(PureBasic) 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 PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkMailMan.pb"
IncludeFile "CkEmailBundle.pb"
IncludeFile "CkEmail.pb"
IncludeFile "CkStringArray.pb"

Procedure ChilkatExample()

    ; 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.i = CkMailMan::ckCreate()
    If mailman.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Set the POP3 server's hostname
    CkMailMan::setCkMailHost(mailman, "pop.someMailServer.com")

    ; Set the POP3 login/password.
    CkMailMan::setCkPopUsername(mailman, "***")
    CkMailMan::setCkPopPassword(mailman, "***")

    ; 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.i = CkStringArray::ckCreate()
    If saSeenUidls.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success.i = CkStringArray::ckLoadFromFile(saSeenUidls,"seenUidls.txt")
    If success <> 1
        Debug "failed to load seenUidls.txt"
        CkMailMan::ckDispose(mailman)
        CkStringArray::ckDispose(saSeenUidls)
        ProcedureReturn
    EndIf

    ; Get the complete list of UIDLs on the mail server.
    saUidls.i = CkMailMan::ckGetUidls(mailman)
    If CkMailMan::ckLastMethodSuccess(mailman) = 0
        Debug CkMailMan::ckLastErrorText(mailman)
        CkMailMan::ckDispose(mailman)
        CkStringArray::ckDispose(saSeenUidls)
        ProcedureReturn
    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.
    saUnseenUidls.i = CkStringArray::ckCreate()
    If saUnseenUidls.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    i.i = 0
    n.i = CkStringArray::ckCount(saUidls)
    While i < n
        If CkStringArray::ckContains(saSeenUidls,CkStringArray::ckGetString(saUidls,i)) <> 1
            success = CkStringArray::ckAppend(saUnseenUidls,CkStringArray::ckGetString(saUidls,i))
        EndIf

        i = i + 1
    Wend

    If CkStringArray::ckCount(saUnseenUidls) = 0
        Debug "No unseen emails!"
        CkStringArray::ckDispose(saUidls)

        CkMailMan::ckDispose(mailman)
        CkStringArray::ckDispose(saSeenUidls)
        CkStringArray::ckDispose(saUnseenUidls)
        ProcedureReturn
    EndIf

    ; Download in full the unseen emails:
    bundle.i = CkMailMan::ckFetchMultiple(mailman,saUnseenUidls)
    If CkMailMan::ckLastMethodSuccess(mailman) = 0
        Debug CkMailMan::ckLastErrorText(mailman)
        CkStringArray::ckDispose(saUidls)

        CkMailMan::ckDispose(mailman)
        CkStringArray::ckDispose(saSeenUidls)
        CkStringArray::ckDispose(saUnseenUidls)
        ProcedureReturn
    EndIf

    email.i
    i = 0
    While i < CkEmailBundle::ckMessageCount(bundle)
        email = CkEmailBundle::ckGetEmail(bundle,i)
        Debug CkEmail::ckFrom(email)
        Debug CkEmail::ckSubject(email)
        Debug "----"
        CkEmail::ckDispose(email)

        i = i + 1
    Wend

    ; Save saUidls to "seenUidls.txt"
    success = CkStringArray::ckSaveToFile(saUidls,"seenUidls.txt")

    CkStringArray::ckDispose(saUidls)



    CkMailMan::ckDispose(mailman)
    CkStringArray::ckDispose(saSeenUidls)
    CkStringArray::ckDispose(saUnseenUidls)


    ProcedureReturn
EndProcedure