// Run Enums.getIfPresent on that other TestEnum and then return a WeakReference containing the
  // new ClassLoader. If Enums.getIfPresent does caching that prevents the shadow TestEnum
  // (and therefore its ClassLoader) from being unloaded, then this WeakReference will never be
  // cleared.
  @J2ktIncompatible
  @GwtIncompatible // weak references

    )


async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
    user = fake_decode_token(token)
    return user


@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):

    return x_key


app = FastAPI(dependencies=[Depends(verify_token), Depends(verify_key)])


@app.get("/items/")
async def read_items():
    return [{"item": "Portal Gun"}, {"item": "Plumbus"}]


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

from fastapi import Depends, FastAPI

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 commons


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

    )


async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
    user = fake_decode_token(token)
    return user


@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):

import secrets
from typing import Annotated

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

app = FastAPI()

security = HTTPBasic()


def get_current_username(
    credentials: Annotated[HTTPBasicCredentials, Depends(security)],
):
    current_username_bytes = credentials.username.encode("utf8")
    correct_username_bytes = b"stanleyjobson"

@app.get("/sub-counter/")
async def get_sub_counter(
    subcount: int = Depends(super_dep), count: int = Depends(dep_counter)
):
    return {"counter": count, "subcounter": subcount}


@app.get("/sub-counter-no-cache/")
async def get_sub_counter_no_cache(
    subcount: int = Depends(super_dep),
    count: int = Depends(dep_counter, use_cache=False),
):
    return {"counter": count, "subcounter": subcount}

from typing import Union

from fastapi import Depends, FastAPI
from typing_extensions import Annotated

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: Annotated[dict, Depends(common_parameters)]):
    return commons


@app.get("/users/")

from typing import Union

from fastapi import Cookie, Depends, FastAPI
from typing_extensions import Annotated

app = FastAPI()


def query_extractor(q: Union[str, None] = None):
    return q


def query_or_cookie_extractor(
    q: Annotated[str, Depends(query_extractor)],
    last_query: Annotated[Union[str, None], Cookie()] = None,
):
    if not q:
        return last_query
    return q


@app.get("/items/")

    ```

**FastAPI** 调用 `CommonQueryParams` 类。这将创建该类的一个 "实例"，该实例将作为参数 `commons` 被传递给你的函数。

## 类型注解 vs `Depends`

注意，我们在上面的代码中编写了两次`CommonQueryParams`：

```Python
commons: CommonQueryParams = Depends(CommonQueryParams)
```

最后的 `CommonQueryParams`:

```Python
... = Depends(CommonQueryParams)
```

...实际上是 **Fastapi** 用来知道依赖项是什么的。

FastAPI 将从依赖项中提取声明的参数，这才是 FastAPI 实际调用的。