from pydantic.fields import FieldInfo
from starlette.background import BackgroundTasks as StarletteBackgroundTasks
from starlette.concurrency import run_in_threadpool
from starlette.datastructures import (
    FormData,
    Headers,
    ImmutableMultiDict,
    QueryParams,
    UploadFile,
)
from starlette.requests import HTTPConnection, Request
from starlette.responses import Response
from starlette.websockets import WebSocket

from fastapi import FastAPI, Form
from pydantic import BaseModel

app = FastAPI()


class FormData(BaseModel):
    username: str
    password: str
    model_config = {"extra": "forbid"}


@app.post("/login/")
async def login(data: Annotated[FormData, Form()]):
    return data
```