(Xojo Plugin) 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.

Dim pdf As New Chilkat.Pdf

// Load a PDF file.
// If the PDF file already has metadata, we'll update it.
// Otherwise this example adds the metadata.
Dim success As Boolean
success = pdf.LoadFile("qa_data/pdf/blank_with_metadata.pdf")
If (success = False) Then
    System.DebugLog(pdf.LastErrorText)
    Return
End If

Dim xml As New Chilkat.Xml
Dim sbExisting As New Chilkat.StringBuilder

Dim hasMetadata As Boolean
hasMetadata = pdf.GetMetadata(sbExisting)
If (hasMetadata = True) Then
    success = xml.LoadSb(sbExisting,True)
Else

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

    Dim dt As New Chilkat.CkDateTime
    success = dt.SetFromCurrentSystemTime()
    Dim ts As 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"

    Dim sbDocId As New Chilkat.StringBuilder
    success = sbDocId.Append("uuid:")
    success = sbDocId.AppendUuid(True)
    xml.UpdateChildContent "rdf:RDF|rdf:Description|xmpMM:DocumentID",sbDocId.GetAsString()

    Dim sbInstanceId As New Chilkat.StringBuilder
    success = sbInstanceId.Append("uuid:")
    success = sbInstanceId.AppendUuid(True)
    xml.UpdateChildContent "rdf:RDF|rdf:Description|xmpMM:InstanceID",sbInstanceId.GetAsString()

End If

// Add our custom metadata tags to either the existing XML metdata, or the newly created metadata.
success = xml.UpdateAttrAt("rdf:RDF|rdf:Description",True,"xmlns:zf","urn:ferd:pdfa:CrossIndustryDocument:invoice:1p0#")
success = 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.
Dim sb As New Chilkat.StringBuilder
success = xml.GetXmlSb(sb)
success = pdf.UpdateMetadata(sb,"c:/temp/qa_output/out.pdf")
If (success = True) Then
    System.DebugLog("Success")
Else
    System.DebugLog(pdf.LastErrorText)
End If

// 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.

System.DebugLog("OK")