Visual FoxPro

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.

Visual FoxPro

LOCAL lnSuccess
LOCAL loPdf
LOCAL loXml
LOCAL loSbExisting
LOCAL lnHasMetadata
LOCAL loDt
LOCAL lcTs
LOCAL loSbDocId
LOCAL loSbInstanceId
LOCAL loSb

lnSuccess = 0

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

loPdf = CreateObject('Chilkat.Pdf')

* Load a PDF file.
* If the PDF file already has metadata, we'll update it.
* Otherwise this example adds the metadata.
lnSuccess = loPdf.LoadFile("qa_data/pdf/blank_with_metadata.pdf")
IF (lnSuccess = 0) THEN
    ? loPdf.LastErrorText
    RELEASE loPdf
    CANCEL
ENDIF

loXml = CreateObject('Chilkat.Xml')
loSbExisting = CreateObject('Chilkat.StringBuilder')

lnHasMetadata = loPdf.GetMetadata(loSbExisting)
IF (lnHasMetadata = 1) THEN
    loXml.LoadSb(loSbExisting,1)
ELSE

    * Otherwise create the bare minimum XMP metadata.
    loXml.Tag = "x:xmpmeta"
    loXml.AddAttribute("xmlns:x","adobe:ns:meta/")
    loXml.AddAttribute("x:xmptk","Adobe XMP Core 9.1-c001 79.675d0f7, 2023/06/11-19:21:16 ")
    loXml.UpdateAttrAt("rdf:RDF",1,"xmlns:rdf","http://www.w3.org/1999/02/22-rdf-syntax-ns#")
    loXml.UpdateAttrAt("rdf:RDF|rdf:Description",1,"rdf:about","")
    loXml.UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:xmp","http://ns.adobe.com/xap/1.0/")
    loXml.UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:dc","http://purl.org/dc/elements/1.1/")
    loXml.UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:xmpMM","http://ns.adobe.com/xap/1.0/mm/")
    loXml.UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:pdf","http://ns.adobe.com/pdf/1.3/")
    loXml.UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:xmpRights","http://ns.adobe.com/xap/1.0/rights/")

    loDt = CreateObject('Chilkat.CkDateTime')
    loDt.SetFromCurrentSystemTime()
    lcTs = loDt.GetAsTimestamp(1)

    loXml.UpdateChildContent("rdf:RDF|rdf:Description|xmp:ModifyDate",lcTs)
    loXml.UpdateChildContent("rdf:RDF|rdf:Description|xmp:CreateDate",lcTs)
    loXml.UpdateChildContent("rdf:RDF|rdf:Description|xmp:MetadataDate",lcTs)

    loXml.UpdateChildContent("rdf:RDF|rdf:Description|xmp:CreatorTool","My Custom Application")
    loXml.UpdateChildContent("rdf:RDF|rdf:Description|dc:format","application/pdf")

    loSbDocId = CreateObject('Chilkat.StringBuilder')
    loSbDocId.Append("uuid:")
    loSbDocId.AppendUuid(1)
    loXml.UpdateChildContent("rdf:RDF|rdf:Description|xmpMM:DocumentID",loSbDocId.GetAsString())

    loSbInstanceId = CreateObject('Chilkat.StringBuilder')
    loSbInstanceId.Append("uuid:")
    loSbInstanceId.AppendUuid(1)
    loXml.UpdateChildContent("rdf:RDF|rdf:Description|xmpMM:InstanceID",loSbInstanceId.GetAsString())

ENDIF

* Add our custom metadata tags to either the existing XML metdata, or the newly created metadata.
loXml.UpdateAttrAt("rdf:RDF|rdf:Description",1,"xmlns:zf","urn:ferd:pdfa:CrossIndustryDocument:invoice:1p0#")
loXml.UpdateAttrAt("rdf:RDF|rdf:Description",1,"rdf:about"," ")
loXml.UpdateChildContent("rdf:RDF|rdf:Description|zf:ConformanceLevel","BASIC")
loXml.UpdateChildContent("rdf:RDF|rdf:Description|zf:DocumentFileName","ZZZZZZ-invoice.xml")
loXml.UpdateChildContent("rdf:RDF|rdf:Description|zf:DocumentType","INVOICE")
loXml.UpdateChildContent("rdf:RDF|rdf:Description|zf:Version","1.0")

* Create a new PDF with the updated metadata.
loSb = CreateObject('Chilkat.StringBuilder')
loXml.GetXmlSb(loSb)
lnSuccess = loPdf.UpdateMetadata(loSb,"c:/temp/qa_output/out.pdf")
IF (lnSuccess = 1) THEN
    ? "Success"
ELSE
    ? loPdf.LastErrorText
ENDIF

* 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.

? "OK"

RELEASE loPdf
RELEASE loXml
RELEASE loSbExisting
RELEASE loDt
RELEASE loSbDocId
RELEASE loSbInstanceId
RELEASE loSb