(PHP Extension) 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.

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<?php

include("chilkat.php");
// Use "chilkat_9_5_0.php" for versions of Chilkat < 10.0.0

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

$pdf = new CkPdf();

// 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) {
    print $pdf->lastErrorText() . "\n";
    exit;
}

$xml = new CkXml();
$sbExisting = new CkStringBuilder();

$hasMetadata = $pdf->GetMetadata($sbExisting);
if ($hasMetadata == true) {
    $xml->LoadSb($sbExisting,true);
}
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',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 = new CkDateTime();
    $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 = new CkStringBuilder();
    $sbDocId->Append('uuid:');
    $sbDocId->AppendUuid(true);
    $xml->UpdateChildContent('rdf:RDF|rdf:Description|xmpMM:DocumentID',$sbDocId->getAsString());

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

}

// Add our custom metadata tags to either the existing XML metdata, or the newly created metadata.
$xml->UpdateAttrAt('rdf:RDF|rdf:Description',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 = new CkStringBuilder();
$xml->GetXmlSb($sb);
$success = $pdf->UpdateMetadata($sb,'c:/temp/qa_output/out.pdf');
if ($success == true) {
    print 'Success' . "\n";
}
else {
    print $pdf->lastErrorText() . "\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' . "\n";

?>