///

## Stream SSE with FastAPI { #stream-sse-with-fastapi }

To stream SSE with FastAPI, use `yield` in your *path operation function* and set `response_class=EventSourceResponse`.

Import `EventSourceResponse` from `fastapi.sse`:

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[1:25] hl[4,22] *}

Each yielded item is encoded as JSON and sent in the `data:` field of an SSE event.

    // Run those tasks together.
    fakePool.runAll();

    // Check that the interruption of a SequentialExecutor's task is restored to the thread once
    // it is yielded. Clear the bit while checking so that the test doesn't hose JUnit or some other
    // test case.
    assertThat(Thread.interrupted()).isTrue();
  }

  public void testInterrupt_doesNotStopExecution() {

And when using `Depends(scope="request")` (the default), the exit code after `yield` is executed after the response is sent.

You can read more about it in the docs for [Dependencies with `yield` - Early exit and `scope`](../tutorial/dependencies/dependencies-with-yield.md#early-exit-and-scope).

### Dependencies with `yield` and `StreamingResponse`, Technical Details { #dependencies-with-yield-and-streamingresponse-technical-details }

    // Run those tasks together.
    fakePool.runAll();

    // Check that the interruption of a SequentialExecutor's task is restored to the thread once
    // it is yielded. Clear the bit while checking so that the test doesn't hose JUnit or some other
    // test case.
    assertThat(Thread.interrupted()).isTrue();
  }

  public void testInterrupt_doesNotStopExecution() {

///

## A database dependency with `yield` { #a-database-dependency-with-yield }

For example, you could use this to create a database session and close it after finishing.

Only the code prior to and including the `yield` statement is executed before creating a response:

{* ../../docs_src/dependencies/tutorial007_py310.py hl[2:4] *}

The yielded value is what is injected into *path operations* and other dependencies:

///

Dependências com `yield` evoluíram ao longo do tempo para contemplar diferentes casos de uso e corrigir alguns problemas, aqui está um resumo do que mudou.

### Dependências com `yield` e `scope` { #dependencies-with-yield-and-scope }

Na versão 0.121.0, o FastAPI adicionou suporte a `Depends(scope="function")` para dependências com `yield`.

O **FastAPI** possui suporte para dependências que realizam <dfn title='às vezes também chamado de "código de saída", "código de limpeza", "código de teardown", "código de fechamento", "código de saída do gerenciador de contexto", etc.'>alguns passos extras ao finalizar</dfn>.

Para fazer isso, utilize `yield` em vez de `return`, e escreva os passos extras (código) depois.

/// tip | Dica

///

## `yield`를 사용하는 데이터베이스 의존성 { #a-database-dependency-with-yield }

예를 들어, 이 기능을 사용하면 데이터베이스 세션을 생성하고 작업이 끝난 후에 세션을 종료할 수 있습니다.

응답을 생성하기 전에는 `yield`문을 포함하여 그 이전의 코드만이 실행됩니다:

{* ../../docs_src/dependencies/tutorial007_py310.py hl[2:4] *}

yield된 값은 *경로 처리* 및 다른 의존성들에 주입되는 값 입니다:

{* ../../docs_src/dependencies/tutorial007_py310.py hl[4] *}

`yield`문 다음의 코드는 응답을 생성한 후 실행됩니다:

///

## Créer une dépendance de base de données avec `yield` { #a-database-dependency-with-yield }

Par exemple, vous pouvez l'utiliser pour créer une session de base de données et la fermer après la fin.

Seul le code précédant et incluant l'instruction `yield` est exécuté avant la création de la réponse :

{* ../../docs_src/dependencies/tutorial007_py310.py hl[2:4] *}

# Зависимости с yield { #dependencies-with-yield }

FastAPI поддерживает зависимости, которые выполняют некоторые <dfn title='иногда также называемые "код выхода", "код очистки", "код завершения", "код закрытия", "код выхода менеджера контекста" и т.п.'>дополнительные шаги после завершения</dfn>.

Для этого используйте `yield` вместо `return`, а дополнительные шаги (код) напишите после него.

/// tip | Подсказка