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.

Download Chilkat Ruby Library

require 'chilkat'

#  The mailman object is used for receiving (POP3)
#  and sending (SMTP) email.
mailman = Chilkat::CkMailMan.new()

#  Any string argument automatically begins the 30-day trial.
success = mailman.UnlockComponent("30-day trial")
if (success != true)
    print "Component unlock failed" + "\n"
    exit
end

#  Set the POP3 server's hostname
mailman.put_MailHost("mail.chilkatsoft.com")

#  Set the POP3 login/password.
mailman.put_PopUsername("***")
mailman.put_PopPassword("***")

#  We're keeping 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::CkStringArray.new()
success = saSeenUidls.LoadFromFile("seenUidls.txt")
if (success != true)
    print "failed to load seenUidls.txt" + "\n"
    exit
end

#  Get the complete list of UIDLs on the mail server.

saUidls = mailman.GetUidls()

if (saUidls == nil )
    print mailman.lastErrorText() + "\n"
    exit
end

#  We don't have set operators (yet) on the StringArray object,
#  so 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::CkStringArray.new()

n = saUidls.get_Count()
for i in 0 .. n - 1
    if (saSeenUidls.Contains(saUidls.GetString(i)) != true)
        saUnseenUidls.Append(saUidls.GetString(i))
    end

end

if (saUnseenUidls.get_Count() == 0)
    print "No unseen emails!" + "\n"

    exit
end

#  Download in full the unseen emails:

bundle = mailman.FetchMultiple(saUnseenUidls)
if (bundle == nil )
    print mailman.lastErrorText() + "\n"

    exit
end

for i in 0 .. bundle.get_MessageCount() - 1
    email = bundle.GetEmail(i)
    print email.ck_from() + "\n";
    print email.subject() + "\n";
    print "----" + "\n";

end

#  We've seen all the emails, save saUidls to "seenUidls.txt"
saUidls.SaveToFile("seenUidls.txt")