from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str | None, Query(min_length=3)] = ...):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

    /**
     * Locates the pom in the given directory.
     *
     * @param dir the directory to locate the pom for, never {@code null}
     * @return a {@code Source} pointing to the located pom or an empty {@code Optional} if none was found by this parser
     */
    @Nonnull
    Optional<Source> locate(@Nonnull Path dir);

    /**
     * Parse the model obtained previously by a previous call to {@link #locate(Path)}.
     *

        {
            "detail": [
                {
                    "type": "missing",
                    "loc": ["body", "files"],
                    "msg": "Field required",
                    "input": None,
                }
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["body", "files"],

```

////

🎏 🕐❔ 📣 🔢 🔢, 🕐❔ 🏷 🔢 ✔️ 🔢 💲, ⚫️ 🚫 ✔. ⏪, ⚫️ ✔. ⚙️ `None` ⚒ ⚫️ 📦.

🖼, 👉 🏷 🔛 📣 🎻 "`object`" (⚖️ 🐍 `dict`) 💖:

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

... `description` & `tax` 📦 (⏮️ 🔢 💲 `None`), 👉 🎻 "`object`" 🔜 ☑:

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## 📦 🔢

🎏 🌌, 👆 💪 📣 📦 🔢 🔢, ⚒ 👫 🔢 `None`:

//// tab | 🐍 3️⃣.6️⃣ & 🔛

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

👉 💼, 🔢 🔢 `q` 🔜 📦, & 🔜 `None` 🔢.

/// check

Fonksiyonunuzdaki parametre değerleri aşağıdaki gibi olacaktır:

* `skip=20`: çünkü bağlantıda böyle tanımlandı.
* `limit=10`: çünkü varsayılan değer buydu.

## İsteğe Bağlı Parametreler

Aynı şekilde, varsayılan değerlerini `None` olarak atayarak isteğe bağlı parametreler tanımlayabilirsiniz:

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

from typing import Union

from fastapi import FastAPI, Response
from fastapi.responses import RedirectResponse

app = FastAPI()


@app.get("/portal", response_model=None)
async def get_portal(teleport: bool = False) -> Union[Response, dict]:
    if teleport:
        return RedirectResponse(url="https://www.youtube.com/watch?v=dQw4w9WgXcQ")

                    "loc": ["header", "x-token"],
                    "msg": "Field required",
                    "input": None,
                },
                {
                    "type": "missing",
                    "loc": ["header", "x-key"],
                    "msg": "Field required",
                    "input": None,
                },
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1

    assert response.status_code == 200
    assert response.json() == {
        "host": "testserver",
        "save_data": True,
        "if_modified_since": None,
        "traceparent": None,
        "x_tag": [],
    }


def test_header_param_model_invalid(client: TestClient):
    response = client.get("/items/")
    assert response.status_code == 422

from typing import Optional

from fastapi import FastAPI
from pydantic import BaseModel


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


app = FastAPI()


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


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