from starlette.status import HTTP_422_UNPROCESSABLE_ENTITY, WS_1008_POLICY_VIOLATION


async def http_exception_handler(request: Request, exc: HTTPException) -> Response:
    headers = getattr(exc, "headers", None)
    if not is_body_allowed_for_status_code(exc.status_code):
        return Response(status_code=exc.status_code, headers=headers)
    return JSONResponse(

```

////

//// tab | Python 3.10+ non-Annotated

/// tip | Dica

Prefira utilizar a versão `Annotated` se possível.

///

```Python hl_lines="4  8  12  46  64  105  107-115  121-124  128-134  139  155"
{!> ../../docs_src/security/tutorial005_py310.py!}
```

////

//// tab | Python 3.9+ non-Annotated

/// tip | Dica

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):

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):

        shapes with `None` entries for axes that are meant to be dynamic). You
        can also disable the input checking entirely by setting
        `model.input_spec = None`.
    *   Several changes have been made to
        `tf.keras.mixed_precision.experimental`. Note that it is now recommended
        to use the non-experimental `tf.keras.mixed_precision` API.

    assertSame(CharMatcher.any(), CharMatcher.none().negate());
    assertSame(CharMatcher.none(), CharMatcher.any().negate());

    assertSame(WHATEVER, CharMatcher.any().and(WHATEVER));
    assertSame(CharMatcher.any(), CharMatcher.any().or(WHATEVER));

    assertSame(CharMatcher.none(), CharMatcher.none().and(WHATEVER));
    assertSame(WHATEVER, CharMatcher.none().or(WHATEVER));
  }

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

In diesem Fall wird der Funktionsparameter `q` optional, und standardmäßig `None` sein.

/// check

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 dataclasses import field  # (1)
from typing import List, Union

from fastapi import FastAPI
from pydantic.dataclasses import dataclass  # (2)


@dataclass
class Item:
    name: str
    description: Union[str, None] = None


@dataclass
class Author:
    name: str
    items: List[Item] = field(default_factory=list)  # (3)


app = FastAPI()


@app.post("/authors/{author_id}/items/", response_model=Author)  # (4)