# Using Dataclasses { #using-dataclasses }

FastAPI is built on top of **Pydantic**, and I have been showing you how to use Pydantic models to declare requests and responses.

But FastAPI also supports using <a href="https://docs.python.org/3/library/dataclasses.html" class="external-link" target="_blank">`dataclasses`</a> the same way:

{* ../../docs_src/dataclasses/tutorial001.py hl[1,7:12,19:20] *}

FastAPI basiert auf **Pydantic** und ich habe Ihnen gezeigt, wie Sie Pydantic-Modelle verwenden können, um Requests und Responses zu deklarieren.

Aber FastAPI unterstützt auf die gleiche Weise auch die Verwendung von <a href="https://docs.python.org/3/library/dataclasses.html" class="external-link" target="_blank">`dataclasses`</a>:

{* ../../docs_src/dataclasses/tutorial001.py hl[1,7:12,19:20] *}

Все те же правила, которые применяются к path-параметрам, также применяются и query-параметрам:

* Поддержка от редактора кода (очевидно)
* <abbr title="преобразование строки, полученной из HTTP запроса в Python данные">"Парсинг"</abbr> данных
* Проверка на соответствие данных (Валидация)
* Автоматическая документация

## Значения по умолчанию

👫 🍕 📛, 👫 "🛎" 🎻.

✋️ 🕐❔ 👆 📣 👫 ⏮️ 🐍 🆎 (🖼 🔛, `int`), 👫 🗜 👈 🆎 & ✔ 🛡 ⚫️.

🌐 🎏 🛠️ 👈 ⚖ ➡ 🔢 ✔ 🔢 🔢:

* 👨‍🎨 🐕‍🦺 (🎲)
* 💽 <abbr title="converting the string that comes from an HTTP request into Python data">"✍"</abbr>
* 💽 🔬
* 🏧 🧾

## 🔢

🔢 🔢 🚫 🔧 🍕 ➡, 👫 💪 📦 &amp; 💪 ✔️ 🔢 💲.

🖼 🔛 👫 ✔️ 🔢 💲 `skip=0` &amp; `limit=10`.

, 🔜 📛:

```
http://127.0.0.1:8000/items/
```

  if (enable) {
    optimizer_options->set_global_jit_level(tensorflow::OptimizerOptions::ON_1);

    // These XLA flags are needed to trigger XLA properly from C (more generally
    // non-Python) clients. If this API is called again with `enable` set to
    // false, it is safe to keep these flag values as is.
    tensorflow::MarkForCompilationPassFlags* flags =
        tensorflow::GetMarkForCompilationPassFlags();

{* ../../docs_src/custom_request_and_route/tutorial001.py hl[18:26] *}

/// note | Technische Details

Ein `Request` hat ein `request.scope`-Attribut, welches einfach ein Python-`dict` ist, welches die mit dem Request verbundenen Metadaten enthält.

Ein `Request` hat auch ein `request.receive`, welches eine Funktion ist, die den Hauptteil des Requests empfängt.

{* ../../docs_src/middleware/tutorial001.py hl[10,12:13] *}

/// tip | Consejo

Aquí usamos <a href="https://docs.python.org/3/library/time.html#time.perf_counter" class="external-link" target="_blank">`time.perf_counter()`</a> en lugar de `time.time()` porque puede ser más preciso para estos casos de uso. 🤓

///

## Otros middlewares

## 🔧

⤴️ 👤 💸 🕰 🔧 👩‍💻 "🛠️" 👤 💚 ✔️ 👩‍💻 (👩‍💻 ⚙️ FastAPI).

👤 💯 📚 💭 🏆 🌟 🐍 👨‍🎨: 🗒, 🆚 📟, 🎠 🧢 👨‍🎨.

🏁 <a href="https://www.jetbrains.com/research/python-developers-survey-2018/#development-tools" class="external-link" target="_blank">🐍 👩‍💻 🔬</a>, 👈 📔 🔃 8️⃣0️⃣ 💯 👩‍💻.

⚫️ ⛓ 👈 **FastAPI** 🎯 💯 ⏮️ 👨‍🎨 ⚙️ 8️⃣0️⃣ 💯 🐍 👩‍💻. &amp; 🏆 🎏 👨‍🎨 😑 👷 ➡, 🌐 🚮 💰 🔜 👷 🌖 🌐 👨‍🎨.

## Install `PyJWT` { #install-pyjwt }

We need to install `PyJWT` to generate and verify the JWT tokens in Python.

Make sure you create a [virtual environment](../../virtual-environments.md){.internal-link target=_blank}, activate it, and then install `pyjwt`:

<div class="termy">

```console
$ pip install pyjwt

## Rode o código

Todos os blocos de código podem ser copiados e utilizados diretamente (eles são, na verdade, arquivos Python testados).

Para rodar qualquer um dos exemplos, copie o codigo para um arquivo `main.py`, e inicie o `uvivorn` com:

<div class="termy">

```console