Pascal (Lazarus/Delphi)

PDF Update or Add XML Metadata

Demonstrates how to add or update the XML metadata stored in a PDF.

Note: This example requires Chilkat v10.1.0 or later.

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.StringBuilder,
  Chilkat.Pdf,
  Chilkat.Xml,
  Chilkat.CkDateTime;

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

procedure RunDemo;
var
  success: Boolean;
  pdf: TPdf;
  xml: TXml;
  sbExisting: TStringBuilder;
  hasMetadata: Boolean;
  dt: TCkDateTime;
  ts: string;
  sbDocId: TStringBuilder;
  sbInstanceId: TStringBuilder;
  sb: TStringBuilder;

begin
  success := False;

  //  This requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  pdf := TPdf.Create;

  //  Load a PDF file.
  //  If the PDF file already has metadata, we'll update it.
  //  Otherwise this example adds the metadata.
  success := pdf.LoadFile('qa_data/pdf/blank_with_metadata.pdf');
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  xml := TXml.Create;
  sbExisting := TStringBuilder.Create;

  hasMetadata := pdf.GetMetadata(sbExisting);
  if (hasMetadata = True) then
    begin
      xml.LoadSb(sbExisting,True);
    end
  else
    begin

      //  Otherwise create the bare minimum XMP metadata.
      xml.Tag := 'x:xmpmeta';
      xml.AddAttribute('xmlns:x','adobe:ns:meta/');
      xml.AddAttribute('x:xmptk','Adobe XMP Core 9.1-c001 79.675d0f7, 2023/06/11-19:21:16 ');
      xml.UpdateAttrAt('rdf:RDF',True,'xmlns:rdf','http://www.w3.org/1999/02/22-rdf-syntax-ns#');
      xml.UpdateAttrAt('rdf:RDF|rdf:Description',True,'rdf:about','');
      xml.UpdateAttrAt('rdf:RDF|rdf:Description',True,'xmlns:xmp','http://ns.adobe.com/xap/1.0/');
      xml.UpdateAttrAt('rdf:RDF|rdf:Description',True,'xmlns:dc','http://purl.org/dc/elements/1.1/');
      xml.UpdateAttrAt('rdf:RDF|rdf:Description',True,'xmlns:xmpMM','http://ns.adobe.com/xap/1.0/mm/');
      xml.UpdateAttrAt('rdf:RDF|rdf:Description',True,'xmlns:pdf','http://ns.adobe.com/pdf/1.3/');
      xml.UpdateAttrAt('rdf:RDF|rdf:Description',True,'xmlns:xmpRights','http://ns.adobe.com/xap/1.0/rights/');

      dt := TCkDateTime.Create;
      dt.SetFromCurrentSystemTime();
      ts := dt.GetAsTimestamp(True);

      xml.UpdateChildContent('rdf:RDF|rdf:Description|xmp:ModifyDate',ts);
      xml.UpdateChildContent('rdf:RDF|rdf:Description|xmp:CreateDate',ts);
      xml.UpdateChildContent('rdf:RDF|rdf:Description|xmp:MetadataDate',ts);

      xml.UpdateChildContent('rdf:RDF|rdf:Description|xmp:CreatorTool','My Custom Application');
      xml.UpdateChildContent('rdf:RDF|rdf:Description|dc:format','application/pdf');

      sbDocId := TStringBuilder.Create;
      sbDocId.Append('uuid:');
      sbDocId.AppendUuid(True);
      xml.UpdateChildContent('rdf:RDF|rdf:Description|xmpMM:DocumentID',sbDocId.GetAsString());

      sbInstanceId := TStringBuilder.Create;
      sbInstanceId.Append('uuid:');
      sbInstanceId.AppendUuid(True);
      xml.UpdateChildContent('rdf:RDF|rdf:Description|xmpMM:InstanceID',sbInstanceId.GetAsString());

    end;

  //  Add our custom metadata tags to either the existing XML metdata, or the newly created metadata.
  xml.UpdateAttrAt('rdf:RDF|rdf:Description',True,'xmlns:zf','urn:ferd:pdfa:CrossIndustryDocument:invoice:1p0#');
  xml.UpdateAttrAt('rdf:RDF|rdf:Description',True,'rdf:about',' ');
  xml.UpdateChildContent('rdf:RDF|rdf:Description|zf:ConformanceLevel','BASIC');
  xml.UpdateChildContent('rdf:RDF|rdf:Description|zf:DocumentFileName','ZZZZZZ-invoice.xml');
  xml.UpdateChildContent('rdf:RDF|rdf:Description|zf:DocumentType','INVOICE');
  xml.UpdateChildContent('rdf:RDF|rdf:Description|zf:Version','1.0');

  //  Create a new PDF with the updated metadata.
  sb := TStringBuilder.Create;
  xml.GetXmlSb(sb);
  success := pdf.UpdateMetadata(sb,'c:/temp/qa_output/out.pdf');
  if (success = True) then
    begin
      WriteLn('Success');
    end
  else
    begin
      WriteLn(pdf.LastErrorText);
    end;

  //  To see the metadata in Adobe Acrobat DC,
  //  1) Open the PDF.
  //  2) CTRL-D to show the Document Properties dialog.
  //  3) In the dialog, click on the "Additional Metadata" button.
  //  4) In the Additional Data dialog, click on "Advanced"
  //  5) Expand the namespace tree for the metadata you added.

  WriteLn('OK');


  pdf.Free;
  xml.Free;
  sbExisting.Free;
      dt.Free;
      sbDocId.Free;
      sbInstanceId.Free;
  sb.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.