feat: add embeds metadata

pkg/modules/pdfengines/multi.go

@@ -22,6 +22,7 @@ type multiPdfEngines struct {
 	writeMetadataEngines  []gotenberg.PdfEngine
 	passwordEngines       []gotenberg.PdfEngine
 	embedEngines          []gotenberg.PdfEngine
+	embedMetadataEngines  []gotenberg.PdfEngine
 	readBookmarksEngines  []gotenberg.PdfEngine
 	writeBookmarksEngines []gotenberg.PdfEngine
 	watermarkEngines      []gotenberg.PdfEngine
@@ -38,6 +39,7 @@ func newMultiPdfEngines(
 	writeMetadataEngines,
 	passwordEngines,
 	embedEngines,
+	embedMetadataEngines,
 	readBookmarksEngines,
 	writeBookmarksEngines,
 	watermarkEngines,
@@ -53,6 +55,7 @@ func newMultiPdfEngines(
 		writeMetadataEngines:  writeMetadataEngines,
 		passwordEngines:       passwordEngines,
 		embedEngines:          embedEngines,
+		embedMetadataEngines:  embedMetadataEngines,
 		readBookmarksEngines:  readBookmarksEngines,
 		writeBookmarksEngines: writeBookmarksEngines,
 		watermarkEngines:      watermarkEngines,
@@ -603,6 +606,43 @@ func (multi *multiPdfEngines) Rotate(ctx context.Context, logger *slog.Logger, i
 	return err
 }
 
+// EmbedFilesMetadata sets metadata on embedded files using the first available
+// engine that supports it.
+//
+//nolint:dupl
+func (multi *multiPdfEngines) EmbedFilesMetadata(ctx context.Context, logger *slog.Logger, metadata map[string]map[string]string, inputPath string) error {
+	tracer := gotenberg.Tracer()
+	ctx, span := tracer.Start(ctx, "pdfengines.EmbedFilesMetadata", trace.WithSpanKind(trace.SpanKindInternal))
+	defer span.End()
+
+	var err error
+	errChan := make(chan error, 1)
+
+	for _, engine := range multi.embedMetadataEngines {
+		go func(engine gotenberg.PdfEngine) {
+			errChan <- engine.EmbedFilesMetadata(ctx, logger, metadata, inputPath)
+		}(engine)
+
+		select {
+		case setErr := <-errChan:
+			if setErr != nil {
+				err = errors.Join(err, setErr)
+			} else {
+				span.SetStatus(codes.Ok, "")
+				return nil
+			}
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+
+	err = fmt.Errorf("set embeds metadata using multi PDF engines: %w", err)
+	span.RecordError(err)
+	span.SetStatus(codes.Error, err.Error())
+
+	return err
+}
+
 // Interface guards.
 var (
 	_ gotenberg.PdfEngine = (*multiPdfEngines)(nil)

pkg/modules/pdfengines/pdfengines.go

@@ -36,6 +36,7 @@ type PdfEngines struct {
 	writeMetadataNames  []string
 	encryptNames        []string
 	embedNames          []string
+	embedMetadataNames  []string
 	readBookmarksNames  []string
 	writeBookmarksNames []string
 	watermarkNames      []string
@@ -59,6 +60,7 @@ func (mod *PdfEngines) Descriptor() gotenberg.ModuleDescriptor {
 			fs.StringSlice("pdfengines-write-metadata-engines", []string{"exiftool"}, "Set the PDF engines and their order for the write metadata feature - empty means all")
 			fs.StringSlice("pdfengines-encrypt-engines", []string{"qpdf", "pdftk", "pdfcpu"}, "Set the PDF engines and their order for the password protection feature - empty means all")
 			fs.StringSlice("pdfengines-embed-engines", []string{"pdfcpu"}, "Set the PDF engines and their order for the file embedding feature - empty means all")
+			fs.StringSlice("pdfengines-embed-metadata-engines", []string{"qpdf"}, "Set the PDF engines and their order for the embed metadata feature - empty means all")
 			fs.StringSlice("pdfengines-read-bookmarks-engines", []string{"pdfcpu"}, "Set the PDF engines and their order for the read bookmarks feature - empty means all")
 			fs.StringSlice("pdfengines-write-bookmarks-engines", []string{"pdfcpu"}, "Set the PDF engines and their order for the write bookmarks feature - empty means all")
 			fs.StringSlice("pdfengines-watermark-engines", []string{"pdfcpu", "pdftk"}, "Set the PDF engines and their order for the watermark feature - empty means all")
@@ -91,6 +93,7 @@ func (mod *PdfEngines) Provision(ctx *gotenberg.Context) error {
 	writeMetadataNames := flags.MustStringSlice("pdfengines-write-metadata-engines")
 	encryptNames := flags.MustStringSlice("pdfengines-encrypt-engines")
 	embedNames := flags.MustStringSlice("pdfengines-embed-engines")
+	embedMetadataNames := flags.MustStringSlice("pdfengines-embed-metadata-engines")
 	readBookmarksNames := flags.MustStringSlice("pdfengines-read-bookmarks-engines")
 	writeBookmarksNames := flags.MustStringSlice("pdfengines-write-bookmarks-engines")
 	watermarkNames := flags.MustStringSlice("pdfengines-watermark-engines")
@@ -162,6 +165,11 @@ func (mod *PdfEngines) Provision(ctx *gotenberg.Context) error {
 		mod.embedNames = embedNames
 	}
 
+	mod.embedMetadataNames = defaultNames
+	if len(embedMetadataNames) > 0 {
+		mod.embedMetadataNames = embedMetadataNames
+	}
+
 	mod.readBookmarksNames = defaultNames
 	if len(readBookmarksNames) > 0 {
 		mod.readBookmarksNames = readBookmarksNames
@@ -236,6 +244,7 @@ func (mod *PdfEngines) Validate() error {
 	findNonExistingEngines(mod.writeMetadataNames)
 	findNonExistingEngines(mod.encryptNames)
 	findNonExistingEngines(mod.embedNames)
+	findNonExistingEngines(mod.embedMetadataNames)
 	findNonExistingEngines(mod.readBookmarksNames)
 	findNonExistingEngines(mod.writeBookmarksNames)
 	findNonExistingEngines(mod.watermarkNames)
@@ -261,6 +270,7 @@ func (mod *PdfEngines) SystemMessages() []string {
 		fmt.Sprintf("write metadata engines - %s", strings.Join(mod.writeMetadataNames, " ")),
 		fmt.Sprintf("encrypt engines - %s", strings.Join(mod.encryptNames, " ")),
 		fmt.Sprintf("embed engines - %s", strings.Join(mod.embedNames, " ")),
+		fmt.Sprintf("embed metadata engines - %s", strings.Join(mod.embedMetadataNames, " ")),
 		fmt.Sprintf("read bookmarks engines - %s", strings.Join(mod.readBookmarksNames, " ")),
 		fmt.Sprintf("write bookmarks engines - %s", strings.Join(mod.writeBookmarksNames, " ")),
 		fmt.Sprintf("watermark engines - %s", strings.Join(mod.watermarkNames, " ")),
@@ -294,6 +304,7 @@ func (mod *PdfEngines) PdfEngine() (gotenberg.PdfEngine, error) {
 		engines(mod.writeMetadataNames),
 		engines(mod.encryptNames),
 		engines(mod.embedNames),
+		engines(mod.embedMetadataNames),
 		engines(mod.readBookmarksNames),
 		engines(mod.writeBookmarksNames),
 		engines(mod.watermarkNames),

pkg/modules/pdfengines/routes.go

@@ -443,6 +443,30 @@ func FormDataPdfEmbeds(form *api.FormData) []string {
 	return embedPaths
 }
 
+// FormDataPdfEmbedsMetadata extracts embeds metadata from form data.
+// The "embedsMetadata" field is a JSON string keyed by filename.
+func FormDataPdfEmbedsMetadata(form *api.FormData) map[string]map[string]string {
+	var metadata map[string]map[string]string
+	form.EmbedsMetadata(&metadata)
+	return metadata
+}
+
+// EmbedFilesMetadataStub sets metadata on embedded files in PDFs.
+func EmbedFilesMetadataStub(ctx *api.Context, engine gotenberg.PdfEngine, metadata map[string]map[string]string, inputPaths []string) error {
+	if len(metadata) == 0 {
+		return nil
+	}
+
+	for _, inputPath := range inputPaths {
+		err := engine.EmbedFilesMetadata(ctx, ctx.Log(), metadata, inputPath)
+		if err != nil {
+			return fmt.Errorf("set embeds metadata on PDF '%s': %w", inputPath, err)
+		}
+	}
+
+	return nil
+}
+
 // FormDataPdfEncrypt extracts encryption parameters from form data.
 func FormDataPdfEncrypt(form *api.FormData) (userPassword, ownerPassword string) {
 	form.String("userPassword", &userPassword, "")
@@ -638,6 +662,7 @@ func mergeRoute(engine gotenberg.PdfEngine) api.Route {
 			stamp := FormDataPdfStamp(form, false)
 			stampFile := FormDataPdfStampFile(form)
 			angle, rotatePages := FormDataPdfRotate(form, false)
+			embedsMetadata := FormDataPdfEmbedsMetadata(form)
 
 			var inputPaths []string
 			var flatten bool
@@ -754,6 +779,11 @@ func mergeRoute(engine gotenberg.PdfEngine) api.Route {
 				return fmt.Errorf("embed files into PDFs: %w", err)
 			}
 
+			err = EmbedFilesMetadataStub(ctx, engine, embedsMetadata, outputPaths)
+			if err != nil {
+				return fmt.Errorf("set embeds metadata: %w", err)
+			}
+
 			err = EncryptPdfStub(ctx, engine, userPassword, ownerPassword, outputPaths)
 			if err != nil {
 				return fmt.Errorf("encrypt PDFs: %w", err)
@@ -789,6 +819,7 @@ func splitRoute(engine gotenberg.PdfEngine) api.Route {
 			stamp := FormDataPdfStamp(form, false)
 			stampFile := FormDataPdfStampFile(form)
 			angle, rotatePages := FormDataPdfRotate(form, false)
+			embedsMetadata := FormDataPdfEmbedsMetadata(form)
 
 			var inputPaths []string
 			var flatten bool
@@ -856,6 +887,11 @@ func splitRoute(engine gotenberg.PdfEngine) api.Route {
 				return fmt.Errorf("embed files into PDFs: %w", err)
 			}
 
+			err = EmbedFilesMetadataStub(ctx, engine, embedsMetadata, convertOutputPaths)
+			if err != nil {
+				return fmt.Errorf("set embeds metadata: %w", err)
+			}
+
 			err = EncryptPdfStub(ctx, engine, userPassword, ownerPassword, convertOutputPaths)
 			if err != nil {
 				return fmt.Errorf("encrypt PDFs: %w", err)
@@ -1180,6 +1216,7 @@ func embedRoute(engine gotenberg.PdfEngine) api.Route {
 
 			form := ctx.FormData()
 			embedPaths := FormDataPdfEmbeds(form)
+			embedsMetadata := FormDataPdfEmbedsMetadata(form)
 
 			var inputPaths []string
 			err := form.
@@ -1193,6 +1230,11 @@ func embedRoute(engine gotenberg.PdfEngine) api.Route {
 				return fmt.Errorf("embed files into PDFs: %w", err)
 			}
 
+			err = EmbedFilesMetadataStub(ctx, engine, embedsMetadata, inputPaths)
+			if err != nil {
+				return fmt.Errorf("set embeds metadata: %w", err)
+			}
+
 			err = ctx.AddOutputPaths(inputPaths...)
 			if err != nil {
 				return fmt.Errorf("add output paths: %w", err)