werden können. <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">Verwenden Sie dafür das Präfix 'X-'</a>.

    Wenn Sie jedoch benutzerdefinierte Header haben, die ein Client in einem Browser sehen soll, müssen Sie sie zu Ihrer CORS-Konfigurationen ([CORS (Cross-Origin Resource Sharing)](cors.md){.internal-link target=_blank}) hinzufügen, indem Sie den Parameter `expose_headers` verwenden, der in der <a href="https://www.starlette.io/...

Então, vamos rever de um ponto de vista simplificado:

* O usuário digita o `username` e a `senha` no frontend e aperta `Enter`.
* O frontend (rodando no browser do usuário) manda o `username` e a `senha` para uma URL específica na sua API (declarada com `tokenUrl="token"`).
* A API checa aquele `username` e `senha`, e responde com um "token" (nós não implementamos nada disso ainda).

So, let's review it from that simplified point of view:

* The user types the `username` and `password` in the frontend, and hits `Enter`.
* The frontend (running in the user's browser) sends that `username` and `password` to a specific URL in our API (declared with `tokenUrl="token"`).
* The API checks that `username` and `password`, and responds with a "token" (we haven't implemented any of this yet).

```Python hl_lines="6-7"
{!../../../docs_src/query_params/tutorial005.py!}
```

Hier ist `needy` ein erforderlicher Query-Parameter vom Typ `str`.

Wenn Sie in Ihrem Browser eine URL wie:

```
http://127.0.0.1:8000/items/foo-item
```

... öffnen, ohne den benötigten Parameter `needy`, dann erhalten Sie einen Fehler wie den folgenden:

```JSON
{
  "detail": [

	"cmd/go/internal/web"
	"cmd/go/internal/work"
)

var CmdBug = &base.Command{
	Run:       runBug,
	UsageLine: "go bug",
	Short:     "start a bug report",
	Long: `
Bug opens the default browser and starts a new bug report.
The report includes useful system information.
	`,
}

func init() {
	CmdBug.Flag.BoolVar(&cfg.BuildV, "v", false, "")
	base.AddChdirFlag(&CmdBug.Flag)
}

# Requestbody

Wenn Sie Daten von einem <abbr title="Client: Eine Software, die sich mit einem Server verbindet.">Client</abbr> (sagen wir, einem Browser) zu Ihrer API senden, dann senden Sie diese als einen **Requestbody** (Deutsch: Anfragekörper).

Ein **Request**body sind Daten, die vom Client zu Ihrer API gesendet werden. Ein **Response**body (Deutsch: Antwortkörper) sind Daten, die Ihre API zum Client sendet.

// TODO: this block will start a background process not handled by the content testing
[listing.terminal]
----
$ wget https://mirrors.jenkins.io/war-stable/latest/jenkins.war
$ java -jar jenkins.war
----

In the browser, navigate to `localhost` with port `8080` to render the Jenkins dashboard.
You will be asked to set up an new administration user and which plugins to install.

=== Installation of plugins

parameter is not, and seeks to preserve the properties below in the face
of untrusted data:

Structure Preservation Property:
"... when a template author writes an HTML tag in a safe templating language,
the browser will interpret the corresponding portion of the output as a tag
regardless of the values of untrusted data, and similarly for other structures
such as attribute boundaries and JS and CSS string boundaries."

		}
		buf.WriteByte('\n')
	}
	return buf.String()
}

// Dot returns the control-flow graph in the [Dot graph description language].
// Use a command such as 'dot -Tsvg' to render it in a form viewable in a browser.
// This method is provided as a debugging aid; the details of the
// output are unspecified and may change.
//
// [Dot graph description language]: ​​https://en.wikipedia.org/wiki/DOT_(graph_description_language)

# Request Body

When you need to send data from a client (let's say, a browser) to your API, you send it as a **request body**.

A **request** body is data sent by the client to your API. A **response** body is the data your API sends to the client.

Your API almost always has to send a **response** body. But clients don't necessarily need to send **request** bodies all the time.