# 响应 - 更改状态码

你可能之前已经了解到，你可以设置默认的[响应状态码](../tutorial/response-status-code.md){.internal-link target=_blank}。

但在某些情况下，你需要返回一个不同于默认值的状态码。

## 使用场景

例如，假设你想默认返回一个HTTP状态码为“OK”`200`。

但如果数据不存在，你想创建它，并返回一个HTTP状态码为“CREATED”`201`。

但你仍然希望能够使用`response_model`过滤和转换你返回的数据。

对于这些情况，你可以使用一个`Response`参数。

## 使用 `Response` 参数

你可以在你的*路径操作函数*中声明一个`Response`类型的参数（就像你可以为cookies和头部做的那样）。

然后你可以在这个*临时*响应对象中设置`status_code`。

 * includes both natural exceptions such as unreachable servers, as well as synthetic exceptions
 * when responses are of an unexpected type or cannot be decoded.
 *
 * Other exception types cancel the current call:
 *
 *  * For synchronous calls made with [Call.execute], the exception is propagated to the caller.
 *

 * that is currently executing does not impact the ongoing run, but it does prevent a recurrence
 * from being scheduled.
 *
 * Tasks may opt-out of cancellation with `cancelable = false`. Such tasks will recur until they
 * decide not to by returning -1L.
 *
 * Task Queues
 * -----------
 *
 * Tasks are bound to the [TaskQueue] they are scheduled in. Each queue is sequential and the tasks

     */
    String findTool(String toolName);

    /**
     * Let the toolchain decide if it matches requirements defined
     * in the toolchain plugin configuration.
     *
     * @param requirements key value pair, may not be {@code null}
     * @return {@code true} if the requirements match, otherwise {@code false}
     */
    boolean matchesRequirements(Map<String, String> requirements);

  docs-all-green:  # This job does nothing and is only used for the branch protection
    if: always()
    needs:
      - build-docs
    runs-on: ubuntu-latest
    steps:
      - name: Decide whether the needed jobs succeeded or failed
        uses: re-actors/alls-green@release/v1
        with:
          jobs: ${{ toJSON(needs) }}

import okhttp3.Headers
import okhttp3.Request
import okhttp3.Response
import okhttp3.Route
import okhttp3.internal.connection.RealCall
import okio.Sink
import okio.Source

/** Encodes HTTP requests and decodes HTTP responses. */
interface ExchangeCodec {
  /** The connection or CONNECT tunnel that owns this codec. */
  val carrier: Carrier

  /** Returns an output stream where the request body can be streamed. */

field; unrepresentable fields are replaced with opaque byte arrays.  A
C union translates into a struct containing the first union member and
perhaps additional padding.  C arrays become Go arrays.  C pointers
become Go pointers.  C function pointers become Go's uintptr.
C void pointers become Go's unsafe.Pointer.

For example, mpz_t is defined in <gmp.h> as:

	typedef unsigned long int mp_limb_t;

	typedef struct
	{
		int _mp_alloc;

          '%'.code,
          '\\'.code,
          '^'.code,
          '`'.code,
          '{'.code,
          '|'.code,
          '}'.code,
        )

    Component.FRAGMENT ->
      UrlComponentEncodingTesterJvmPlatform()
        .escapeForUri(
          '%'.code,
          ' '.code,
          '"'.code,
          '#'.code,
          '<'.code,
          '>'.code,
          '\\'.code,

     * didn't see that discussed in the review, which included many other
     * changes: https://mail.openjdk.org/pipermail/core-libs-dev/2013-May/thread.html#17367
     *
     * TODO(cpovirk): decide what the best long-term action here is: force users
     * to suppress (as we do now), stop testing entrySet().add() at all, make
     * entrySet().add() tests tolerant of either behavior, introduce a map

### TLS Handshake Start

The browser would then communicate with that IP address on **port 443** (the HTTPS port).

The first part of the communication is just to establish the connection between the client and the server and to decide the cryptographic keys they will use, etc.

<img src="/img/deployment/https/https02.svg">

This interaction between the client and the server to establish the TLS connection is called the **TLS handshake**.