add support for fs.FS, embed.FS (in addition of string and http.FileSystem) for i18n locales and view engine's templates

view/handlebars.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"html/template"
 	"io"
-	"net/http"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
@@ -15,7 +15,7 @@ import (
 
 // HandlebarsEngine contains the handlebars view engine structure.
 type HandlebarsEngine struct {
-	fs http.FileSystem
+	fs fs.FS
 	// files configuration
 	rootDir   string
 	extension string
@@ -41,7 +41,7 @@ var (
 // Usage:
 // Handlebars("./views", ".html") or
 // Handlebars(iris.Dir("./views"), ".html") or
-// Handlebars(AssetFile(), ".html") for embedded data.
+// Handlebars(embed.FS, ".html") or Handlebars(AssetFile(), ".html") for embedded data.
 func Handlebars(fs interface{}, extension string) *HandlebarsEngine {
 	s := &HandlebarsEngine{
 		fs:            getFS(fs),
@@ -66,6 +66,15 @@ func Handlebars(fs interface{}, extension string) *HandlebarsEngine {
 // RootDir sets the directory to be used as a starting point
 // to load templates from the provided file system.
 func (s *HandlebarsEngine) RootDir(root string) *HandlebarsEngine {
+	if s.fs != nil && root != "" && root != "/" && root != "." && root != s.rootDir {
+		sub, err := fs.Sub(s.fs, s.rootDir)
+		if err != nil {
+			panic(err)
+		}
+
+		s.fs = sub // here so the "middleware" can work.
+	}
+
 	s.rootDir = filepath.ToSlash(root)
 	return s
 }
@@ -125,7 +134,7 @@ func (s *HandlebarsEngine) AddGlobalFunc(funcName string, funcBody interface{})
 //
 // Returns an error if something bad happens, user is responsible to catch it.
 func (s *HandlebarsEngine) Load() error {
-	return walk(s.fs, s.rootDir, func(path string, info os.FileInfo, _ error) error {
+	return walk(s.fs, "", func(path string, info os.FileInfo, _ error) error {
 		if info == nil || info.IsDir() {
 			return nil
 		}