feat: Locale extension to parse the Accept-Language header

selfprivacy_api/graphql/__init__.py

@@ -1,10 +1,13 @@
 """GraphQL API for SelfPrivacy."""
 # pylint: disable=too-few-public-methods
 import typing
+
 from strawberry.permission import BasePermission
 from strawberry.types import Info
+from strawberry.extensions import Extension
 
 from selfprivacy_api.actions.api_tokens import is_token_valid
+from selfprivacy_api.utils.localization import Localization
 
 
 class IsAuthenticated(BasePermission):
@@ -19,3 +22,14 @@ class IsAuthenticated(BasePermission):
         if token is None:
             return False
         return is_token_valid(token.replace("Bearer ", ""))
+
+
+class LocaleExtension(Extension):
+    """Parse the Accept-Language header and set the locale in the context as one of the supported locales."""
+
+    def resolve(self, _next, root, info: Info, *args, **kwargs):
+        locale = Localization().get_locale(
+            info.context["request"].headers.get("Accept-Language")
+        )
+        info.context["locale"] = locale
+        return _next(root, info, *args, **kwargs)

selfprivacy_api/graphql/schema.py

@@ -6,7 +6,7 @@ from typing import AsyncGenerator
 import strawberry
 from strawberry.types import Info
 
-from selfprivacy_api.graphql import IsAuthenticated
+from selfprivacy_api.graphql import IsAuthenticated, LocaleExtension
 from selfprivacy_api.graphql.mutations.api_mutations import ApiMutations
 from selfprivacy_api.graphql.mutations.job_mutations import JobMutations
 from selfprivacy_api.graphql.mutations.mutation_interface import GenericMutationReturn
@@ -63,7 +63,7 @@ class Query:
     @strawberry.field()
     def test(self, info: Info) -> str:
         """Test query"""
-        return info.context["request"].headers["Accept-Language"]
+        return info.context["locale"]
 
 
 @strawberry.type
@@ -102,4 +102,9 @@ class Subscription:
             await asyncio.sleep(0.5)
 
 
-schema = strawberry.Schema(query=Query, mutation=Mutation, subscription=Subscription)
+schema = strawberry.Schema(
+    query=Query,
+    mutation=Mutation,
+    subscription=Subscription,
+    extensions=[LocaleExtension],
+)

selfprivacy_api/utils/localization.py

@@ -45,6 +45,20 @@ class Localization(metaclass=SingletonMetaclass):
             return self.locales[DEFAULT_LOCALE][string_id]
         return string_id
 
+    def supported_locales(self) -> typing.List[str]:
+        """Return a list of supported languages."""
+        return list(self.locales.keys())
+
+    def get_locale(self, locale: typing.Optional[str]) -> str:
+        """Parse the value of Accept-Language header and return the most preferred supported locale."""
+        if locale is None:
+            return DEFAULT_LOCALE
+        for lang in locale.split(","):
+            lang = lang.split(";")[0]
+            if lang in self.locales:
+                return lang
+        return DEFAULT_LOCALE
+
     def flatten_dict(
         self, d: typing.Dict[str, typing.Any], parent_key: str = "", sep: str = "."
     ) -> typing.Dict[str, str]: