Merge pull request #35 from modern-python/24-feature-add-object-provider

add object provider

docs/index.md

@@ -25,6 +25,7 @@
     providers/factories
     providers/collections
     providers/context-providers
+    providers/object
 
 .. toctree::
     :maxdepth: 1

docs/providers/object.md

@@ -0,0 +1,15 @@
+# Object
+
+Object provider returns an object “as is”.
+
+```python
+from modern_di import BaseGraph, Container, Scope, providers
+
+
+class Dependencies(BaseGraph):
+    object_provider = providers.Object(Scope.APP, 1)
+
+
+with Container(scope=Scope.APP) as container:
+    assert Dependencies.object_provider.sync_resolve(container) == 1
+```

packages/modern-di/modern_di/providers/__init__.py

@@ -4,6 +4,7 @@
 from modern_di.providers.dict import Dict
 from modern_di.providers.factory import Factory
 from modern_di.providers.list import List
+from modern_di.providers.object import Object
 from modern_di.providers.resource import Resource
 from modern_di.providers.selector import Selector
 from modern_di.providers.singleton import Singleton
@@ -16,6 +17,7 @@
     "Dict",
     "Factory",
     "List",
+    "Object",
     "Resource",
     "Selector",
     "Singleton",

packages/modern-di/modern_di/providers/object.py

@@ -0,0 +1,27 @@
+import enum
+import typing
+
+from modern_di import Container
+from modern_di.providers.abstract import AbstractOverrideProvider
+
+
+T_co = typing.TypeVar("T_co", covariant=True)
+P = typing.ParamSpec("P")
+
+
+class Object(AbstractOverrideProvider[T_co]):
+    __slots__ = [*AbstractOverrideProvider.BASE_SLOTS, "_obj"]
+
+    def __init__(self, scope: enum.IntEnum, obj: T_co) -> None:
+        super().__init__(scope)
+        self._obj: typing.Final = obj
+
+    async def async_resolve(self, container: Container) -> T_co:
+        return self.sync_resolve(container)
+
+    def sync_resolve(self, container: Container) -> T_co:
+        container = container.find_container(self.scope)
+        if (override := container.fetch_override(self.provider_id)) is not None:
+            return typing.cast(T_co, override)
+
+        return self._obj

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

@@ -0,0 +1,29 @@
+from modern_di import Container, Scope, providers
+
+
+instance = ["some item"]
+
+
+object_provider = providers.Object(Scope.APP, instance)
+
+
+async def test_object_provider() -> None:
+    async with Container(scope=Scope.APP) as app_container:
+        instance1 = await object_provider.async_resolve(app_container)
+        instance2 = object_provider.sync_resolve(app_container)
+
+        assert instance1 is instance2 is instance
+
+
+async def test_object_provider_overridden() -> None:
+    async with Container(scope=Scope.APP) as app_container:
+        instance1 = await object_provider.async_resolve(app_container)
+
+        object_provider.override(["override"], container=app_container)
+
+        instance2 = await object_provider.async_resolve(app_container)
+        instance3 = object_provider.sync_resolve(app_container)
+
+        assert instance1 is instance
+        assert instance2 is not instance
+        assert instance2 is instance3