}
        }
    }

    @Nested
    @DisplayName("Master browser enumeration tests")
    class MasterBrowserEnumerationTests {

        @Test
        @DisplayName("doEnum with empty host throws SmbUnsupportedOperationException when master browser not found")
        void doEnum_withEmptyHost_throwsUnsupportedWithoutNetwork() throws Exception {

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>

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

      override fun fromDer(reader: DerReader): Long {
        val peekHeader =
          reader.peekHeader()
            ?: throw ProtocolException("expected time but was exhausted at $reader")

        return when {
          peekHeader.tagClass == Adapters.UTC_TIME.tagClass &&
            peekHeader.tag == Adapters.UTC_TIME.tag -> {
            Adapters.UTC_TIME.fromDer(reader)
          }

↩️ 👥 ✔️ 🗳 ⏮️ ➡ 🔡 `/api/v1` 👆 📱, 🕸 💪 ☕ 🗄 🔗 `/api/v1/openapi.json`.

```mermaid
graph LR

browser("Browser")
proxy["Proxy on http://0.0.0.0:9999/api/v1/app"]
server["Server on http://127.0.0.1:8000/app"]

browser --> proxy
proxy --> server
```

/// tip

📢 `0.0.0.0` 🛎 ⚙️ ⛓ 👈 📋 👂 🔛 🌐 📢 💪 👈 🎰/💽.

///

Das Frontend (das im Browser läuft) würde also versuchen, `/openapi.json` zu erreichen und wäre nicht in der Lage, das OpenAPI-Schema abzurufen.

Da wir für unsere Anwendung einen Proxy mit dem Pfadpräfix `/api/v1` haben, muss das Frontend das OpenAPI-Schema unter `/api/v1/openapi.json` abrufen.

```mermaid
graph LR

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

```mermaid
graph LR

browser("Browser")
proxy["Proxy on http://0.0.0.0:9999/api/v1/app"]
server["Server on http://127.0.0.1:8000/app"]

browser --> proxy
proxy --> server
```

/// tip | Dica

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Environment (please complete the following information):**
 - OS: [e.g. Windows 10]
 - Browser [e.g. chrome, safari]
 - Version [e.g. 13.5.0]

**Additional context**

<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">

///

## Data <abbr title="also known as: serialization, parsing, marshalling">conversion</abbr> { #data-conversion }

If you run this example and open your browser at <a href="http://127.0.0.1:8000/items/3" class="external-link" target="_blank">http://127.0.0.1:8000/items/3</a>, you will see a response of:

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

/// check