(Go) Reading Unread POP3 Email

The POP3 protocol does not provide the ability to ask the server which emails are "unread". Furthermore, a pure POP3 server does not even keep this information. Some servers, such as Exchange Server, expose both POP3 and IMAP interfaces. In these cases, information about read/unread status exists on the server, but it is only available via the IMAP protocol. Email clients such as Outlook and Thunderbird keep read/unread information on the client computer. This example demonstrates how UIDLs can be saved to track and read "unread" email.

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

    // The mailman object is used for receiving (POP3) 
    // and sending (SMTP) email.
    mailman := chilkat.NewMailMan()

    // Set the POP3 server's hostname
    mailman.SetMailHost("pop.someMailServer.com")

    // Set the POP3 login/password.
    mailman.SetPopUsername("***")
    mailman.SetPopPassword("***")

    // You may keep a list of already-seen UIDLs in a text file:
    // If this is the first time you're running this example,
    // create an empty text file named "seenUidls.txt"
    saSeenUidls := chilkat.NewStringArray()
    success := saSeenUidls.LoadFromFile("seenUidls.txt")
    if success != true {
        fmt.Println("failed to load seenUidls.txt")
        mailman.DisposeMailMan()
        saSeenUidls.DisposeStringArray()
        return
    }

    // Get the complete list of UIDLs on the mail server.
    saUidls := mailman.GetUidls()
    if mailman.LastMethodSuccess() == false {
        fmt.Println(mailman.LastErrorText())
        mailman.DisposeMailMan()
        saSeenUidls.DisposeStringArray()
        return
    }

    // Create a new string array object (it's an object, not an actual array)
    // and add the UIDLs from saUidls that aren't already seen.
    saUnseenUidls := chilkat.NewStringArray()

    i := 0
    n := saUidls.Count()
    for i < n {
        if saSeenUidls.Contains(*saUidls.GetString(i)) != true {
            success = saUnseenUidls.Append(*saUidls.GetString(i))
        }

        i = i + 1
    }

    if saUnseenUidls.Count() == 0 {
        fmt.Println("No unseen emails!")
        saUidls.DisposeStringArray()
        mailman.DisposeMailMan()
        saSeenUidls.DisposeStringArray()
        saUnseenUidls.DisposeStringArray()
        return
    }

    // Download in full the unseen emails:
    bundle := mailman.FetchMultiple(saUnseenUidls)
    if mailman.LastMethodSuccess() == false {
        fmt.Println(mailman.LastErrorText())
        saUidls.DisposeStringArray()
        mailman.DisposeMailMan()
        saSeenUidls.DisposeStringArray()
        saUnseenUidls.DisposeStringArray()
        return
    }

    // email is a Email
    i = 0
    for i < bundle.MessageCount() {
        email := bundle.GetEmail(i)
        fmt.Println(email.From())
        fmt.Println(email.Subject())
        fmt.Println("----")
        email.DisposeEmail()
        i = i + 1
    }

    // Save saUidls to "seenUidls.txt"
    success = saUidls.SaveToFile("seenUidls.txt")

    saUidls.DisposeStringArray()

    mailman.DisposeMailMan()
    saSeenUidls.DisposeStringArray()
    saUnseenUidls.DisposeStringArray()