{* ../../docs_src/middleware/tutorial001_py310.py hl[8:9,11,14] *}

/// tip

Keep in mind that custom proprietary headers can be added [using the `X-` prefix](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers).

This is similar to [Stream JSON Lines](stream-json-lines.md), but uses the `text/event-stream` format, which is supported natively by browsers with the [`EventSource` API](https://developer.mozilla.org/en-US/docs/Web/API/EventSource).

/// info

Added in FastAPI 0.135.0.

///

## What are Server-Sent Events? { #what-are-server-sent-events }

* Giving and gracefully accepting constructive feedback
* Accepting responsibility and apologizing to those affected by our mistakes,
  and learning from the experience
* Focusing on what is best not just for us as individuals, but for the
  overall community

Examples of unacceptable behavior include:

* The use of sexualized language or imagery, and sexual attention or
  advances of any kind

--------------

We accept Pull Requests via GitHub. The [developer mailing list][dev-ml-list] is the
main channel of communication for contributors.  
There are some guidelines which will make applying PRs easier for us:
+ Create a topic branch from where you want to base your work (this is usually the master branch).
  Push your changes to a topic branch in your fork of the repository.
+ Make commits of logical units.

* `500 - 599` 表示伺服器錯誤。你幾乎不會直接使用它們。當你的應用程式或伺服器某處出錯時，會自動回傳其中一個狀態碼。

/// tip | 提示

想深入瞭解各狀態碼與其用途，請參考 [<abbr title="Mozilla Developer Network - Mozilla 開發者網路">MDN</abbr> 關於 HTTP 狀態碼的文件](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status)。

///

## 快速記住名稱 { #shortcut-to-remember-the-names }

再看一次前面的範例：

{* ../../docs_src/response_status_code/tutorial001_py310.py hl[6] *}

`201` 是「已建立（Created）」的狀態碼。

            writer: DerWriter,
            value: String,
          ) = writer.writeUtf8(value)
        },
    )

  /**
   * Based on International Alphabet No. 5. Note that there are bytes that IA5 and US-ASCII
   * disagree on interpretation.
   *
   * TODO(jwilson): constrain to IA5 characters.
   */
  val IA5_STRING =
    BasicDerAdapter(
      name = "IA5 STRING",

    private static final Logger log = LoggerFactory.getLogger(Strings.class);

    private static final Charset UNI_ENCODING = Charset.forName("UTF-16LE");
    private static final Charset ASCII_ENCODING = Charset.forName("US-ASCII");

    private static final boolean MASK_SECRET_VALUE = System.getProperty("jcifs.maskSecretValue", "true") == "true";
    private static final String SECRET_PATTERN = "^(smb.*:).*(@.*)$";

    - 然後回傳對應*路徑操作*所產生的 `response`。
- 然後你可以在回傳之前進一步修改 `response`。

{* ../../docs_src/middleware/tutorial001_py310.py hl[8:9,11,14] *}

/// tip

請記得，自訂的非標準標頭可以[使用 `X-` 前綴](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers)。

但如果你有自訂標頭並希望瀏覽器端的用戶端能看到它們，你需要在 CORS 設定（[CORS（跨來源資源共用）](cors.md)）中使用 [Starlette 的 CORS 文件](https://www.starlette.dev/middleware/#corsmiddleware)所記載的參數 `expose_headers` 將它們加入。

///

/// note | 技術細節

   * href="https://msdn.microsoft.com/en-us/library/windows/desktop/dd562994(v=vs.85).aspx">file
   * name extensions for Windows Media metafiles</a>.
   *
   * @since 20.0
   */
  public static final MediaType WMA_AUDIO = createConstant(AUDIO_TYPE, "x-ms-wma");

  /**
   * Windows Media metafiles. For more information, see <a
   * href="https://msdn.microsoft.com/en-us/library/windows/desktop/dd562994(v=vs.85).aspx">file

  // to the given dividend, so that we don't have half of our divisions being
  // trivial because the divisor is bigger than the dividend.
  // Using remainder here does not give us a uniform distribution but it should
  // not have a big impact on the measurement.
  private static long randomDivisor(long dividend) {
    long r = randomSource.nextLong();
    if (dividend == -1) {
      return r;