// NOTE: Fields are named 'client' and 'server' for cognitive simplicity. This differentiation has
  // zero effect on the behavior of the WebSocket API which is why tests are only written once
  // from the perspective of a single peer.
  private val random = Random(0)
  private val taskFaker = TaskFaker()
  private val sockets = inMemorySocketPair(8192L)
  private val client = TestStreams(taskFaker, sockets[0], client = true)

				return
			}
		}()
		h.ServeHTTP(w, r)
	})
}

// setUploadForwardingMiddleware middleware forwards multiparts requests
// in a site replication setup to peer that initiated the upload
func setUploadForwardingMiddleware(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if !globalSiteReplicationSys.isEnabled() ||

/// tip | Consejo

Pydantic tiene un comportamiento especial cuando utilizas `Optional` o `Union[Something, None]` sin un valor por defecto, puedes leer más sobre ello en la documentación de Pydantic sobre <a href="https://docs.pydantic.dev/2.3/usage/models/#required-fields" class="external-link" target="_blank">Required Optional fields</a>.

///

        }
      }
    }
  ]
}
```

  reasonable contribution (meaning it is not a single liner cosmetic PR).

**2. Valid?**

-   If the PR passes all the quality checks then we go ahead and assign a
    reviewer.
-   If the PR didn't meet the validation criteria, we request for additional
    changes to be made to PR to pass quality checks and send it back or on a
    rare occasion we may reject it.

**3. Review**

		s.writeErrorResponse(w, err)
		return false
	}

	diskID := r.Form.Get(storageRESTDiskID)
	if diskID == "" {
		// Request sent empty disk-id, we allow the request
		// as the peer might be coming up and trying to read format.json
		// or create format.json
		return true
	}

	storedDiskID, err := s.getStorage().GetDiskID()
	if err != nil {
		s.writeErrorResponse(w, err)
		return false

Vemos que vamos a necesitar algunas dependencias usadas en varios lugares de la aplicación.

Así que las ponemos en su propio módulo `dependencies` (`app/dependencies.py`).

Ahora utilizaremos una dependencia simple para leer un encabezado `X-Token` personalizado:

//// tab | Python 3.9+

```Python hl_lines="3  6-8" title="app/dependencies.py"
{!> ../../docs_src/bigger_applications/app_an_py39/dependencies.py!}
```

////

```Python
from .routers import items, users
```

Die zweite Version ist ein „absoluter Import“:

```Python
from app.routers import items, users
```

Um mehr über Python-Packages und -Module zu erfahren, lesen Sie <a href="https://docs.python.org/3/tutorial/modules.html" class="external-link" target="_blank">die offizielle Python-Dokumentation über Module</a>.

///

		HTTPStatusCode: http.StatusRequestedRangeNotSatisfiable,
	},
	ErrInvalidPolicyDocument: {
		Code:           "InvalidPolicyDocument",
		Description:    "The content of the form does not meet the conditions specified in the policy document.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrAccessDenied: {
		Code:           "AccessDenied",
		Description:    "Access Denied.",

/// tip | Consejo

Pydantic, que es lo que impulsa toda la validación y serialización de datos en FastAPI, tiene un comportamiento especial cuando usas `Optional` o `Union[Something, None]` sin un valor por defecto, puedes leer más al respecto en la documentación de Pydantic sobre <a href="https://docs.pydantic.dev/2.3/usage/models/#required-optional-fields" class="external-link" target="_blank">Campos requeridos</a>.

///

/// tip | Consejo