### Dependency Injection { #dependency-injection }

FastAPI includes an extremely easy to use, but extremely powerful <abbr title='also known as "components", "resources", "services", "providers"'><strong>Dependency Injection</strong></abbr> system.

### Dependency injection

FastAPI'ın inanılmaz derecede kullanımı kolay, fakat inanılmaz derecede güçlü <abbr title='"components", "resources", "services", "providers" olarak da bilinen'><strong>Dependency Injection </strong></abbr> sistemi var.

* Dependencylerin bile dependencies'i olabiliyor, FastAPI bunun  için **graph of "dependency"** yaratıyor.

    @get:Input
    val name: Provider<String> = homeDir.asFile.map { it.parentFile.parentFile.name }

    /**
     * Make sure this stays type FileCollection (lazy) to avoid losing dependency information.
     */
    @get:InputFiles
    @get:PathSensitive(PathSensitivity.RELATIVE)
    val staticContent: FileCollection
        get() = homeDir.asFileTree.matching {
            exclude("lib/**")

Es erreicht etwas Ähnliches wie Flask-apispec.

Es verfügt über ein integriertes Dependency Injection System, welches von Angular 2 inspiriert ist. Erfordert ein Vorab-Registrieren der „Injectables“ (wie alle anderen Dependency Injection Systeme, welche ich kenne), sodass der Code ausschweifender wird und es mehr Codeverdoppelung gibt.

    /**
     * Transform Graph into a Collection of metadata objects that
     * could serve as a classpath for a particular scope
     *
     * @param dirtyGraph - dependency graph
     * @param scope - which classpath to extract
     * @param resolve - whether to resolve artifacts.
     * @return Collection of metadata objects in the linked subgraph of the graph which

def test_broken_raise():
    with pytest.raises(ValueError, match="Broken after yield"):
        client.get("/broken")


def test_broken_no_raise():
    """
    When a dependency with yield raises after the yield (not in an except), the
    response is already "successfully" sent back to the client, but there's still
    an error in the server afterwards, an exception is raised and captured or shown

        with(details) {
            when {
                // Nullaway-enabled targets must not depend on nullaway-disabled ones.
                // They can depend on nullaway-undefined, which any external dependency is going to be.
                producerValue == NullawayState.DISABLED && consumerValue == NullawayState.ENABLED -> incompatible()
                else -> compatible()
            }
        }
    }

import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;

/**
 * A test which demonstrates maven's dependency management
 *
 */
@Deprecated
class ProjectInheritanceTest extends AbstractProjectInheritanceTestCase {
    // ----------------------------------------------------------------------
    //
    // p1 inherits from p0

                event.getException().getMessage());
    }

    @Override
    public void artifactDescriptorMissing(RepositoryEvent event) {
        logger.warn("The POM for {} is missing, no dependency information available", event.getArtifact());
    }

import java.util.Map;

/**
 * A core extension to monitor Maven's execution. Typically, such an extension gets loaded into Maven by specifying the
 * property {@code maven.ext.class.path} on the command line. As soon as dependency injection is set up, Maven
 * looks up all implementers of this interface and calls their {@link #init(Context)} method. Note: