///

## Crear un middleware { #create-a-middleware }

Para crear un middleware usas el decorador `@app.middleware("http")` encima de una función.

La función middleware recibe:

* La `request`.
* Una función `call_next` que recibirá la `request` como parámetro.
    * Esta función pasará la `request` a la correspondiente *path operation*.

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[1,4,7:9] *}

### Generate the OpenAPI schema { #generate-the-openapi-schema }

Then, use the same utility function to generate the OpenAPI schema, inside a `custom_openapi()` function:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[2,15:21] *}

### Modify the OpenAPI schema { #modify-the-openapi-schema }

#### Union { #union }

You can declare that a variable can be any of **several types**, for example, an `int` or a `str`.

In Python 3.6 and above (including Python 3.10) you can use the `Union` type from `typing` and put inside the square brackets the possible types to accept.

{* ../../docs_src/security/tutorial002_an_py310.py hl[31] *}

Notice that we declare the type of `current_user` as the Pydantic model `User`.

This will help us inside of the function with all the completion and type checks.

/// tip

You might remember that request bodies are also declared with Pydantic models.

Here **FastAPI** won't get confused because you are using `Depends`.

    // We are going to take the project packaging and find all plugins in the default lifecycle and create
    // fully populated Plugin objects, including executions with goals and default configuration taken
    // from the plugin.xml inside a plugin.

    @Override
    public Set<Plugin> getPluginsBoundByDefaultToAllLifecycles(String packaging) {
        if (logger.isDebugEnabled()) {

 * good job of distributing the elements to the buckets to a distribution not far from uniform), and
 * amortized since some operations can trigger a hash table resize.
 *
 * <p>This implementation consumes significantly less memory than {@code java.util.LinkedHashSet} or
 * even {@code java.util.HashSet}, and places considerably less load on the garbage collector. Like

 * good job of distributing the elements to the buckets to a distribution not far from uniform), and
 * amortized since some operations can trigger a hash table resize.
 *
 * <p>This implementation consumes significantly less memory than {@code java.util.LinkedHashSet} or
 * even {@code java.util.HashSet}, and places considerably less load on the garbage collector. Like

                } catch (ClassNotFoundException e) {
                    // assume it is not assignable from Collection or Map
                }
            }

            messageBuffer.append("Inside the definition for plugin '");
            messageBuffer.append(mojo.getPluginDescriptor().getArtifactId());
            messageBuffer.append("', specify the following:").append(LS).append(LS);

# À propos des versions de FastAPI

**FastAPI** est déjà utilisé en production dans de nombreuses applications et systèmes. Et la couverture de test est maintenue à 100 %. Mais son développement est toujours aussi rapide.

De nouvelles fonctionnalités sont ajoutées fréquemment, des bogues sont corrigés régulièrement et le code est
amélioré continuellement.

C'est pourquoi les versions actuelles sont toujours `0.x.x`, cela reflète que chaque version peut potentiellement

 * be registered in {@code META-INF/services/org.apache.maven.api.model.ModelObjectProcessor}.</p>
 *
 * <p>The service is called during model building for all model objects, allowing
 * implementations to decide which objects to process and how to optimize them.</p>
 *
 * @since 4.0.0
 */
public interface ModelObjectProcessor {

    /**
     * Process a model object, potentially returning a pooled or optimized version.