For that you need to access the request directly.

```Python hl_lines="1  7-8"
{!../../../docs_src/using_request_directly/tutorial001.py!}
```

By declaring a *path operation function* parameter with the type being the `Request` **FastAPI** will know to pass the `Request` in that parameter.

!!! tip

## Get the user

Now create a function that will:

* Take a username.
* Generate a document ID from it.
* Get the document with that ID.
* Put the contents of the document in a `UserInDB` model.

## Mounting a **FastAPI** application

"Mounting" means adding a completely "independent" application in a specific path, that then takes care of handling everything under that path, with the _path operations_ declared in that sub-application.

### Top-level application

First, create the main, top-level, **FastAPI** application, and its *path operations*:

```Python hl_lines="3  6-8"

{% endif %}

I'm the creator of **FastAPI**. You can read more about that in [Help FastAPI - Get Help - Connect with the author](help-fastapi.md#connect-with-the-author){.internal-link target=_blank}.

...But here I want to show you the community.

---

**FastAPI** receives a lot of support from the community. And I want to highlight their contributions.

These are the people that:

client = TestClient(app)


def test_dependency_contextvars():
    """
    Check that custom middlewares don't affect the contextvar context for dependencies.

    The code before yield and the code after yield should be run in the same contextvar
    context, so that request_state_context_var.reset(contextvar_token).

    If they are run in a different context, that raises an error.
    """
    response = client.get("/user")

---

"_Honestly, what you've built looks super solid and polished. In many ways, it's what I wanted **Hug** to be - it's really inspiring to see someone build that._"

```Python hl_lines="55-58"
{!../../../docs_src/async_sql_databases/tutorial001.py!}
```

!!! note
    Notice that as we communicate with the database using `await`, the *path operation function* is declared with `async`.

### Notice the `response_model=List[Note]`

It uses `typing.List`.

That documents (and validates, serializes, filters) the output data, as a `list` of `Note`s.

## Create notes

### Create metadata for tags

Let's try that in an example with tags for `users` and `items`.

Create metadata for your tags and pass it to the `openapi_tags` parameter:

```Python hl_lines="3-16  18"
{!../../../docs_src/metadata/tutorial004.py!}
```

It is provided directly by Starlette, but you can import it from `fastapi`:

```python
from fastapi import WebSocket
```

!!! tip
    When you want to define dependencies that should be compatible with both HTTP and WebSockets, you can define a parameter that takes an `HTTPConnection` instead of a `Request` or a `WebSocket`.

::: fastapi.WebSocket
    options:
        members:
            - scope
            - app
            - url

        data = websocket.receive_text()
        assert data == "path/to/file"
        data = websocket.receive_text()
        assert data == "a_query_param"


def test_wrong_uri():
    """
    Verify that a websocket connection to a non-existent endpoing returns in a shutdown
    """
    client = TestClient(app)
    with pytest.raises(WebSocketDisconnect) as e:
        with client.websocket_connect("/no-router/"):