(Perl) 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.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

$pdf = chilkat::CkPdf->new();

# 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 == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

$xml = chilkat::CkXml->new();
$sbExisting = chilkat::CkStringBuilder->new();

$hasMetadata = $pdf->GetMetadata($sbExisting);
if ($hasMetadata == 1) {
    $xml->LoadSb($sbExisting,1);
}
else {

    # Otherwise create the bare minimum XMP metadata.
    $xml->put_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",1,"xmlns:rdf","http://www.w3.org/1999/02/22-rdf-syntax-ns#");
    $xml->UpdateAttrAt("rdf:RDF|rdf:Description",1,"rdf:about","");
    $xml->UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:xmp","http://ns.adobe.com/xap/1.0/");
    $xml->UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:dc","http://purl.org/dc/elements/1.1/");
    $xml->UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:xmpMM","http://ns.adobe.com/xap/1.0/mm/");
    $xml->UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:pdf","http://ns.adobe.com/pdf/1.3/");
    $xml->UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:xmpRights","http://ns.adobe.com/xap/1.0/rights/");

    $dt = chilkat::CkDateTime->new();
    $dt->SetFromCurrentSystemTime();
    $ts = $dt->getAsTimestamp(1);

    $xml->UpdateChildContent("rdf:RDF|rdf:Description|xmp:ModifyDate",$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 = chilkat::CkStringBuilder->new();
    $sbDocId->Append("uuid:");
    $sbDocId->AppendUuid(1);
    $xml->UpdateChildContent("rdf:RDF|rdf:Description|xmpMM:DocumentID",$sbDocId->getAsString());

    $sbInstanceId = chilkat::CkStringBuilder->new();
    $sbInstanceId->Append("uuid:");
    $sbInstanceId->AppendUuid(1);
    $xml->UpdateChildContent("rdf:RDF|rdf:Description|xmpMM:InstanceID",$sbInstanceId->getAsString());

}

# Add our custom metadata tags to either the existing XML metdata, or the newly created metadata.
$xml->UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:zf","urn:ferd:pdfa:CrossIndustryDocument:invoice:1p0#");
$xml->UpdateAttrAt("rdf:RDF|rdf:Description",1,"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 = chilkat::CkStringBuilder->new();
$xml->GetXmlSb($sb);
$success = $pdf->UpdateMetadata($sb,"c:/temp/qa_output/out.pdf");
if ($success == 1) {
    print "Success" . "\r\n";
}
else {
    print $pdf->lastErrorText() . "\r\n";
}

# 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.

print "OK" . "\r\n";