# 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> :


```Python hl_lines="6-7"
{!../../../docs_src/path_params/tutorial001.py!}
```

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

* Из загруженного файла можно получить метаданные.
* Он реализует <a href="https://docs.python.org/3/glossary.html#term-file-like-object" class="external-link" target="_blank">file-like</a> `async` интерфейс.

!!! info

```Python hl_lines="1  6-9"
{!../../../docs_src/path_params/tutorial005.py!}
```

!!! info "Дополнительная информация"
    <a href="https://docs.python.org/3/library/enum.html" class="external-link" target="_blank">Перечисления (enum) доступны в Python</a> начиная с версии 3.4.

!!! tip "Подсказка"

!!! info

    })"""

    if init_oauth:
        html += f"""
        ui.initOAuth({json.dumps(jsonable_encoder(init_oauth))})
        """

    html += """
    </script>
    </body>
    </html>
    """
    return HTMLResponse(html)


def get_redoc_html(
    *,
    openapi_url: Annotated[
        str,
        Doc(
            """
            The OpenAPI URL that ReDoc should load and use.

```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`

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.

🖼 👆 💪 ✔️ 📁 `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

```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.