fix default language fallback (#7479)

* fix default language fallback

* Update services/userlog/pkg/config/config.go

Co-authored-by: Martin <github@diemattels.at>

* Update services/notifications/pkg/config/config.go

Co-authored-by: Martin <github@diemattels.at>

* readme updated. local env vars removed

* Update changelog/unreleased/fix-default-mail-language-fallback.md

Co-authored-by: Martin <github@diemattels.at>

* update readme's and envvar texts

* fix changelog text

---------

Co-authored-by: Roman Perekhod <rperekhod@owncloud.com>
Co-authored-by: Martin <github@diemattels.at>

services/notifications/pkg/email/composer.go

@@ -9,9 +9,9 @@ import (
 )
 
 // NewTextTemplate replace the body message template placeholders with the translated template
-func NewTextTemplate(mt MessageTemplate, locale string, translationPath string, vars map[string]string) (MessageTemplate, error) {
+func NewTextTemplate(mt MessageTemplate, locale, defaultLocale string, translationPath string, vars map[string]string) (MessageTemplate, error) {
 	var err error
-	t := l10n.NewTranslator(locale, translationPath)
+	t := l10n.NewTranslator(locale, defaultLocale, translationPath)
 	mt.Subject, err = composeMessage(t.Translate(mt.Subject), vars)
 	if err != nil {
 		return mt, err
@@ -32,9 +32,9 @@ func NewTextTemplate(mt MessageTemplate, locale string, translationPath string,
 }
 
 // NewHTMLTemplate replace the body message template placeholders with the translated template
-func NewHTMLTemplate(mt MessageTemplate, locale string, translationPath string, vars map[string]string) (MessageTemplate, error) {
+func NewHTMLTemplate(mt MessageTemplate, locale, defaultLocale string, translationPath string, vars map[string]string) (MessageTemplate, error) {
 	var err error
-	t := l10n.NewTranslator(locale, translationPath)
+	t := l10n.NewTranslator(locale, defaultLocale, translationPath)
 	mt.Subject, err = composeMessage(t.Translate(mt.Subject), vars)
 	if err != nil {
 		return mt, err

services/notifications/pkg/email/email.go

@@ -26,8 +26,8 @@ var (
 )
 
 // RenderEmailTemplate renders the email template for a new share
-func RenderEmailTemplate(mt MessageTemplate, locale string, emailTemplatePath string, translationPath string, vars map[string]string) (*channels.Message, error) {
-	textMt, err := NewTextTemplate(mt, locale, translationPath, vars)
+func RenderEmailTemplate(mt MessageTemplate, locale, defaultLocale string, emailTemplatePath string, translationPath string, vars map[string]string) (*channels.Message, error) {
+	textMt, err := NewTextTemplate(mt, locale, defaultLocale, translationPath, vars)
 	if err != nil {
 		return nil, err
 	}
@@ -39,7 +39,7 @@ func RenderEmailTemplate(mt MessageTemplate, locale string, emailTemplatePath st
 	if err != nil {
 		return nil, err
 	}
-	htmlMt, err := NewHTMLTemplate(mt, locale, translationPath, escapeStringMap(vars))
+	htmlMt, err := NewHTMLTemplate(mt, locale, defaultLocale, translationPath, escapeStringMap(vars))
 	if err != nil {
 		return nil, err
 	}

services/notifications/pkg/email/l10n/locate.go

@@ -22,11 +22,19 @@ type Translator interface {
 }
 
 type translator struct {
-	l *gotext.Locale
+	locale *gotext.Locale
 }
 
 // NewTranslator Create Translator with library path and language code and load default domain
-func NewTranslator(local string, path string) Translator {
+func NewTranslator(locale, defaultLocale string, path string) Translator {
+	l := newLocate(locale, path)
+	if locale != "en" && len(l.GetTranslations()) == 0 {
+		l = newLocate(defaultLocale, path)
+	}
+	return &translator{locale: l}
+}
+
+func newLocate(local string, path string) *gotext.Locale {
 	var l *gotext.Locale
 	if path == "" {
 		filesystem, _ := fs.Sub(_translationFS, "locale")
@@ -35,9 +43,9 @@ func NewTranslator(local string, path string) Translator {
 		l = gotext.NewLocale(path, local)
 	}
 	l.AddDomain(_domain) // make domain configurable only if needed
-	return &translator{l: l}
+	return l
 }
 
 func (t *translator) Translate(str string) string {
-	return t.l.Get(str)
+	return t.locale.Get(str)
 }