## Steps { #steps }

So, let's say you have a frontend running in your browser at `http://localhost:8080`, and its JavaScript is trying to communicate with a backend running at `http://localhost` (because we don't specify a port, the browser will assume the default port `80`).

You can see the defined cookies in the docs UI at `/docs`:

<div class="screenshot">
<img src="/img/tutorial/cookie-param-models/image01.png">
</div>

/// info

Have in mind that, as **browsers handle cookies** in special ways and behind the scenes, they **don't** easily allow **JavaScript** to touch them.

 *  New: Don't include the `Content-Length` header in multipart bodies. Servers must delimit
    OkHttp's request bodies using the boundary only. (This change makes OkHttp more consistent with
    browsers and other HTTP clients.)
 *  New: Drop the `tunnelProxy` argument in `MockWebServer.useHttps()`. This change only impacts
    the OkHttp 5.x API which uses the `mockwebserver3` package.

            `/openapi.json`.
            """
        ),
    ],
    title: Annotated[
        str,
        Doc(
            """
            The HTML `<title>` content, normally shown in the browser tab.
            """
        ),
    ],
    swagger_js_url: Annotated[
        str,
        Doc(
            """
            The URL to use to load the Swagger UI JavaScript.

You can test the deployment using the MinIO Console, an embedded web-based object browser built into MinIO Server.
Point a web browser running on the host machine to <http://127.0.0.1:9000> and log in with the root credentials.
You can use the Browser to create buckets, upload objects, and browse the contents of the MinIO server.

## Schritte { #steps }

Angenommen, Sie haben ein Frontend, das in Ihrem Browser unter `http://localhost:8080` läuft, und dessen JavaScript versucht, mit einem Backend zu kommunizieren, das unter `http://localhost` läuft (da wir keinen Port angegeben haben, geht der Browser vom Default-Port `80` aus).

So, the frontend (that runs in the browser) would try to reach `/openapi.json` and wouldn't be able to get the OpenAPI schema.

Because we have a proxy with a path prefix of `/api/v1` for our app, the frontend needs to fetch the OpenAPI schema at `/api/v1/openapi.json`.

```mermaid
graph LR

browser("Browser")
proxy["Proxy on http://0.0.0.0:9999/api/v1/app"]

///

## Daten-<abbr title="Auch bekannt als: Serialisierung, Parsen, Marshalling">Konversion</abbr> { #data-conversion }

Wenn Sie dieses Beispiel ausführen und Ihren Browser unter <a href="http://127.0.0.1:8000/items/3" class="external-link" target="_blank">http://127.0.0.1:8000/items/3</a> öffnen, sehen Sie als Response:

```JSON
{"item_id":3}
```

/// check | Testen

<div class="termy">

```console
$ fastapi dev main.py

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

</div>

Öffnen Sie Ihren Browser unter <a href="http://127.0.0.1:8000" class="external-link" target="_blank">http://127.0.0.1:8000</a>.

Sie sehen eine einfache Seite wie:

<img src="/img/tutorial/websockets/image01.png">

<div class="termy">

```console
$ fastapi dev main.py

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

</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>.

You will see a simple page like:

<img src="/img/tutorial/websockets/image01.png">