DataFlex

Add a Custom Header to a Related Item

Demonstrates the Chilkat Email.AddRelatedHeader method, which adds a custom MIME header field to an existing related item identified by its zero-based index. This example first adds a related style sheet (which becomes index 0) and captures its generated Content-ID, builds an HTML body that references the style sheet by that cid:, then attaches an extra header field to the related item and prints the resulting MIME.

Background: Like attachments, each related item (an inline image, style sheet, etc.) is a MIME part with its own small header block describing that part — Content-Type, Content-ID, Content-Location, and so on. AddRelatedHeader lets you insert additional fields into that per-part block, which is occasionally required for interoperability with clients that look for specific custom headers on embedded resources.

Chilkat DataFlex Downloads

Download Chilkat for DataFlex

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoEmail
    String sCid
    Handle hoSbHtml
    Boolean iSuccess
    Integer iNumReplaced
    String sTemp1
    Boolean bTemp1

    //  Demonstrates the AddRelatedHeader method, which adds a custom MIME header field to an
    //  existing related item, identified by its zero-based index.

    Get Create (RefClass(cComChilkatEmail)) To hoEmail
    If (Not(IsComObjectCreated(hoEmail))) Begin
        Send CreateComObject of hoEmail
    End
    Set ComSubject Of hoEmail To "Related item with a custom header"

    //  Add a related item first (a style sheet); capture its generated Content-ID.  It becomes
    //  related-item index 0.
    Get ComAddRelatedString Of hoEmail "styles.css" "body { color: black; }" "utf-8" To sCid
    Get ComLastMethodSuccess Of hoEmail To bTemp1
    If (bTemp1 = False) Begin
        Get ComLastErrorText Of hoEmail To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Build the HTML body, referencing the related style sheet by its Content-ID.  A
    //  placeholder is used and then replaced with the actual Content-ID.
    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbHtml
    If (Not(IsComObjectCreated(hoSbHtml))) Begin
        Send CreateComObject of hoSbHtml
    End
    Get ComAppend Of hoSbHtml '<html><head><link rel="stylesheet" href="cid:PLACEHOLDER_CID"/></head><body>Styled content.</body></html>' To iSuccess
    Get ComReplace Of hoSbHtml "PLACEHOLDER_CID" sCid To iNumReplaced
    Get ComGetAsString Of hoSbHtml To sTemp1
    Send ComSetHtmlBody To hoEmail sTemp1

    //  Add a custom header field to the first related item (index 0).
    Send ComAddRelatedHeader To hoEmail 0 "X-Custom-Related-Header" "some value"

    //  The custom header now appears in the related item's MIME part.
    Get ComGetMime Of hoEmail To sTemp1
    Showln sTemp1


End_Procedure