(Swift 3,4,5...) Download IMAP Message Set using FetchBundle

Demonstrates how to read IMAP emails using the FetchBundle method.

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 imap = CkoImap()!

    // Connect using TLS.
    imap.ssl = true
    imap.port = 993
    var success: Bool = imap.connect("imap.example.com")
    if success != true {
        print("\(imap.lastErrorText!)")
        return
    }

    // Authenticate
    success = imap.login("email_account_login", password: "email_account_password")
    if success != true {
        print("\(imap.lastErrorText!)")
        return
    }

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

    // Search for messages with the word "test" in the subject.
    var fetchUids: Bool = true
    var messageSet: CkoMessageSet? = imap.search("Subject test", bUid: fetchUids)
    if imap.lastMethodSuccess != true {
        print("\(imap.lastErrorText!)")
        return
    }

    // Download the messages in a single call to FetchBundle.
    // 
    // This only makes sense if the number of emails to be downloaded is not too large.  
    // For example, you wouldn't want to download 10000 emails in a single call to FetchBundle.
    // Why? For two reasons:  (1) It could potentially cause an out-of-memory condition, and 
    // (2) it would take an extremely large amount of time.  The longer the amount of time,
    // the greater the likelihood of some kind of external networking or server problem occuring,
    // and if it happens, then you would need to re-download everything from the beginning again.
    // For large numbers of emails, it's better to loop over the emails in the message set
    // and download/process one at a time as shown here: Download IMAP Messages One at a Time
    // Downloading one message at a time makes it possible to resume the downloads rather than restart the entire operation all over again.

    // If the message set is reasonable in size, you can download all at once using FetchBundle:

    print("Number of messages = \(messageSet!.count.intValue)")

    var bundle: CkoEmailBundle? = imap.fetchBundle(messageSet)
    if imap.lastMethodSuccess == false {
        messageSet = nil
        print("\(imap.lastErrorText!)")
        return
    }

    // Display the Subject and From of each email.
    var i: Int = 0
    var numEmails: Int = bundle!.messageCount.intValue
    while i < numEmails {
        var email: CkoEmail? = bundle!.getEmail(i)

        print("\(email!.getHeaderField("Date")!)")
        print("\(email!.subject!)")
        print("\(email!.from!)")
        print("--")

        email = nil
        i = i + 1
    }

    messageSet = nil
    bundle = nil

}