在FastAPI中仍然可以单独使用 `BackgroundTask`，但您必须在代码中创建对象，并返回包含它的Starlette `Response`。

更多细节查看 <a href="https://www.starlette.dev/background/" class="external-link" target="_blank">Starlette's official docs for Background Tasks</a>.

## 告诫

如果您需要执行繁重的后台计算，并且不一定需要由同一进程运行（例如，您不需要共享内存、变量等），那么使用其他更大的工具（如 <a href="https://docs.celeryq.dev" class="external-link" target="_blank">Celery</a>）可能更好。

它们往往需要更复杂的配置，即消息/作业队列管理器，如RabbitMQ或Redis，但它们允许您在多个进程中运行后台任务，甚至是在多个服务器中。

이를 위해 `with` 문에서 `TestClient`를 사용하여 WebSocket에 연결합니다:

{* ../../docs_src/app_testing/tutorial002.py hl[27:31] *}

/// note | 참고

자세한 내용은 Starlette의 <a href="https://www.starlette.dev/testclient/#testing-websocket-sessions" class="external-link" target="_blank"> WebSocket 테스트</a>에 관한 설명서를 참고하시길 바랍니다.

from typing import Annotated, Union

from fastapi import Depends, FastAPI

app = FastAPI()


fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"}]


class CommonQueryParams:
    def __init__(self, q: Union[str, None] = None, skip: int = 0, limit: int = 100):
        self.q = q
        self.skip = skip
        self.limit = limit


@app.get("/items/")

from typing import Annotated, Union

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Annotated[
        Item,
        Body(
            examples=[

import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.repository.WorkspaceRepository;

/**
 */
@Named
@Singleton
public class DefaultProjectArtifactsCache implements ProjectArtifactsCache {
    /**
     * CacheKey
     */
    protected static class CacheKey implements Key {

        private final String groupId;

        private final String artifactId;

        private final String version;

## Atualização de dados existentes com `PUT` { #update-replacing-with-put }

Para atualizar um item, você pode usar a operação <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/PUT" class="external-link" target="_blank">HTTP `PUT`</a>.

 *
 * @deprecated use {@code org.apache.maven.api.services.ModelBuilder} instead
 */
@Named("core-default")
@Singleton
@Typed(ModelProcessor.class)
@Deprecated(since = "4.0.0")
public class DefaultModelProcessor implements ModelProcessor {

    @Inject
    private ModelLocator locator;

    @Inject
    private ModelReader reader;

Por exemplo, vamos adicionar <a href="https://github.com/Rebilly/ReDoc/blob/master/docs/redoc-vendor-extensions.md#x-logo" class="external-link" target="_blank">Extensão OpenAPI do ReDoc para incluir um logo personalizado</a>.

### **FastAPI** Normal { #normal-fastapi }

Primeiro, escreva toda a sua aplicação **FastAPI** normalmente:

 * limitations under the License.
 */
package gradlebuild.docs.dsl.docbook;

import java.util.*;

/**
 * Normalises and cleans up HTML to convert it to XML semantics.
 */
public class HtmlToXmlJavadocLexer implements JavadocLexer {
    private final JavadocLexer lexer;
    private final Set<String> blockElements = new HashSet<String>();
    private final Set<String> blockContent = new HashSet<String>();

/**
 * Handles deserialization of settings from the default textual format.
 *
 * @deprecated since 4.0.0, use {@link SettingsStaxReader} instead
 */
@Named
@Singleton
@Deprecated(since = "4.0.0")
public class DefaultSettingsReader implements SettingsReader {

    @Override
    public Settings read(File input, Map<String, ?> options) throws IOException {
        Objects.requireNonNull(input, "input cannot be null");