Lua Requires Chilkat v10.1.0+

PDF Update or Add XML Metadata

Demonstrates how to add or update the XML metadata stored in a PDF. Lua

local chilkat = require("chilkat")

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

local pdf = chilkat.Pdf.new()

-- Load a PDF file.
-- If the PDF file already has metadata, we'll update it.
-- Otherwise this example adds the metadata.
local success = pdf:load_file("qa_data/pdf/blank_with_metadata.pdf")
if not success then
    print(pdf.last_error_text)
    return
end

local xml = chilkat.Xml.new()
local sbExisting = chilkat.StringBuilder.new()

local hasMetadata = pdf:get_metadata(sbExisting)
if hasMetadata then
    xml:load_sb(sbExisting, true)
else

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

    local dt = chilkat.DateTime.new()
    dt:set_from_current_system_time()
    local ts = dt:get_as_timestamp(true)

    xml:update_child_content("rdf:RDF|rdf:Description|xmp:ModifyDate", ts)
    xml:update_child_content("rdf:RDF|rdf:Description|xmp:CreateDate", ts)
    xml:update_child_content("rdf:RDF|rdf:Description|xmp:MetadataDate", ts)

    xml:update_child_content("rdf:RDF|rdf:Description|xmp:CreatorTool", "My Custom Application")
    xml:update_child_content("rdf:RDF|rdf:Description|dc:format", "application/pdf")

    local sbDocId = chilkat.StringBuilder.new()
    sbDocId:append("uuid:")
    sbDocId:append_uuid(true)
    xml:update_child_content("rdf:RDF|rdf:Description|xmpMM:DocumentID", sbDocId:get_as_string())

    local sbInstanceId = chilkat.StringBuilder.new()
    sbInstanceId:append("uuid:")
    sbInstanceId:append_uuid(true)
    xml:update_child_content("rdf:RDF|rdf:Description|xmpMM:InstanceID", sbInstanceId:get_as_string())
end

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

-- Create a new PDF with the updated metadata.
local sb = chilkat.StringBuilder.new()
xml:get_xml_sb(sb)
success = pdf:update_metadata(sb, "c:/temp/qa_output/out.pdf")
if success then
    print("Success")
else
    print(pdf.last_error_text)
end

-- 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.

print("OK")