### Use cases: external service { #use-cases-external-service }

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

import java.util.Objects;
import java.util.Set;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.versioning.VersionRange;
import org.codehaus.plexus.logging.Logger;

/**
 * Send resolution events to the debug log.
 *
 */
@Deprecated
public class DebugResolutionListener implements ResolutionListener, ResolutionListenerForDepMgmt {
    private Logger logger;

    private String indent = "";

     */
    public int getShareAccessHint() {
        return shareAccessHint;
    }

    @Override
    protected int writeBytesWireFormat(byte[] dst, int dstIndex) {
        // Lease break notifications are sent by the server, not written by client
        return 0;
    }

    @Override
    protected int readBytesWireFormat(byte[] buffer, int bufferIndex) throws SMBProtocolDecodingException {
        int start = bufferIndex;

                    resp.setContentType("text/html");
                    doDirectory(req, resp, smbFile);
                } else {
                    // Send 401
                    resp.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
                    resp.setHeader("WWW-Authenticate", "NTLM");
                    resp.flushBuffer();
                }
            }

  "full_name": "John Doe",
  "disabled": false
}
```

<img src="/img/tutorial/security/image09.png">

If you open the developer tools, you could see how the data sent only includes the token, the password is only sent in the first request to authenticate the user and get that access token, but not afterwards:

<img src="/img/tutorial/security/image10.png">

/// note

```JSON
{
    "message": "Hello World",
    "root_path": "/api/v1"
}
```

Así que no se esperará que sea accedido en `http://127.0.0.1:8000/api/v1/app`.

Uvicorn esperará que el proxy acceda a Uvicorn en `http://127.0.0.1:8000/app`, y luego será responsabilidad del proxy añadir el prefijo extra `/api/v1` encima.

## Sobre proxies con un prefijo de path eliminado

/// warning | Advertencia

Una `Response` devuelta directamente por tu *path operation function* no se documentará en OpenAPI (por ejemplo, el `Content-Type` no se documentará) y no será visible en la documentación interactiva automática.

///

/// info | Información

Por supuesto, el `Content-Type` header real, el código de estado, etc., provendrán del objeto `Response` que devolviste.

///

Lá você pode definir:

* O "Item ID", usado na rota.
* O "Token" usado como um parâmetro de consulta.

/// tip | Dica

Perceba que a consulta `token` será manipulada por uma dependência.

///

Com isso você pode conectar o WebSocket e então enviar e receber mensagens:

<img src="/img/tutorial/websockets/image05.png">

		return
	}

	eventData, err := getLambdaEventData(bucket, object, cred, r)
	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	resp, err := target.Send(eventData)
	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}
	defer resp.Body.Close()

	if eventData.GetObjectContext.OutputRoute != resp.Header.Get(xhttp.AmzRequestRoute) {

/// tip

Note that the test function is now `async def` instead of just `def` as before when using the `TestClient`.

///

Then we can create an `AsyncClient` with the app, and send async requests to it, using `await`.

{* ../../docs_src/async_tests/test_main.py hl[9:12] *}

This is the equivalent to:

```Python
response = client.get('/')
```