* If the parameter is declared to be of the type of a **Pydantic model**, it will be interpreted as a request **body**.

/// note

FastAPI will know that the value of `q` is not required because of the default value `= None`.

{* ../../docs_src/websockets/tutorial001.py hl[2,6:38,41:43] *}

## `websocket` 생성하기

**FastAPI** 응용 프로그램에서 `websocket`을 생성합니다:

{* ../../docs_src/websockets/tutorial001.py hl[1,46:47] *}

/// note | 기술적 세부사항

`from starlette.websockets import WebSocket`을 사용할 수도 있습니다.

**FastAPI**는 개발자를 위한 편의를 위해 동일한 `WebSocket`을 직접 제공합니다. 하지만 이는 Starlette에서 가져옵니다.

///

## 메시지를 대기하고 전송하기

            }
        }
        return false;
    }

    /**
     * Extracts text content from multiple nodes using XPath expression.
     *
     * @param document the parsed HTML document
     * @param xpath the XPath expression to evaluate
     * @return the concatenated text content from all matching nodes
     */
    protected String getMultipleNodeValue(final Document document, final String xpath) {

 * in a few ways:
 *
 * <ul>
 *   <li>Each task may be associated with a different executor.
 *   <li>Tasks may be of type {@code AsyncCallable}.
 *   <li>Running tasks <i>cannot</i> be interrupted. (Note that {@code newSequentialExecutor} does
 *       not return {@code Future} objects, so it doesn't support interruption directly, either.
 *       However, utilities that <i>use</i> that executor have the ability to interrupt tasks

しかし、これは`unicorn_exception_handler`で処理されます。

そのため、HTTPステータスコードが`418`で、JSONの内容が以下のような明確なエラーを受け取ることになります:

```JSON
{"message": "Oops! yolo did something. There goes a rainbow..."}
```

/// note | 技術詳細

また、`from starlette.requests import Request`と`from starlette.responses import JSONResponse`を使用することもできます。

     * Finally, if right hand <code>GAV</code> is absent (line looks like <code>GAV&gt;</code>), the left hand matching
     * <code>GAV</code> is banned fully (from resolving).
     * <br/>
     * Note: the <code>&gt;</code> means project level, while <code>&gt;&gt;</code> means global (whole session level,
     * so even plugins will get relocated artifacts) relocation.
     * <br/>
     * For example,

 *       uppercase, hexadecimal representation of the byte value.
 * </ul>
 *
 * <p>For performance reasons the only currently supported character encoding of this class is
 * UTF-8.
 *
 * <p><b>Note:</b> This escaper produces <a
 * href="https://url.spec.whatwg.org/#percent-encode">uppercase</a> hexadecimal sequences.
 *
 * @author David Beaumont
 * @since 15.0
 */
@GwtCompatible

   * during {@code Executor.execute} (e.g., a {@code RejectedExecutionException} or an exception
   * thrown by {@linkplain MoreExecutors#directExecutor direct execution}) will be caught and
   * logged.
   *
   * <p>Note: If your listener is lightweight -- and will not cause stack overflow by completing
   * more futures or adding more {@code directExecutor()} listeners inline -- consider {@link

        }

        /*
         * if there is an andx and it itself is an andx then just recur by
         * calling this method for it. otherwise just read it's parameter words
         * and bytes as usual. Note how we can't just call andx.readWireFormat
         * because there's no header.
         */

        if (errorCode != 0 || andxCommand == (byte) 0xFF) {
            andxCommand = (byte) 0xFF;

## OpenAPI Extra { #openapi-extra }

When you declare a *path operation* in your application, **FastAPI** automatically generates the relevant metadata about that *path operation* to be included in the OpenAPI schema.

/// note | Technical details

In the OpenAPI specification it is called the <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#operation-object" class="external-link" target="_blank">Operation Object</a>.