# Background Tasks - `BackgroundTasks`

You can declare a parameter in a *path operation function* or dependency function with the type `BackgroundTasks`, and then you can use it to schedule the execution of background tasks after the response is sent.

You can import it directly from `fastapi`:

```python
from fastapi import BackgroundTasks
```

 * cancelled).
 *
 * <p>This class serializes execution of <i>submitted</i> tasks but not any <i>listeners</i> of
 * those tasks.
 *
 * <p>Submitted tasks have a happens-before order as defined in the Java Language Specification.
 * Tasks execute with the same happens-before order that the function calls to {@link #submit} and
 * {@link #submitAsync} that submitted those tasks had.
 *

    ignore("okhttp3/osgi/workspace/cnf/repo/index.xml.gz.sha")
  }
}

// Expose OSGi jars to the test environment.
val osgiTestDeploy: Configuration by configurations.creating

val test = tasks.named("test")
val copyOsgiTestDeployment = tasks.register<Copy>("copyOsgiTestDeployment") {
  from(osgiTestDeploy)
  into(layout.buildDirectory.dir("resources/test/okhttp3/osgi/deployments"))
}

test.configure {

    end

    operation ->> client: Return response to client
    Note over client,operation: Response is already sent, can't change it anymore
    opt Tasks
        operation -->> tasks: Send background tasks
    end
    opt Raise other exception
        tasks -->> tasks: Handle exceptions in the background task code
    end
```

/// info | Дополнительная информация

    </dependency>

  </dependencies>

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <configuration>
          <tasks><echo>${project.parent.basedir}</echo></tasks>
        </configuration>
      </plugin>
    </plugins>
  </build>

 * cancelled).
 *
 * <p>This class serializes execution of <i>submitted</i> tasks but not any <i>listeners</i> of
 * those tasks.
 *
 * <p>Submitted tasks have a happens-before order as defined in the Java Language Specification.
 * Tasks execute with the same happens-before order that the function calls to {@link #submit} and
 * {@link #submitAsync} that submitted those tasks had.
 *

    final Queue<Runnable> tasks = new ArrayDeque<>();

    @Override
    public void execute(Runnable command) {
      tasks.add(command);
    }

    boolean hasNext() {
      return !tasks.isEmpty();
    }

    void runNext() {
      assertTrue("expected at least one task to run", hasNext());
      tasks.remove().run();
    }

    void runAll() {

  internal var activeTask: Task? = null

  /** Scheduled tasks ordered by [Task.nextExecuteNanoTime]. */
  internal val futureTasks = mutableListOf<Task>()

  /** True if the [activeTask] should be canceled when it completes. */
  internal var cancelActiveTask = false

  /**
   * Returns a snapshot of tasks currently scheduled for execution. Does not include the

    </dependency>

  </dependencies>

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <configuration>
          <tasks><echo>${project.parent.basedir}</echo></tasks>
        </configuration>
      </plugin>
    </plugins>
  </build>

    </dependency>

  </dependencies>

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <configuration>
          <tasks><echo>${project.parent.basedir}</echo></tasks>
        </configuration>
      </plugin>
    </plugins>
  </build>