The proxy headers are:

* <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-For" class="external-link" target="_blank">X-Forwarded-For</a>
* <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-Proto" class="external-link" target="_blank">X-Forwarded-Proto</a>

{* ../../docs_src/middleware/tutorial001_py39.py hl[8:9,11,14] *}

/// tip

Keep in mind that custom proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the `X-` prefix</a>.

This code is something you can actually use in your application, save the password hashes in your database, etc.

We are going to start from where we left in the previous chapter and increment it.

## About JWT { #about-jwt }

JWT means "JSON Web Tokens".

     *       <td>Relative path → resolve against output directory</td>
     *     </tr>
     *     <tr>
     *       <td>{@code Optional.of(Path.of("WEB-INF/classes"))}</td>
     *       <td>{@code /home/user/myproject/target/classes}</td>
     *       <td>{@code /home/user/myproject/target/classes/WEB-INF/classes}</td>
     *       <td>Relative path with subdirectories</td>
     *     </tr>
     *     <tr>

* 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.

그리고 액세스 토큰을 포함하는 문자열과 함께 `access_token`이 있어야 합니다.

이 간단한 예제에서는 완전히 안전하지 않고, 동일한 `username`을 토큰으로 반환합니다.

/// tip | 팁

다음 장에서는 패스워드 해싱 및 <abbr title="JSON Web Tokens">JWT</abbr> 토큰을 사용하여 실제 보안 구현을 볼 수 있습니다.

하지만 지금은 필요한 세부 정보에 집중하겠습니다.

///

{* ../../docs_src/security/tutorial003.py hl[85] *}

/// tip | 팁

set JVM_OPTS=-XX:+UseG1GC%FESS_JAVA_OPTS: =;%

if "%FESS_START_TYPE%" == "" set FESS_START_TYPE=manual
if "%FESS_STOP_TIMEOUT%" == "" set FESS_STOP_TIMEOUT=0

# WebSockets { #websockets }

Puedes usar <a href="https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API" class="external-link" target="_blank">WebSockets</a> con **FastAPI**.

## Instalar `websockets` { #install-websockets }

Asegúrate de crear un [entorno virtual](../virtual-environments.md){.internal-link target=_blank}, activarlo e instalar `websockets` (un paquete de Python que facilita usar el protocolo "WebSocket"):

<div class="termy">

### Nebenläufigkeit + Parallelität: Web + maschinelles Lernen { #concurrency-parallelism-web-machine-learning }

Mit **FastAPI** können Sie die Vorteile der Nebenläufigkeit nutzen, die in der Webentwicklung weit verbreitet ist (derselbe Hauptvorteil von NodeJS).

フォームからのデータは通常、`application/x-www-form-urlencoded`の「media type」を使用してエンコードされます。

しかし、フォームがファイルを含む場合は、`multipart/form-data`としてエンコードされます。ファイルの扱いについては次の章で説明します。

これらのエンコーディングやフォームフィールドの詳細については、<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/POST" class="external-link" target="_blank"><abbr title="Mozilla Developer Network">MDN</abbr>の<code>POST</code></a>のウェブドキュメントを参照してください。

///

/// warning | 注意