/// note | "`async` Technical Details"

When you use the `async` methods, **FastAPI** runs the file methods in a threadpool and awaits for them.

///

/// note | "Starlette Technical Details"

**FastAPI**'s `UploadFile` inherits directly from **Starlette**'s `UploadFile`, but adds some necessary parts to make it compatible with **Pydantic** and the other parts of FastAPI.

///

## What is "Form Data"

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 Union

from fastapi import Body, FastAPI
from pydantic import BaseModel
from typing_extensions import Annotated

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: Annotated[
        Item,
        Body(

from typing import Annotated

from fastapi import FastAPI, Form

app = FastAPI()


@app.post("/login/")
async def login(username: Annotated[str, Form()], password: Annotated[str, Form()]):

from contextvars import ContextVar
from typing import Any, Awaitable, Callable, Dict, Optional

from fastapi import Depends, FastAPI, Request, Response
from fastapi.testclient import TestClient

legacy_request_state_context_var: ContextVar[Optional[Dict[str, Any]]] = ContextVar(
    "legacy_request_state_context_var", default=None
)

app = FastAPI()


async def set_up_request_state_dependency():
    request_state = {"user": "deadpond"}

from typing import Union

from fastapi import Body, FastAPI, Query
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/query")
def read_query(q: Union[str, None]):
    return q


@app.get("/explicit-query")
def read_explicit_query(q: Union[str, None] = Query()):
    return q


@app.post("/body-embed")
def send_body_embed(b: Union[str, None] = Body(embed=True)):
    return b

from fastapi import FastAPI

app = FastAPI()


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

from typing import Annotated, Union

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(
    strange_header: Annotated[
        Union[str, None], Header(convert_underscores=False)
    ] = None,
):

    Read more about it in the
    [FastAPI docs for HTTP Basic Auth](https://fastapi.tiangolo.com/advanced/security/http-basic-auth/).

    ## Example

    ```python
    from typing import Annotated

    from fastapi import Depends, FastAPI
    from fastapi.security import HTTPBasic, HTTPBasicCredentials

    app = FastAPI()

    security = HTTPBasic()

검사를 해보고 난 후에, **FastAPI** 버전을 더 최신으로 업그레이드 할 수 있습니다. 그리고 코드들이 테스트에 정상적으로 작동하는지 확인을 해야합니다.

만약에 모든 것이 정상 작동하거나 필요한 부분을 변경하고, 모든 검사를 통과한다면, 새로운 버전의  `fastapi`를 표시할 수 있습니다.

## Starlette에 대해

`starlette`의 버전은 표시할 수 없습니다.

서로다른 버전의 **FastAPI**가 구체적이고 새로운 버전의 Starlette을 사용할 것입니다.

그러므로 **FastAPI**가 알맞은 Starlette 버전을 사용하도록 하십시오.

## Pydantic에 대해

Pydantic은 **FastAPI** 를 위한 검사를 포함하고 있습니다. 따라서, 새로운 버전의 Pydantic(`1.0.0`이상)은 항상 FastAPI와 호환됩니다.