Pascal (Lazarus/Delphi)

Add a Related File to an HTML Email

Demonstrates the Chilkat Email.AddRelatedFile method, which adds the contents of a local file as a related MIME resource and returns the generated Content-ID. The returned value is the bare Content-ID — no angle brackets and no cid: prefix — so if it returns CID-123@example, the HTML reference is cid:CID-123@example. Because the Content-ID is generated by the call, this example adds the image first, then builds the HTML body in a StringBuilder — using a placeholder in the <img> tag that is replaced with the returned Content-ID — and passes the result to SetHtmlBody.

Background: To embed an image so it displays inside an HTML email (rather than being downloaded from a web server), you add it as a "related" part and reference it from the HTML with a cid: URL that matches the part's Content-ID. Since Chilkat assigns that ID when you add the file, the natural order is: add the related file, capture the returned ID, then build the <img src="cid:..."> reference from it. A StringBuilder makes assembling and updating the HTML convenient.

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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.Email,
  Chilkat.StringBuilder;

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

procedure RunDemo;
var
  email: TEmail;
  cid: string;
  sbHtml: TStringBuilder;
  numReplaced: Integer;

begin
  //  Demonstrates the AddRelatedFile method, which adds a local file as a related MIME
  //  resource (such as an image displayed by an HTML body) and returns the generated
  //  Content-ID.  The HTML references the item using cid:<Content-ID>.

  email := TEmail.Create;
  email.Subject := 'Email with a related image';

  //  Add the image file as a related item first.  The return value is the bare Content-ID
  //  (no angle brackets and no "cid:" prefix).
  cid := email.AddRelatedFile('qa_data/images/logo.png');
  if (email.LastMethodSuccess = False) then
    begin
      WriteLn(email.LastErrorText);
      Exit;
    end;

  //  Build the HTML body in a StringBuilder, using a placeholder where the image's
  //  Content-ID will go.
  sbHtml := TStringBuilder.Create;
  sbHtml.Append('<html><body><img src="cid:PLACEHOLDER_CID"/></body></html>');

  //  Replace the placeholder with the actual Content-ID returned by AddRelatedFile.
  numReplaced := sbHtml.Replace('PLACEHOLDER_CID',cid);

  //  Set the HTML body from the StringBuilder result.
  email.SetHtmlBody(sbHtml.GetAsString());

  WriteLn('Related Content-ID = ' + cid);
  WriteLn('NumRelatedItems = ' + email.NumRelatedItems);

  //  Note: The path "qa_data/images/logo.png" is a relative local filesystem path,
  //  relative to the current working directory of the running application.


  email.Free;
  sbHtml.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.