(Lianja) 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.
loMailman = createobject("CkMailMan")

// Set the POP3 server's hostname
loMailman.MailHost = "pop.someMailServer.com"

// Set the POP3 login/password.
loMailman.PopUsername = "***"
loMailman.PopPassword = "***"

// 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"
loSaSeenUidls = createobject("CkStringArray")
llSuccess = loSaSeenUidls.LoadFromFile("seenUidls.txt")
if (llSuccess <> .T.) then
    ? "failed to load seenUidls.txt"
    release loMailman
    release loSaSeenUidls
    return
endif

// Get the complete list of UIDLs on the mail server.
loSaUidls = loMailman.GetUidls()
if (loMailman.LastMethodSuccess = .F.) then
    ? loMailman.LastErrorText
    release loMailman
    release loSaSeenUidls
    return
endif

// 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.
loSaUnseenUidls = createobject("CkStringArray")

i = 0
n = loSaUidls.Count
do while i < n
    if (loSaSeenUidls.Contains(loSaUidls.GetString(i)) <> .T.) then
        llSuccess = loSaUnseenUidls.Append(loSaUidls.GetString(i))
    endif

    i = i + 1
enddo

if (loSaUnseenUidls.Count = 0) then
    ? "No unseen emails!"
    release loSaUidls
    release loMailman
    release loSaSeenUidls
    release loSaUnseenUidls
    return
endif

// Download in full the unseen emails:
loBundle = loMailman.FetchMultiple(loSaUnseenUidls)
if (loMailman.LastMethodSuccess = .F.) then
    ? loMailman.LastErrorText
    release loSaUidls
    release loMailman
    release loSaSeenUidls
    release loSaUnseenUidls
    return
endif

i = 0
do while i < loBundle.MessageCount
    loEmail = loBundle.GetEmail(i)
    ? loEmail.From
    ? loEmail.Subject
    ? "----"
    release loEmail
    i = i + 1
enddo

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

release loSaUidls


release loMailman
release loSaSeenUidls
release loSaUnseenUidls