(DataFlex) Read IMAP Email Headers

This example demonstrates how to connect to an IMAP server and download only the email headers for all messages in a mailbox. Downloading headers only is much faster and more efficient than downloading complete emails because the message bodies and attachment contents are not retrieved.

The example shows how to:

• Connect to an IMAP server using SSL/TLS
• Authenticate and select a mailbox
• Query for all messages in the mailbox
• Fetch header-only email information
• Display sender, subject, recipients, and total message size
• Retrieve attachment metadata such as filenames and sizes without downloading the actual attachments

This technique is useful for quickly scanning large mailboxes, building message summaries, or inspecting attachment information while minimizing bandwidth and memory usage.

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoImap
    Boolean iFetchUids
    Variant vMessageSet
    Handle hoMessageSet
    Variant vBundle
    Handle hoBundle
    Boolean iHeadersOnly
    Variant vEmail
    Handle hoEmail
    String sName
    String sAddr
    Integer i
    Integer j
    Integer iNumAttach
    Integer iAttachSize
    String sTemp1
    String sTemp2
    Integer iTemp1

    Move False To iSuccess

    Move False To iSuccess

    // This example assumes the Chilkat API has already been unlocked.
    // See Global Unlock Sample for example code.

    Get Create (RefClass(cComChilkatImap)) To hoImap
    If (Not(IsComObjectCreated(hoImap))) Begin
        Send CreateComObject of hoImap
    End

    // Connect to the IMAP server using SSL/TLS on the standard secure IMAP port.
    Set ComSsl Of hoImap To True
    Set ComPort Of hoImap To 993
    Get ComConnect Of hoImap "imap.example.com" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Authenticate with the IMAP server.
    Get ComLogin Of hoImap "****" "****" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Select the mailbox (folder) to access.
    Get ComSelectMailbox Of hoImap "Inbox" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Get the identifiers for all messages in the selected mailbox.
    // Setting fetchUids = cktrue causes IMAP UIDs to be returned.
    // If ckfalse, IMAP sequence numbers are returned instead.
    Move True To iFetchUids
    Get Create (RefClass(cComChilkatMessageSet)) To hoMessageSet
    If (Not(IsComObjectCreated(hoMessageSet))) Begin
        Send CreateComObject of hoMessageSet
    End
    Get pvComObject of hoMessageSet to vMessageSet
    Get ComQueryMbx Of hoImap "ALL" iFetchUids vMessageSet To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Download only the email headers for the messages in the set.
    // This is much faster than downloading full emails because the
    // message bodies and attachment contents are not retrieved.
    // 
    // Even though the attachments themselves are not downloaded,
    // Chilkat can still provide information such as attachment
    // filenames, attachment sizes, and the total message size.
    Get Create (RefClass(cComChilkatEmailBundle)) To hoBundle
    If (Not(IsComObjectCreated(hoBundle))) Begin
        Send CreateComObject of hoBundle
    End
    Move True To iHeadersOnly
    Get pvComObject of hoMessageSet to vMessageSet
    Get pvComObject of hoBundle to vBundle
    Get ComFetchMsgSet Of hoImap iHeadersOnly vMessageSet vBundle To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Iterate over each email in the bundle and display summary information.
    Get Create (RefClass(cComChilkatEmail)) To hoEmail
    If (Not(IsComObjectCreated(hoEmail))) Begin
        Send CreateComObject of hoEmail
    End

    Move 0 To i
    Move 0 To j
    While (i < (ComMessageCount(hoBundle)))
        Get pvComObject of hoEmail to vEmail
        Get ComEmailAt Of hoBundle i vEmail To iSuccess

        // Display the sender and subject line.
        Get ComFrom Of hoEmail To sTemp1
        Showln sTemp1
        Get ComSubject Of hoEmail To sTemp1
        Showln sTemp1

        // Display all "To" recipients.
        Move 0 To j
        While (j < (ComNumTo(hoEmail)))
            Get ComGetToName Of hoEmail j To sTemp1
            Get ComGetToAddr Of hoEmail j To sTemp2
            Showln "TO: " sTemp1 ", " sTemp2
            Move (j + 1) To j
        Loop

        // Display all "CC" recipients.
        Move 0 To j
        While (j < (ComNumCC(hoEmail)))
            Get ComGetCcName Of hoEmail j To sTemp1
            Get ComGetCcAddr Of hoEmail j To sTemp2
            Showln "CC: " sTemp1 ", " sTemp2
            Move (j + 1) To j
        Loop

        // Display the total size of the email message, including
        // the body and all attachments, even though only headers
        // were downloaded.
        Get ComSize Of hoEmail To iTemp1
        Showln iTemp1

        // When full emails are downloaded, attachment information
        // is accessed using the email.NumAttachments property and
        // the email.GetMailAttach* methods.
        // 
        // However, because this example downloaded headers only,
        // attachment metadata must be obtained using the IMAP object.
        Get pvComObject of hoEmail to vEmail
        Get ComGetMailNumAttach Of hoImap vEmail To iNumAttach

        Move 0 To j
        While (j < iNumAttach)

            // Display the attachment filename.
            Get ComGetMailAttachFilename Of hoImap             Get pvComObject of hoEmail to vEmail
vEmail j To sTemp1
            Showln sTemp1

            // Display the attachment size in bytes.
            Get pvComObject of hoEmail to vEmail
            Get ComGetMailAttachSize Of hoImap vEmail j To iAttachSize
            Showln "    size = " iAttachSize " bytes"

            Move (j + 1) To j
        Loop

        Showln "--"

        Move (i + 1) To i
    Loop

    // Disconnect from the IMAP server.
    Get ComDisconnect Of hoImap To iSuccess


End_Procedure