///

* `app` 目录包含了所有内容。并且它有一个空文件 `app/__init__.py`，因此它是一个「Python 包」（「Python 模块」的集合）：`app`。
* 它包含一个 `app/main.py` 文件。由于它位于一个 Python 包（一个包含 `__init__.py` 文件的目录）中，因此它是该包的一个「模块」：`app.main`。
* 还有一个 `app/dependencies.py` 文件，就像 `app/main.py` 一样，它是一个「模块」：`app.dependencies`。
* 有一个子目录 `app/routers/` 包含另一个 `__init__.py` 文件，因此它是一个「Python 子包」：`app.routers`。
* 文件 `app/routers/items.py` 位于 `app/routers/` 包中，因此它是一个子模块：`app.routers.items`。

from fastapi import FastAPI
from fastapi.testclient import TestClient


def test_root_path_does_not_persist_across_requests():
    app = FastAPI()

    @app.get("/")
    def read_root():  # pragma: no cover
        return {"ok": True}

    # Attacker request with a spoofed root_path
    attacker_client = TestClient(app, root_path="/evil-api")
    response1 = attacker_client.get("/openapi.json")
    data1 = response1.json()

import org.codelibs.fess.app.web.CrudMode;
import org.codelibs.fess.app.web.api.ApiResult;
import org.codelibs.fess.app.web.api.ApiResult.ApiConfigResponse;
import org.codelibs.fess.app.web.api.ApiResult.ApiResponse;
import org.codelibs.fess.app.web.api.ApiResult.ApiUpdateResponse;
import org.codelibs.fess.app.web.api.ApiResult.Status;
import org.codelibs.fess.app.web.api.admin.FessApiAdminAction;

The simplicity of the dependency injection system makes **FastAPI** compatible with:

* all the relational databases
* NoSQL databases
* external packages
* external APIs
* authentication and authorization systems
* API usage monitoring systems
* response data injection systems
* etc.

## Simple and Powerful { #simple-and-powerful }

from docs_src.advanced_middleware.tutorial002_py310 import app


def test_middleware():
    client = TestClient(app, base_url="http://example.com")
    response = client.get("/")
    assert response.status_code == 200, response.text
    client = TestClient(app, base_url="http://subdomain.example.com")
    response = client.get("/")
    assert response.status_code == 200, response.text
    client = TestClient(app, base_url="http://invalidhost")

import org.codelibs.fess.app.web.admin.dashboard.AdminDashboardAction;
import org.codelibs.fess.app.web.admin.dataconfig.AdminDataconfigAction;
import org.codelibs.fess.app.web.admin.design.AdminDesignAction;
import org.codelibs.fess.app.web.admin.dict.AdminDictAction;
import org.codelibs.fess.app.web.admin.duplicatehost.AdminDuplicatehostAction;
import org.codelibs.fess.app.web.admin.elevateword.AdminElevatewordAction;

]


app = FastAPI()


@app.get("/items/stream", response_class=EventSourceResponse)
async def sse_items() -> AsyncIterable[Item]:
    for item in items:
        yield item


@app.get("/items/stream-sync", response_class=EventSourceResponse)
def sse_items_sync() -> Iterable[Item]:
    yield from items

    with Session(engine) as session:
        yield session


app = FastAPI()


@app.on_event("startup")
def on_startup():
    create_db_and_tables()


@app.post("/heroes/")
def create_hero(hero: Hero, session: Session = Depends(get_session)) -> Hero:
    session.add(hero)
    session.commit()
    session.refresh(hero)
    return hero


@app.get("/heroes/")
def read_heroes(

    def __init__(
        self, app: ASGIApp, context_name: str = "fastapi_middleware_astack"
    ) -> None:
        self.app = app
        self.context_name = context_name

    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
        async with AsyncExitStack() as stack:
            scope[self.context_name] = stack

@app.post("/users/", response_model=User)
async def create_user(user: UserCreate):
    return user


@app.get("/pets/{pet_id}", response_model=PetOut)
async def read_pet(pet_id: int):
    user = UserDB(
        email="******@****.***",
        hashed_password="secrethashed",
    )
    pet = PetDB(name="Nibbler", owner=user)
    return pet


@app.get("/pets/", response_model=list[PetOut])