///

**FastAPI** 将自动对请求中的数据进行转换，因此 `item` 参数将接收指定的内容，`user` 参数也是如此。

它将执行对复合数据的校验，并且像现在这样为 OpenAPI 模式和自动化文档对其进行记录。

## 请求体中的单一值

与使用 `Query` 和 `Path` 为查询参数和路径参数定义额外数据的方式相同，**FastAPI** 提供了一个同等的 `Body`。

例如，为了扩展先前的模型，你可能决定除了 `item` 和 `user` 之外，还想在同一请求体中具有另一个键 `importance`。

如果你就按原样声明它，因为它是一个单一值，**FastAPI** 将假定它是一个查询参数。

但是你可以使用 `Body` 指示 **FastAPI** 将其作为请求体的另一个键进行处理。

from typing import Annotated

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

app = FastAPI()

security = HTTPBasic()


@app.get("/users/me")
def read_current_user(credentials: Annotated[HTTPBasicCredentials, Depends(security)]):

from fastapi import FastAPI
from fastapi.encoders import jsonable_encoder
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str | None = None
    description: str | None = None
    price: float | None = None
    tax: float = 10.5
    tags: list[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},

from fastapi import FastAPI, File, UploadFile
from fastapi.responses import HTMLResponse

app = FastAPI()


@app.post("/files/")
async def create_files(files: list[bytes] = File()):
    return {"file_sizes": [len(file) for file in files]}


@app.post("/uploadfiles/")
async def create_upload_files(files: list[UploadFile]):
    return {"filenames": [file.filename for file in files]}


@app.get("/")
async def main():

from fastapi import FastAPI
from fastapi.responses import JSONResponse

app = FastAPI()


@app.get("/headers/")
def get_headers():
    content = {"message": "Hello World"}
    headers = {"X-Cat-Dog": "alone in the world", "Content-Language": "en-US"}

## Full Stack FastAPI PostgreSQL

GitHub : <a href="https://github.com/tiangolo/full-stack-fastapi-postgresql" class="external-link" target="_blank">https://github.com/tiangolo/full-stack-fastapi-postgresql</a>

### Full Stack FastAPI PostgreSQL - Fonctionnalités

* Intégration **Docker** complète (basée sur Docker).

from __future__ import annotations

from typing import TYPE_CHECKING, Annotated

import pytest
from fastapi import Depends, FastAPI
from fastapi.testclient import TestClient
from inline_snapshot import snapshot

if TYPE_CHECKING:  # pragma: no cover
    from collections.abc import AsyncGenerator


class DummyClient:
    async def get_people(self) -> list:
        return ["John Doe", "Jane Doe"]

    async def close(self) -> None:

import pytest
from fastapi import FastAPI, Request, WebSocket, WebSocketDisconnect
from fastapi.routing import APIRoute, APIWebSocketRoute
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/users/{user_id}")
async def get_user(user_id: str, request: Request):
    route: APIRoute = request.scope["route"]
    return {"user_id": user_id, "path": route.path}


@app.websocket("/items/{item_id}")

```

But FastAPI (actually Starlette) provides a simpler way to do it that makes sure that the internal middlewares handle server errors and custom exception handlers work properly.

For that, you use `app.add_middleware()` (as in the example for CORS).

```Python
from fastapi import FastAPI
from unicorn import UnicornMiddleware

app = FastAPI()

from collections.abc import AsyncGenerator
from contextlib import asynccontextmanager
from typing import Union

import pytest
from fastapi import APIRouter, FastAPI, Request
from fastapi.testclient import TestClient
from pydantic import BaseModel


class State(BaseModel):
    app_startup: bool = False
    app_shutdown: bool = False
    router_startup: bool = False
    router_shutdown: bool = False
    sub_router_startup: bool = False