DataFlex

Get the Content-ID of a Related Item

Demonstrates the Chilkat Email.GetRelatedContentID method, which returns the Content-ID of a related item (typically an image or style sheet embedded within an HTML email). The index is zero-based. This example loads an image from a file into a BinData object, adds it as a related item with AddRelatedBd (capturing the generated Content-ID and referencing it from the HTML), then reads that Content-ID back.

Background: The Content-ID is the anchor that ties an inline resource to the HTML that displays it: the body references cid: plus the ID, and the matching related part carries that same Content-ID. Because an image is binary, it is loaded into a BinData object (here from a file) and added with AddRelatedBd. Reading the Content-ID back lets a program verify or rewrite those links — for example when relocating embedded images or converting a message for display outside a mail client.

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DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoEmail
    Variant vBdImage
    Handle hoBdImage
    String sCid
    Handle hoSbHtml
    Integer iNumReplaced
    String sCid0
    String sTemp1
    Boolean bTemp1

    Move False To iSuccess

    //  Demonstrates the GetRelatedContentID method, which returns the Content-ID of a related
    //  item.  Related items are typically images and style sheets embedded within HTML emails.
    //  The index is zero-based.

    Get Create (RefClass(cComChilkatEmail)) To hoEmail
    If (Not(IsComObjectCreated(hoEmail))) Begin
        Send CreateComObject of hoEmail
    End
    Set ComSubject Of hoEmail To "GetRelatedContentID example"

    //  Load the image data from a file into a BinData object.
    Get Create (RefClass(cComChilkatBinData)) To hoBdImage
    If (Not(IsComObjectCreated(hoBdImage))) Begin
        Send CreateComObject of hoBdImage
    End
    Get ComLoadFile Of hoBdImage "qa_data/images/logo.png" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoBdImage To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Add the image as a related item from the BinData; capture its generated Content-ID.
    Get pvComObject of hoBdImage to vBdImage
    Get ComAddRelatedBd Of hoEmail "logo.png" vBdImage To sCid
    Get ComLastMethodSuccess Of hoEmail To bTemp1
    If (bTemp1 = False) Begin
        Get ComLastErrorText Of hoEmail To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Reference the related item in the HTML body by its Content-ID.
    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbHtml
    If (Not(IsComObjectCreated(hoSbHtml))) Begin
        Send CreateComObject of hoSbHtml
    End
    Get ComAppend Of hoSbHtml '<html><body><img src="cid:PLACEHOLDER_CID"/></body></html>' To iSuccess
    Get ComReplace Of hoSbHtml "PLACEHOLDER_CID" sCid To iNumReplaced
    Get ComGetAsString Of hoSbHtml To sTemp1
    Send ComSetHtmlBody To hoEmail sTemp1

    //  Read the Content-ID of the first related item (index 0).
    Get ComGetRelatedContentID Of hoEmail 0 To sCid0
    Showln "Related item 0 Content-ID: " sCid0

    //  Note: The path "qa_data/images/logo.png" is a relative local filesystem path,
    //  relative to the current working directory of the running application.


End_Procedure