*
 *  * **Connecting:** the initial state of each web socket. Messages may be enqueued but they won't
 *    be transmitted until the web socket is open.
 *
 *  * **Open:** the web socket has been accepted by the remote peer and is fully operational.
 *    Messages in either direction are enqueued for immediate transmission.
 *
 *  * **Closing:** one of the peers on the web socket has initiated a graceful shutdown. The web

        return createPathMatcher(baseDirectory, includes, null, false);
    }

    /**
     * Returns a filter for directories that may contain paths accepted by the given matcher.
     * The given path matcher should be an instance created by this service.
     * The path matcher returned by this method expects directory paths.

# 后台任务

你可以定义在返回响应后运行的后台任务。

这对需要在请求之后执行的操作很有用，但客户端不必在接收响应之前等待操作完成。

包括这些例子：

* 执行操作后发送的电子邮件通知：
    * 由于连接到电子邮件服务器并发送电子邮件往往很“慢”（几秒钟），您可以立即返回响应并在后台发送电子邮件通知。
* 处理数据：
    * 例如，假设您收到的文件必须经过一个缓慢的过程，您可以返回一个"Accepted"(HTTP 202)响应并在后台处理它。

## 使用 `BackgroundTasks`

首先导入 `BackgroundTasks` 并在 *路径操作函数* 中使用类型声明 `BackgroundTasks` 定义一个参数：

{* ../../docs_src/background_tasks/tutorial001.py hl[1, 13] *}

                If you did this intentionally, please accept the change and provide an explanation:
                <a class="btn btn-info" role="button" data-toggle="collapse" href="#accept-${changeId}" aria-expanded="false" aria-controls="collapseExample">Accept this change</a>
                <div class="collapse" id="accept-${changeId}">
                  <div class="well">

                context.terminal
                        .writer()
                        .println(messageBuilderFactory
                                .builder()
                                .warning("Values not accepted; not saving configuration.")
                                .build());
                return CANCELED;
            }
        }

        return OK;
    }

// Write is non-blocking, if the writer's queue is not full.
// Write is blocking otherwise.
func (w *Writer) Write(p []byte) (n int, err error) {
	return w.pw.Write(p)
}

// Close closes the writer.
// Any accepted writes will be flushed. Any new writes will be rejected.
// Once Close() exits, files are synchronized to disk.
func (w *Writer) Close() error {
	w.pw.CloseWithError(nil)

	if w.f != nil {

body:
  - type: markdown
    attributes:
      value: >
        Filing feature requests is one of the most popular ways to contribute to Guava.


        Be aware, though: most feature requests are not accepted, even if they're suggested by
        a full-time Guava team member. [Feedback](https://stackoverflow.com/a/4543114) from our
        users indicates that they really appreciate Guava's high power-to-weight ratio. It's

    val denied = server.takeRequest()
    assertThat(denied.headers["Authorization"]).isNull()
    val accepted = server.takeRequest()
    assertThat(accepted.requestLine).isEqualTo("GET / HTTP/2")
    assertThat(accepted.headers["Authorization"]).isEqualTo(credential)
  }

  @Test
  fun redirect() {
    server.enqueue(
      MockResponse(

   * href="https://url.spec.whatwg.org/#syntax-url-path-segment">URL path segments</a>. The returned
   * escaper escapes all non-ASCII characters, even though <a
   * href="https://url.spec.whatwg.org/#url-code-points">many of these are accepted in modern
   * URLs</a>. (<a href="https://url.spec.whatwg.org/#path-state">If the escaper were to leave these
   * characters unescaped, they would be escaped by the consumer at parse time, anyway.</a>)

   * href="https://url.spec.whatwg.org/#syntax-url-path-segment">URL path segments</a>. The returned
   * escaper escapes all non-ASCII characters, even though <a
   * href="https://url.spec.whatwg.org/#url-code-points">many of these are accepted in modern
   * URLs</a>. (<a href="https://url.spec.whatwg.org/#path-state">If the escaper were to leave these
   * characters unescaped, they would be escaped by the consumer at parse time, anyway.</a>)