(Swift 2) Using IMAP IDLE to Wait for Updates

This example demonstrates how to use the IMAP IDLE functionality in Chilkat.

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func chilkatTest() {
    let imap = CkoImap()

    var success: Bool

    // ....
    // ....
    // ....

    // Select an IMAP mailbox
    success = imap.SelectMailbox("INBOX")
    if success != true {
        print("\(imap.LastErrorText)")
        return
    }

    // After a mailbox has been selected, IDLE may begin.
    // Idling tells the IMAP server to push unsolicited updates for the selected
    // mailbox to the connected client (which is your application).
    success = imap.IdleStart()
    if success != true {
        print("\(imap.LastErrorText)")
        return
    }

    // Once idling has started, your code still has to periodically check to see
    // if any updates have arrived.  However, this is significantly different
    // then what normally occurs when checking email.  The IdleCheck does NOT
    // send a message to the IMAP server.  It simply checks the connection to see
    // if any data has arrived.  If so, it can be consumed and the client (your app)
    // can react appropriately.  

    // Note: It is recommended that idling only run for a max of 20 minutes before stopping and
    // re-starting the IDLE.  This is to maintain a minimum low level of activity so that 
    // the IMAP server does not disconnect (which it may do if it considers the connection to 
    // be truly inactive, i.e. forgotten).

    // To check the connection for IDLE updates, call IdleCheck.  The 1st argument indicates how
    // long we're willing to wait. We'll wait 1 millisecond:
    var idleResultXml: String?
    idleResultXml = imap.IdleCheck(1)
    if imap.LastMethodSuccess != true {
        print("\(imap.LastErrorText)")
        return
    }

    // See the online reference documentation for details regarding the XML that is returned.
    // Your application code would parse the XML to determine what action to take.
    // If the XML contains "<idle></idle>", then no updates are available and your application
    // would call IdleCheck again at some point in the future.

    // If updates are available, the IDLE must be terminated by calling IdleDone, like this:
    success = imap.IdleDone()
    if success != true {
        print("\(imap.LastErrorText)")
        return
    }

    // Once the IDLE is terminated, your application can make calls to fetch email, etc.
    // Any attempt to communicate with the IMAP server prior to terminating the IDLE will
    // result in failure.

    // IMPORTANT: Please realize that your application code will be structured differently than shown here.
    // The call to IdleCheck will likely be in a function/procedure that is periodically called
    // after the IdleStart has been called from some other location in your app

}