/// tip | Consejo

Las siguientes secciones **no son necesariamente "avanzadas"**.

Y es posible que para tu caso de uso, la solución esté en una de ellas.

///

## Lee primero el Tutorial

E então você também leu como lidar com [CORS com o `CORSMiddleware`](../tutorial/cors.md){.internal-link target=_blank}.

Nesta seção, veremos como usar outros middlewares.

## Adicionando middlewares ASGI

En utilisant seulement `BackgroundTasks` (et non `BackgroundTask`), il est possible de l'utiliser en tant que paramètre de *fonction de chemin* et de laisser **FastAPI** gérer le reste pour vous, comme en utilisant l'objet `Request` directement.

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)


Daha önceden düşünüp en imkansız diyebileceğin durumlarda bile otomatik tamamlama alacaksın, örnek olarak `price` JSON body içerisinde (nested bir JSON body de olabilirdi.) direkt olarak istekten geliyor, bu durumda bile oto-tammalama sağlıyor.

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)

You will get completion in code you might even consider impossible before. As for example, the `price` key inside a JSON body (that could have been nested) that comes from a request.

No more typing the wrong key names, coming back and forth between docs, or scrolling up and down to find if you finally used `username` or `user_name`.

### Short { #short }

                foundTestMethod = true;
                break;
            }
        }
        assertTrue(foundTestMethod);
    }

    public void test_nestedExceptions() {
        // Test nested exception handling
        Exception innerCause = new IllegalArgumentException("Invalid LDAP parameter");
        RuntimeException middleCause = new RuntimeException("LDAP configuration error", innerCause);

                        attributes.put(name, parseArray(jsonParser));
                    } else if (jsonParser.getCurrentToken() == JsonToken.START_OBJECT) {
                        // Handle nested object type
                        attributes.put(name, parseObject(jsonParser));
                    } else {
                        // Handle primitive types (string, number, boolean, etc.)

import static org.mockito.Mockito.never;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;

        StackTraceElement topElement = stackTrace[0];
        assertEquals(this.getClass().getName(), topElement.getClassName());
    }

    public void test_nestedExceptions() {
        // Test nested exception handling
        Exception level3 = new RuntimeException("Level 3 error");
        Exception level2 = new IllegalStateException("Level 2 error", level3);

	// Composite Index: Flattened structure.
	Data0A string `gorm:"index:,composite:comp_id0"`
	Data0B string `gorm:"index:,composite:comp_id0"`

	// Composite Index: Nested structure.
	Data1A string `gorm:"index:,composite:comp_id1"`
	CompIdxLevel1C

	// Composite Index: Unique and priority.
	Data2A string `gorm:"index:,unique,composite:comp_id2,priority:2"`
	CompIdxLevel2C
}