* Wenn der Parameter vom Typ eines **Pydantic-Modells** ist, wird er als Request**body** interpretiert.

/// note | "Hinweis"

FastAPI weiß, dass der Wert von `q` nicht erforderlich ist, wegen des definierten Defaultwertes `= None`

Das `Union` in `Union[str, None]` wird von FastAPI nicht verwendet, aber es erlaubt Ihrem Editor, Sie besser zu unterstützen und Fehler zu erkennen.

///

## Ohne Pydantic

* Se o parâmetro é declarado como um **modelo Pydantic**, será interpretado como o **corpo** da requisição.

/// note | "Observação"

O FastAPI saberá que o valor de `q` não é obrigatório por causa do valor padrão `= None`.

O `Union` em `Union[str, None]` não é utilizado pelo FastAPI, mas permite ao seu editor de texto lhe dar um suporte melhor e detectar erros.

///

## Sem o Pydantic

///

**FastAPI** tamamen Pydantic'e dayanmaktadır.

Daha fazlasini görmek için [Tutorial - User Guide](tutorial/index.md){.internal-link target=_blank}.

##  **FastAPI** tip belirteçleri

**FastAPI** birkaç şey yapmak için bu tür tip belirteçlerinden faydalanır.

**FastAPI** ile parametre tiplerini bildirirsiniz ve şunları elde edersiniz:

from fastapi import BackgroundTasks, FastAPI

app = FastAPI()


def write_notification(email: str, message=""):
    with open("log.txt", mode="w") as email_file:
        content = f"notification for {email}: {message}"
        email_file.write(content)


@app.post("/send-notification/{email}")
async def send_notification(email: str, background_tasks: BackgroundTasks):

from fastapi.testclient import TestClient

from docs_src.extra_models.tutorial005 import app

client = TestClient(app)


def test_get_items():
    response = client.get("/keyword-weights/")
    assert response.status_code == 200, response.text
    assert response.json() == {"foo": 2.3, "bar": 3.4}


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

from fastapi import FastAPI, File, UploadFile

app = FastAPI()


@app.post("/files/")
async def create_file(file: bytes | None = File(default=None)):
    if not file:
        return {"message": "No file sent"}
    else:
        return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(file: UploadFile | None = None):
    if not file:
        return {"message": "No upload file sent"}
    else:

from typing import Optional

from fastapi import FastAPI
from pydantic import BaseModel


class Item(BaseModel):
    name: str
    description: Optional[str] = None


app = FastAPI(separate_input_output_schemas=False)


@app.post("/items/")
def create_item(item: Item):
    return item


@app.get("/items/")
def read_items() -> list[Item]:
    return [
        Item(
            name="Portal Gun",

from fastapi import Depends, FastAPI

from .dependencies import get_query_token, get_token_header
from .internal import admin
from .routers import items, users

app = FastAPI(dependencies=[Depends(get_query_token)])


app.include_router(users.router)
app.include_router(items.router)
app.include_router(
    admin.router,
    prefix="/admin",
    tags=["admin"],
    dependencies=[Depends(get_token_header)],

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel


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


app = FastAPI()


@app.post("/items/")
async def create_item(item: Item):
    item_dict = item.dict()
    if item.tax:
        price_with_tax = item.price + item.tax

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Image(BaseModel):
    url: str
    name: str


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


@app.put("/items/{item_id}")
async def update_item(item_id: int, item: Item):