(Node.js) 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.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOS

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

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

    var pdf = new chilkat.Pdf();

    // Load a PDF file.
    // If the PDF file already has metadata, we'll update it.
    // Otherwise this example adds the metadata.
    var success = pdf.LoadFile("qa_data/pdf/blank_with_metadata.pdf");
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    var xml = new chilkat.Xml();
    var sbExisting = new chilkat.StringBuilder();

    var hasMetadata = pdf.GetMetadata(sbExisting);
    if (hasMetadata == true) {
        xml.LoadSb(sbExisting,true);
    }
    else {

        // 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/");

        var dt = new chilkat.CkDateTime();
        dt.SetFromCurrentSystemTime();
        var 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");

        var sbDocId = new chilkat.StringBuilder();
        sbDocId.Append("uuid:");
        sbDocId.AppendUuid(true);
        xml.UpdateChildContent("rdf:RDF|rdf:Description|xmpMM:DocumentID",sbDocId.GetAsString());

        var sbInstanceId = new chilkat.StringBuilder();
        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.
    var sb = new chilkat.StringBuilder();
    xml.GetXmlSb(sb);
    success = pdf.UpdateMetadata(sb,"c:/temp/qa_output/out.pdf");
    if (success == true) {
        console.log("Success");
    }
    else {
        console.log(pdf.LastErrorText);
    }

    // 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.

    console.log("OK");

}

chilkatExample();