Add support for typing.Annotated

examples/wiring/example.py

@@ -2,6 +2,7 @@
 
 from dependency_injector import containers, providers
 from dependency_injector.wiring import Provide, inject
+from typing import Annotated
 
 
 class Service:
@@ -12,12 +13,18 @@ class Container(containers.DeclarativeContainer):
 
     service = providers.Factory(Service)
 
-
+# You can place marker on parameter default value
 @inject
 def main(service: Service = Provide[Container.service]) -> None:
     ...
 
 
+# Also, you can place marker with typing.Annotated
+@inject
+def main_with_annotated(service: Annotated[Service, Provide[Container.service]]) -> None:
+    ...
+
+
 if __name__ == "__main__":
     container = Container()
     container.wire(modules=[__name__])

requirements-dev.txt

@@ -16,5 +16,6 @@ numpy
 scipy
 boto3
 mypy_boto3_s3
+typing_extensions
 
 -r requirements-ext.txt

src/dependency_injector/wiring.py

@@ -36,6 +36,20 @@ class GenericMeta(type):
 else:
     GenericAlias = None
 
+if sys.version_info >= (3, 9):
+    from typing import Annotated, get_args, get_origin
+else:
+    try:
+        from typing_extensions import Annotated, get_args, get_origin
+    except ImportError:
+        Annotated = object()
+
+        # For preventing NameError. Never executes
+        def get_args(hint):
+            return ()
+
+        def get_origin(tp):
+            return None
 
 try:
     import fastapi.params
@@ -548,6 +562,24 @@ def _unpatch_attribute(patched: PatchedAttribute) -> None:
     setattr(patched.member, patched.name, patched.marker)
 
 
+def _extract_marker(parameter: inspect.Parameter) -> Optional["_Marker"]:
+    if get_origin(parameter.annotation) is Annotated:
+        marker = get_args(parameter.annotation)[1]
+    else:
+        marker = parameter.default
+
+    if not isinstance(marker, _Marker) and not _is_fastapi_depends(marker):
+        return None
+
+    if _is_fastapi_depends(marker):
+        marker = marker.dependency
+
+        if not isinstance(marker, _Marker):
+            return None
+
+    return marker
+
+
 def _fetch_reference_injections(  # noqa: C901
         fn: Callable[..., Any],
 ) -> Tuple[Dict[str, Any], Dict[str, Any]]:
@@ -573,17 +605,10 @@ def _fetch_reference_injections(  # noqa: C901
     injections = {}
     closing = {}
     for parameter_name, parameter in signature.parameters.items():
-        if not isinstance(parameter.default, _Marker) \
-                and not _is_fastapi_depends(parameter.default):
-            continue
+        marker = _extract_marker(parameter)
 
-        marker = parameter.default
-
-        if _is_fastapi_depends(marker):
-            marker = marker.dependency
-
-            if not isinstance(marker, _Marker):
-                continue
+        if marker is None:
+            continue
 
         if isinstance(marker, Closing):
             marker = marker.provider

tests/unit/samples/wiringfastapi/web.py

@@ -1,5 +1,7 @@
 import sys
 
+from typing_extensions import Annotated
+
 from fastapi import FastAPI, Depends
 from fastapi import Request  # See: https://github.com/ets-labs/python-dependency-injector/issues/398
 from fastapi.security import HTTPBasic, HTTPBasicCredentials
@@ -27,6 +29,11 @@ async def index(service: Service = Depends(Provide[Container.service])):
     result = await service.process()
     return {"result": result}
 
+@app.api_route('/annotated')
+@inject
+async def annotated(service: Annotated[Service, Depends(Provide[Container.service])]):
+    result = await service.process()
+    return {'result': result}
 
 @app.get("/auth")
 @inject

tests/unit/samples/wiringflask/web.py

@@ -1,3 +1,5 @@
+from typing_extensions import Annotated
+
 from flask import Flask, jsonify, request, current_app, session, g
 from flask import _request_ctx_stack, _app_ctx_stack
 from dependency_injector import containers, providers
@@ -28,5 +30,12 @@ def index(service: Service = Provide[Container.service]):
     return jsonify({"result": result})
 
 
+@app.route("/annotated")
+@inject
+def annotated(service: Annotated[Service, Provide[Container.service]]):
+    result = service.process()
+    return jsonify({'result': result})
+
+
 container = Container()
 container.wire(modules=[__name__])

tests/unit/wiring/test_fastapi_py36.py

@@ -36,6 +36,20 @@ async def process(self):
     assert response.json() == {"result": "Foo"}
 
 
+@mark.asyncio
+async def test_depends_with_annotated(async_client: AsyncClient):
+    class ServiceMock:
+        async def process(self):
+            return "Foo"
+
+    with web.container.service.override(ServiceMock()):
+        response = await async_client.get("/")
+
+    assert response.status_code == 200
+    assert response.json() == {"result": "Foo"}
+
+
+
 @mark.asyncio
 async def test_depends_injection(async_client: AsyncClient):
     response = await async_client.get("/auth", auth=("john_smith", "secret"))

tests/unit/wiring/test_flask_py36.py

@@ -29,3 +29,13 @@ def test_wiring_with_flask():
 
     assert response.status_code == 200
     assert json.loads(response.data) == {"result": "OK"}
+
+
+def test_wiring_with_annotated():
+    client = web.app.test_client()
+
+    with web.app.app_context():
+        response = client.get("/annotated")
+
+    assert response.status_code == 200
+    assert json.loads(response.data) == {"result": "OK"}