## `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()`

For many scenarios, you can handle security (authorization, authentication, etc.) with dependencies, using `Depends()`.

Da einfache Werte standardmäßig als Query-Parameter interpretiert werden, müssen Sie `Query` nicht explizit hinzufügen, Sie können einfach schreiben:

```Python
q: Union[str, None] = None
```

Oder in Python 3.10 und darüber:

```Python
q: str | None = None
```

Zum Beispiel:

{* ../../docs_src/body_multiple_params/tutorial004_an_py310.py hl[27] *}

/// info

As, by default, singular values are interpreted as query parameters, you don't have to explicitly add a `Query`, you can just do:

```Python
q: Union[str, None] = None
```

Or in Python 3.10 and above:

```Python
q: str | None = None
```

For example:

{* ../../docs_src/body_multiple_params/tutorial004_an_py310.py hl[28] *}


/// info

      - name: Configure JDK
        uses: actions/setup-java@v5
        with:
          distribution: 'zulu'
          java-version: 17

      - uses: actions/setup-python@v5
        with:
          python-version: 3.x

      - run: pip install mkdocs-material mkdocs-redirects

      - name: Generate Docs
        run: ./test_docs.sh

      - uses: actions/upload-artifact@v4
        with:

---

רק גרדנו את קצה הקרחון, אבל כבר יש לכם רעיון של איך הכל עובד.

נסו לשנות את השורה:

```Python
    return {"item_name": item.name, "item_id": item_id}
```

...מ:

```Python
        ... "item_name": item.name ...
```

...ל:

```Python
        ... "item_price": item.price ...
```

...וראו איך העורך שלכם משלים את המאפיינים ויודע את הטיפוסים שלהם:

Переконайтеся, що Ви створили [віртуальне середовище](../virtual-environments.md){.internal-link target=_blank}, активували його, а потім встановили бібліотеку, наприклад:

```console
$ pip install python-multipart
```

///

## Імпорт `File` та `Form`

```Python hl_lines="1"
async def get_burgers(number: int):
    # Mach Sie hier etwas Asynchrones, um die Burger zu erstellen
    return burgers
```

... statt mit `def`:

```Python hl_lines="2"
# Die ist nicht asynchron
def get_sequential_burgers(number: int):
    # Mach Sie hier etwas Sequentielles, um die Burger zu erstellen
    return burgers
```

Pero una variable como `user-agent` es inválida en Python.

Así que, por defecto, `Header` convertirá los caracteres de los nombres de los parámetros de guion bajo (`_`) a guion (`-`) para extraer y documentar los headers.

Además, los headers HTTP no diferencian entre mayúsculas y minúsculas, por lo que los puedes declarar con el estilo estándar de Python (también conocido como "snake_case").

# Status Codes

You can import the `status` module from `fastapi`:

```python
from fastapi import status
```

`status` is provided directly by Starlette.

It contains a group of named constants (variables) with integer status codes.

For example:

* 200: `status.HTTP_200_OK`
* 403: `status.HTTP_403_FORBIDDEN`
* etc.

# 파일 요청

`File`을 사용하여 클라이언트가 업로드할 파일들을 정의할 수 있습니다.

/// info | 정보

업로드된 파일을 전달받기 위해 먼저 <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>를 설치해야합니다.

예시) `pip install python-multipart`.

업로드된 파일들은 "폼 데이터"의 형태로 전송되기 때문에 이 작업이 필요합니다.

///

## `File` 임포트

`fastapi` 에서 `File` 과 `UploadFile` 을 임포트 합니다:

{* ../../docs_src/request_files/tutorial001.py hl[1] *}