## Testing locally with Traefik

* There can be **multiple processes** of the **same program** running at the same time.

If you check out the "task manager" or "system monitor" (or similar tools) in your operating system, you will be able to see many of those processes running.

```Python hl_lines="9-13  36-53"
{!../../../docs_src/openapi_webhooks/tutorial001.py!}
```

The webhooks that you define will end up in the **OpenAPI** schema and the automatic **docs UI**.

!!! info

* Add note to docs: [Include the same router multiple times with different `prefix`](https://fastapi.tiangolo.com/tutorial/bigger-applications/#include-the-same-router-multiple-times-with-different-prefix). PR [#348](https://github.com/tiangolo/fastapi/pull/348).

* Fix OpenAPI/JSON Schema generation for two functions with the same name (in different modules) with the same composite bodies.

def main(user_id: str):
    return user_id


# A Pydantic model
class User(BaseModel):
    id: int
    name: str
    joined: date
```

That can then be used like:

```Python
my_user: User = User(id=3, name="John Doe", joined="2018-07-19")

second_user_data = {
    "id": 4,
    "name": "Mary",
    "joined": "2018-11-30",
}

my_second_user: User = User(**second_user_data)
```

!!! info

The process that happens when your API app calls the *external API* is named a "callback". Because the software that the external developer wrote sends a request to your API and then your API *calls back*, sending a request to an *external API* (that was probably created by the same developer).

        uses: actions/setup-python@v5
        with:
          python-version: "3.10"
          # Issue ref: https://github.com/actions/setup-python/issues/436
          # cache: "pip"
          # cache-dependency-path: pyproject.toml
      - name: Install build dependencies
        run: pip install build
      - name: Build distribution
        env:
          TIANGOLO_BUILD_PACKAGE: ${{ matrix.package }}

<img src="/img/tutorial/websockets/image04.png">

And all of them will use the same WebSocket connection.

## Using `Depends` and others

In WebSocket endpoints you can import from `fastapi` and use:

* `Depends`
* `Security`
* `Cookie`
* `Header`
* `Path`
* `Query`

They work the same way as for other FastAPI endpoints/*path operations*:

=== "Python 3.10+"

---

To dopiero początek, ale już masz mniej-więcej pojęcie jak to wszystko działa.

Spróbuj zmienić linijkę:

```Python
    return {"item_name": item.name, "item_id": item_id}
```

...z:

```Python
        ... "item_name": item.name ...
```

...na:

```Python
        ... "item_price": item.price ...
```

---

Мы только немного копнули поверхность, но вы уже поняли, как все это работает.

Попробуйте изменить строку с помощью:

```Python
    return {"item_name": item.name, "item_id": item_id}
```

...из:

```Python
        ... "item_name": item.name ...
```

...в:

```Python
        ... "item_price": item.price ...
```