This part is pretty normal, most of the code is probably already familiar to you:

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

!!! tip
    The `callback_url` query parameter uses a Pydantic <a href="https://docs.pydantic.dev/latest/concepts/types/#urls" class="external-link" target="_blank">URL</a> type.

    ```

=== "Python 3.10+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="66-67  79"
    {!> ../../../docs_src/websockets/tutorial002_py310.py!}
    ```

=== "Python 3.8+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="68-69  81"

    {!> ../../../docs_src/settings/app02_an/main.py!}
    ```

=== "Python 3.8+ non-Annotated"

    !!! tip
        Prefer to use the `Annotated` version if possible.

    ```Python hl_lines="5  11-12"
    {!> ../../../docs_src/settings/app02/main.py!}
    ```

!!! tip
    We'll discuss the `@lru_cache` in a bit.

    For now you can assume `get_settings()` is a normal function.

    }
}
```

!!! tip
    Notice the auto-generated server with a `url` value of `/api/v1`, taken from the `root_path`.

In the docs UI at <a href="http://127.0.0.1:9999/api/v1/docs" class="external-link" target="_blank">http://127.0.0.1:9999/api/v1/docs</a> it would look like:

<img src="/img/tutorial/behind-a-proxy/image03.png">

!!! tip
    The docs UI will interact with the server that you select.

Using Linux containers has several advantages including **security**, **replicability**, **simplicity**, and others.

!!! tip
    In a hurry and already know this stuff? Jump to the [`Dockerfile` below 👇](#build-a-docker-image-for-fastapi).

<details>
<summary>Dockerfile Preview 👀</summary>

```Dockerfile
FROM python:3.9

WORKDIR /code

### Restart After Crash

But in those cases with really bad errors that crash the running **process**, you would want an external component that is in charge of **restarting** the process, at least a couple of times...

!!! tip
    ...Although if the whole application is just **crashing immediately** it probably doesn't make sense to keep restarting it forever. But in those cases, you will probably notice it during development, or at least right after deployment.

**Kaynak Kod**: <a href="https://github.com/tiangolo/fastapi" target="_blank">https://github.com/tiangolo/fastapi</a>

---

FastAPI, Python 'nin standart <abbr title="Tip Belirteçleri: Type Hints">tip belirteçleri</abbr>ne dayalı, modern ve hızlı (yüksek performanslı) API'lar oluşturmak için kullanılabilecek web framework'tür.

Temel özellikleri şunlardır:

**Qaynaq Kodu**: <a href="https://github.com/tiangolo/fastapi" target="_blank">https://github.com/tiangolo/fastapi</a>

---

FastAPI Python ilə API yaratmaq üçün standart Python <abbr title="Tip Məsləhətləri: Type Hints">tip məsləhətlərinə</abbr> əsaslanan, müasir, sürətli (yüksək performanslı) framework-dür.

Əsas xüsusiyyətləri bunlardır:

In most cases you would (and should) have a "termination proxy" handling HTTPS for you on top, this will depend on how you deploy your application, your provider might do this for you, or you might need to set it up yourself.

!!! tip

   */
  // Note: 90% of the time we don't add type parameters or wildcards that serve only to "tweak" the
  // desired return type. However, *nested* generics introduce a special class of problems that we
  // think tip it over into being worthwhile.
  public static <T extends @Nullable Object, S extends T> Comparator<Iterable<S>> lexicographical(
      Comparator<T> comparator) {
    return new LexicographicalOrdering<S>(checkNotNull(comparator));