from typing import Annotated

from fastapi import Depends, FastAPI

app = FastAPI()


async def common_parameters(q: str | None = None, skip: int = 0, limit: int = 100):
    return {"q": q, "skip": skip, "limit": limit}


@app.get("/items/")
async def read_items(commons: Annotated[dict, Depends(common_parameters)]):
    return commons


@app.get("/users/")
async def read_users(commons: Annotated[dict, Depends(common_parameters)]):

from fastapi import FastAPI
from pydantic.v1 import BaseModel

app = FastAPI()


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

    class Config:
        schema_extra = {
            "examples": [
                {
                    "name": "Foo",
                    "description": "A very nice Item",
                    "price": 35.4,

```JSON
{"item_id":3}
```

/// check | Заметка

Обратите внимание на значение `3`, которое получила (и вернула) функция. Это целочисленный Python `int`, а не строка `"3"`.

Используя такое объявление типов, **FastAPI** выполняет автоматический <abbr title="преобразование строк из HTTP-запроса в типы данных Python">"парсинг"</abbr> запросов.

///

## Валидация данных { #data-validation }

from fastapi import FastAPI
from pydantic import BaseModel, HttpUrl

app = FastAPI()


class Image(BaseModel):
    url: HttpUrl
    name: str


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


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

from dataclasses import dataclass, field

from fastapi import FastAPI


@dataclass
class Item:
    name: str
    price: float
    tags: list[str] = field(default_factory=list)
    description: str | None = None
    tax: float | None = None


app = FastAPI()


@app.get("/items/next", response_model=Item)
async def read_next_item():
    return {
        "name": "Island In The Moon",
        "price": 12.99,

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",

Deploy your app to **<a href="https://fastapicloud.com" class="external-link" target="_blank">FastAPI Cloud</a>** with one command: `fastapi deploy`. 🎉

#### About FastAPI Cloud { #about-fastapi-cloud }

**<a href="https://fastapicloud.com" class="external-link" target="_blank">FastAPI Cloud</a>** is built by the same author and team behind **FastAPI**.

Stellen Sie Ihre App in der **<a href="https://fastapicloud.com" class="external-link" target="_blank">FastAPI Cloud</a>** mit einem Befehl bereit: `fastapi deploy`. 🎉

#### Über FastAPI Cloud { #about-fastapi-cloud }

**<a href="https://fastapicloud.com" class="external-link" target="_blank">FastAPI Cloud</a>** wird vom selben Autor und Team hinter **FastAPI** entwickelt.

### `app.dependency_overrides` 속성 사용하기

이런 경우를 위해 **FastAPI** 응용 프로그램에는 `app.dependency_overrides`라는 속성이 있습니다. 이는 간단한 `dict`입니다.

테스트를 위해 의존성을 오버라이드하려면, 원래 의존성(함수)을 키로 설정하고 오버라이드할 의존성(다른 함수)을 값으로 설정합니다.

그럼 **FastAPI**는 원래 의존성 대신 오버라이드된 의존성을 호출합니다.

{* ../../docs_src/dependency_testing/tutorial001_an_py310.py hl[26:27,30] *}

/// tip | 팁

**FastAPI** 애플리케이션 어디에서든 사용된 의존성에 대해 오버라이드를 설정할 수 있습니다.

///

## Type hints in **FastAPI** { #type-hints-in-fastapi }

**FastAPI** takes advantage of these type hints to do several things.

With **FastAPI** you declare parameters with type hints and you get:

* **Editor support**.
* **Type checks**.

...and **FastAPI** uses the same declarations to: