(Xojo Plugin) 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.

Chilkat Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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.
Dim mailman As New Chilkat.MailMan

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

// Set the POP3 login/password.
mailman.PopUsername = "***"
mailman.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"
Dim saSeenUidls As New Chilkat.StringArray
Dim success As Boolean
success = saSeenUidls.LoadFromFile("seenUidls.txt")
If (success <> True) Then
    System.DebugLog("failed to load seenUidls.txt")
    Return
End If

// Get the complete list of UIDLs on the mail server.
Dim saUidls As Chilkat.StringArray
saUidls = mailman.GetUidls()
If (mailman.LastMethodSuccess = False) Then
    System.DebugLog(mailman.LastErrorText)
    Return
End If

// 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.
Dim saUnseenUidls As New Chilkat.StringArray

Dim i As Int32
i = 0
Dim n As Int32
n = saUidls.Count
While i < n
    If (saSeenUidls.Contains(saUidls.GetString(i)) <> True) Then
        success = saUnseenUidls.Append(saUidls.GetString(i))
    End If

    i = i + 1
Wend

If (saUnseenUidls.Count = 0) Then
    System.DebugLog("No unseen emails!")

    Return
End If

// Download in full the unseen emails:
Dim bundle As Chilkat.EmailBundle
bundle = mailman.FetchMultiple(saUnseenUidls)
If (mailman.LastMethodSuccess = False) Then
    System.DebugLog(mailman.LastErrorText)

    Return
End If

Dim email As Chilkat.Email
i = 0
While i < bundle.MessageCount
    email = bundle.GetEmail(i)
    System.DebugLog(email.From)
    System.DebugLog(email.Subject)
    System.DebugLog("----")

    i = i + 1
Wend

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