PureBasic

Download an IMAP Message Set

Demonstrates how to read a set of IMAP emails. PureBasic

IncludeFile "CkImap.pb"
IncludeFile "CkEmailBundle.pb"
IncludeFile "CkMessageSet.pb"
IncludeFile "CkEmail.pb"

Procedure ChilkatExample()

    success.i = 0

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

    imap.i = CkImap::ckCreate()
    If imap.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Connect using TLS.
    CkImap::setCkSsl(imap, 1)
    CkImap::setCkPort(imap, 993)
    success = CkImap::ckConnect(imap,"imap.example.com")
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        ProcedureReturn
    EndIf

    ; Authenticate
    success = CkImap::ckLogin(imap,"email_account_login","email_account_password")
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        ProcedureReturn
    EndIf

    ; Select an IMAP mailbox
    success = CkImap::ckSelectMailbox(imap,"Inbox")
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        ProcedureReturn
    EndIf

    ; Search for messages with the word "test" in the subject.
    fetchUids.i = 1

    messageSet.i = CkMessageSet::ckCreate()
    If messageSet.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkImap::ckQueryMbx(imap,"Subject test",fetchUids,messageSet)
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        CkMessageSet::ckDispose(messageSet)
        ProcedureReturn
    EndIf

    ; Download the messages in a single call to FetchMsgSet.
    ; 
    ; This only makes sense if the number of emails to be downloaded is not too large.  
    ; For example, you wouldn't want to download 10000 emails in a single call to FetchMsgSet.
    ; Why? For two reasons:  (1) It could potentially cause an out-of-memory condition, and 
    ; (2) it would take an extremely large amount of time.  The longer the amount of time,
    ; the greater the likelihood of some kind of external networking or server problem occuring,
    ; and if it happens, then you would need to re-download everything from the beginning again.
    ; For large numbers of emails, it's better to loop over the emails in the message set
    ; and download/process one at a time as shown here: Download IMAP Messages One at a Time
    ; Downloading one message at a time makes it possible to resume the downloads rather than restart the entire operation all over again.

    ; If the message set is reasonable in size, you can download all at once using FetchMsgSet:

    Debug "Number of messages = " + Str(CkMessageSet::ckCount(messageSet))

    bundle.i = CkEmailBundle::ckCreate()
    If bundle.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    headersOnly.i = 0
    success = CkImap::ckFetchMsgSet(imap,headersOnly,messageSet,bundle)
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        CkMessageSet::ckDispose(messageSet)
        CkEmailBundle::ckDispose(bundle)
        ProcedureReturn
    EndIf

    ; Display the Subject and From of each email.
    email.i = CkEmail::ckCreate()
    If email.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    i.i = 0
    numEmails.i = CkEmailBundle::ckMessageCount(bundle)
    While i < numEmails
        CkEmailBundle::ckEmailAt(bundle,i,email)

        Debug CkEmail::ckGetHeaderField(email,"Date")
        Debug CkEmail::ckSubject(email)
        Debug CkEmail::ckFrom(email)
        Debug "--"
        i = i + 1
    Wend


    CkImap::ckDispose(imap)
    CkMessageSet::ckDispose(messageSet)
    CkEmailBundle::ckDispose(bundle)
    CkEmail::ckDispose(email)


    ProcedureReturn
EndProcedure