@router.websocket("/depends-err/")
async def router_ws_depends_err(websocket: WebSocket, data=Depends(ws_dependency_err)):
    pass  # pragma: no cover


async def ws_dependency_validate(x_missing: str = Header()):
    pass  # pragma: no cover


@router.websocket("/depends-validate/")
async def router_ws_depends_validate(
    websocket: WebSocket, data=Depends(ws_dependency_validate)
):

async def get_current_active_user(
    current_user: Annotated[User, Depends(get_current_user)],
):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user


@app.post("/token")
async def login_for_access_token(
    form_data: Annotated[OAuth2PasswordRequestForm, Depends()],
) -> Token:

    )


async def get_current_user(token: str = Depends(oauth2_scheme)):
    user = fake_decode_token(token)
    return user


@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):

import secrets

from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import HTTPBasic, HTTPBasicCredentials

app = FastAPI()

security = HTTPBasic()


def get_current_username(credentials: HTTPBasicCredentials = Depends(security)):
    current_username_bytes = credentials.username.encode("utf8")
    correct_username_bytes = b"stanleyjobson"
    is_correct_username = secrets.compare_digest(

In version 0.121.0, FastAPI added support for `Depends(scope="function")` for dependencies with `yield`.

Using `Depends(scope="function")`, the exit code after `yield` is executed right after the *path operation function* is finished, before the response is sent back to the client.

And when using `Depends(scope="request")` (the default), the exit code after `yield` is executed after the response is sent.

def get_user(user_id: int, session: Annotated[Session, Depends(get_session)]):
    user = session.get(User, user_id)
    if not user:
        raise HTTPException(status_code=403, detail="Not authorized")


def generate_stream(query: str):
    for ch in query:
        yield ch
        time.sleep(0.1)


@app.get("/generate", dependencies=[Depends(get_user)])
def generate(query: str):

@app.post("/heroes/", response_model=HeroPublic)
def create_hero(hero: HeroCreate, session: Session = Depends(get_session)):
    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: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
):

Obwohl Sie `Depends` in den Parametern Ihrer Funktion genauso verwenden wie `Body`, `Query`, usw., funktioniert `Depends` etwas anders.

Sie übergeben `Depends` nur einen einzigen Parameter.

Dieser Parameter muss so etwas wie eine Funktion sein.

Sie **rufen diese nicht direkt auf** (fügen Sie am Ende keine Klammern hinzu), sondern übergeben sie einfach als Parameter an `Depends()`.

//// tab | Python 3.9+

```Python hl_lines="1"
async def needy_dependency(fresh_value: Annotated[str, Depends(get_value, use_cache=False)]):
    return {"fresh_value": fresh_value}
```

////

//// tab | Python 3.9+ sin Anotaciones

/// tip | Consejo

/// info | Technical Details

`Security` is actually a subclass of `Depends`, and it has just one extra parameter that we'll see later.

But by using `Security` instead of `Depends`, **FastAPI** will know that it can declare security scopes, use them internally, and document the API with OpenAPI.

But when you import `Query`, `Path`, `Depends`, `Security` and others from `fastapi`, those are actually functions that return special classes.