size: Annotated[int | None, Body()] = None,
):
    if item_id in items:
        item = items[item_id]
        item["name"] = name
        item["size"] = size
        return item
    else:
        item = {"name": name, "size": size}
        items[item_id] = item

        "tax": 10.5,
    },
}


@app.get(
    "/items/{item_id}/name",
    response_model=Item,
    response_model_include={"name", "description"},
)
async def read_item_name(item_id: str):
    return items[item_id]


@app.get("/items/{item_id}/public", response_model=Item, response_model_exclude={"tax"})
async def read_item_public_data(item_id: str):

    except yaml.YAMLError:
        raise HTTPException(status_code=422, detail="Invalid YAML")
    try:
        item = Item.model_validate(data)
    except ValidationError as e:
        raise HTTPException(status_code=422, detail=e.errors(include_url=False))

from fastapi import FastAPI
from pydantic import BaseModel


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None


app = FastAPI()


@app.post("/items/")
async def create_item(item: Item):
    item_dict = item.model_dump()
    if item.tax is not None:
        price_with_tax = item.price + item.tax
        item_dict.update({"price_with_tax": price_with_tax})

    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    }
}
```

/// note | Not

`item` daha öncekiyle aynı şekilde tanımlanmış olsa bile, artık body içinde `item` anahtarı altında gelmesi beklenir.

///

**FastAPI**, request'ten otomatik dönüşümü yapar; böylece `item` parametresi kendi içeriğini alır, `user` için de aynı şekilde olur.

constraints.URL.message = {item} is not a valid URL.
constraints.Required.message = {item} is required.
constraints.TypeInteger.message = {item} must be a number.
constraints.TypeLong.message = {item} must be a number.
constraints.TypeFloat.message = {item} must be a number.
constraints.TypeDouble.message = {item} must be a number.
constraints.TypeAny.message = {item} cannot be converted to {propertyType}.
constraints.UriType.message = {item} has an unrecognized URI.

constraints.URL.message = {item} is not a valid URL.
constraints.Required.message = {item} is required.
constraints.TypeInteger.message = {item} must be a number.
constraints.TypeLong.message = {item} must be a number.
constraints.TypeFloat.message = {item} must be a number.
constraints.TypeDouble.message = {item} must be a number.
constraints.TypeAny.message = {item} cannot be converted to {propertyType}.
constraints.UriType.message = {item} has an unrecognized URI.

    return id


@app.get("/items/")
async def read_items(
    id: Annotated[str | None, AfterValidator(check_valid_id)] = None,
):
    if id:
        item = data.get(id)
    else:
        id, item = random.choice(list(data.items()))

#d6d8db;\n}\n\n.list-group-item-secondary.list-group-item-action:hover, .list-group-item-secondary.list-group-item-action:focus {\n  color: #383d41;\n  background-color: #c8cbcf;\n}\n\n.list-group-item-secondary.list-group-item-action.active {\n  color: #fff;\n  background-color: #383d41;\n  border-color: #383d41;\n}\n\n.list-group-item-success {\n  color: #155724;\n  background-color: #c3e6cb;\n}\n\n.list-group-item-success.list-group-item-action:hover, .list-group-item-success.list-group-item-action:focus {\n...

```JSON
{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    },
    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    }
}
```

/// note | Hinweis

Beachten Sie, dass, obwohl `item` wie zuvor deklariert wurde, es nun unter einem Schlüssel `item` im Body erwartet wird.

///