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

<details markdown="1">
<summary>または<code>async def</code>を使います...</summary>

`async` / `await`を使用するときは、 `async def`を使います:

```Python hl_lines="7 12"
from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}

          object : WebSocketListener() {
            override fun onOpen(
              webSocket: WebSocket,
              response: Response,
            ) {
              try {
                latch.await() // The server can't respond to pings!
              } catch (e: InterruptedException) {
                throw AssertionError(e)
              }
            }
          },
        )
        .build(),
    )

It doesn't matter. **FastAPI** will know what to do.

/// note

If you don't know, check the [Async: *"In a hurry?"*](../../async.md#in-a-hurry){.internal-link target=_blank} section about `async` and `await` in the docs.

///

## Integrated with OpenAPI

All the request declarations, validations and requirements of your dependencies (and sub-dependencies) will be integrated in the same OpenAPI schema.

        override fun responseHeadersEnd(
          call: Call,
          response: Response,
        ) {
          try {
            // Wait for the server to send the duplex response before acting on the 301 response
            // and resetting the stream.
            duplexResponseSent.await()
          } catch (e: InterruptedException) {
            throw AssertionError()
          }

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Or use <code>async def</code>...</summary>

If your code uses `async` / `await`, use `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>또는 <code>async def</code> 사용하기...</summary>

여러분의 코드가 `async` / `await`을 사용한다면, `async def`를 사용하십시오.

```Python hl_lines="9 14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

包括许多与云存储，视频处理等交互的库。

```Python hl_lines="2  10-12  14"
{!../../docs_src/custom_response/tutorial008.py!}
```

/// tip | "小贴士"

注意在这里，因为我们使用的是不支持 `async` 和 `await` 的标准 `open()`，我们使用普通的 `def` 声明了路径操作。

///

### `FileResponse`

异步传输文件作为响应。

与其他响应类型相比，接受不同的参数集进行实例化：

* `path` - 要流式传输的文件的文件路径。
* `headers` - 任何自定义响应头，传入字典类型。

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

/// note | "Nota"

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

///

## Integrando com OpenAPI

Todas as declarações de requisições, validações e requisitos para suas dependências (e sub-dependências) serão integradas em um mesmo esquema OpenAPI.

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Or use <code>async def</code>...</summary>

If your code uses `async` / `await`, use `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}

これにはクラウドストレージとの連携や映像処理など、多くのライブラリが含まれています。

```Python hl_lines="2  10-12  14"
{!../../docs_src/custom_response/tutorial008.py!}
```

/// tip | "豆知識"

ここでは `async` や `await` をサポートしていない標準の `open()` を使っているので、通常の `def` でpath operationを宣言していることに注意してください。

///

### `FileResponse`

レスポンスとしてファイルを非同期的にストリームします。

他のレスポンスタイプとは異なる引数のセットを受け取りインスタンス化します。