@app.get("/items/{item_id}")
async def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

**注意**：

如果你不知道是否會用到，可以查看 _"In a hurry?"_ 章節中，關於 <a href="https://fastapi.tiangolo.com/async/#in-a-hurry" target="_blank">`async` 和 `await` 的部分</a>。

</details>

### 運行

使用以下指令運行伺服器：

<div class="termy">

```console
$ uvicorn main:app --reload

	instructions["JB"] = x86.AJCS   /* alternate */
	instructions["JBE"] = x86.AJLS  /* alternate */
	instructions["JC"] = x86.AJCS   /* alternate */
	instructions["JCC"] = x86.AJCC  /* carry clear (CF = 0) */
	instructions["JCS"] = x86.AJCS  /* carry set (CF = 1) */
	instructions["JE"] = x86.AJEQ   /* alternate */
	instructions["JEQ"] = x86.AJEQ  /* equal (ZF = 1) */
	instructions["JG"] = x86.AJGT   /* alternate */

      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

      (c) You must retain, in the Source form of any Derivative Works
          that You distribute, all copyright, patent, trademark, and

      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

      (c) You must retain, in the Source form of any Derivative Works
          that You distribute, all copyright, patent, trademark, and

      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

      (c) You must retain, in the Source form of any Derivative Works
          that You distribute, all copyright, patent, trademark, and

      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

      (c) You must retain, in the Source form of any Derivative Works
          that You distribute, all copyright, patent, trademark, and

      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

      (c) You must retain, in the Source form of any Derivative Works
          that You distribute, all copyright, patent, trademark, and

      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

      (c) You must retain, in the Source form of any Derivative Works
          that You distribute, all copyright, patent, trademark, and

Não faz diferença. O **FastAPI** sabe o que fazer.

/// note | Nota

Caso você não conheça, veja em [Async: *"Com Pressa?"*](../../async.md#in-a-hurry){.internal-link target=_blank} a sessão acerca de `async` e `await` na documentação.

///

## Integrando com OpenAPI { #integrated-with-openapi }

# Concorrência e async / await { #concurrency-and-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? { #in-a-hurry }

<abbr title="too long; didn't read – 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