## Использование `CORSMiddleware` { #use-corsmiddleware }

Вы можете настроить это в вашем **FastAPI**-приложении, используя `CORSMiddleware`.

* Импортируйте `CORSMiddleware`.
* Создайте список разрешённых источников (в виде строк).
* Добавьте его как "middleware" (промежуточный слой) к вашему **FastAPI**-приложению.

Вы также можете указать, разрешает ли ваш бэкенд использование:

`201` 表示**已创建**的状态码。

但我们没有必要记住所有代码的含义。

可以使用 `fastapi.status` 中的快捷变量。

{* ../../docs_src/response_status_code/tutorial002.py hl[1,6] *}

这只是一种快捷方式，具有相同的数字代码，但它可以使用编辑器的自动补全功能：

<img src="../../../../../../img/tutorial/response-status-code/image02.png">

/// note | 技术细节

也可以使用 `from starlette import status`。

为了让开发者更方便，**FastAPI** 提供了与 `starlette.status` 完全相同的 `fastapi.status`。但它直接来自于 Starlette。

///

## 更改默认状态码

/// check | 확인

그저 파이썬 타입 선언을 하기만 하면 **FastAPI**는 자동 대화형 API 문서(Swagger UI)를 제공합니다.

경로 매개변수가 정수형으로 명시된 것을 확인할 수 있습니다.

///

## 표준 기반의 이점, 대체 문서

그리고 생성된 스키마는 <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md" class="external-link" target="_blank">OpenAPI</a> 표준에서 나온 것이기 때문에 호환되는 도구가 많이 있습니다.

from fastapi.encoders import jsonable_encoder
from fastapi.exceptions import RequestValidationError, WebSocketRequestValidationError
from fastapi.utils import is_body_allowed_for_status_code
from fastapi.websockets import WebSocket
from starlette.exceptions import HTTPException
from starlette.requests import Request
from starlette.responses import JSONResponse, Response
from starlette.status import WS_1008_POLICY_VIOLATION

from typing import Union

from fastapi import FastAPI
from fastapi.encoders import jsonable_encoder
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Union[str, None] = None
    description: Union[str, None] = None
    price: Union[float, None] = None
    tax: float = 10.5
    tags: list[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},

from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException
from fastapi.responses import StreamingResponse
from sqlmodel import Field, Session, SQLModel, create_engine

engine = create_engine("postgresql+psycopg://postgres:postgres@localhost/db")


class User(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str


app = FastAPI()


def get_session():

from typing import Annotated

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None


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

from typing import 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: Item = Body(
        openapi_examples={
            "normal": {

### Pequenos erros são tratados automaticamente { #small-errors-automatically-handled }

Ao criar APIs da web com FastAPI, se houver um erro em nosso código, o FastAPI normalmente o conterá na única solicitação que acionou o erro. 🛡

from typing import Optional

from fastapi import FastAPI
from pydantic import BaseModel, Field
from starlette.testclient import TestClient

app = FastAPI()


class Item(BaseModel):
    name: str = Field(alias="aliased_name")
    price: Optional[float] = None
    owner_ids: Optional[list[int]] = None


@app.get("/items/valid", response_model=Item)
def get_valid():
    return Item(aliased_name="valid", price=1.0)