WIP: Add XMP metadata to ZUGFeRD

invopop · Dec 20, 2024 · da7011e · da7011e
1 parent 7bb8736
commit da7011e
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diff --git a/assets/zugferd.xmp b/assets/zugferd.xmp
@@ -0,0 +1,57 @@
+<?xpacket begin=""?>
+<x:xmpmeta xmlns:x="adobe:ns:meta/"
+           xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
+  <rdf:RDF>
+    <rdf:Description xmlns:pdfaExtension="http://www.aiim.org/pdfa/ns/extension/"
+                     xmlns:pdfaField="http://www.aiim.org/pdfa/ns/field#"
+                     xmlns:pdfaProperty="http://www.aiim.org/pdfa/ns/property#"
+                     xmlns:pdfaSchema="http://www.aiim.org/pdfa/ns/schema#"
+                     xmlns:pdfaType="http://www.aiim.org/pdfa/ns/type#"
+                     rdf:about="">
+      <pdfaExtension:schemas>
+        <rdf:Bag>
+          <rdf:li rdf:parseType="Resource">
+            <pdfaSchema:schema>ZUGFeRD PDFA Extension Schema</pdfaSchema:schema>
+            <pdfaSchema:namespaceURI>urn:zugferd:pdfa:CrossIndustryDocument:invoice:2p0#</pdfaSchema:namespaceURI>
+            <pdfaSchema:prefix>fx</pdfaSchema:prefix>
+            <pdfaSchema:property>
+              <rdf:Seq>
+                <rdf:li rdf:parseType="Resource">
+                  <pdfaProperty:name>DocumentFileName</pdfaProperty:name>
+                  <pdfaProperty:valueType>Text</pdfaProperty:valueType>
+                  <pdfaProperty:category>external</pdfaProperty:category>
+                  <pdfaProperty:description>name of the embedded XML invoice file</pdfaProperty:description>
+                </rdf:li>
+                <rdf:li rdf:parseType="Resource">
+                  <pdfaProperty:name>DocumentType</pdfaProperty:name>
+                  <pdfaProperty:valueType>Text</pdfaProperty:valueType>
+                  <pdfaProperty:category>external</pdfaProperty:category>
+                  <pdfaProperty:description>INVOICE</pdfaProperty:description>
+                </rdf:li>
+                <rdf:li rdf:parseType="Resource">
+                  <pdfaProperty:name>Version</pdfaProperty:name>
+                  <pdfaProperty:valueType>Text</pdfaProperty:valueType>
+                  <pdfaProperty:category>external</pdfaProperty:category>
+                  <pdfaProperty:description>The actual version of the ZUGFeRD data</pdfaProperty:description>
+                </rdf:li>
+                <rdf:li rdf:parseType="Resource">
+                  <pdfaProperty:name>ConformanceLevel</pdfaProperty:name>
+                  <pdfaProperty:valueType>Text</pdfaProperty:valueType>
+                  <pdfaProperty:category>external</pdfaProperty:category>
+                  <pdfaProperty:description>The conformance level of the ZUGFeRD data</pdfaProperty:description>
+                </rdf:li>
+              </rdf:Seq>
+            </pdfaSchema:property>
+          </rdf:li>
+        </rdf:Bag>
+      </pdfaExtension:schemas>
+    </rdf:Description>
+    <rdf:Description xmlns:fx="urn:zugferd:pdfa:CrossIndustryDocument:invoice:2p0#"
+                     fx:ConformanceLevel="EN 16931"
+                     fx:DocumentFileName="zugferd-invoice.xml"
+                     fx:DocumentType="INVOICE"
+                     fx:Version="1p0"
+                     rdf:about=""/>
+  </rdf:RDF>
+</x:xmpmeta>
+<?xpacket end="w"?>
diff --git a/pkg/pdf/pdf.go b/pkg/pdf/pdf.go
@@ -6,6 +6,7 @@ import (
 	"context"
 	"fmt"
 	"io/fs"
+	"os"
 	"path/filepath"
 )
 
@@ -24,6 +25,7 @@ type options struct {
 	metadata    *Metadata
 	styles      []*Stylesheet
 	attachments []*Attachment
+	xmpMetadata *XMPMetadata
 }
 
 // Metadata contains additional information to add to the PDF
@@ -49,6 +51,12 @@ type Attachment struct {
 	Description string
 }
 
+// XMPMetadata is used to add XMP metadata to the PDF.
+type XMPMetadata struct {
+	Data     []byte
+	Filename string
+}
+
 // WithURL sets the URL to use for the connection to a remote server if needed.
 func WithURL(url string) Config {
 	return func(in any) {
@@ -104,6 +112,16 @@ func WithAttachment(a *Attachment) Option {
 	}
 }
 
+// WithXMPMetadata adds the XMP metadata to the conversion request.
+func WithXMPMetadata() Option {
+	return func(o *options) {
+		o.xmpMetadata = &XMPMetadata{
+			Data:     loadXMP(),
+			Filename: "zugferd.xmp",
+		}
+	}
+}
+
 // Convertor defines the interface expected to be able to convert sources into PDF
 type Convertor interface {
 	// HTML is the default implementation that takes a raw HTML file and converts it
@@ -134,3 +152,11 @@ func prepareOptions(opts []Option) *options {
 	}
 	return o
 }
+
+func loadXMP() []byte {
+	data, err := os.ReadFile("assets/zugferd.xmp")
+	if err != nil {
+		panic(err)
+	}
+	return data
+}
diff --git a/pkg/pdf/prince.go b/pkg/pdf/prince.go
@@ -62,5 +62,18 @@ func (pc *princeConvertor) HTML(_ context.Context, data []byte, opts ...Option)
 		}
 	}
 
+	if o.xmpMetadata != nil {
+		xmpFilename := "metadata.xmp"
+		j.Files[xmpFilename] = o.xmpMetadata.Data
+		if j.PDF == nil {
+			j.PDF = new(princepdf.PDF)
+		}
+		j.PDF.Attach = append(j.PDF.Attach, &princepdf.Attachment{
+			URL:         xmpFilename,
+			Filename:    xmpFilename,
+			Description: "XMP Metadata File",
+		})
+	}
+
 	return pc.client.Run(j)
 }