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] *}

///

Dem `status_code`-Parameter wird eine Zahl mit dem HTTP-Statuscode übergeben.

/// info

Alternativ kann `status_code` auch ein `IntEnum` erhalten, so wie Pythons <a href="https://docs.python.org/3/library/http.html#http.HTTPStatus" class="external-link" target="_blank">`http.HTTPStatus`</a>.

///

Das wird:

* Diesen Statuscode mit der Response zurücksenden.

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] *}

/// info | Информация

В качестве значения параметра `status_code` также может использоваться `IntEnum`, например, из библиотеки <a href="https://docs.python.org/3/library/http.html#http.HTTPStatus" class="external-link" target="_blank">`http.HTTPStatus`</a> в Python.

///

Это позволит:

* Возвращать указанный код статуса в ответе.

# Paramètres de chemin

Vous pouvez déclarer des "paramètres" ou "variables" de chemin avec la même syntaxe que celle utilisée par le
<a href="https://docs.python.org/fr/3/library/string.html#format-string-syntax" class="external-link" target="_blank">formatage de chaîne Python</a> :


{* ../../docs_src/path_params/tutorial001.py hl[6:7] *}

La valeur du paramètre `item_id` sera transmise à la fonction dans l'argument `item_id`.

<%@page pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>
<%-- query matched some document --%>
<div id="subheader" class="row">
	<div class="col">
		<p>
			<c:if test="${allRecordCountRelation=='EQUAL_TO'}">
				<la:message key="labels.search_result_status"
					arg0="${displayQuery}" arg1="${fe:formatNumber(allRecordCount,'###,###')}"
					arg2="${f:h(currentStartRecordNumber)}"
					arg3="${f:h(currentEndRecordNumber)}" />

⤴️ ✍ 🎓 🔢 ⏮️ 🔧 💲, ❔ 🔜 💪 ☑ 💲:

{* ../../docs_src/path_params/tutorial005.py hl[1,6:9] *}

/// info

<a href="https://docs.python.org/3/library/enum.html" class="external-link" target="_blank">🔢 (⚖️ 🔢) 💪 🐍</a> ↩️ ⏬ 3️⃣.4️⃣.

///

/// tip

🚥 👆 💭, "📊", "🎓", &amp; "🍏" 📛 🎰 🏫 <abbr title="Technically, Deep Learning model architectures">🏷</abbr>.

Kemudian buat atribut *class* dengan nilai tetap *string* yang benar:

{* ../../docs_src/path_params/tutorial005.py hl[1,6:9] *}

/// info

<a href="https://docs.python.org/3/library/enum.html" class="external-link" target="_blank">Enumerasi (atau enum) tersedia di Python</a> sejak versi 3.4.

///

/// tip | Tips

```Python hl_lines="3"
import os

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

/// tip

آرگومان دوم <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> مقدار پیش‌فرضیه که برمی‌گردونه.

اگه ندی، به‌صورت پیش‌فرض `None` هست، اینجا ما `"World"` رو به‌عنوان مقدار پیش‌فرض گذاشتیم.

///

{* ../../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