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: set[str] = set()


@app.post("/items/", response_model=Item, tags=["items"])
async def create_item(item: Item):
    return item


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

app = FastAPI()


@app.post("/files/")
async def create_file(file: Annotated[Union[bytes, None], File()] = None):
    if not file:
        return {"message": "No file sent"}
    else:
        return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(file: Union[UploadFile, None] = None):
    if not file:
        return {"message": "No upload file sent"}
    else:

/// note | Заметка

FastAPI понимает, что значение `q` не является обязательным из-за значения по умолчанию `= None`.

Аннотации типов `str | None` (Python 3.10+) или `Union[str, None]` (Python 3.9+) не используются FastAPI для определения обязательности; он узнает, что параметр не обязателен, потому что у него есть значение по умолчанию `= None`.

Но добавление аннотаций типов позволит вашему редактору кода лучше вас поддерживать и обнаруживать ошибки.

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: str | None = Query(default=None, title="Query string", min_length=3),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

app = FastAPI()


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


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


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

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str | None, Query(max_length=50)] = None):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

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
    tags: set[str] = set()


@app.post(
    "/items/",
    response_model=Item,
    summary="Create an item",

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Union[str, None] = Query(default=None, max_length=50)):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

                new RequestParam[] { RequestParam.NONE, RequestParam.NO_TIMEOUT, RequestParam.NO_RETRY, RequestParam.RETAIN_PAYLOAD },
                values, "values() order should match declaration order");
    }

    // Happy path: valueOf resolves each constant name; toString equals name; ordinal is stable
    @ParameterizedTest
    @ValueSource(strings = { "NONE", "NO_TIMEOUT", "NO_RETRY", "RETAIN_PAYLOAD" })

 *
 */
public interface BeanConfigurationRequest {

    /**
     * Gets the bean to configure. Eventually, a valid request must have a bean set.
     *
     * @return The bean to configure, or {@code null} if none.
     */
    Object getBean();

    /**
     * Sets the bean to configure. Eventually, a valid request must have a bean set.
     *
     * @param bean The bean to configure, may be {@code null}.