{* ../../docs_src/app_testing/tutorial002_py310.py hl[27:31] *}

/// note | Nota

Para más detalles, revisa la documentación de Starlette sobre [probar WebSockets](https://www.starlette.dev/testclient/#testing-websocket-sessions).

 *
 * Otherwise, this performs IDN ToASCII encoding and canonicalize the result to lowercase. For
 * example this converts `☃.net` to `xn--n3h.net`, and `WwW.GoOgLe.cOm` to `www.google.com`.
 * `null` will be returned if the host cannot be ToASCII encoded or if the result contains
 * unsupported ASCII characters.
 */
internal fun String.toCanonicalHost(): String? {

 *
 * 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,

## Details zum `Request`-Objekt { #details-about-the-request-object }

Da **FastAPI** unter der Haube eigentlich **Starlette** ist, mit einer Ebene von mehreren Tools darüber, können Sie Starlettes [`Request`](https://www.starlette.dev/requests/)-Objekt direkt verwenden, wenn Sie es benötigen.

## Detalhes sobre o objeto `Request` { #details-about-the-request-object }

Como o **FastAPI** é na verdade o **Starlette** por baixo, com camadas de diversas funcionalidades por cima, você pode utilizar o objeto [`Request`](https://www.starlette.dev/requests/) do Starlette diretamente quando precisar.

  - 💾 [PostgreSQL](https://www.postgresql.org) 作为 SQL 数据库。
- 🚀 [React](https://react.dev) 用于前端。
  - 💃 使用 TypeScript、hooks、Vite 以及现代前端技术栈的其他部分。
  - 🎨 [Tailwind CSS](https://tailwindcss.com) 与 [shadcn/ui](https://ui.shadcn.com) 用于前端组件。
  - 🤖 自动生成的前端客户端。
  - 🧪 [Playwright](https://playwright.dev) 用于端到端测试。
  - 🦇 支持暗黑模式。
- 🐋 [Docker Compose](https://www.docker.com) 用于开发与生产。
- 🔒 默认启用安全的密码哈希。

  to you 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, WITHOUT WARRANTIES OR CONDITIONS OF ANY

regarding copyright ownership.  The ASF licenses this file
to you 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, WITHOUT WARRANTIES OR CONDITIONS OF ANY

```
https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

JSON ボディは:

```JSON
{
    "id": "2expen51ve",
    "customer": "Mr. Richie Rich",
    "total": "9999"
}
```

その後 *あなたの API* は請求書を処理し、のちほど `callback_url`（*外部 API*）へコールバックのリクエストを送ります:

```
https://www.external.org/events/invoices/2expen51ve
```

JSON ボディは次のような内容です:

        assertTrue(transformer.isValidUrl("http://www.example.com"));
        assertTrue(transformer.isValidUrl("http://www.example.com/aaa"));
        assertTrue(transformer.isValidUrl("https://www.example.com"));
        assertTrue(transformer.isValidUrl("://www.example.com"));
        assertTrue(transformer.isValidUrl("//www.example.com"));

        assertFalse(transformer.isValidUrl(null));