安装命令： `pip install python-multipart`。

这是因为 **OAuth2** 使用**表单数据**发送 `username` 与 `password`。

///

用下面的命令运行该示例：

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

## 查看文档

<div align="center">
  <img src="https://www.tensorflow.org/images/tf_logo_horizontal.png">
</div>

[![Python](https://img.shields.io/pypi/pyversions/tensorflow.svg)](https://badge.fury.io/py/tensorflow)
[![PyPI](https://badge.fury.io/py/tensorflow.svg)](https://badge.fury.io/py/tensorflow)
[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.4724125.svg)](https://doi.org/10.5281/zenodo.4724125)

# 第一步

最簡單的 FastAPI 檔案可能看起來像這樣：

{* ../../docs_src/first_steps/tutorial001.py *}

將其複製到一個名為 `main.py` 的文件中。

執行即時重新載入伺服器（live server）：

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>

// Mul sets z = x * y and returns z.
func (z *Int) Mul(x, y *Int) *Int {
	x.doinit()
	y.doinit()
	z.doinit()
	C.mpz_mul(&z.i[0], &x.i[0], &y.i[0])
	return z
}

// Div sets z = x / y, rounding toward zero, and returns z.
func (z *Int) Div(x, y *Int) *Int {
	x.doinit()
	y.doinit()
	z.doinit()
	C.mpz_tdiv_q(&z.i[0], &x.i[0], &y.i[0])
	return z
}

// Mod sets z = x % y and returns z.

fastapi[standard]>=0.113.0,<0.114.0
pydantic>=2.7.0,<3.0.0
```

Y normalmente instalarías esas dependencias de los paquetes con `pip`, por ejemplo:

<div class="termy">

```console
$ pip install -r requirements.txt
---> 100%
Successfully installed fastapi pydantic
```

</div>

/// info | Información

Existen otros formatos y herramientas para definir e instalar dependencias de paquetes.

///

figure,footer,header,hgroup,main,nav,section{display:block}mark{background:#FF0;color:#000}template{display:none}")),l||i(a,d),a}var k,l,m="3.7.3",n=a.html5||{},o=/^<|^(?:button|map|select|textarea|object|iframe|option|optgroup)$/i,p=/^(?:a|b|code|div|fieldset|h1|h2|h3|h4|h5|h6|i|label|li|ol|p|q|span|strong|style|table|tbody|td|th|tr|ul)$/i,q="_html5shiv",r=0,s={};!function(){try{var a=b.createElement("a");a.innerHTML="<xyz></xyz>",k="hidden"in a,l=1==a.childNodes.length||function(){b.createElement("a");var...

fastapi[standard]>=0.113.0,<0.114.0
pydantic>=2.7.0,<3.0.0
```

E você normalmente instalaria essas dependências de pacote com `pip`, por exemplo:

<div class="termy">

```console
$ pip install -r requirements.txt
---> 100%
Successfully installed fastapi pydantic
```

</div>

/// info | Informação

Há outros formatos e ferramentas para definir e instalar dependências de pacotes.

///

Isso ocorre porque o **OAuth2** usa "form data" para enviar o `username` e o `password`.

///

Execute o exemplo com:

<div class="termy">

```console
$ fastapi dev main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

## Verifique-o { #check-it }

Esto se debe a que **OAuth2** utiliza "form data" para enviar el `username` y `password`.

///

Ejecuta el ejemplo con:

<div class="termy">

```console
$ fastapi dev main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

## Revisa { #check-it }

line-height:18px !important;
}

a[class="cut"]{
display:none !important;
}

}


@media only screen and (max-width: 480px) {

table[class="collapse"]{
width:100% !important;
}

div[class="collapse"]{
width:100% !important;
}

td[class="logo_space"]{
height:12px !important;
}

span[class="address"]{
display:block !important;
width:240px !important;
}
td[class="cut"]{