from typing import List

import yaml
from fastapi import FastAPI, HTTPException, Request
from pydantic import BaseModel, ValidationError

app = FastAPI()


class Item(BaseModel):
    name: str
    tags: List[str]


@app.post(
    "/items/",
    openapi_extra={
        "requestBody": {
            "content": {"application/x-yaml": {"schema": Item.model_json_schema()}},
            "required": True,
        },
    },

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


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


@app.put("/items/{item_id}")
async def update_item(item_id: int, item: Item):
    results = {"item_id": item_id, "item": item}

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel


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


app = FastAPI()


@app.put("/items/{item_id}")
async def update_item(item_id: int, item: Item):

from typing import List

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str


items = [
    {"name": "Foo", "description": "There comes my hero"},
    {"name": "Red", "description": "It's my aeroplane"},
]


@app.get("/items/", response_model=List[Item])
async def read_items():

def get_username():
    try:
        yield "Rick"
    except OwnerError as e:
        raise HTTPException(status_code=400, detail=f"Owner error: {e}")


@app.get("/items/{item_id}")
def get_item(item_id: str, username: Annotated[str, Depends(get_username)]):
    if item_id not in data:
        raise HTTPException(status_code=404, detail="Item not found")
    item = data[item_id]
    if item["owner"] != username:

    /**
     * ブランクかどうか返します。
     *
     * @param str
     *            文字列
     * @return ブランクなら{@literal true}
     */
    public static boolean isBlank(final String str) {
        if (str == null || str.length() == 0) {
            return true;
        }
        for (int i = 0; i < str.length(); i++) {
            if (!Character.isWhitespace(str.charAt(i))) {
                return false;
            }

from typing import Annotated

from fastapi import Depends, FastAPI

app = FastAPI()


class FixedContentQueryChecker:
    def __init__(self, fixed_content: str):
        self.fixed_content = fixed_content

    def __call__(self, q: str = ""):
        if q:
            return self.fixed_content in q
        return False


checker = FixedContentQueryChecker("bar")


@app.get("/query-checker/")

**FastAPI**는 `item_id`가 경로 매개변수이고 `q`는 경로 매개변수가 아닌 쿼리 매개변수라는 것을 알 정도로 충분히 똑똑합니다.

///

/// note | "참고"

FastAPI는 `q`가 `= None`이므로 선택적이라는 것을 인지합니다.

`Union[str, None]`에 있는 `Union`은 FastAPI(FastAPI는 `str` 부분만 사용합니다)가 사용하는게 아니지만, `Union[str, None]`은 편집기에게 코드에서 오류를 찾아낼 수 있게 도와줍니다.

///

## 쿼리 매개변수 형변환

`bool` 형으로 선언할 수도 있고, 아래처럼 변환됩니다:

```Python hl_lines="9"
{!../../docs_src/query_params/tutorial003.py!}

from fastapi.testclient import TestClient
from pydantic import BaseModel, HttpUrl

app = FastAPI()


class Invoice(BaseModel):
    id: str
    title: Optional[str] = None
    customer: str
    total: float


class InvoiceEvent(BaseModel):
    description: str
    paid: bool


class InvoiceEventReceived(BaseModel):
    ok: bool


invoices_callback_router = APIRouter()

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


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

    model_config = {
        "json_schema_extra": {
            "examples": [
                {
                    "name": "Foo",
                    "description": "A very nice Item",