!!! info

```Python hl_lines="7  21  23"
{!../../../docs_src/custom_response/tutorial004.py!}
```

In diesem Beispiel generiert die Funktion `generate_html_response()` bereits eine `Response` und gibt sie zurück, anstatt das HTML in einem `str` zurückzugeben.

Indem Sie das Ergebnis des Aufrufs von `generate_html_response()` zurückgeben, geben Sie bereits eine `Response` zurück, die das Standardverhalten von **FastAPI** überschreibt.

```Python hl_lines="7  21  23"
{!../../../docs_src/custom_response/tutorial004.py!}
```

In this example, the function `generate_html_response()` already generates and returns a `Response` instead of returning the HTML in a `str`.

By returning the result of calling `generate_html_response()`, you are already returning a `Response` that will override the default **FastAPI** behavior.

<img src="https://fastapi.tiangolo.com/img/tutorial/body-fields/image01.png">

## 技術詳細

`example` と `examples`について...

JSON Schemaの最新バージョンでは<a href="https://json-schema.org/draft/2019-09/json-schema-validation.html#rfc.section.9.5" class="external-link" target="_blank">`examples`</a>というフィールドを定義していますが、OpenAPIは`examples`を持たない古いバージョンのJSON Schemaをベースにしています。

    If you are just starting with **FastAPI** you might want to skip this section.

## Use cases

Some use cases include:

* Converting non-JSON request bodies to JSON (e.g. <a href="https://msgpack.org/index.html" class="external-link" target="_blank">`msgpack`</a>).
* Decompressing gzip-compressed request bodies.
* Automatically logging all request bodies.

## Handling custom request body encodings

🖼, 🚥 👆 💚 ✍ ⚖️ 🔬 📨 💪 ⏭ ⚫️ 🛠️ 👆 🈸.

!!! danger
    👉 "🏧" ⚒.

    🚥 👆 ▶️ ⏮️ **FastAPI** 👆 💪 💚 🚶 👉 📄.

## ⚙️ 💼

⚙️ 💼 🔌:

* 🏭 🚫-🎻 📨 💪 🎻 (✅ <a href="https://msgpack.org/index.html" class="external-link" target="_blank">`msgpack`</a>).
* 🗜 🗜-🗜 📨 💪.
* 🔁 🚨 🌐 📨 💪.

## 🚚 🛃 📨 💪 🔢

➡️ 👀 ❔ ⚒ ⚙️ 🛃 `Request` 🏿 🗜 🗜 📨.

&amp; `APIRoute` 🏿 ⚙️ 👈 🛃 📨 🎓.

```Python hl_lines="7"
{!../../../docs_src/query_params_str_validations/tutorial006b.py!}
```

!!! info
    🚥 👆 🚫 👀 👈 `...` ⏭: ⚫️ 🎁 👁 💲, ⚫️ <a href="https://docs.python.org/3/library/constants.html#Ellipsis" class="external-link" target="_blank">🍕 🐍 &amp; 🤙 "❕"</a>.

    ⚫️ ⚙️ Pydantic &amp; FastAPI 🎯 📣 👈 💲 ✔.

👉 🔜 ➡️ **FastAPI** 💭 👈 👉 🔢 ✔.

### ✔ ⏮️ `None`

!!! note "Technische Details"
    Jede Funktion, die dekoriert werden kann mit:

    * <a href="https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager" class="external-link" target="_blank">`@contextlib.contextmanager`</a> oder
    * <a href="https://docs.python.org/3/library/contextlib.html#contextlib.asynccontextmanager" class="external-link" target="_blank">`@contextlib.asynccontextmanager`</a>

🖼 👆 💪 ✔️ 📁 `main.py` ⏮️:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

!!! tip
    🥈 ❌ <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 🔢 💲 📨.

    🚥 🚫 🚚, ⚫️ `None` 🔢, 📥 👥 🚚 `"World"` 🔢 💲 ⚙️.

⤴️ 👆 💪 🤙 👈 🐍 📋:

<div class="termy">

```console

It's relatively tightly coupled with relational databases (like MySQL or PostgreSQL), so, having a NoSQL database (like Couchbase, MongoDB, Cassandra, etc) as the main store engine is not very easy.

It was created to generate the HTML in the backend, not to create APIs used by a modern frontend (like React, Vue.js and Angular) or by other systems (like <abbr title="Internet of Things">IoT</abbr> devices) communicating with it.