results = await some_library()
```
Alors, déclarez vos *fonctions de chemins* avec `async def` comme ceci :

```Python hl_lines="2"
@app.get('/')
async def read_results():
    results = await some_library()
    return results
```

!!! note
    Vous pouvez uniquement utiliser `await` dans les fonctions créées avec `async def`.

---

    // Cause acceptConnections() to break out.
    serverSocket.close()

    // Await shutdown.
    for (queue in taskRunner.activeQueues()) {
      if (!queue.idleLatch().await(5, TimeUnit.SECONDS)) {
        throw IOException("Gave up waiting for queue to shut down")
      }
    }
    taskRunnerBackend.shutdown()
  }

# Concorrência e async / await

Detalhes sobre a sintaxe `async def` para *funções de operação de rota* e alguns conceitos de código assíncrono, concorrência e paralelismo.

## Com pressa?

<abbr title="muito longo; não li"><strong>TL;DR:</strong></abbr>

Se você estiver utilizando bibliotecas de terceiros que dizem para você chamar as funções com `await`, como:

```Python
results = await some_library()
```

# 並行処理と async / await

*path operation 関数*のための `async def` に関する詳細と非同期 (asynchronous) コード、並行処理 (Concurrency)、そして、並列処理 (Parallelism) の背景について。

## 急いでいますか？

<abbr title="too long; didn't read (長すぎて読めない人のための要約という意味のスラング)"><strong>TL;DR:</strong></abbr>

次のような、`await` を使用して呼び出すべきサードパーティライブラリを使用している場合:

```Python
results = await some_library()
```

以下の様に `async def` を使用して*path operation 関数*を宣言します。

```Python hl_lines="2"
@app.get('/')

    }
  }

  /**
   * Like [Object.wait], but throws an [InterruptedIOException] when interrupted instead of the more
   * awkward [InterruptedException].
   */
  @Throws(InterruptedIOException::class)
  internal fun waitForIo() {
    try {
      condition.await()
    } catch (_: InterruptedException) {

          t: Throwable,
          response: Response?,
        ) {
          t.printStackTrace(System.out)
          latch.countDown()
        }
      },
    )

    check(latch.await(30, TimeUnit.SECONDS)) { "Timed out waiting for test $number to finish." }
    val endNanos = System.nanoTime()
    val tookMs = TimeUnit.NANOSECONDS.toMillis(endNanos - startNanos.get())
    println("Took ${tookMs}ms")
  }

```Python hl_lines="9-10"
{!../../../docs_src/async_tests/test_main.py!}
```

Das ist das Äquivalent zu:

```Python
response = client.get('/')
```

... welches wir verwendet haben, um unsere Requests mit dem `TestClient` zu machen.

!!! tip "Tipp"

* `read(size)`：按指定数量的字节或字符（`size` (`int`)）读取文件内容；
* `seek(offset)`：移动至文件 `offset` （`int`）字节处的位置；
    * 例如，`await myfile.seek(0) ` 移动到文件开头；
    * 执行 `await myfile.read()` 后，需再次读取已读取内容时，这种方法特别好用；
* `close()`：关闭文件。

因为上述方法都是 `async` 方法，要搭配「await」使用。

例如，在 `async` *路径操作函数* 内，要用以下方式读取文件内容：

```Python
contents = await myfile.read()
```

在普通 `def` *路径操作函数*  内，则可以直接访问 `UploadFile.file`，例如：

```Python

You can also use <a href="https://github.com/encode/databases" class="external-link" target="_blank">`encode/databases`</a> with **FastAPI** to connect to databases using `async` and `await`.

It is compatible with:

* PostgreSQL
* MySQL
* SQLite

In this example, we'll use **SQLite**, because it uses a single file and Python has integrated support. So, you can copy this example and run it as is.

### Configuring connection (wait) deadline

This value works in conjunction with max connection setting, setting this value allows for long waiting requests to quickly time out when there is no slot available to perform the request.