## `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()`.

    [`tf.dtypes`](https://www.tensorflow.org/versions/master/api_docs/python/tf/dtypes),
    [`tf.image`](https://www.tensorflow.org/versions/master/api_docs/python/tf/image),
    [`tf.io`](https://www.tensorflow.org/versions/master/api_docs/python/tf/io),
    [`tf.linalg`](https://www.tensorflow.org/versions/master/api_docs/python/tf/linalg),

# 表单模型 { #form-models }

你可以在 FastAPI 中使用 **Pydantic 模型**声明**表单字段**。

/// info | 信息

要使用表单，首先安装 [`python-multipart`](https://github.com/Kludex/python-multipart)。

确保你创建一个[虚拟环境](../virtual-environments.md)，激活它，然后再安装，例如：

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

///

/// note | 注意

自 FastAPI 版本 `0.113.0` 起支持此功能。🤓

///

## 表单的 Pydantic 模型 { #pydantic-models-for-forms }

# 폼 모델 { #form-models }

FastAPI에서 **Pydantic 모델**을 이용하여 **폼 필드**를 선언할 수 있습니다.

/// info | 정보

폼을 사용하려면, 먼저 [`python-multipart`](https://github.com/Kludex/python-multipart)를 설치하세요.

[가상 환경](../virtual-environments.md)을 생성하고 활성화한 다음, 예를 들어 아래와 같이 설치하세요:

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

///

/// note | 참고

이 기능은 FastAPI 버전 `0.113.0` 이후부터 지원됩니다. 🤓

///

Ayrıca HTTP header'ları büyük/küçük harfe duyarlı değildir; dolayısıyla onları standart Python stiliyle (diğer adıyla "snake_case") tanımlayabilirsiniz.

Yani `User_Agent` gibi bir şey yazıp ilk harfleri büyütmeniz gerekmeden, Python kodunda normalde kullandığınız gibi `user_agent` kullanabilirsiniz.

When you need to receive form fields instead of JSON, you can use `Form`.

/// info

To use forms, first install [`python-multipart`](https://github.com/Kludex/python-multipart).

Make sure you create a [virtual environment](../virtual-environments.md), activate it, and then install it, for example:

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

///

## Import `Form` { #import-form }

Import `Form` from `fastapi`:

//// tab | Python 3.10+

```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 3.10+ 非 Annotated

/// tip | 提示

尽可能优先使用 `Annotated` 版本。

///

```Python hl_lines="1"

Tüm attribute'lar için standart Python type'larını kullanın:

{* ../../docs_src/body/tutorial001_py310.py hl[5:9] *}


Query parametrelerini tanımlarken olduğu gibi, bir model attribute'ü default bir değere sahipse zorunlu değildir. Aksi halde zorunludur. Sadece opsiyonel yapmak için `None` kullanın.

Örneğin, yukarıdaki model şu şekilde bir JSON "`object`" (veya Python `dict`) tanımlar:

```JSON
{
    "name": "Foo",

/// info | Información

Para usar formularios, primero instala [`python-multipart`](https://github.com/Kludex/python-multipart).

Asegúrate de crear un [entorno virtual](../virtual-environments.md), activarlo, y luego instalarlo, por ejemplo:

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

///

## Importar `Form` { #import-form }

Importar `Form` desde `fastapi`:

/// info | Info

Um Formulare zu verwenden, installieren Sie zuerst [`python-multipart`](https://github.com/Kludex/python-multipart).

Erstellen Sie unbedingt eine [virtuelle Umgebung](../virtual-environments.md), aktivieren Sie diese und installieren Sie dann das Paket, zum Beispiel:

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

///

## `Form` importieren { #import-form }