(.NET Core C#) 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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// This requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Chilkat.Pdf 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.
bool success = pdf.LoadFile("qa_data/pdf/blank_with_metadata.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Chilkat.Xml xml = new Chilkat.Xml();
Chilkat.StringBuilder sbExisting = new Chilkat.StringBuilder();

bool 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/");

    Chilkat.CkDateTime dt = new Chilkat.CkDateTime();
    dt.SetFromCurrentSystemTime();
    string 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");

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

    Chilkat.StringBuilder 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.
Chilkat.StringBuilder sb = new Chilkat.StringBuilder();
xml.GetXmlSb(sb);
success = pdf.UpdateMetadata(sb,"c:/temp/qa_output/out.pdf");
if (success == true) {
    Debug.WriteLine("Success");
}
else {
    Debug.WriteLine(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.

Debug.WriteLine("OK");