Merge pull request #127 from modern-python/set-context

allow setting context after container creation

Author: lesnik512

README.md

@@ -17,6 +17,11 @@ supports the following:
 - Fully typed and tested
 - Integrations with `FastAPI`, `FastStream` and `LiteStar`
 
+Usage examples:
+
+- with LiteStar - [litestar-sqlalchemy-template](https://github.com/modern-python/litestar-sqlalchemy-template)
+- with FastAPI - [fastapi-sqlalchemy-template](https://github.com/modern-python/fastapi-sqlalchemy-template)
+
 ## 📚 [Documentation](https://modern-di.readthedocs.io)
 
 ## 📦 [PyPi](https://pypi.org/project/modern-di)

packages/modern-di/modern_di/container.py

@@ -122,6 +122,9 @@ def reset_override(
         self.cache_registry.clear_kwargs()
         return self.providers_registry.reset_override(dependency_name=dependency_name, dependency_type=dependency_type)
 
+    def set_context(self, context_type: type[types.T], obj: types.T) -> None:
+        self.context_registry.set_context(context_type, obj)
+
     def __deepcopy__(self, *_: object, **__: object) -> "typing_extensions.Self":
         """Prevent cloning object."""
         return self

packages/modern-di/modern_di/registries/context_registry.py

@@ -1,16 +1,18 @@
 import dataclasses
 import typing
 
-
-T = typing.TypeVar("T")
+from modern_di import types
 
 
 @dataclasses.dataclass(kw_only=True, slots=True, frozen=True)
 class ContextRegistry:
     context: dict[type[typing.Any], typing.Any]
 
-    def find_context(self, context_type: type[T]) -> T | None:
+    def find_context(self, context_type: type[types.T]) -> types.T | None:
         if context_type and (context := self.context.get(context_type)):
-            return typing.cast(T, context)
+            return typing.cast(types.T, context)
 
         return None
+
+    def set_context(self, context_type: type[types.T], obj: types.T) -> None:
+        self.context[context_type] = obj

packages/modern-di/modern_di/types.py

@@ -2,5 +2,6 @@
 
 
 T_co = typing.TypeVar("T_co", covariant=True)
+T = typing.TypeVar("T")
 P = typing.ParamSpec("P")
 UNSET = object()

packages/modern-di/tests_core/providers/test_context_provider.py

@@ -15,6 +15,15 @@ def test_context_provider() -> None:
     assert instance1 is instance2 is now
 
 
+def test_context_provider_set_context_after_creation() -> None:
+    now = datetime.datetime.now(tz=datetime.timezone.utc)
+    app_container = Container()
+    app_container.set_context(datetime.datetime, now)
+    instance1 = app_container.resolve_provider(context_provider)
+    instance2 = app_container.resolve_provider(context_provider)
+    assert instance1 is instance2 is now
+
+
 def test_context_provider_not_found() -> None:
     app_container = Container()
     assert app_container.resolve_provider(context_provider) is None