### About `{**note.dict(), "id": last_record_id}`

`note` is a Pydantic `Note` object.

`note.dict()` returns a `dict` with its data, something like:

```Python
{
    "text": "Some note",
    "completed": False,
}
```

but it doesn't have the `id` field.

Let's say you have a *path operation* with a path `/files/{file_path}`.

But you need `file_path` itself to contain a *path*, like `home/johndoe/myfile.txt`.

So, the URL for that file would be something like: `/files/home/johndoe/myfile.txt`.

### OpenAPI support

OpenAPI doesn't support a way to declare a *path parameter* to contain a *path* inside, as that could lead to scenarios that are difficult to test and define.

        That including `uvloop`, the high-performance drop-in replacement for `asyncio`, that provides the big concurrency performance boost.

        When you install FastAPI with something like `pip install fastapi` you already get `uvicorn[standard]` as well.

=== "Hypercorn"

```

请求 `/unicorns/yolo` 时，路径操作会触发 `UnicornException`。

但该异常将会被 `unicorn_exception_handler` 处理。

接收到的错误信息清晰明了，HTTP 状态码为 `418`，JSON 内容如下：

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

```

!!! note "技术细节"

    `from starlette.requests import Request` 和 `from starlette.responses import JSONResponse` 也可以用于导入 `Request` 和 `JSONResponse`。

📥, 🚥 👆 📨 `/unicorns/yolo`, *➡ 🛠️* 🔜 `raise` `UnicornException`.

✋️ ⚫️ 🔜 🍵 `unicorn_exception_handler`.

, 👆 🔜 📨 🧹 ❌, ⏮️ 🇺🇸🔍 👔 📟 `418` & 🎻 🎚:

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

!!! note "📡 ℹ"
    👆 💪 ⚙️ `from starlette.requests import Request` & `from starlette.responses import JSONResponse`.

```

`@app.get("/")` 💬 **FastAPI** 👈 🔢 ▶️️ 🔛 🈚 🚚 📨 👈 🚶:

* ➡ `/`
* ⚙️ <abbr title="an HTTP GET method"><code>get</code> 🛠️</abbr>

!!! info "`@decorator` ℹ"
    👈 `@something` ❕ 🐍 🤙 "👨‍🎨".

    👆 🚮 ⚫️ 🔛 🔝 🔢. 💖 📶 📔 👒 (👤 💭 👈 🌐❔ ⚖ 👟 ⚪️➡️).

     "👨‍🎨" ✊ 🔢 🔛 &amp; 🔨 🕳 ⏮️ ⚫️.

    👆 💼, 👉 👨‍🎨 💬 **FastAPI** 👈 🔢 🔛 🔗 **➡** `/` ⏮️ **🛠️** `get`.

```

</div>

## Check it

Go to the interactive docs at: <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

You will see something like this:

<img src="/img/tutorial/security/image01.png">

!!! check "Authorize button!"
    You already have a shiny new "Authorize" button.

### Async Context Manager

If you check, the function is decorated with an `@asynccontextmanager`.

That converts the function into something called an "**async context manager**".

```Python hl_lines="1  13"
{!../../../docs_src/events/tutorial003.py!}
```

A **context manager** in Python is something that you can use in a `with` statement, for example, `open()` can be used as a context manager:

```Python
with open("file.txt") as file:

!!! tip
    The actual callback is just an HTTP request.

    When implementing the callback yourself, you could use something like <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a> or <a href="https://requests.readthedocs.io/" class="external-link" target="_blank">Requests</a>.

## Write the callback documentation code

But at some point, there was no other option than creating something that provided all these features, taking the best ideas from previous tools, and combining them in the best way possible, using language features that weren't even available before (Python 3.6+ type hints).

</blockquote>