from fastapi import FastAPI

app = FastAPI()


@app.get("/items/", include_in_schema=False)
async def read_items():

Pythonのformat文字列と同様のシンタックスで「パスパラメータ」や「パス変数」を宣言できます:

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

パスパラメータ `item_id` の値は、引数 `item_id` として関数に渡されます。

しがたって、この例を実行して <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a> にアクセスすると、次のレスポンスが表示されます。

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

## パスパラメータと型

標準のPythonの型アノテーションを使用して、関数内のパスパラメータの型を宣言できます:

```JSON
{
  "item": "The Foo Wrestlers"
}
```

But if the client requests `http://example.com/items/bar` (a non-existent `item_id` `"bar"`), that client will receive an HTTP status code of 404 (the "not found" error), and a JSON response of:

```JSON
{
  "detail": "Item not found"
}
```

/// tip

When raising an `HTTPException`, you can pass any value that can be converted to JSON as the parameter `detail`, not only `str`.

            },
            "/items/{item_id}": {
                "get": {
                    "tags": ["items"],
                    "summary": "Read Item",
                    "operationId": "read_item_items__item_id__get",
                    "parameters": [
                        {
                            "required": True,
                            "schema": {"title": "Item Id", "type": "string"},

Если клиент запросит `http://example.com/items/foo` (`item_id` `"foo"`), то он получит статус-код 200 и ответ в формате JSON:

```JSON
{
  "item": "The Foo Wrestlers"
}
```

Но если клиент запросит `http://example.com/items/bar` (несуществующий `item_id` `"bar"`), то он получит статус-код 404 (ошибка "не найдено") и JSON-ответ в виде:

```JSON
{
  "detail": "Item not found"
}
```

/// tip | Подсказка

但是你仍然需要使用 `Path` 来声明路径参数 `item_id`。

如果你将带有「默认值」的参数放在没有「默认值」的参数之前，Python 将会报错。

但是你可以对其重新排序，并将不带默认值的值（查询参数 `q`）放到最前面。

对 **FastAPI** 来说这无关紧要。它将通过参数的名称、类型和默认值声明（`Query`、`Path` 等）来检测参数，而不在乎参数的顺序。

因此，你可以将函数声明为：

{* ../../docs_src/path_params_numeric_validations/tutorial002.py hl[7] *}

## 按需对参数排序的技巧

如果你想不使用 `Query` 声明没有默认值的查询参数 `q`，同时使用 `Path` 声明路径参数 `item_id`，并使它们的顺序与上面不同，Python 对此有一些特殊的语法。

        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items/{item_id}": {
                "get": {
                    "responses": {
                        "404": {"description": "Item not found"},
                        "302": {"description": "The item was moved"},
                        "403": {"description": "Not enough privileges"},
                        "200": {

        "paths": {
            "/items/{item_id}": {
                "put": {
                    "summary": "Update Item",
                    "operationId": "update_item_items__item_id__put",
                    "parameters": [
                        {
                            "required": True,
                            "schema": {"title": "Item Id", "type": "integer"},

from docs_src.custom_response.tutorial001b_py39 import app

client = TestClient(app)


def test_get_custom_response():
    response = client.get("/items/")
    assert response.status_code == 200, response.text
    assert response.json() == [{"item_id": "Foo"}]


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {

from fastapi import FastAPI
from fastapi.routing import APIRoute

app = FastAPI()


@app.get("/items/")
async def read_items():
    return [{"item_id": "Foo"}]


def use_route_names_as_operation_ids(app: FastAPI) -> None:
    """
    Simplify operation IDs so that generated API clients have simpler function
    names.

    Should be called only after all routes have been added.
    """
    for route in app.routes: