```

=== "Python 3.8 non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python
    commons: CommonQueryParams = Depends()
    ```

You declare the dependency as the type of the parameter, and you use `Depends()` without any parameter, instead of having to write the full class *again* inside of `Depends(CommonQueryParams)`.

    ## Usage

    Create an instance object and use that object as the dependency in `Depends()`.

    The dependency result will be a string containing the key value.

    ## Example

    ```python
    from fastapi import Depends, FastAPI
    from fastapi.security import APIKeyQuery

    app = FastAPI()

    query_scheme = APIKeyQuery(name="api_key")

# Dependencies - `Depends()` and `Security()`

## `Depends()`

Dependencies are handled mainly with the special function `Depends()` that takes a callable.

Here is the reference for it and its parameters.

You can import it directly from `fastapi`:

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

# Abhängigkeiten – `Depends()` und `Security()`

## `Depends()`

Abhängigkeiten werden hauptsächlich mit der speziellen Funktion `Depends()` behandelt, die ein Callable entgegennimmt.

Hier finden Sie deren Referenz und Parameter.

Sie können sie direkt von `fastapi` importieren:

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

    return user


async def get_current_active_user(current_user: 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: OAuth2PasswordRequestForm = Depends(),
) -> Token:

@app.get("/async")
async def get_async(state: str = Depends(asyncgen_state)):
    return state


@app.get("/sync")
async def get_sync(state: str = Depends(generator_state)):
    return state


@app.get("/async_raise")
async def get_async_raise(state: str = Depends(asyncgen_state_try)):
    assert state == "asyncgen raise started"
    raise AsyncDependencyError()

from typing import Union

from fastapi import Cookie, Depends, FastAPI
from typing_extensions import Annotated

app = FastAPI()


def query_extractor(q: Union[str, None] = None):
    return q


def query_or_cookie_extractor(
    q: Annotated[str, Depends(query_extractor)],
    last_query: Annotated[Union[str, None], Cookie()] = None,
):
    if not q:
        return last_query
    return q


@app.get("/items/")

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_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:

**FastAPI**는 `CommonQueryParams` 클래스를 호출합니다. 이것은 해당 클래스의 "인스턴스"를 생성하고 그 인스턴스는 함수의 매개변수 `commons`로 전달됩니다.

## 타입 힌팅 vs `Depends`

위 코드에서 `CommonQueryParams`를 두 번 작성한 방식에 주목하십시오:

```Python
commons: CommonQueryParams = Depends(CommonQueryParams)
```

마지막 `CommonQueryParams` 변수를 보면:

```Python
... = Depends(CommonQueryParams)
```

... **FastAPI**가 실제로 어떤 것이 의존성인지 알기 위해서 사용하는 방법입니다.