperBound {
        upperBound = msgCount
    }

    // Download up to the 1st 10 messages.
    let email = CkoEmail()!
    var i: Int
    var bUid: Bool = false
    for i = 1; i <= upperBound; i++ {

        success = imap.fetchEmail(headerOnly: false, msgId: i, bUid: bUid, email: email)
        if success == false {
            print("\(imap.lastErrorText!)")
            return
        }

        print("\(email.from!)")
        print("\(email.subject!)")

    }

    // Disconnect from the IMAP server.
    // The SSH tunnel remains open.
    success = imap.disconnect()
    if success == false {
        print("\(imap.lastErrorText!)")
        return
    }

    // It is possible to re-use the existing SSH tunnel for the next connection:
    success = imap.connect(hostname: "imap.my-imap-server2.com")
    if success == false {
        print("\(imap.lastErrorText!)")
        return
    }

    // Review the LastErrorText to see that the connection was made via the SSH tunnel:
    print("\(imap.lastErrorText!)")

    // This closes the SSH channel, which is the connection with the IMAP server.
    // It does not close the SSH tunnel
    success = imap.disconnect()
    if success == false {
        print("\(imap.lastErrorText!)")
        return
    }

    // Finally, close the SSH tunnel.

    // Note: If other objects are using the same SSH tunnel, the tunnel is not 
    // actually closed.  It is only closed when the last object using the tunnel closes it.

    // At this point, both the imap and tunnel objects have references to the internal
    // SSH tunnel.  We need to close each.

    // This call doesn't actually close the tunnel yet, because the tunnel object still
    // holds an internal reference.
    success = imap.sshCloseTunnel()
    if success == false {
        print("\(imap.lastErrorText!)")
        return
    }

    // This actually closes the SSH tunnel because it's the last object using it.
    success = tunnel.sshCloseTunnel()
    if success == false {
        print("\(tunnel.lastErrorText!)")
        return
    }

    print("IMAP pre-existing SSH tunnel example completed.")

}