listener.start(String.format("class %s", classDoc.getName()));
        try {
            Element chapter = parent.getOwnerDocument().createElement("chapter");
            parent.appendChild(chapter);
            chapter.setAttribute("id", classDoc.getId());
            descriptionRenderer.renderTo(classDoc, chapter);
            merge(classDoc, chapter);
        } finally {
            listener.finish();
        }
    }

            <title>Script blocks</title>
            <para>No script blocks</para>
        </section>
    </chapter>
</root>'''
    }

    def rendersKnownSubtypes() {
        def sourceContent = parse('''
            <chapter>
                <section><title>Properties</title></section>
            </chapter>
        ''')

/// tip

If you want to **learn FastAPI** in a structured way (recommended), go and read the [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank} chapter by chapter instead.

In particular, when running on **Kubernetes** you will probably **not** want to use workers and instead run **a single Uvicorn process per container**, but I'll tell you about it later in that chapter.

///

## Multiple Workers { #multiple-workers }

# Simple OAuth2 with Password and Bearer { #simple-oauth2-with-password-and-bearer }

Now let's build from the previous chapter and add the missing parts to have a complete security flow.

## Get the `username` and `password` { #get-the-username-and-password }

We are going to use **FastAPI** security utilities to get the `username` and `password`.

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// https://www.eclipse.org/jetty/documentation/current/alpn-chapter.html#alpn-versions
private fun alpnBootVersionForPatchVersion(patchVersion: Int): String? =
  when (patchVersion) {
    in 0..24 -> "8.1.0.v20141016"
    in 25..30 -> "8.1.2.v20141202"
    in 31..50 -> "8.1.3.v20150130"

        id = className
        simpleName = className.tokenize('.').last()
        this.classMetaData = classMetaData
        this.extensionMetaData = extensionMetaData

        classSection = targetDocument.createElement('chapter')

        classContent.childNodes.each { Node n ->
            classSection << n
        }

        propertiesTable = getTable('Properties')
        propertiesSection = propertiesTable.parentNode

///

/// info

In this example we use invented custom headers `X-Key` and `X-Token`.

But in real cases, when implementing security, you would get more benefits from using the integrated [Security utilities (the next chapter)](../security/index.md){.internal-link target=_blank}.

///

## Dependencies errors and return values { #dependencies-errors-and-return-values }

You can use the same dependency *functions* you use normally.

Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded`.

But when the form includes files, it is encoded as `multipart/form-data`. You'll read about handling files in the next chapter.

# Get Current User { #get-current-user }

In the previous chapter the security system (which is based on the dependency injection system) was giving the *path operation function* a `token` as a `str`:

{* ../../docs_src/security/tutorial001_an_py39.py hl[12] *}

But that is still not that useful.

Let's make it give us the current user.

## Create a user model { #create-a-user-model }

First, let's create a Pydantic user model.