VB.NET

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.

VB.NET

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 New Chilkat.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
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


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

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

    Dim sbInstanceId As New Chilkat.StringBuilder
    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 New Chilkat.StringBuilder
xml.GetXmlSb(sb)
success = pdf.UpdateMetadata(sb,"c:/temp/qa_output/out.pdf")
If (success = True) Then
    Debug.WriteLine("Success")
Else
    Debug.WriteLine(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.

Debug.WriteLine("OK")