In some situations, you might need to use a **proxy** server like Traefik or Nginx with a configuration that adds an extra path prefix that is not seen by your application.

In these cases you can use `root_path` to configure your application.

The `root_path` is a mechanism provided by the ASGI specification (that FastAPI is built on, through Starlette).

The `root_path` is used to handle these specific cases.

You can use simple tools like `htop` to see the CPU and RAM used in your server or the amount used by each process. Or you can use more complex monitoring tools, which may be distributed across servers, etc.

## Recap

# Run a Server Manually

## Use the `fastapi run` Command

In short, use `fastapi run` to serve your FastAPI application:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> run <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>

    # For templates
    "jinja2 >=2.11.2",
    # For forms and file uploads
    "python-multipart >=0.0.7",
    # For Starlette's SessionMiddleware, not commonly used with FastAPI
    "itsdangerous >=1.1.0",
    # For Starlette's schema generation, would not be used with FastAPI
    "pyyaml >=5.3.1",
    # For UJSONResponse
    "ujson >=4.0.1,!=4.0.2,!=4.1.0,!=4.2.0,!=4.3.0,!=5.0.0,!=5.1.0",
    # For ORJSONResponse

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
    `**second_user_data` means:

```Python
def get_current_user(token: str):
    # authenticate user
    return User()


@app.get("/items/")
def read_items(user: User = Depends(get_current_user)):
    ...


@app.post("/items/")
def create_item(*, user: User = Depends(get_current_user), item: Item):
    ...


@app.get("/items/{item_id}")
def read_item(*, user: User = Depends(get_current_user), item_id: int):

<font color="#3465A4">INFO    </font> Resolved absolute path <font color="#75507B">/home/user/code/awesomeapp/</font><font color="#AD7FA8">main.py</font>
<font color="#3465A4">INFO    </font> Searching for package file structure from directories with <font color="#3465A4">__init__.py</font> files
<font color="#3465A4">INFO    </font> Importing from <font color="#75507B">/home/user/code/</font><font color="#AD7FA8">awesomeapp</font>

      id-token: write
    steps:
      - name: Dump GitHub context
        env:
          GITHUB_CONTEXT: ${{ toJson(github) }}
        run: echo "$GITHUB_CONTEXT"
      - uses: actions/checkout@v4
      - name: Set up Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.10"
          # Issue ref: https://github.com/actions/setup-python/issues/436
          # cache: "pip"

![editor support](https://fastapi.tiangolo.com/img/vscode-completion.png)

Dla bardziej kompletnych przykładów posiadających więcej funkcjonalności, zobacz <a href="https://fastapi.tiangolo.com/tutorial/">Tutorial - User Guide</a>.

**Uwaga Spoiler**: tutorial - user guide zawiera:

* Deklaracje **parametrów** z innych miejsc takich jak: **nagłówki**, **pliki cookies**, **formularze** i **pliki**.

```

</div>

Open your browser at <a href="http://127.0.0.1:8000" class="external-link" target="_blank">http://127.0.0.1:8000</a>.

There you can set:

* The "Item ID", used in the path.
* The "Token" used as a query parameter.

!!! tip
    Notice that the query `token` will be handled by a dependency.

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