Your API almost always has to send a **response** body. But clients don't necessarily need to send **request** bodies all the time.

To declare a **request** body, you use <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> models with all their power and benefits.

!!! info

    * 📨 & 📨 🔜 🎨 `str` 💾 8️⃣6️⃣0️⃣1️⃣ 📁, 💖: `2008-09-15T15:53:00+05:00`.
* `datetime.date`:
    * 🐍 `datetime.date`.
    * 📨 & 📨 🔜 🎨 `str` 💾 8️⃣6️⃣0️⃣1️⃣ 📁, 💖: `2008-09-15`.
* `datetime.time`:
    * 🐍 `datetime.time`.
    * 📨 & 📨 🔜 🎨 `str` 💾 8️⃣6️⃣0️⃣1️⃣ 📁, 💖: `14:23:55.003`.
* `datetime.timedelta`:
    * 🐍 `datetime.timedelta`.
    * 📨 & 📨 🔜 🎨 `float` 🌐 🥈.

    Using the cache in this step will **save** you a lot of **time** when building the image again and again during development, instead of **downloading and installing** all the dependencies **every time**.

5. Copy the `./app` directory inside the `/code` directory.

from typing_extensions import Annotated, Doc

from ._compat import PYDANTIC_V2, UndefinedType, Url, _model_dump


# Taken from Pydantic v1 as is
def isoformat(o: Union[datetime.date, datetime.time]) -> str:
    return o.isoformat()


# Taken from Pydantic v1 as is
# TODO: pv2 should this return strings instead?
def decimal_encoder(dec_value: Decimal) -> Union[int, float]:
    """

* `expose_headers` - Indicate any response headers that should be made accessible to the browser. Defaults to `[]`.
* `max_age` - Sets a maximum time in seconds for browsers to cache CORS responses. Defaults to `600`.

The middleware responds to two particular types of HTTP request...

### CORS preflight requests

Claro que este não é o frontend para os usuários finais, mas é uma ótima ferramenta automática para documentar interativamente toda sua API.

Pode ser usado pelo time de frontend (que pode ser você no caso).

Pode ser usado por aplicações e sistemas third party (de terceiros).

E também pode ser usada por você mesmo, para debugar, checar e testar a mesma aplicação.

---

"_**FastAPI**가 너무 좋아서 구름 위를 걷는듯 합니다. 정말 즐겁습니다!_"

<div style="text-align: right; margin-right: 10%;">Brian Okken - <strong><a href="https://pythonbytes.fm/episodes/show/123/time-to-right-the-py-wrongs?time_in_sec=855" target="_blank">Python Bytes</a> 팟캐스트 호스트</strong> <a href="https://twitter.com/brianokken/status/1112220079972728832" target="_blank"><small>(ref)</small></a></div>

---

---

"_我對 **FastAPI** 興奮得不得了。它太有趣了！_"

<div style="text-align: right; margin-right: 10%;">Brian Okken - <strong><a href="https://pythonbytes.fm/episodes/show/123/time-to-right-the-py-wrongs?time_in_sec=855" target="_blank">Python Bytes</a> podcast host</strong> <a href="https://twitter.com/brianokken/status/1112220079972728832" target="_blank"><small>(ref)</small></a></div>

---

你可以查看不同时期的 **FastAPI 专家**：

* [上个月](#fastapi-experts-last-month) 🤓
* [三个月](#fastapi-experts-3-months) 😎
* [六个月](#fastapi-experts-6-months) 🧐
* [一年](#fastapi-experts-1-year) 🧑‍🔬
* [**全部时间**](#fastapi-experts-all-time) 🧙

## FastAPI 专家 - 上个月

这些是在过去一个月中 [在 GitHub 上帮助他人解答最多问题](help-fastapi.md#github_1){.internal-link target=_blank} 的用户。 🤓

{% if people %}
<div class="user-list user-list-center">

    {!> ../../../docs_src/schema_extra_example/tutorial004.py!}
    ```

When you do this, the examples will be part of the internal **JSON Schema** for that body data.

Nevertheless, at the <abbr title="2023-08-26">time of writing this</abbr>, Swagger UI, the tool in charge of showing the docs UI, doesn't support showing multiple examples for the data in **JSON Schema**. But read below for a workaround.

### OpenAPI-specific `examples`