from fastapi import FastAPI

app = FastAPI()


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

constraints.Future.message      = {item} muss in der Zukunft liegen.
constraints.Max.message         = {item} muss kleiner oder gleich {value} sein.
constraints.Min.message         = {item} muss größer oder gleich {value} sein.
constraints.NotNull.message     = {item} darf nicht leer sein.
constraints.Null.message        = {item} muss leer sein.
constraints.Past.message        = {item} muss in der Vergangenheit liegen.

        response = c.get("/items/")
    assert response.status_code == 200
    assert response.json() == {
        "session_id": "123",
        "fatebook_tracker": "456",
        "googall_tracker": "789",
    }


def test_cookie_param_model_defaults(client: TestClient):
    with client as c:
        c.cookies.set("session_id", "123")
        response = c.get("/items/")
    assert response.status_code == 200

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str, Query(min_length=3)] = ...):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: str | None = Query(
        default=None, min_length=3, max_length=50, pattern="^fixedquery$"
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


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

🖼, ➡️ 💬 👆 ✔️ 4️⃣ 🛠️ 🔗 (*➡ 🛠️*):

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

⤴️ 👆 💪 🚮 🎏 ✔ 📄 🔠 👫 ⏮️ 🔗 & 🎧-🔗:

```mermaid
graph TB

current_user(["current_user"])
active_user(["active_user"])
admin_user(["admin_user"])
paying_user(["paying_user"])

public["/items/public/"]
private["/items/private/"]

from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


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

{!../../docs_src/path_params/tutorial001.py!}
```

Yol parametresi olan `item_id`'nin değeri, fonksiyonunuza `item_id` argümanı olarak aktarılacaktır.

Eğer bu örneği çalıştırıp <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a> sayfasına giderseniz, şöyle bir çıktı ile karşılaşırsınız:

```JSON
{"item_id":"foo"}
```

## Tip İçeren Yol Parametreleri

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