<img src="/img/python-types/image06.png">

Beachten Sie, das bedeutet: „`one_person` ist eine **Instanz** der Klasse `Person`“.

Es bedeutet nicht: „`one_person` ist die **Klasse** genannt `Person`“.

## Pydantic Modelle

<a href="https://pydantic-docs.helpmanual.io/" class="external-link" target="_blank">Pydantic</a> ist eine Python-Bibliothek für die Validierung von Daten.

    db_user = crud.get_user_by_email(db, email=user.email)
    if db_user:
        raise HTTPException(status_code=400, detail="Email already registered")
    return crud.create_user(db=db, user=user)


@app.get("/users/", response_model=list[schemas.User])
def read_users(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
    users = crud.get_users(db, skip=skip, limit=limit)
    return users

def test_websocket_with_cookie():
    client = TestClient(app, cookies={"session": "fakesession"})
    with pytest.raises(WebSocketDisconnect):
        with client.websocket_connect("/items/foo/ws") as websocket:
            message = "Message one"
            websocket.send_text(message)
            data = websocket.receive_text()
            assert data == "Session cookie or query token value is: fakesession"

from fastapi._compat import PYDANTIC_V2

needs_py39 = pytest.mark.skipif(sys.version_info < (3, 9), reason="requires python3.9+")
needs_py310 = pytest.mark.skipif(
    sys.version_info < (3, 10), reason="requires python3.10+"
)
needs_pydanticv2 = pytest.mark.skipif(not PYDANTIC_V2, reason="requires Pydantic v2")

    return HTMLResponse(html)


async def get_cookie_or_token(
    websocket: WebSocket,
    session: str | None = Cookie(default=None),
    token: str | None = Query(default=None),
):
    if session is None and token is None:
        raise WebSocketException(code=status.WS_1008_POLICY_VIOLATION)
    return session or token


@app.websocket("/items/{item_id}/ws")
async def websocket_endpoint(
    websocket: WebSocket,

from .utils import needs_pydanticv1, needs_pydanticv2


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):

### Create a `SessionLocal` class

Each instance of the `SessionLocal` class will be a database session. The class itself is not a database session yet.

But once we create an instance of the `SessionLocal` class, this instance will be the actual database session.

    from fastapi.security import APIKeyCookie

    app = FastAPI()

    cookie_scheme = APIKeyCookie(name="session")


    @app.get("/items/")
    async def read_items(session: str = Depends(cookie_scheme)):
        return {"session": session}
    ```
    """

    def __init__(
        self,
        *,
        name: Annotated[str, Doc("Cookie name.")],

Das bedeutet allerdings auch, dass, wenn Sie Daten direkt vom `Request`-Objekt nehmen (z. B. dessen Body lesen), diese von FastAPI nicht validiert, konvertiert oder dokumentiert werden (mit OpenAPI, für die automatische API-Benutzeroberfläche).

        ("/items", {"ads_id": "ads_track"}, 200, {"ads_id": "ads_track"}),
        (
            "/items",
            {"ads_id": "ads_track", "session": "cookiesession"},
            200,
            {"ads_id": "ads_track"},
        ),
        ("/items", {"session": "cookiesession"}, 200, {"ads_id": None}),
    ],
)
def test(path, cookies, expected_status, expected_response):