Pascal (Lazarus/Delphi)

Get the Content-ID of a Related Item

Demonstrates the Chilkat Email.GetRelatedContentID method, which returns the Content-ID of a related item (typically an image or style sheet embedded within an HTML email). The index is zero-based. This example loads an image from a file into a BinData object, adds it as a related item with AddRelatedBd (capturing the generated Content-ID and referencing it from the HTML), then reads that Content-ID back.

Background: The Content-ID is the anchor that ties an inline resource to the HTML that displays it: the body references cid: plus the ID, and the matching related part carries that same Content-ID. Because an image is binary, it is loaded into a BinData object (here from a file) and added with AddRelatedBd. Reading the Content-ID back lets a program verify or rewrite those links — for example when relocating embedded images or converting a message for display outside a mail client.

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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.BinData,
  Chilkat.StringBuilder,
  Chilkat.Email;

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

procedure RunDemo;
var
  success: Boolean;
  email: TEmail;
  bdImage: TBinData;
  cid: string;
  sbHtml: TStringBuilder;
  numReplaced: Integer;
  cid0: string;

begin
  success := False;

  //  Demonstrates the GetRelatedContentID method, which returns the Content-ID of a related
  //  item.  Related items are typically images and style sheets embedded within HTML emails.
  //  The index is zero-based.

  email := TEmail.Create;
  email.Subject := 'GetRelatedContentID example';

  //  Load the image data from a file into a BinData object.
  bdImage := TBinData.Create;
  success := bdImage.LoadFile('qa_data/images/logo.png');
  if (success = False) then
    begin
      WriteLn(bdImage.LastErrorText);
      Exit;
    end;

  //  Add the image as a related item from the BinData; capture its generated Content-ID.
  cid := email.AddRelatedBd('logo.png',bdImage);
  if (email.LastMethodSuccess = False) then
    begin
      WriteLn(email.LastErrorText);
      Exit;
    end;

  //  Reference the related item in the HTML body by its Content-ID.
  sbHtml := TStringBuilder.Create;
  sbHtml.Append('<html><body><img src="cid:PLACEHOLDER_CID"/></body></html>');
  numReplaced := sbHtml.Replace('PLACEHOLDER_CID',cid);
  email.SetHtmlBody(sbHtml.GetAsString());

  //  Read the Content-ID of the first related item (index 0).
  cid0 := email.GetRelatedContentID(0);
  WriteLn('Related item 0 Content-ID: ' + cid0);

  //  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;
  bdImage.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.