support i18n

src/capport/api/app_cls.py

@@ -18,6 +18,26 @@ class DispatchingJinjaLoader(quart.templating.DispatchingJinjaLoader):
     def __init__(self, app: MyQuartApp) -> None:
         super().__init__(app)
 
+    def get_source(
+        self, environment: jinja2.Environment, template: str
+    ) -> typing.Tuple[str, typing.Optional[str], typing.Optional[typing.Callable[[], bool]]]:
+        """Returns the template source from the environment.
+
+        This considers the loaders on the :attr:`app` and blueprints.
+        """
+        langs: typing.List[str] = quart.g.langs
+        for loader in self._loaders():
+            for lang in langs:
+                try:
+                    return loader.get_source(environment, os.path.join('i18n', lang, template))
+                except jinja2.TemplateNotFound:
+                    continue
+            try:
+                return loader.get_source(environment, template)
+            except jinja2.TemplateNotFound:
+                continue
+        raise jinja2.TemplateNotFound(template)
+
     def _loaders(self) -> typing.Generator[jinja2.BaseLoader, None, None]:
         if self.app.custom_loader:
             yield self.app.custom_loader