# Dependencias en decoradores de *path operation*

En algunos casos realmente no necesitas el valor de retorno de una dependencia dentro de tu *path operation function*.

O la dependencia no devuelve un valor.

Pero aún necesitas que sea ejecutada/resuelta.

Para esos casos, en lugar de declarar un parámetro de *path operation function* con `Depends`, puedes añadir una `list` de `dependencies` al decorador de *path operation*.

    * Required scopes `["items"]` with the dependency:
    * `get_current_active_user`:
        *  The dependency function `get_current_active_user` has:
            * Required scopes `["me"]` with the dependency:
            * `get_current_user`:
                * The dependency function `get_current_user` has:
                    * No scopes required by itself.
                    * A dependency using `oauth2_scheme`.

And that way we are able to "parameterize" our dependency, that now has `"bar"` inside of it, as the attribute `checker.fixed_content`.

## Use the instance as a dependency { #use-the-instance-as-a-dependency }

Then, we could use this `checker` in a `Depends(checker)`, instead of `Depends(FixedContentQueryChecker)`, because the dependency is the instance, `checker`, not the class itself.

  <dependencies>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-api-core</artifactId>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter-api</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>

Es ist so konzipiert, sehr einfach zu verwenden zu sein und es jedem Entwickler sehr leicht zu machen, andere Komponenten mit **FastAPI** zu integrieren.

## Was ist „Dependency Injection“

	</build>
	<dependencies>
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>1.7.26</version>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>commons-logging</groupId>
			<artifactId>commons-logging</artifactId>
			<version>1.3.5</version>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>junit</groupId>

It is designed to be very simple to use, and to make it very easy for any developer to integrate other components with **FastAPI**.

## What is "Dependency Injection" { #what-is-dependency-injection }

Y de esa manera podemos "parametrizar" nuestra dependencia, que ahora tiene `"bar"` dentro de ella, como el atributo `checker.fixed_content`.

## Usar la instance como una dependencia

Luego, podríamos usar este `checker` en un `Depends(checker)`, en lugar de `Depends(FixedContentQueryChecker)`, porque la dependencia es la instance, `checker`, no la clase en sí.

Y al resolver la dependencia, **FastAPI** llamará a este `checker` así:

```Python

**FastAPI** will do the right thing with each, the same as with normal dependencies.

///

## A dependency with `yield` and `try` { #a-dependency-with-yield-and-try }

If you use a `try` block in a dependency with `yield`, you'll receive any exception that was thrown when using the dependency.

///

## Uma dependência com `yield` e `try`

Se você utilizar um bloco `try` em uma dependência com `yield`, você irá capturar qualquer exceção que for lançada enquanto a dependência é utilizada.