Elle peut être une fonction asynchrone (`async def`) ou une fonction normale (`def`), **FastAPI** saura la gérer correctement.

Dans cet exemple, la fonction de tâche écrira dans un fichier (afin de simuler un envoi d'email).

L'opération d'écriture n'utilisant ni `async` ni `await`, on définit la fonction avec un `def` normal.

    images: Union[List[Image], None] = None


class Offer(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    items: List[Item]


@app.post("/offers/")
async def create_offer(offer: Offer):

class CommonQueryParams:
    def __init__(self, q: Union[str, None] = None, skip: int = 0, limit: int = 100):
        self.q = q
        self.skip = skip
        self.limit = limit


@app.get("/items/")
async def read_items(commons: CommonQueryParams = Depends(CommonQueryParams)):
    response = {}
    if commons.q:
        response.update({"q": commons.q})
    items = fake_items_db[commons.skip : commons.skip + commons.limit]

class CommonQueryParams:
    def __init__(self, q: Union[str, None] = None, skip: int = 0, limit: int = 100):
        self.q = q
        self.skip = skip
        self.limit = limit


@app.get("/items/")
async def read_items(commons: Annotated[CommonQueryParams, Depends()]):
    response = {}
    if commons.q:
        response.update({"q": commons.q})
    items = fake_items_db[commons.skip : commons.skip + commons.limit]

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Annotated[
        Item,
        Body(
            examples=[
                {
                    "name": "Foo",

    "item2": {
        "description": "Music is my aeroplane, it's my aeroplane",
        "type": "plane",
        "size": 5,
    },
}


@app.get("/items/{item_id}", response_model=Union[PlaneItem, CarItem])
async def read_item(item_id: str):

from fastapi import FastAPI, Form

app = FastAPI()


@app.post("/login/")
async def login(username: str = Form(), password: str = Form()):

from fastapi import FastAPI

app = FastAPI()


@app.get("/keyword-weights/", response_model=dict[str, float])
async def read_keyword_weights():

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/", openapi_extra={"x-aperture-labs-portal": "blue"})
async def read_items():

app = FastAPI()


class Cookies(BaseModel):
    session_id: str
    fatebook_tracker: Union[str, None] = None
    googall_tracker: Union[str, None] = None


@app.get("/items/")
async def read_items(cookies: Annotated[Cookies, Cookie()]):