how environment variables would be useful and applicable right away. But they keep showing up in many different scenarios when you are developing, so it's good to know about them.

For example, you will need this information in the next section, about [Virtual Environments](virtual-environments.md)....

/*
 * Copyright 2025 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

* The frontend stores that token temporarily somewhere.
* The user clicks in the frontend to go to another section of the frontend web app.
* The frontend needs to fetch some more data from the API.
    * But it needs authentication for that specific endpoint.

/// tip | Astuce

Le `shutdown` se produit lorsque vous **arrêtez** l'application.

Peut-être devez-vous démarrer une nouvelle version, ou vous en avez simplement assez de l'exécuter. 🤷

///

### Fonction de cycle de vie { #lifespan-function }

- Le frontend stocke ce token temporairement quelque part.
- L'utilisateur clique dans le frontend pour aller vers une autre section de l'application web frontend.
- Le frontend doit récupérer d'autres données depuis l'API.
    - Mais cela nécessite une authentification pour cet endpoint spécifique.

///

### Campo `examples` do JSON Schema { #json-schemas-examples-field }

Depois, o JSON Schema adicionou um campo [`examples`](https://json-schema.org/draft/2019-09/json-schema-validation.html#rfc.section.9.5) em uma nova versão da especificação.

E então o novo OpenAPI 3.1.0 passou a se basear na versão mais recente (JSON Schema 2020-12), que incluiu esse novo campo `examples`.

"@webassemblyjs/helper-wasm-bytecode@1.11.6":
  version "1.11.6"
  resolved "https://registry.yarnpkg.com/@webassemblyjs/helper-wasm-bytecode/-/helper-wasm-bytecode-1.11.6.tgz#bb2ebdb3b83aa26d9baad4c46d4315283acd51e9"
  integrity sha512-sFFHKwcmBprO9e7Icf0+gddyWYDViL8bpPjJJl0WHxCdETktXdmtWLGVzoHbqUcY4Be1LkNfwTmXOJUFZYSJdA==

"@webassemblyjs/helper-wasm-section@1.11.6":
  version "1.11.6"

/*
 * Copyright (C) 2009 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License

/// info | 情報

これはWebSocketであるため、`HTTPException` を発生させることはあまり意味がありません。代わりに `WebSocketException` を発生させます。

クロージングコードは、[仕様で定義された有効なコード](https://tools.ietf.org/html/rfc6455#section-7.4.1)の中から使用することができます。

///

### 依存関係を用いてWebSocketsを試してみる { #try-the-websockets-with-dependencies }

アプリケーションを実行します。

<div class="termy">

```console
$ fastapi dev

Nous pourrions aussi les importer ainsi :

```Python
from app.routers import items, users
```

/// info

La première version est un « import relatif » :

```Python
from .routers import items, users
```

La deuxième version est un « import absolu » :

```Python
from app.routers import items, users
```