app = FastAPI()


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


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

        raise ValueError('Invalid ID format, it must start with "isbn-" or "imdb-"')
    return id


@app.get("/items/")
async def read_items(
    id: Annotated[Union[str, None], AfterValidator(check_valid_id)] = None,
):
    if id:
        item = data.get(id)
    else:
        id, item = random.choice(list(data.items()))

app = FastAPI()


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


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

app = FastAPI()


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


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

from sqlmodel import Field, Session, SQLModel, create_engine

engine = create_engine("postgresql+psycopg://postgres:postgres@localhost/db")


class User(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str


app = FastAPI()


def get_session():
    with Session(engine) as session:
        yield session

        "lib/gcc/arm-rpi-linux-gnueabihf/**",
        "include/**",
    ]),
)

filegroup(
    name = "aarch64_compiler_pieces",
    srcs = glob([
        "aarch64-none-linux-gnu/**",
        "libexec/**",
        "lib/gcc/aarch64-none-linux-gnu/**",
        "include/**",
    ]),
)

filegroup(
    name = "compiler_components",
    srcs = [
        ":ar",
        ":as",
        ":gcc",

}


app = FastAPI()


@app.get(
    "/items/{item_id}",
    response_model=Item,
    responses={**responses, 200: {"content": {"image/png": {}}}},
)
async def read_item(item_id: str, img: bool | None = None):
    if img:
        return FileResponse("image.png", media_type="image/png")
    else:

from fastapi import Depends, FastAPI

app = FastAPI()


fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"}]


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


@app.get("/items/")

    assert response.json() == {
        "item_id": 5,
        "item": {
            "name": "Foo",
            "description": None,
            "price": 35.4,
            "tax": None,
            "tags": [],
            "image": None,
        },
    }


def test_put_empty_body(client: TestClient):
    response = client.put(
        "/items/5",
        json={},
    )

Аналогично, вы можете объявлять необязательные query-параметры, установив их значение по умолчанию, равное `None`:

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

В этом случае, параметр  `q` будет не обязательным и будет иметь значение `None` по умолчанию.

/// check | Важно