app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: bool | None = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: str | None = None):
    return {"item_id": item_id, "q": q}


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

使用瀏覽器開啟 [http://127.0.0.1:8000/items/5?q=somequery](http://127.0.0.1:8000/items/5?q=somequery)。

你將會看到以下 JSON 回應：

```JSON
{"item_id": 5, "q": "somequery"}
```

你已經建立了一個具有以下功能的 API：

* 透過路徑 `/` 和 `/items/{item_id}` 接受 HTTP 請求。
* 以上兩個路徑都接受 `GET` 操作（也被稱為 HTTP _方法_）。
* 路徑 `/items/{item_id}` 有一個 `int` 型別的路徑參數 `item_id`。
* 路徑 `/items/{item_id}` 有一個可選的 `str` 查詢參數 `q`。

    ```python
    from fastapi import FastAPI, HTTPException

    app = FastAPI()

    items = {"foo": "The Foo Wrestlers"}


    @app.get("/items/{item_id}")
    async def read_item(item_id: str):
        if item_id not in items:
            raise HTTPException(status_code=404, detail="Item not found")
        return {"item": items[item_id]}
    ```
    """

    def __init__(
        self,
        status_code: Annotated[

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})

from fastapi import FastAPI, Query

app = FastAPI()


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

                            },
                        },
                    }
                },
                "/items/{item_id}": {
                    "get": {
                        "tags": ["items"],
                        "summary": "Read Item",
                        "operationId": "read_item_items__item_id__get",
                        "parameters": [
                            {

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: str | None = Query(default=None, alias="item-query")):
    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 Annotated

from fastapi import FastAPI, Query

app = FastAPI()


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

{* ../../docs_src/path_params/tutorial001_py310.py hl[6:7] *}

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

Yani, bu örneği çalıştırıp [http://127.0.0.1:8000/items/foo](http://127.0.0.1:8000/items/foo) adresine giderseniz, şöyle bir response görürsünüz:

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

## Tip İçeren Yol Parametreleri { #path-parameters-with-types }