from typing import Annotated, Union

from fastapi import Depends, FastAPI

app = FastAPI()


fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"}]


class CommonQueryParams:
    def __init__(self, q: Union[str, None] = None, skip: int = 0, limit: int = 100):
        self.q = q
        self.skip = skip
        self.limit = limit


@app.get("/items/")

from typing import Annotated, Any, Union

from fastapi import Depends, FastAPI

app = FastAPI()


fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"}]


class CommonQueryParams:
    def __init__(self, q: Union[str, None] = None, skip: int = 0, limit: int = 100):
        self.q = q
        self.skip = skip
        self.limit = limit


@app.get("/items/")

from typing import Union

from fastapi import BackgroundTasks, Depends, FastAPI

app = FastAPI()


def write_log(message: str):
    with open("log.txt", mode="a") as log:
        log.write(message)


def get_query(background_tasks: BackgroundTasks, q: Union[str, None] = None):
    if q:
        message = f"found query: {q}\n"
        background_tasks.add_task(write_log, message)
    return q

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(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> List[Hero]:

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(
    session: Session = Depends(get_session),
    offset: int = 0,
    limit: int = Query(default=100, le=100),
) -> list[Hero]:

🎏 🌌 👆 ⚙️ `Body`, `Query`, ♒️. ⏮️ 👆 *➡ 🛠️ 🔢* 🔢, ⚙️ `Depends` ⏮️ 🆕 🔢:

//// tab | 🐍 3️⃣.6️⃣ & 🔛

```Python hl_lines="15  20"
{!> ../../docs_src/dependencies/tutorial001.py!}
```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="11  16"
{!> ../../docs_src/dependencies/tutorial001_py310.py!}
```

////

👐 👆 ⚙️ `Depends` 🔢 👆 🔢 🎏 🌌 👆 ⚙️ `Body`, `Query`, ♒️, `Depends` 👷 👄 🎏.

```

////

//// tab | Python 3.8 non-Annotated

/// tip | "Dica"

Utilize a versão com `Annotated` se possível.

///

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

////

Você declara a dependência como o tipo do parâmetro, e utiliza `Depends()` sem nenhum parâmetro, em vez de ter que escrever a classe *novamente* dentro de `Depends(CommonQueryParams)`.

```

////

//// tab | Python 3.8 non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

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

////

You declare the dependency as the type of the parameter, and you use `Depends()` without any parameter, instead of having to write the full class *again* inside of `Depends(CommonQueryParams)`.

from typing import Optional

from fastapi import Depends, FastAPI
from pydantic import BaseModel, validator

app = FastAPI()


class ModelB(BaseModel):
    username: str


class ModelC(ModelB):
    password: str


class ModelA(BaseModel):
    name: str
    description: Optional[str] = None
    model_b: ModelB

    @validator("name")
    def lower_username(cls, name: str, values):

from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from typing_extensions import Annotated

app = FastAPI()

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


@app.get("/items/")
async def read_items(token: Annotated[str, Depends(oauth2_scheme)]):