def test_path_operation(client: TestClient):
    response = client.put(
        "/items/1",
        json={
            "title": "Foo",
            "timestamp": "2023-01-01T12:00:00",
            "description": "A test item",
        },
    )
    assert response.status_code == 200, response.text
    assert response.json() == {
        "description": "A test item",
        "timestamp": "2023-01-01T12:00:00",
        "title": "Foo",
    }

Der Wert des Pfad-Parameters `item_id` wird Ihrer Funktion als das Argument `item_id` übergeben.

Wenn Sie dieses Beispiel ausführen und auf <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a> gehen, sehen Sie als <abbr title="Response – Antwort: Daten, die der Server zum anfragenden Client zurücksendet">Response</abbr>:

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

        },
        "openapi": "3.1.0",
        "paths": {
            "/items/{item_id}": {
                "put": {
                    "operationId": "update_item_items__item_id__put",
                    "parameters": [
                        {
                            "in": "path",
                            "name": "item_id",
                            "required": True,
                            "schema": {

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",

{* ../../docs_src/path_params/tutorial001.py hl[6:7] *}

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

from fastapi import FastAPI, Query

app = FastAPI()


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

client = TestClient(app)


def test_foo_needy_very():
    response = client.get("/items/foo?needy=very")
    assert response.status_code == 200
    assert response.json() == {"item_id": "foo", "needy": "very"}


def test_foo_no_needy():
    response = client.get("/items/foo")
    assert response.status_code == 422
    assert response.json() == {
        "detail": [
            {

from typing import Union

from fastapi import FastAPI

app = FastAPI()


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

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)] = "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(min_length=3)):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})