!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

## Read the Tutorial first

The next sections assume you already read the main [Tutorial - User Guide: Security](../../tutorial/security/index.md){.internal-link target=_blank}.

This is different from using an `APIRouter` as a mounted application is completely independent. The OpenAPI and docs from your main application won't include anything from the mounted application, etc.

You can read more about this in the [Advanced User Guide](../advanced/index.md){.internal-link target=_blank}.

## Details

### Providing the `root_path`

To achieve this, you can use the command line option `--root-path` like:

<div class="termy">

```console
$ fastapi run main.py --root-path /api/v1

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

If you use Hypercorn, it also has the option `--root-path`.

            ]
        }
    )


def test_main_depends_q_foo():
    response = client.get("/main-depends/?q=foo")
    assert response.status_code == 200
    assert response.json() == {
        "in": "main-depends",
        "params": {"q": "foo", "skip": 0, "limit": 100},
    }


def test_main_depends_q_foo_skip_100_limit_200():
    response = client.get("/main-depends/?q=foo&skip=100&limit=200")

## 🗄 ➕

🕐❔ 👆 📣 *➡ 🛠️* 👆 🈸, **FastAPI** 🔁 🏗 🔗 🗃 🔃 👈 *➡ 🛠️* 🔌 🗄 🔗.

!!! note "📡 ℹ"
    🗄 🔧 ⚫️ 🤙 <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#operation-object" class="external-link" target="_blank">🛠️ 🎚</a>.

⚫️ ✔️ 🌐 ℹ 🔃 *➡ 🛠️* &amp; ⚙️ 🏗 🏧 🧾.

⚫️ 🔌 `tags`, `parameters`, `requestBody`, `responses`, ♒️.

## The main `FastAPI`

Now, let's see the module at `app/main.py`.

Here's where you import and use the class `FastAPI`.

This will be the main file in your application that ties everything together.

And as most of your logic will now live in its own specific module, the main file will be quite simple.

### Import `FastAPI`

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

Die Datei `main.py` hätte als Inhalt:

```Python
{!../../../docs_src/async_tests/main.py!}
```

Die Datei `test_main.py` hätte die Tests für `main.py`, das könnte jetzt so aussehen:

```Python
{!../../../docs_src/async_tests/test_main.py!}
```

## Es ausführen

            Swagger UI (that provides the `/docs` interface) has better support for the
            OpenAPI-specific examples than the JSON Schema `examples`, that's the main
            use case for this.

            Read more about it in the

В вашем FastAPI приложении, импортируйте и вызовите `uvicorn` напрямую:

```Python hl_lines="1  15"
{!../../../docs_src/debugging/tutorial001.py!}
```

### Описание `__name__ == "__main__"`

Главная цель использования `__name__ == "__main__"` в том, чтобы код выполнялся при запуске файла с помощью:

<div class="termy">

```console
$ python myapp.py
```

</div>

That way, you can edit the documentation/source files and see the changes live.

!!! tip
    Alternatively, you can perform the same steps that scripts does manually.

    Go into the language directory, for the main docs in English it's at `docs/en/`:

    ```console
    $ cd docs/en/
    ```

    Then run `mkdocs` in that directory:

    ```console
    $ mkdocs serve --dev-addr 8008
    ```