async def context_b(state: dict = Depends(context_a)):
    state["context_b"] = "started b"
    try:
        yield state
    finally:
        state["context_b"] = f"finished b with a: {state['context_a']}"


@app.get("/async")
async def get_async(state: str = Depends(asyncgen_state)):
    return state


@app.get("/sync")
async def get_sync(state: str = Depends(generator_state)):

@app.post("/optional-list-str", operation_id="optional_list_str")
async def read_optional_list_str(
    p: Annotated[Optional[list[str]], Body(embed=True)] = None,
):
    return {"p": p}


class BodyModelOptionalListStr(BaseModel):
    p: Optional[list[str]] = None


@app.post("/model-optional-list-str", operation_id="model_optional_list_str")
async def read_model_optional_list_str(p: BodyModelOptionalListStr):
    return {"p": p.p}

async def routerindexparams(websocket: WebSocket, pathparam: str, queryparam: str):
    await websocket.accept()
    await websocket.send_text(pathparam)
    await websocket.send_text(queryparam)
    await websocket.close()


async def ws_dependency():
    return "Socket Dependency"


@router.websocket("/router-ws-depends/")
async def router_ws_decorator_depends(
    websocket: WebSocket, data=Depends(ws_dependency)
):

from fastapi.testclient import TestClient

global_context: ContextVar[dict[str, Any]] = ContextVar("global_context", default={})  # noqa: B039


class Session:
    def __init__(self) -> None:
        self.open = True


async def dep_session() -> Any:
    s = Session()
    yield s
    s.open = False
    global_state = global_context.get()
    global_state["session_closed"] = True

# Without aliases


@app.get("/optional-str")
async def read_optional_str(p: Annotated[Optional[str], Header()] = None):
    return {"p": p}


class HeaderModelOptionalStr(BaseModel):
    p: Optional[str] = None


@app.get("/model-optional-str")
async def read_model_optional_str(p: Annotated[HeaderModelOptionalStr, Header()]):
    return {"p": p.p}

from fastapi.testclient import TestClient


def test_upload_file_invalid_pydantic_v2():
    with pytest.raises(ValueError):
        UploadFile._validate("not a Starlette UploadFile", {})


def test_default_placeholder_equals():
    placeholder_1 = Default("a")
    placeholder_2 = Default("a")
    assert placeholder_1 == placeholder_2
    assert placeholder_1.value == placeholder_2.value


def test_default_placeholder_bool():

class Person:
    def __init__(self, name: str):
        self.name = name


class Pet:
    def __init__(self, owner: Person, name: str):
        self.owner = owner
        self.name = name


@dataclass
class Item:
    name: str
    count: int


class DictablePerson(Person):
    def __iter__(self):
        return ((k, v) for k, v in self.__dict__.items())

# Without aliases


@app.get("/required-str")
async def read_required_str(p: Annotated[str, Header()]):
    return {"p": p}


class HeaderModelRequiredStr(BaseModel):
    p: str


@app.get("/model-required-str")
async def read_model_required_str(p: Annotated[HeaderModelRequiredStr, Header()]):
    return {"p": p.p}


@pytest.mark.parametrize(

En fait, `FastAPI` est un sous composant de `Starlette`. Donc, si vous savez déjà comment utiliser Starlette, la plupart des fonctionnalités fonctionneront de la même manière.

Avec **FastAPI** vous aurez toutes les fonctionnalités de **Starlette** (FastAPI est juste Starlette sous stéroïdes):

    owner_ids: Optional[list[int]] = None


@app.get("/items/valid", response_model=Item)
def get_valid():
    return Item(aliased_name="valid", price=1.0)


@app.get("/items/coerce", response_model=Item)
def get_coerce():
    return Item(aliased_name="coerce", price="1.0")


@app.get("/items/validlist", response_model=list[Item])
def get_validlist():
    return [
        Item(aliased_name="foo"),