# 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`.

Routes are declared in a single place, using functions declared in other places (instead of using decorators that can be placed right on top of the function that handles the endpoint). This is closer to how Django does it than to how Flask (and Starlette) does it. It separates in the code things that are relatively tightly coupled.

!!! check "Inspired **FastAPI** to"

### Создание класса `Enum`

Импортируйте `Enum` и создайте подкласс, который наследуется от `str` и `Enum`.

Мы наследуемся от `str`, чтобы документация API могла понять, что значения должны быть типа `string` и отображалась правильно.

Затем создайте атрибуты класса с фиксированными допустимыми значениями:

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

For it to sort them correctly, you need to have FastAPI installed locally in your environment, with the command in the section above using `-e`.

## Docs

First, make sure you set up your environment as described above, that will install all the requirements.

### Docs live

During local development, there is a script that builds the site and checks for any changes, live-reloading:

<div class="termy">

```console

    ```

=== "Python 3.8+"

    ```Python hl_lines="4  10"
    {!> ../../../docs_src/body_nested_models/tutorial005.py!}
    ```

Es wird getestet, ob der String eine gültige URL ist, und als solche wird er in JSON Schema / OpenAPI dokumentiert.

## Attribute mit Listen von Kindmodellen

Sie können Pydantic-Modelle auch als Typen innerhalb von `list`, `set`, usw. verwenden:

You can customize that function. It takes an `APIRoute` and outputs a string.

For example, here it is using the first tag (you will probably have only one tag) and the *path operation* name (the function name).

You can then pass that custom function to **FastAPI** as the `generate_unique_id_function` parameter:

* HTTP Basic.
* **OAuth2** (với **JWT tokens**). Xem hướng dẫn [OAuth2 with JWT](tutorial/security/oauth2-jwt.md){.internal-link target=_blank}.
* API keys in:
    * Headers.
    * Các tham số trong query string.
    * Cookies, etc.

Cộng với tất cả các tính năng bảo mật từ Starlette (bao gồm **session cookies**).

 │                          │
 ╰──────────────────────────╯

<font color="#3465A4">INFO    </font> Using import string <font color="#8AE234"><b>main:app</b></font>

 <span style="background-color:#C4A000"><font color="#2E3436">╭────────── FastAPI CLI - Development mode ───────────╮</font></span>

这个`__tablename__`属性是用来告诉 SQLAlchemy 要在数据库中为每个模型使用的数据库表的名称。

### 创建模型属性/列

现在创建所有模型（类）属性。

这些属性中的每一个都代表其相应数据库表中的一列。

我们使用`Column`来表示 SQLAlchemy 中的默认值。

我们传递一个 SQLAlchemy “类型”，如`Integer`、`String`和`Boolean`，它定义了数据库中的类型，作为参数。

```Python hl_lines="1  10-13  21-24"
{!../../../docs_src/sql_databases/sql_app/models.py!}
```

### 创建关系

现在创建关系。

为此，我们使用SQLAlchemy  ORM提供的`relationship`。

* **Modify some DNS records**.
    * For this, the renewal program needs to support the APIs of the DNS provider, so, depending on the DNS provider you are using, this might or might not be an option.
* **Run as a server** (at least during the certificate acquisition process) on the public IP address associated with the domain.
    * As we said above, only one process can be listening on a specific IP and port.