feat: added xmp data

lib/append.go

@@ -1,6 +1,7 @@
 package lib
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -19,10 +20,13 @@ func AppendToPdf(
 	outputFilePath string,
 	embedName string,
 	description string,
-) error {
+) (err error) {
 	logger := GetDebugLogger()
 	logger.Log(fmt.Sprintf("enter appendToPdf(%s, %s, %s)", inputPdfFilePath, inputXmlFilePath, outputFilePath))
 	defer func() {
+		if err != nil {
+			logger.Log("append err:", err)
+		}
 		logger.Log("leave appendToPdf")
 	}()
 
@@ -58,30 +62,62 @@ func AppendToPdf(
 		),
 	)
 
-	inputFile, err := os.Open(inputPdfFilePath)
+	var inputFile *os.File
+	inputFile, err = os.Open(inputPdfFilePath)
 	if err != nil {
 		return err
 	}
 	defer inputFile.Close()
 
-	var doc *pdf.Document
-	doc, err = pdf.OpenReaderWithOptions(inputFile, pdf.OpenOptions{
+	var result io.Reader
+	result, err = addAttachment(inputFile, inputXmlFilePath, embedName, description)
+	if err != nil {
+		return err
+	}
+
+	result, err = addXmpData(result)
+	if err != nil {
+		return err
+	}
+
+	var outputFile *os.File
+	outputFile, err = os.Create(outputFilePath)
+	if err != nil {
+		return err
+	}
+	defer outputFile.Close()
+
+	_, err = io.Copy(outputFile, result)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func addAttachment(
+	data io.Reader,
+	inputXmlFilePath string,
+	embedName string,
+	description string,
+) (io.Reader, error) {
+	doc, err := pdf.OpenReaderWithOptions(data, pdf.OpenOptions{
 		Writable: true,
 	})
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	var inputXmlFile *os.File
 	inputXmlFile, err = os.Open(inputXmlFilePath)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	var inputData []byte
 	inputData, err = io.ReadAll(inputXmlFile)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	err = doc.AddAttachment(attachment.Attachment{
@@ -93,15 +129,52 @@ func AppendToPdf(
 		ModDate:      time.Now(),
 	}, inputData)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	logger.Log(doc.Writer().Version)
-	err = doc.Writer().SaveAs(outputFilePath)
+	result := bytes.NewBuffer([]byte{})
+	_, err = doc.Writer().WriteTo(result)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	return nil
+	return result, nil
+}
 
+func addXmpData(data io.Reader) (io.Reader, error) {
+	doc, err := pdf.OpenReaderWithOptions(data, pdf.OpenOptions{
+		Writable: true,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	var xmpData []byte
+	xmpData, err = doc.XMPMetadata()
+	if err != nil {
+		return nil, err
+	}
+
+	xmpData, err = addFacturXXmpData(xmpData)
+	if err != nil {
+		return nil, err
+	}
+
+	err = doc.SetXMPMetadata(xmpData)
+	if err != nil {
+		return nil, err
+	}
+
+	xmpData, err = doc.XMPMetadata()
+	if err != nil {
+		return nil, err
+	}
+
+	result := bytes.NewBuffer([]byte{})
+	_, err = doc.Writer().WriteTo(result)
+	if err != nil {
+		return nil, err
+	}
+
+	return result, nil
 }

lib/xmp.go

@@ -0,0 +1,73 @@
+package lib
+
+import (
+	xmpbase "github.com/trimmer-io/go-xmp/models/xmp_base"
+	"github.com/trimmer-io/go-xmp/xmp"
+)
+
+const (
+	FacturXNamespace = "Factur-X PDFA Erweiterungsschema"
+	FacturXUri       = "urn:factur-x:pdfa:CrossIndustryDocument:invoice:1p0#"
+	FacturXPrefix    = "fx:"
+)
+
+func addFacturXXmpData(data []byte) ([]byte, error) {
+	doc := &xmp.Document{}
+	err := xmp.Unmarshal(data, doc)
+	if err != nil {
+		return nil, err
+	}
+
+	// --- Register Factur-X namespace ---
+	ns := &xmp.Namespace{
+		Name: "fx",
+		URI:  FacturXUri,
+		Factory: func(name string) xmp.Model {
+			return &xmpbase.XmpBase{}
+		},
+	}
+	xmp.Register(ns)
+	_, err = doc.MakeModel(ns)
+	if err != nil {
+		return nil, err
+	}
+
+	// --- Set Factur-X properties ---
+	err = doc.SetPath(xmp.PathValue{
+		Path:      FacturXPrefix + "ConformanceLevel",
+		Namespace: FacturXUri,
+		Value:     "EN 16931",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	err = doc.SetPath(xmp.PathValue{
+		Path:      FacturXPrefix + "DocumentType",
+		Namespace: FacturXUri,
+		Value:     "INVOICE",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	err = doc.SetPath(xmp.PathValue{
+		Path:      FacturXPrefix + "DocumentFileName",
+		Namespace: FacturXUri,
+		Value:     "factur-x.xml",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	err = doc.SetPath(xmp.PathValue{
+		Path:      FacturXPrefix + "Version",
+		Namespace: FacturXUri,
+		Value:     "1.0",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return xmp.Marshal(doc)
+}