# `Response` class

You can declare a parameter in a *path operation function* or dependency to be of type `Response` and then you can set data for the response like headers or cookies.

You can also use it directly to create an instance of it and return it from your *path operations*.

You can import it directly from `fastapi`:

```python
from fastapi import Response
```

    - tutorial/handling-errors.md
    - tutorial/path-operation-configuration.md
    - tutorial/encoder.md
    - tutorial/body-updates.md
    - Dependencies:
      - tutorial/dependencies/index.md
      - tutorial/dependencies/classes-as-dependencies.md
      - tutorial/dependencies/sub-dependencies.md
      - tutorial/dependencies/dependencies-in-path-operation-decorators.md
      - tutorial/dependencies/global-dependencies.md

$ uvicorn main:my_awesome_api --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

### Шаг 3: определите *операцию пути (path operation)*

#### Путь (path)

"Путь" это часть URL, после первого символа `/`, следующего за именем домена.

Для URL:

```
https://example.com/items/foo
```

...путь выглядит так:

    /**
     * Deletes all crawling sessions and their parameters except for the specified active sessions.
     * This is a cleanup operation that removes inactive session data while preserving active ones.
     *
     * @param activeSessionId a set of session IDs to preserve during the cleanup operation
     */
    public void deleteOldSessions(final Set<String> activeSessionId) {
        final List<CrawlingInfo> activeSessionList =

   *     no change will be made.
   * @return the count of the element before the operation; possibly zero
   * @throws IllegalArgumentException if {@code occurrences} is negative, or if this operation would
   *     result in more than {@link Integer#MAX_VALUE} occurrences of the element

  }

  private static void runConcurrentlyMutatedTest(WrapWithIterable wrap) {
    /*
     * TODO: Iterate over many array sizes and all possible operation lists,
     * performing adds and removes in different ways.
     */
    runConcurrentlyMutatedTest(elements(), ops(add(1), add(2)), wrap);

    runConcurrentlyMutatedTest(elements(), ops(add(1), nop()), wrap);

8. Notice that this *path operation function* uses regular `def` instead of `async def`.

    As always, in FastAPI you can combine `def` and `async def` as needed.

    If you need a refresher about when to use which, check out the section _"In a hurry?"_ in the docs about [`async` and `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

# 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
```

# `UploadFile` class

You can define *path operation function* parameters to be of the type `UploadFile` to receive files from the request.

You can import it directly from `fastapi`:

```python
from fastapi import UploadFile
```

::: fastapi.UploadFile
    options:
        members:
            - file
            - filename
            - size
            - headers
            - content_type
            - read

    public static class ShareEnumAll extends DcerpcMessage {

        @Override
        public int getOpnum() {
            return 0x0f;
        }

        /**
         * The return value of the operation.
         */
        public int retval;
        /**
         * The name of the server.
         */
        public String servername;
        /**
         * The information level to return.