```Python
with open("file.txt") as file:
    file.read()
```

최근 버전의 파이썬에는 **비동기 컨텍스트 매니저**도 있습니다. 이를 `async with`와 함께 사용합니다:

```Python
async with lifespan(app):
    await do_stuff()
```

위와 같은 컨텍스트 매니저 또는 비동기 컨텍스트 매니저를 만들면, `with` 블록에 들어가기 전에 `yield` 이전의 코드를 실행하고, `with` 블록을 벗어난 후에는 `yield` 이후의 코드를 실행합니다.

위의 코드 예제에서는 직접 사용하지 않고, FastAPI에 전달하여 FastAPI가 이를 사용하도록 합니다.

class MySuperContextManager:
    def __init__(self):
        self.db = DBSession()

    def __enter__(self):
        return self.db

    def __exit__(self, exc_type, exc_value, traceback):
        self.db.close()


async def get_db():
    with MySuperContextManager() as db:

@app.post("/required-list-alias", operation_id="required_list_alias")
async def read_required_list_alias(
    p: Annotated[list[str], Body(embed=True, alias="p_alias")],
):
    return {"p": p}


class BodyModelRequiredListAlias(BaseModel):
    p: list[str] = Field(alias="p_alias")


@app.post("/model-required-list-alias", operation_id="model_required_list_alias")
async def read_model_required_list_alias(p: BodyModelRequiredListAlias):

# Without aliases


@app.post("/optional-str", operation_id="optional_str")
async def read_optional_str(p: Annotated[str | None, Body(embed=True)] = None):
    return {"p": p}


class BodyModelOptionalStr(BaseModel):
    p: str | None = None


@app.post("/model-optional-str", operation_id="model_optional_str")
async def read_model_optional_str(p: BodyModelOptionalStr):
    return {"p": p.p}

from fastapi import FastAPI
from fastapi.responses import RedirectResponse

app = FastAPI()


@app.get("/teleport")
async def get_teleport() -> RedirectResponse:

from typing import Any

from fastapi import FastAPI

app = FastAPI()


@app.vibe(
    "/vibe/",
    prompt="pls return json of users from database. make no mistakes",
)

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/{item_id}")
async def read_item(item_id: str, q: str | None = None):
    if q:
        return {"item_id": item_id, "q": q}

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[list[str], Query()] = ["foo", "bar"]):
    query_items = {"q": q}

from fastapi import FastAPI

app = FastAPI()


@app.get("/items/{item_id}")
async def read_user_item(
    item_id: str, needy: str, skip: int = 0, limit: int | None = None
):
    item = {"item_id": item_id, "needy": needy, "skip": skip, "limit": limit}

        when(request.allowChain(any())).thenReturn(true);

        // When
        boolean async = request.isResponseAsync();
        int size = request.size();
        Integer timeout = request.getOverrideTimeout();
        boolean canChain = request.allowChain(nextRequest);

        // Then
        assertTrue(async);
        assertEquals(100, size);
        assertEquals(3000, timeout);
        assertTrue(canChain);