# Nebenläufigkeit und async / await

Details zur `async def`-Syntax für *Pfadoperation-Funktionen* und Hintergrundinformationen zu asynchronem Code, Nebenläufigkeit und Parallelität.

## In Eile?

<abbr title="too long; didn't read – Zu lang; nicht gelesen"><strong>TL;DR:</strong></abbr>

Wenn Sie Bibliotheken von Dritten verwenden, die mit `await` aufgerufen werden müssen, wie zum Beispiel:

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

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

В этом случае *функции обработки пути* необходимо объявлять с использованием синтаксиса `async def`:

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

!!! note
    `await` можно использовать только внутри функций, объявленных с использованием `async def`.

---

# Concurrencia y async / await

Detalles sobre la sintaxis `async def` para *path operation functions* y un poco de información sobre código asíncrono, concurrencia y paralelismo.

## ¿Tienes prisa?

<abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>

Si estás utilizando libraries de terceros que te dicen que las llames con `await`, del tipo:

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

# 并发 async / await

有关路径操作函数的 `async def` 语法以及异步代码、并发和并行的一些背景知识。

## 赶时间吗？

<abbr title="too long; didn't read(长文警告)"><strong>TL;DR:</strong></abbr>

如果你正在使用第三方库，它们会告诉你使用 `await` 关键字来调用它们，就像这样：

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

然后，通过 `async def` 声明你的 *路径操作函数*：

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

!!! note

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

**توجه**:

اگر با `async / await` آشنا نیستید، به بخش _"عجله‌ دارید?"_ در صفحه درباره <a href="https://fastapi.tiangolo.com/async/#in-a-hurry" target="_blank">`async` و `await` در مستندات</a> مراجعه کنید.


</details>

### اجرا کنید

با استفاده از دستور زیر سرور را اجرا کنید:

<div class="termy">

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"}

    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Oder verwenden Sie <code>async def</code> ...</summary>

Wenn Ihr Code `async` / `await` verwendet, benutzen Sie `async def`:

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

from fastapi import FastAPI

app = FastAPI()


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

    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>או השתמשו ב - <code>async def</code>...</summary>

אם הקוד שלכם משתמש ב - `async` / `await`, השתמשו ב - `async def`:

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

from fastapi import FastAPI

app = FastAPI()


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

```Python hl_lines="32-37  40-43  46-53  56-62  65-68  71-79"
{!../../../docs_src/sql_databases_peewee/sql_app/main.py!}
```

### 🔃 `def` 🆚 `async def`

🎏 ⏮️ 🇸🇲, 👥 🚫 🔨 🕳 💖:

```Python
user = await models.User.select().first()
```

...✋️ ↩️ 👥 ⚙️:

```Python
user = models.User.select().first()
```

, 🔄, 👥 🔜 📣 *➡ 🛠️ 🔢* & 🔗 🍵 `async def`, ⏮️ 😐 `def`,:

```Python hl_lines="2"

That could potentially require some "waiting".

But as SQLAlchemy doesn't have compatibility for using `await` directly, as would be with something like:

```Python
user = await db.query(User).first()
```

...and instead we are using:

```Python
user = db.query(User).first()
```