{!../../../docs_src/custom_response/tutorial008.py!}
```

1. This is the generator function. It's a "generator function" because it contains `yield` statements inside.
2. By using a `with` block, we make sure that the file-like object is closed after the generator function is done. So, after it finishes sending the response.

With that you can connect the WebSocket and then send and receive messages:

<img src="/img/tutorial/websockets/image05.png">

## Handling disconnections and multiple clients

When a WebSocket connection is closed, the `await websocket.receive_text()` will raise a `WebSocketDisconnect` exception, which you can then catch and handle like in this example.

=== "Python 3.9+"

    ```Python hl_lines="79-81"

## Developing

If you already cloned the <a href="https://github.com/tiangolo/fastapi" class="external-link" target="_blank">fastapi repository</a> and you want to deep dive in the code, here are some guidelines to set up your environment.

### Virtual environment with `venv`

You can create an isolated virtual local environment in a directory using Python's `venv` module. Let's do this in the cloned repository (where the `requirements.txt` is):

* `read(size)`: ✍ `size` (`int`) 🔢/🦹 📁.
* `seek(offset)`: 🚶 🔢 🧘 `offset` (`int`) 📁.
    * 🤶 Ⓜ., `await myfile.seek(0)` 🔜 🚶 ▶️ 📁.
    * 👉 ✴️ ⚠ 🚥 👆 🏃 `await myfile.read()` 🕐 & ⤴️ 💪 ✍ 🎚 🔄.
* `close()`: 🔐 📁.

🌐 👫 👩‍🔬 `async` 👩‍🔬, 👆 💪 "⌛" 👫.

🖼, 🔘 `async` *➡ 🛠️ 🔢* 👆 💪 🤚 🎚 ⏮️:

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

* `read(size)`: 파일의 바이트 및 글자의 `size`(`int`)를 읽습니다.
* `seek(offset)`: 파일 내 `offset`(`int`) 위치의 바이트로 이동합니다.
    * 예) `await myfile.seek(0)` 를 사용하면 파일의 시작부분으로 이동합니다.
    * `await myfile.read()` 를 사용한 후 내용을 다시 읽을 때 유용합니다.
* `close()`: 파일을 닫습니다.

상기 모든 메소드들이 `async` 메소드이기 때문에 “await”을 사용하여야 합니다.

예를들어, `async` *경로 작동 함수*의 내부에서 다음과 같은 방식으로 내용을 가져올 수 있습니다:

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

Routes are declared in a single place, using functions declared in other places (instead of using decorators that can be placed right on top of the function that handles the endpoint). This is closer to how Django does it than to how Flask (and Starlette) does it. It separates in the code things that are relatively tightly coupled.

!!! check "Inspired **FastAPI** to"

    ```

!!! info
    We put the creation of the `SessionLocal()` and handling of the requests in a `try` block.

    And then we close it in the `finally` block.

    This way we make sure the database session is always closed after the request. Even if there was an exception while processing the request.

        members:
            - file
            - filename
            - size
            - headers
            - content_type
            - read
            - write
            - seek

            - receive_bytes
            - receive_json
            - iter_text
            - iter_bytes
            - iter_json
            - send_text
            - send_bytes
            - send_json
            - close

When a client disconnects, a `WebSocketDisconnect` exception is raised, you can catch it.

You can import it directly form `fastapi`:

```python
from fastapi import WebSocketDisconnect
```

# 🔗 ⏮️ 🌾

FastAPI 🐕‍🦺 🔗 👈 <abbr title='sometimes also called "exit", "cleanup", "teardown", "close", "context managers", ...'>➕ 🔁 ⏮️ 🏁</abbr>.

👉, ⚙️ `yield` ↩️ `return`, &amp; ✍ ➕ 🔁 ⏮️.

!!! tip
    ⚒ 💭 ⚙️ `yield` 1️⃣ 👁 🕰.

!!! note "📡 ℹ"
    🙆 🔢 👈 ☑ ⚙️ ⏮️:

    * <a href="https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager" class="external-link" target="_blank">`@contextlib.contextmanager`</a> ⚖️