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: FormData = Form()):

from fastapi import FastAPI, File, Form, UploadFile

app = FastAPI()


@app.post("/files/")
async def create_file(
    file: bytes = File(), fileb: UploadFile = File(), token: str = Form()
):
    return {
        "file_size": len(file),
        "token": token,
        "fileb_content_type": fileb.content_type,

from fastapi import FastAPI, Query

app = FastAPI()


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

from datetime import datetime, timedelta, timezone

import jwt
from fastapi import Depends, FastAPI, HTTPException, Security, status
from fastapi.security import (
    OAuth2PasswordBearer,
    OAuth2PasswordRequestForm,
    SecurityScopes,
)
from jwt.exceptions import InvalidTokenError
from pwdlib import PasswordHash
from pydantic import BaseModel, ValidationError

# to get a string like this run:
# openssl rand -hex 32

from typing import Union

from fastapi import FastAPI

app = FastAPI()


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

但在我们上面的例子里，我们并不是直接使用，而是传递给 FastAPI 来供其使用。

`FastAPI()` 的 `lifespan` 参数接受一个**异步上下文管理器**，所以我们可以把我们新定义的上下文管理器 `lifespan` 传给它。

```Python hl_lines="22"
{!../../docs_src/events/tutorial003.py!}
```

## 替代事件（弃用）

/// warning | 警告

/// note | Нотатки

Ця можливість підтримується починаючи з версії FastAPI `0.115.0`. 🤓

///

## Параметри Заголовків з Використанням Pydantic Model

Оголосіть потрібні **параметри заголовків** у **Pydantic моделі**, а потім оголосіть параметр як `Header`:

{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

from typing import Annotated

import pytest
from fastapi import FastAPI, Path
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/required-str/{p}")
async def read_required_str(p: Annotated[str, Path()]):
    return {"p": p}


@app.get("/required-alias/{p_alias}")
async def read_required_alias(p: Annotated[str, Path(alias="p_alias")]):
    return {"p": p}

from fastapi.testclient import TestClient

from docs_src.custom_response.tutorial001b_py39 import app

client = TestClient(app)


def test_get_custom_response():
    response = client.get("/items/")
    assert response.status_code == 200, response.text
    assert response.json() == [{"item_id": "Foo"}]


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

from fastapi.testclient import TestClient

from docs_src.custom_response.tutorial005_py39 import app

client = TestClient(app)


def test_get():
    response = client.get("/")
    assert response.status_code == 200, response.text
    assert response.text == "Hello World"


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {