feat(pdfengines): add watermark and stamp feature

pkg/modules/pdfengines/pdfengines.go

@@ -38,6 +38,8 @@ type PdfEngines struct {
 	embedNames          []string
 	readBookmarksNames  []string
 	writeBookmarksNames []string
+	watermarkNames      []string
+	stampNames          []string
 	engines             []gotenberg.PdfEngine
 	disableRoutes       bool
 }
@@ -58,6 +60,8 @@ func (mod *PdfEngines) Descriptor() gotenberg.ModuleDescriptor {
 			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-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")
+			fs.StringSlice("pdfengines-stamp-engines", []string{"pdfcpu", "pdftk"}, "Set the PDF engines and their order for the stamp feature - empty means all")
 			fs.Bool("pdfengines-disable-routes", false, "Disable the routes")
 
 			// Deprecated flags.
@@ -87,6 +91,8 @@ func (mod *PdfEngines) Provision(ctx *gotenberg.Context) error {
 	embedNames := flags.MustStringSlice("pdfengines-embed-engines")
 	readBookmarksNames := flags.MustStringSlice("pdfengines-read-bookmarks-engines")
 	writeBookmarksNames := flags.MustStringSlice("pdfengines-write-bookmarks-engines")
+	watermarkNames := flags.MustStringSlice("pdfengines-watermark-engines")
+	stampNames := flags.MustStringSlice("pdfengines-stamp-engines")
 	mod.disableRoutes = flags.MustBool("pdfengines-disable-routes")
 
 	engines, err := ctx.Modules(new(gotenberg.PdfEngine))
@@ -163,6 +169,16 @@ func (mod *PdfEngines) Provision(ctx *gotenberg.Context) error {
 		mod.writeBookmarksNames = writeBookmarksNames
 	}
 
+	mod.watermarkNames = defaultNames
+	if len(watermarkNames) > 0 {
+		mod.watermarkNames = watermarkNames
+	}
+
+	mod.stampNames = defaultNames
+	if len(stampNames) > 0 {
+		mod.stampNames = stampNames
+	}
+
 	return nil
 }
 
@@ -214,6 +230,8 @@ func (mod *PdfEngines) Validate() error {
 	findNonExistingEngines(mod.embedNames)
 	findNonExistingEngines(mod.readBookmarksNames)
 	findNonExistingEngines(mod.writeBookmarksNames)
+	findNonExistingEngines(mod.watermarkNames)
+	findNonExistingEngines(mod.stampNames)
 
 	if len(nonExistingEngines) == 0 {
 		return nil
@@ -236,6 +254,8 @@ func (mod *PdfEngines) SystemMessages() []string {
 		fmt.Sprintf("embed engines - %s", strings.Join(mod.embedNames[:], " ")),
 		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[:], " ")),
+		fmt.Sprintf("stamp engines - %s", strings.Join(mod.stampNames[:], " ")),
 	}
 }
 
@@ -266,6 +286,8 @@ func (mod *PdfEngines) PdfEngine() (gotenberg.PdfEngine, error) {
 		engines(mod.embedNames),
 		engines(mod.readBookmarksNames),
 		engines(mod.writeBookmarksNames),
+		engines(mod.watermarkNames),
+		engines(mod.stampNames),
 	), nil
 }
 
@@ -293,6 +315,8 @@ func (mod *PdfEngines) Routes() ([]api.Route, error) {
 		writeBookmarksRoute(engine),
 		encryptRoute(engine),
 		embedRoute(engine),
+		watermarkRoute(engine),
+		stampRoute(engine),
 	}, nil
 }