Um eine Middleware zu erstellen, verwenden Sie den Dekorator `@app.middleware("http")` über einer Funktion.

Die Middleware-Funktion erhält:

* Den `request`.
* Eine Funktion `call_next`, die den `request` als Parameter erhält.
    * Diese Funktion gibt den `request` an die entsprechende *Pfadoperation* weiter.
    * Dann gibt es die von der entsprechenden *Pfadoperation* generierte `response` zurück.

import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;

/** Tests for a directed {@link ImmutableNetwork}. */
@AndroidIncompatible
@RunWith(Parameterized.class)
@NullUnmarked
public class StandardImmutableDirectedNetworkTest extends AbstractStandardDirectedNetworkTest {

  @Parameters(name = "allowsSelfLoops={0}, allowsParallelEdges={1}, nodeOrder={2}, edgeOrder={3}")

# Corpo - Campos

Da mesma forma que você pode declarar validações adicionais e metadados nos parâmetros de *funções de operações de rota* com `Query`, `Path` e `Body`, você pode declarar validações e metadados dentro de modelos do Pydantic usando `Field` do Pydantic.

## Importe `Field`

Primeiro, você tem que importá-lo:

{* ../../docs_src/body_fields/tutorial001.py hl[4] *}

/// warning | Aviso

## OpenAPI operationId { #openapi-operationid }

/// warning

If you are not an "expert" in OpenAPI, you probably don't need this.

///

You can set the OpenAPI `operationId` to be used in your *path operation* with the parameter `operation_id`.

You would have to make sure that it is unique for each operation.

{* ../../docs_src/path_operation_advanced_configuration/tutorial001.py hl[6] *}

Mas existem vários casos em que você pode se beneficiar ao usar `UploadFile`.

## Parâmetros de arquivo com `UploadFile`

Defina um parâmetro de arquivo com o tipo `UploadFile`

{* ../../docs_src/request_files/tutorial001_an_py39.py hl[14] *}

Utilizando `UploadFile` tem várias vantagens sobre `bytes`:

* Você não precisa utilizar `File()` como o valor padrão do parâmetro.
* A classe utiliza um arquivo em "spool":

import static java.lang.annotation.ElementType.CONSTRUCTOR;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

    String[] NT_STATUS_MESSAGES = { "The operation completed successfully.", "A device attached to the system is not functioning.",
            "Incorrect function.", "The parameter is incorrect.", "Invalid access to memory location.", "The handle is invalid.",
            "The parameter is incorrect.", "The system cannot find the file specified.", "The system cannot find the file specified.",

   *       uppercase, hexadecimal representation of the byte value.
   * </ul>
   *
   * <p>This escaper is suitable for escaping parameter names and values even when <a
   * href="https://www.w3.org/TR/html401/appendix/notes.html#h-B.2.2">using the non-standard
   * semicolon</a>, rather than the ampersand, as a parameter delimiter. Nevertheless, we recommend
   * using the ampersand unless you must interoperate with systems that require semicolons.
   *

}

// ServeHTTP - implements http.Handler interface.
//
// When the `list` query parameter is provided (its value is ignored), the
// server lists all metrics that could be returned for the requested path.
//
// The (repeatable) `buckets` query parameter is a list of bucket names (or it
// could be a comma separated value) to return metrics with a bucket label.

* `@app.get()`
* `@app.post()`
* `@app.put()`
* `@app.delete()`
* etc.

{* ../../docs_src/response_status_code/tutorial001.py hl[6] *}

/// note | Nota