from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: str | None = Query(default=None, alias="item-query")):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

/// tip

FastAPI automatically generates **OpenAPI 3.1** specifications, so any tool you use must support this version.

///

## SDK Generators from FastAPI Sponsors { #sdk-generators-from-fastapi-sponsors }

Isto é suportado desde a versão `0.113.0` do FastAPI. 🤓

///

## Modelos Pydantic para Formulários { #pydantic-models-for-forms }

Você precisa apenas declarar um **modelo Pydantic** com os campos que deseja receber como **campos de formulários**, e então declarar o parâmetro como um `Form`:

{* ../../docs_src/request_form_models/tutorial001_an_py39.py hl[9:11,15] *}

from fastapi import APIRouter, FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel


class ResponseModel(BaseModel):
    message: str


app = FastAPI()
router = APIRouter()


@router.get("/a", responses={501: {"description": "Error 1"}})
async def a():
    return "a"


@router.get(
    "/b",
    responses={
        502: {"description": "Error 2"},

# Unteranwendungen – Mounts { #sub-applications-mounts }

Wenn Sie zwei unabhängige FastAPI-Anwendungen mit deren eigenen unabhängigen OpenAPI und deren eigenen Dokumentationsoberflächen benötigen, können Sie eine Hauptanwendung haben und dann eine (oder mehrere) Unteranwendung(en) „mounten“.

## Eine **FastAPI**-Anwendung mounten { #mounting-a-fastapi-application }

from fastapi import APIRouter, FastAPI, Request
from fastapi.responses import JSONResponse
from fastapi.testclient import TestClient

app = FastAPI()
router = APIRouter()


@router.route("/items/")
def read_items(request: Request):
    return JSONResponse({"hello": "world"})


app.include_router(router)

client = TestClient(app)


def test_sub_router():
    response = client.get("/items/")

该依赖项使用字符串（`str`）接收*路径操作函数*的参数 `token` 。

**FastAPI** 使用依赖项在 OpenAPI 概图（及 API 文档）中定义**安全方案**。

/// info | 技术细节

**FastAPI** 使用（在依赖项中声明的）类 `OAuth2PasswordBearer` 在 OpenAPI 中定义安全方案，这是因为它继承自 `fastapi.security.oauth2.OAuth2`，而该类又是继承自`fastapi.security.base.SecurityBase`。

所有与 OpenAPI（及 API 文档）集成的安全工具都继承自 `SecurityBase`， 这就是为什么 **FastAPI** 能把它们集成至 OpenAPI 的原因。

///

## 实现的操作

It is imported/included directly into FastAPI so that you can import it from `fastapi` and avoid accidentally importing the alternative `BackgroundTask` (without the `s` at the end) from `starlette.background`.

By only using `BackgroundTasks` (and not `BackgroundTask`), it's then possible to use it as a *path operation function* parameter and have **FastAPI** handle the rest for you, just like when using the `Request` object directly.

Ela é importada/incluída diretamente no FastAPI para que você possa importá-la de `fastapi` e evitar importar acidentalmente a alternativa `BackgroundTask` (sem o `s` no final) de `starlette.background`.

Usando apenas `BackgroundTasks` (e não `BackgroundTask`), é possível usá-la como um parâmetro de *função de operação de rota* e deixar o **FastAPI** cuidar do resto para você, assim como ao usar o objeto `Request` diretamente.

И это будет задокументировано как таковое в OpenAPI.

///

/// tip | Совет

`ORJSONResponse` доступен только в FastAPI, а не в Starlette.

///

## HTML-ответ { #html-response }

Чтобы вернуть ответ с HTML напрямую из **FastAPI**, используйте `HTMLResponse`.

- Импортируйте `HTMLResponse`.
- Передайте `HTMLResponse` в параметр `response_class` вашего декоратора операции пути.