# WebSockets

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

## Instalando `WebSockets`

Garanta que você criou um [ambiente virtual](../virtual-environments.md){.internal-link target=_blank}, o ativou e instalou o `websockets`:

<div class="termy">

```console
$ pip install websockets

---> 100%
```

</div>

**Source Code**: <a href="https://github.com/fastapi/fastapi" target="_blank">https://github.com/fastapi/fastapi</a>

---

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python based on standard Python type hints.

The key features are:

Если вы хотите узнать больше об этих кодировках и полях форм, перейдите по ссылке <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> web docs for <code>POST</code></a>.

///

/// warning | "Внимание"

import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * The presence of this annotation on a type indicates that the type may be used with the <a
 * href="http://code.google.com/webtoolkit/">Google Web Toolkit</a> (GWT). When applied to a method,
 * the return type of the method is GWT compatible. It's useful to indicate that an instance created
 * by factory methods has a GWT serializable type. In the following example,
 *

{!../../docs_src/middleware/tutorial001.py!}
```

/// tip | "Tipp"

Beachten Sie, dass benutzerdefinierte proprietäre Header hinzugefügt werden können. <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">Verwenden Sie dafür das Präfix 'X-'</a>.

 * there is no guarantee that the domain actually exists on the internet.
 *
 * <p>One common use of this class is to determine whether a given string is likely to represent an
 * addressable domain on the web -- that is, for a candidate string {@code "xxx"}, might browsing to
 * {@code "http://xxx/"} result in a webpage being displayed? In the past, this test was frequently

 *
 * <h2>Standard Packaging Types</h2>
 * <ul>
 *     <li>{@code jar}: Packages the project as a Java Archive (JAR) file.</li>
 *     <li>{@code war}: Packages the project as a Web Application Archive (WAR) file.</li>
 *     <li>{@code pom}: Indicates that the project does not produce a deployable artifact but is used for dependency management or as an aggregator.</li>

Wenn Sie mehr über Formularfelder und ihre Kodierungen lesen möchten, besuchen Sie die <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/POST" class="external-link" target="_blank"><abbr title="Mozilla Developer Network – Mozilla-Entwickler-Netzwerk">MDN</abbr>-Webdokumentation für <code>POST</code></a>.

///

/// warning | "Achtung"

  if (result == null) {
    result = CacheControl.parse(headers)
    lazyCacheControl = result
  }
  return result
}

internal fun canonicalUrl(url: String): String {
  // Silently replace web socket URLs with HTTP URLs.
  return when {
    url.startsWith("ws:", ignoreCase = true) -> {
      "http:${url.substring(3)}"
    }
    url.startsWith("wss:", ignoreCase = true) -> {
      "https:${url.substring(4)}"

但表单包含文件时，编码为 `multipart/form-data`。使用了 `File`，**FastAPI** 就知道要从请求体的正确位置获取文件。

编码和表单字段详见 <a href="https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Methods/POST" class="external-link" target="_blank"><abbr title="Mozilla Developer Network">MDN</abbr> Web 文档的 <code>POST </code></a> 小节。

///

/// warning | "警告"