Pascal (Lazarus/Delphi)

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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Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Mime;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  mime: TMime;
  htmlPart: TMime;

begin
  success := False;

  mime := TMime.Create;
  success := mime.LoadMimeFile('qa_data/message.eml');
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      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 := mime.ConvertToMultipartAlt();
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      Exit;
    end;

  //  Add an alternative representation of the same content.
  htmlPart := TMime.Create;
  success := htmlPart.SetBodyFromHtml('<html><body>HTML alternative.</body></html>');
  if (success = False) then
    begin
      WriteLn(htmlPart.LastErrorText);
      Exit;
    end;
  success := mime.AppendPart(htmlPart);
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      Exit;
    end;

  WriteLn('Number of parts: ' + mime.NumParts);


  mime.Free;
  htmlPart.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.