Delphi DLL

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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var
success: Boolean;
mime: HCkMime;
htmlPart: HCkMime;

begin
success := False;

mime := CkMime_Create();
success := CkMime_LoadMimeFile(mime,'qa_data/message.eml');
if (success = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;

//  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.
success := CkMime_ConvertToMultipartAlt(mime);
if (success = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;

//  Add an alternative representation of the same content.
htmlPart := CkMime_Create();
success := CkMime_SetBodyFromHtml(htmlPart,'<html><body>HTML alternative.</body></html>');
if (success = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(htmlPart));
    Exit;
  end;
success := CkMime_AppendPart(mime,htmlPart);
if (success = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;

Memo1.Lines.Add('Number of parts: ' + IntToStr(CkMime_getNumParts(mime)));

CkMime_Dispose(mime);
CkMime_Dispose(htmlPart);