B4X

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.

B4X

Dim success As Boolean = False

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

Dim pdf As ChilkatPdf
pdf.Initialize("pdf")

'  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 Then
    Log(pdf.LastErrorText)
    Return
End If


Dim xml As ChilkatXml
xml.Initialize
Dim sbExisting As ChilkatStringBuilder
sbExisting.Initialize

Dim hasMetadata As Boolean = pdf.GetMetadata(sbExisting)
If hasMetadata = True Then
    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/")

    Dim dt As ChilkatDateTime
    dt.Initialize
    dt.SetFromCurrentSystemTime
    Dim ts As String = 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 ChilkatStringBuilder
    sbDocId.Initialize
    sbDocId.Append("uuid:")
    sbDocId.AppendUuid(True)
    xml.UpdateChildContent("rdf:RDF|rdf:Description|xmpMM:DocumentID", sbDocId.GetAsString)

    Dim sbInstanceId As ChilkatStringBuilder
    sbInstanceId.Initialize
    sbInstanceId.Append("uuid:")
    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.
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.
Dim sb As ChilkatStringBuilder
sb.Initialize
xml.GetXmlSb(sb)
success = pdf.UpdateMetadata(sb, "c:/temp/qa_output/out.pdf")
If success = True Then
    Log("Success")
Else
    Log(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.

Log("OK")