from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


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


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},

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: Item = Body(
        examples=[
            {
                "name": "Foo",
                "description": "A very nice Item",

from datetime import datetime

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Subscription(BaseModel):
    username: str
    monthly_fee: float
    start_date: datetime


@app.webhooks.post("new-subscription")
def new_subscription(body: Subscription):
    """
    When a new user subscribes to your service we'll send you a POST request with this

from pydantic import BaseModel


def forwardref_method(input: "ForwardRefModel") -> "ForwardRefModel":
    return ForwardRefModel(x=input.x + 1)


class ForwardRefModel(BaseModel):

from typing import Union

from fastapi import FastAPI
from fastapi.responses import FileResponse
from pydantic import BaseModel


class Item(BaseModel):
    id: str
    value: str


app = FastAPI()


@app.get(
    "/items/{item_id}",
    response_model=Item,
    responses={
        200: {
            "content": {"image/png": {}},
            "description": "Return the JSON item or an image.",
        }
    },

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(
            examples=[
                {

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

app = FastAPI()


class UserBase(BaseModel):
    email: str


class UserCreate(UserBase):
    password: str


class UserDB(UserBase):
    hashed_password: str


class PetDB(BaseModel):
    name: str
    owner: UserDB


class PetOut(BaseModel):
    name: str
    owner: UserBase

import pytest
from fastapi import FastAPI
from pydantic import BaseModel


def test_invalid_sequence():
    with pytest.raises(AssertionError):
        app = FastAPI()

        class Item(BaseModel):
            title: str

        @app.get("/items/{id}")
        def read_items(id: list[Item]):
            pass  # pragma: no cover


def test_invalid_tuple():
    with pytest.raises(AssertionError):
        app = FastAPI()

# 본문 - 필드

`Query`, `Path`와 `Body`를 사용해 *경로 작동 함수* 매개변수 내에서 추가적인 검증이나 메타데이터를 선언한 것처럼 Pydantic의 `Field`를 사용하여 모델 내에서 검증과 메타데이터를 선언할 수 있습니다.

## `Field` 임포트

먼저 이를 임포트해야 합니다:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[4] *}

/// warning | 경고

`Field`는 다른 것들처럼 (`Query`, `Path`, `Body` 등) `fastapi`에서가 아닌 `pydantic`에서 바로 임포트 되는 점에 주의하세요.

///

## 모델 어트리뷰트 선언

그 다음 모델 어트리뷰트와 함께 `Field`를 사용할 수 있습니다:

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class BaseItem(BaseModel):
    description: str
    type: str


class CarItem(BaseItem):
    type: str = "car"


class PlaneItem(BaseItem):
    type: str = "plane"
    size: int


items = {
    "item1": {"description": "All my friends drive a low rider", "type": "car"},
    "item2": {