Delphi DLL

Convert 8-bit MIME Parts to Base64

Demonstrates the Chilkat Mime.Convert8Bit method, which recursively converts every part whose Content-Transfer-Encoding is 8bit or binary to base64. It takes no arguments and is a void method.

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: The original SMTP standard only guaranteed 7-bit transport, and some legacy servers still reject or mangle raw 8-bit and binary content. Converting those parts to base64 — a 7-bit-safe encoding — makes the whole message safe to relay through such systems without loss. It walks the entire tree, so a multipart message with several offending parts is fixed in one call.

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Delphi DLL

var
success: Boolean;
mime: HCkMime;
mimeText: PWideChar;

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;

//  Recursively convert every part whose Content-Transfer-Encoding is 8bit or binary to base64.
//  This makes the MIME safe to transmit over channels that only support 7-bit text (such as some
//  legacy SMTP servers).
CkMime_Convert8Bit(mime);

Memo1.Lines.Add('8bit/binary parts converted to base64.');
mimeText := CkMime__getMime(mime);
if (CkMime_getLastMethodSuccess(mime) = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;
Memo1.Lines.Add(mimeText);

CkMime_Dispose(mime);