from fastapi.responses import HTMLResponse

app = FastAPI()


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


@app.post("/uploadfiles/")
async def create_upload_files(
    files: list[UploadFile] = File(description="Multiple files as UploadFile"),
):

def test_merged_mixed_state_lifespans() -> None:
    @asynccontextmanager
    async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
        yield

    @asynccontextmanager
    async def router_lifespan(app: FastAPI) -> AsyncGenerator[dict[str, bool], None]:
        yield {"router": True}

    @asynccontextmanager
    async def sub_router_lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
        yield

router = APIRouter()


@router.get("/users/", tags=["users"])
async def read_users():
    return [{"username": "Rick"}, {"username": "Morty"}]


@router.get("/users/me", tags=["users"])
async def read_user_me():
    return {"username": "fakecurrentuser"}


@router.get("/users/{username}", tags=["users"])
async def read_user(username: str):

router = APIRouter()


@router.get("/users/", tags=["users"])
async def read_users():
    return [{"username": "Rick"}, {"username": "Morty"}]


@router.get("/users/me", tags=["users"])
async def read_user_me():
    return {"username": "fakecurrentuser"}


@router.get("/users/{username}", tags=["users"])
async def read_user(username: str):

app = FastAPI()


async def common_parameters(q: str | None = None, skip: int = 0, limit: int = 100):
    return {"q": q, "skip": skip, "limit": limit}


@app.get("/items/")
async def read_items(commons: Annotated[dict, Depends(common_parameters)]):
    return {"message": "Hello Items!", "params": commons}


@app.get("/users/")
async def read_users(commons: Annotated[dict, Depends(common_parameters)]):

from typing import Annotated

from fastapi import Depends


async def dependency_a():
    dep_a = generate_dep_a()
    try:
        yield dep_a
    finally:
        dep_a.close()


async def dependency_b(dep_a: Annotated[DepA, Depends(dependency_a)]):
    dep_b = generate_dep_b()
    try:
        yield dep_b
    finally:
        dep_b.close(dep_a)


async def dependency_c(dep_b: Annotated[DepB, Depends(dependency_b)]):

app = FastAPI()


async def common_parameters(
    q: Union[str, None] = None, skip: int = 0, limit: int = 100
):
    return {"q": q, "skip": skip, "limit": limit}


CommonsDep = Annotated[dict, Depends(common_parameters)]


@app.get("/items/")
async def read_items(commons: CommonsDep):
    return commons


@app.get("/users/")
async def read_users(commons: CommonsDep):

from fastapi import Depends, FastAPI

app = FastAPI()


async def common_parameters(
    q: Union[str, None] = None, skip: int = 0, limit: int = 100
):
    return {"q": q, "skip": skip, "limit": limit}


@app.get("/items/")
async def read_items(commons: dict = Depends(common_parameters)):
    return commons


@app.get("/users/")
async def read_users(commons: dict = Depends(common_parameters)):

	}

	// Attempt all calls.
	_, err = lkClient.RLock(t.Context(), dsync.LockArgs{})
	if err == nil {
		t.Fatal("Expected for Rlock to fail")
	}

	_, err = lkClient.Lock(t.Context(), dsync.LockArgs{})
	if err == nil {
		t.Fatal("Expected for Lock to fail")
	}

	_, err = lkClient.RUnlock(t.Context(), dsync.LockArgs{})
	if err == nil {
		t.Fatal("Expected for RUnlock to fail")
	}

{* ../../docs_src/events/tutorial003_py39.py hl[14:19] *}

The first part of the function, before the `yield`, will be executed **before** the application starts.

And the part after the `yield` will be executed **after** the application has finished.

### Async Context Manager { #async-context-manager }