And if you declared a `response_model`, it will still be used to filter and convert the object you returned.

**FastAPI** will use that *temporal* response to extract the cookies (also headers and status code), and will put them in the final response that contains the value you returned, filtered by any `response_model`.

    "baz": {"name": "Baz", "description": None, "price": 50.2, "tax": 10.5, "tags": []},
}


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


@app.patch("/items/{item_id}", response_model=Item)
async def update_item(item_id: str, item: Item):
    stored_item_data = items[item_id]
    stored_item_model = Item(**stored_item_data)

    owner_ids: Optional[list[int]] = None


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


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


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

Но если у вас уже есть набор dataclasses, это полезный приём — задействовать их для веб-API на FastAPI. 🤓

///

## Dataclasses в `response_model` { #dataclasses-in-response-model }

Вы также можете использовать `dataclasses` в параметре `response_model`:

{* ../../docs_src/dataclasses_/tutorial002_py310.py hl[1,6:12,18] *}

Этот dataclass будет автоматически преобразован в Pydantic dataclass.

class PetDB(BaseModel):
    name: str
    owner: UserDB


class PetOut(BaseModel):
    name: str
    owner: User


@app.post("/users/", response_model=User)
async def create_user(user: UserCreate):
    return user


@app.get("/pets/{pet_id}", response_model=PetOut)
async def read_pet(pet_id: int):
    user = UserDB(
        email="******@****.***",
        hashed_password="secrethashed",
    )

    message: str


class User(BaseModel):
    username: str
    email: str


@app.post("/items/", response_model=ResponseMessage, tags=["items"])
async def create_item(item: Item):
    return {"message": "Item received"}


@app.get("/items/", response_model=list[Item], tags=["items"])
async def get_items():
    return [
        {"name": "Plumbus", "price": 3},

@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: SessionDep):
    db_hero = Hero.model_validate(hero)
    session.add(db_hero)
    session.commit()
    session.refresh(db_hero)
    return db_hero


@app.get("/heroes/", response_model=list[HeroPublic])
def read_heroes(
    session: SessionDep,
    offset: int = 0,

    message: str


class User(BaseModel):
    username: str
    email: str


@app.post("/items/", response_model=ResponseMessage, tags=["items"])
async def create_item(item: Item):
    return {"message": "Item received"}


@app.get("/items/", response_model=list[Item], tags=["items"])
async def get_items():
    return [
        {"name": "Plumbus", "price": 3},

///

## 出力モデルの追加

代わりに、平文のパスワードを持つ入力モデルと、パスワードを持たない出力モデルを作成することができます:

{* ../../docs_src/response_model/tutorial003.py hl[9,11,16] *}

ここでは、*path operation関数*がパスワードを含む同じ入力ユーザーを返しているにもかかわらず:

{* ../../docs_src/response_model/tutorial003.py hl[24] *}

...`response_model`を`UserOut`と宣言したことで、パスワードが含まれていません:

{* ../../docs_src/response_model/tutorial003.py hl[22] *}

そのため、**FastAPI** は出力モデルで宣言されていない全てのデータをフィルタリングしてくれます（Pydanticを使用）。

And if you declared a `response_model`, it will still be used to filter and convert the object you returned.

**FastAPI** will use that *temporal* response to extract the status code (also cookies and headers), and will put them in the final response that contains the value you returned, filtered by any `response_model`.