你还可以通过将默认值设置为 `None` 来将请求体参数声明为可选参数：

//// tab | Python 3.10+

```Python hl_lines="18-20"
{!> ../../docs_src/body_multiple_params/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="18-20"
{!> ../../docs_src/body_multiple_params/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="19-21"

## 导入 `Field`

首先，从 Pydantic 中导入 `Field`：

//// tab | Python 3.10+

```Python hl_lines="4"
{!> ../../docs_src/body_fields/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="4"
{!> ../../docs_src/body_fields/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="4"
{!> ../../docs_src/body_fields/tutorial001_an.py!}
```

In diesem Fall werden sie auf alle *Pfadoperationen* in der Anwendung angewendet:

//// tab | Python 3.9+

```Python hl_lines="16"
{!> ../../docs_src/dependencies/tutorial012_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="16"
{!> ../../docs_src/dependencies/tutorial012_an.py!}
```

## `main.py` erstellen

Kopieren Sie das Beispiel in eine Datei `main.py`:

//// tab | Python 3.9+

```Python
{!> ../../docs_src/security/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/security/tutorial001_an.py!}
```

////

//// tab | Python 3.10+

```Python hl_lines="8  49  56-57  60-61  70-76"
{!> ../../docs_src/security/tutorial004_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="8  49  56-57  60-61  70-76"
{!> ../../docs_src/security/tutorial004_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="8  50  57-58  61-62  71-77"

        env:
          GITHUB_CONTEXT: ${{ toJson(github) }}
        run: echo "$GITHUB_CONTEXT"
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: '3.9'
      - name: Setup uv
        uses: astral-sh/setup-uv@v3
        with:
          version: "0.4.15"
          enable-cache: true
          cache-dependency-glob: |
            requirements**.txt

Z. B. `pip install python-multipart`.

///

## `Form` importieren

Importieren Sie `Form` von `fastapi`:

//// tab | Python 3.9+

```Python hl_lines="3"
{!> ../../docs_src/request_forms/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="1"
{!> ../../docs_src/request_forms/tutorial001_an.py!}
```

In that case, they will be applied to all the *path operations* in the application:

//// tab | Python 3.9+

```Python hl_lines="16"
{!> ../../docs_src/dependencies/tutorial012_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="16"
{!> ../../docs_src/dependencies/tutorial012_an.py!}
```

* Utilize o `security` com uma dependência em sua *operação de rota*.
* Isso retorna um objeto do tipo `HTTPBasicCredentials`:
    * Isto contém o `username` e o `password` enviado.

//// tab | Python 3.9+

```Python hl_lines="4  8  12"
{!> ../../docs_src/security/tutorial006_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="2  7  11"
{!> ../../docs_src/security/tutorial006_an.py!}

There are also several other companies offering similar services that you can search and find online. 🤓

## Generate a TypeScript Frontend Client

Let's start with a simple FastAPI application:

//// tab | Python 3.9+

```Python hl_lines="7-9  12-13  16-17  21"
{!> ../../docs_src/generate_clients/tutorial001_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9-11  14-15  18  19  23"