[okhttp_312x]: https://github.com/square/okhttp/tree/okhttp_3.12.x
 [okhttp]: https://square.github.io/okhttp/
 [okio]: https://github.com/square/okio
 [post_example]: https://raw.github.com/square/okhttp/master/samples/guide/src/main/java/okhttp3/guide/PostExample.java
 [r8_proguard]: https://square.github.io/okhttp/features/r8_proguard/
 [recipes]: https://square.github.io/okhttp/recipes/

So, all these are different origins:

* `http://localhost`
* `https://localhost`
* `http://localhost:8080`

Even if they are all in `localhost`, they use different protocols or ports, so, they are different "origins".

## Steps

  /**
   * The HTTP <a href="https://datatracker.ietf.org/doc/html/rfc7540#section-3.2.1">{@code
   * HTTP2-Settings} </a> header field name.
   *
   * @since 24.0
   */
  public static final String HTTP2_SETTINGS = "HTTP2-Settings";

  /** The HTTP {@code If-Match} header field name. */
  public static final String IF_MATCH = "If-Match";
  /** The HTTP {@code If-Modified-Since} header field name. */

 - [Gitbucket](https://github.com/codelibs/fess-ds-gitbucket)
 - [G Suite](https://github.com/codelibs/fess-ds-gsuite)
 - [JSON](https://github.com/codelibs/fess-ds-json)
 - [Office 365](https://github.com/codelibs/fess-ds-office365)
 - [S3](https://github.com/codelibs/fess-ds-s3)
 - [Salesforce](https://github.com/codelibs/fess-ds-salesforce)
 - [SharePoint](https://github.com/codelibs/fess-ds-sharepoint)

   * implementation of this pattern is [gRPC][grpc].
   *
   * Because the encoding of interleaved data is not well-defined for HTTP/1, duplex request
   * bodies may only be used with HTTP/2. Calls to HTTP/1 servers will fail before the HTTP request
   * is transmitted. If you cannot ensure that your client and server both support HTTP/2, do not
   * use this feature.
   *
   * ### Duplex APIs
   *

okhttp3.internal.connection.RouteSelectorTest
okhttp3.internal.http.CancelTest
okhttp3.internal.http.HttpDateTest
okhttp3.internal.http.StatusLineTest
okhttp3.internal.http.ThreadInterruptTest
okhttp3.internal.http2.FrameLogTest
okhttp3.internal.http2.HpackTest
okhttp3.internal.http2.Http2ConnectionTest
okhttp3.internal.http2.Http2Test
okhttp3.internal.http2.HttpOverHttp2Test
okhttp3.internal.http2.HuffmanTest
okhttp3.internal.http2.SettingsTest

`status_code` 는 파이썬의 `http.HTTPStatus` 와 같은 `IntEnum` 을 입력받을 수도 있습니다.

///

`status_code` 매개변수는:

* 응답에서 해당 상태 코드를 반환합니다.
* 상태 코드를 OpenAPI 스키마(및 사용자 인터페이스)에 문서화 합니다.

<img src="https://fastapi.tiangolo.com/img/tutorial/response-status-code/image01.png">

/// note | "참고"

어떤 응답 코드들은 해당 응답에 본문이 없다는 것을 의미하기도 합니다 (다음 항목 참고).

이에 따라 FastAPI는 응답 본문이 없음을 명시하는 OpenAPI를 생성합니다.

///

## HTTP 상태 코드에 대하여

/// note | "참고"

# CORS（跨域资源共享）

<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS" class="external-link" target="_blank">CORS 或者「跨域资源共享」</a> 指浏览器中运行的前端拥有与后端通信的 JavaScript 代码，而后端处于与前端不同的「源」的情况。

## 源

源是协议（`http`，`https`）、域（`myapp.com`，`localhost`，`localhost.tiangolo.com`）以及端口（`80`、`443`、`8080`）的组合。

因此，这些都是不同的源：

* `http://localhost`
* `https://localhost`
* `http://localhost:8080`

即使它们都在 `localhost` 中，但是它们使用不同的协议或者端口，所以它们都是不同的「源」。

## 步骤

import java.net.Socket

/**
 * The sockets and streams of an HTTP, HTTPS, or HTTPS+HTTP/2 connection. May be used for multiple
 * HTTP request/response exchanges. Connections may be direct to the origin server or via a proxy.
 *
 * Typically instances of this class are created, connected and exercised automatically by the HTTP
 * client. Applications may use this class to monitor HTTP connections as members of a
 * [connection pool][ConnectionPool].
 *

		success   bool
	}{
		// Invalid inputs
		{"https://localhost:2379,http://localhost:2380", nil, false, false},
		{",,,", nil, false, false},
		{"", nil, false, false},
		{"ftp://localhost:2379", nil, false, false},
		{"http://localhost:2379000", nil, false, false},

		// Valid inputs
		{
			"https://localhost:2379,https://localhost:2380",
			[]string{
				"https://localhost:2379", "https://localhost:2380",
			},
			true, true,