# 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()`

    {!> ../../../docs_src/dependencies/tutorial012_an.py!}
    ```

=== "Python 3.8 nicht annotiert"

    !!! tip "Tipp"
        Bevorzugen Sie die `Annotated`-Version, falls möglich.

    ```Python hl_lines="15"
    {!> ../../../docs_src/dependencies/tutorial012.py!}
    ```

    ```

=== "Python 3.8 Annotated가 없는 경우"

    !!! tip "팁"
        가능하다면 `Annotated`가 달린 버전을 권장합니다.

    ```Python hl_lines="15"
    {!> ../../../docs_src/dependencies/tutorial012.py!}
    ```

그리고 [*경로 작동 데코레이터*에 `dependencies` 추가하기](dependencies-in-path-operation-decorators.md){.internal-link target=_blank}에 대한 아이디어는 여전히 적용되지만 여기에서는 앱에 있는 모든 *경로 작동*에 적용됩니다.

## *경로 작동* 모음에 대한 의존성

Nils Lindemann <******@****.***> 1711822605 +0100

Dazu deklarieren wir eine Methode `__call__`:

=== "Python 3.9+"

    ```Python hl_lines="12"
    {!> ../../../docs_src/dependencies/tutorial011_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="11"
    {!> ../../../docs_src/dependencies/tutorial011_an.py!}
    ```

=== "Python 3.8+ nicht annotiert"

    !!! tip "Tipp"
        Bevorzugen Sie die `Annotated`-Version, falls möglich.

=== "Python 3.10+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial005_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="8-9"
    {!> ../../../docs_src/dependencies/tutorial005_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9-10"
    {!> ../../../docs_src/dependencies/tutorial005_an.py!}
    ```

=== "Python 3.10 nicht annotiert"

```Python hl_lines="2-4"
{!../../../docs_src/dependencies/tutorial007.py!}
```

Полученное значение и есть то, что будет внедрено в функцию операции пути и другие зависимости:

```Python hl_lines="4"
{!../../../docs_src/dependencies/tutorial007.py!}
```

Код, следующий за оператором `yield`, выполняется после доставки ответа:

```Python hl_lines="5-6"
{!../../../docs_src/dependencies/tutorial007.py!}
```

!!! tip "Подсказка"

例如，您可以使用这种方式创建一个数据库会话，并在完成后关闭它。

在发送响应之前，只会执行 `yield` 语句及之前的代码：

```Python hl_lines="2-4"
{!../../../docs_src/dependencies/tutorial007.py!}
```

生成的值会注入到*路径操作*和其他依赖项中：

```Python hl_lines="4"
{!../../../docs_src/dependencies/tutorial007.py!}
```

"yield"语句后面的代码会在发送响应后执行：：

```Python hl_lines="5-6"
{!../../../docs_src/dependencies/tutorial007.py!}
```

!!! tip "提示"

    您可以使用 `async` 或普通函数。

Nils Lindemann <******@****.***> 1711829852 +0100

jaystone776 <******@****.***> 1711838753 +0800