app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None
    tags: set[str] = set()


@app.post(
    "/items/",
    response_model=Item,
    summary="Create an item",
    response_description="The created item",
)
async def create_item(item: Item):
    """
    Create an item with all the information:

from pydantic import BaseModel


class Item(BaseModel):
    id: str
    value: str


responses = {
    404: {"description": "Item not found"},
    302: {"description": "The item was moved"},
    403: {"description": "Not enough privileges"},
}


app = FastAPI()


@app.get(
    "/items/{item_id}",
    response_model=Item,
    responses={**responses, 200: {"content": {"image/png": {}}}},

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None
    tags: Set[str] = set()


@app.post("/items/", response_model=Item, summary="Create an item")
async def create_item(item: Item):
    """
    Create an item with all the information:

    - **name**: each item must have a name

        raise


@app.get("/items/{item_id}")
def get_item(item_id: str, username: Annotated[str, Depends(get_username)]):
    if item_id == "portal-gun":
        raise InternalError(
            f"The portal gun is too dangerous to be owned by {username}"
        )
    if item_id != "plumbus":
        raise HTTPException(
            status_code=404, detail="Item not found, there's only a plumbus here"
        )

Por exemplo, vamos supor que você possua 4 endpoints na sua API (*operações de rota*):

* `/items/public/`
* `/items/private/`
* `/users/{user_id}/activate`
* `/items/pro/`

Você poderia adicionar diferentes requisitos de permissão para cada um deles utilizando apenas dependências e sub-dependências:

```mermaid
graph TB

from fastapi import FastAPI, Query
from typing_extensions import Annotated

app = FastAPI()


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

from typing import Union

from fastapi import Cookie, FastAPI

app = FastAPI()


@app.get("/items/")
async def read_items(ads_id: Union[str, None] = Cookie(default=None)):

from fastapi import FastAPI, status

app = FastAPI()


@app.post("/items/", status_code=status.HTTP_201_CREATED)
async def create_item(name: str):

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(
    strange_header: str | None = Header(default=None, convert_underscores=False),
):

        buf.enc_ndr_short(max_recv);
        buf.enc_ndr_long(0); /* assoc. group */
        buf.enc_ndr_small(1); /* num context items */
        buf.enc_ndr_small(0); /* reserved */
        buf.enc_ndr_short(0); /* reserved2 */
        buf.enc_ndr_short(0); /* context id */
        buf.enc_ndr_small(1); /* number of items */
        buf.enc_ndr_small(0); /* reserved */
        binding.uuid.encode(buf);
        buf.enc_ndr_short(binding.major);