Add supporting for callable object

fastapi/dependencies/utils.py

@@ -1,4 +1,6 @@
+import asyncio
 import dataclasses
+import functools
 import inspect
 from contextlib import contextmanager
 from copy import deepcopy
@@ -261,6 +263,15 @@ def get_typed_signature(call: Callable[..., Any]) -> inspect.Signature:
     return typed_signature
 
 
+def is_coroutine_function(obj: Any) -> bool:
+    while isinstance(obj, functools.partial):
+        obj = obj.func
+
+    return asyncio.iscoroutinefunction(obj) or (
+        callable(obj) and asyncio.iscoroutinefunction(obj.__call__)
+    )
+
+
 def get_typed_annotation(param: inspect.Parameter, globalns: Dict[str, Any]) -> Any:
     annotation = param.annotation
     if isinstance(annotation, str):

fastapi/routing.py

@@ -1,4 +1,3 @@
-import asyncio
 import dataclasses
 import email.message
 import inspect
@@ -26,6 +25,7 @@ from fastapi.dependencies.utils import (
     get_dependant,
     get_parameterless_sub_dependant,
     solve_dependencies,
+    is_coroutine_function,
 )
 from fastapi.encoders import DictIntStrAny, SetIntStr, jsonable_encoder
 from fastapi.exceptions import RequestValidationError, WebSocketRequestValidationError
@@ -177,7 +177,7 @@ def get_request_handler(
     dependency_overrides_provider: Optional[Any] = None,
 ) -> Callable[[Request], Coroutine[Any, Any, Response]]:
     assert dependant.call is not None, "dependant.call must be a function"
-    is_coroutine = asyncio.iscoroutinefunction(dependant.call)
+    is_coroutine = is_coroutine_function(dependant.call)
     is_body_form = body_field and isinstance(body_field.field_info, params.Form)
     if isinstance(response_class, DefaultPlaceholder):
         actual_response_class: Type[Response] = response_class.value

tests/test_callable_endpoint.py

@@ -5,15 +5,29 @@ from fastapi import FastAPI
 from fastapi.testclient import TestClient
 
 
+class CallableObjectEndpoint:
+    def __call__(self, some_arg, q: Optional[str] = None):
+        return {"some_arg": some_arg, "q": q}
+
+
+class AsyncCallableObjectEndpoint:
+    async def __call__(self, some_arg, q: Optional[str] = None):
+        return {"some_arg": some_arg, "q": q}
+
+
 def main(some_arg, q: Optional[str] = None):
     return {"some_arg": some_arg, "q": q}
 
 
 endpoint = partial(main, "foo")
+obj_endpoint = partial(CallableObjectEndpoint(), "foo")
+async_obj_endpoint = partial(AsyncCallableObjectEndpoint(), "foo")
 
 app = FastAPI()
 
 app.get("/")(endpoint)
+app.get("/obj")(obj_endpoint)
+app.get("/async_obj")(async_obj_endpoint)
 
 
 client = TestClient(app)
@@ -23,3 +37,11 @@ def test_partial():
     response = client.get("/?q=bar")
     data = response.json()
     assert data == {"some_arg": "foo", "q": "bar"}
+
+    response = client.get("/obj?q=bar")
+    data = response.json()
+    assert data == {"some_arg": "foo", "q": "bar"}
+
+    response = client.get("/async_obj?q=bar")
+    data = response.json()
+    assert data == {"some_arg": "foo", "q": "bar"}