Xbase++

Convert a MIME Entity to multipart/alternative

Demonstrates the Chilkat Mime.ConvertToMultipartAlt method, which wraps the current entity in a new outer multipart/alternative, making the original the first child. It takes no arguments.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Use this to add an alternate rendering to an existing message — for example, promoting a plain-text message so an HTML version can be added alongside it. The original content becomes the first (least-preferred) alternative, and you append the richer representation after it. As with the mixed conversion, message-level headers move to the new outer entity.

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LOCAL nSuccess
LOCAL oMime
LOCAL oHtmlPart

nSuccess := 0

oMime := CreateObject("Chilkat.Mime")
nSuccess := oMime:LoadMimeFile("qa_data/message.eml")
IF (nSuccess == 0)
    ? oMime:LastErrorText
    oMime:destroy()
    RETURN
ENDIF

//  Wrap the current entity in a new outer multipart/alternative entity.  The original entity
//  becomes the first child, ready for an alternate representation to be added.
nSuccess := oMime:ConvertToMultipartAlt()
IF (nSuccess == 0)
    ? oMime:LastErrorText
    oMime:destroy()
    RETURN
ENDIF

//  Add an alternative representation of the same content.
oHtmlPart := CreateObject("Chilkat.Mime")
nSuccess := oHtmlPart:SetBodyFromHtml("<html><body>HTML alternative.</body></html>")
IF (nSuccess == 0)
    ? oHtmlPart:LastErrorText
    oMime:destroy()
    oHtmlPart:destroy()
    RETURN
ENDIF

nSuccess := oMime:AppendPart(oHtmlPart)
IF (nSuccess == 0)
    ? oMime:LastErrorText
    oMime:destroy()
    oHtmlPart:destroy()
    RETURN
ENDIF

? "Number of parts: " + Str(oMime:NumParts)

oMime:destroy()
oHtmlPart:destroy()