Pascal (Lazarus/Delphi)

Fetch Only an IMAP Message's Headers

Demonstrates the Chilkat Imap.FetchSingleHeaderAsMime method, which downloads and returns the MIME header block for one message, without downloading the body. If the second argument (bUID) is true, the first argument is a UID; otherwise it is a sequence number. This example fetches message 1's headers.

Background: Headers are tiny compared to a full message with attachments, so fetching just the header block is the fast, bandwidth-friendly way to build a message list — sender, subject, date — without pulling every body. It is also gentler on read state: retrieving only headers does not mark a message as seen. Download the full message later, on demand, when the user opens it.

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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.Imap;

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

procedure RunDemo;
var
  success: Boolean;
  imap: TImap;
  headers: string;

begin
  success := False;

  //  Demonstrates the Imap.FetchSingleHeaderAsMime method, which downloads and returns the MIME
  //  header block for one message, without downloading the body.  If the 2nd argument (bUID)
  //  is True, the 1st argument is a UID; otherwise it is a sequence number.

  imap := TImap.Create;

  imap.Ssl := True;
  imap.Port := 993;

  success := imap.Connect('imap.example.com');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;
  success := imap.Login('user@example.com','myPassword');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  success := imap.SelectMailbox('Inbox');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  //  Download only the MIME header block of message sequence number 1.  bUID = False.
  headers := imap.FetchSingleHeaderAsMime(1,False);
  if (imap.LastMethodSuccess = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;
  WriteLn(headers);

  success := imap.Disconnect();
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;


  imap.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.