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

しかし、クライアントが`http://example.com/items/bar`（存在しない`item_id` `"bar"`）をリクエストした場合、HTTPステータスコード404（"not found"エラー）と以下のJSONレスポンスが返されます:

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

!!! tip "豆知識"
    `HTTPException`を発生させる際には、`str`だけでなく、JSONに変換できる任意の値を`detail`パラメータとして渡すことができます。

        return foo

    client = TestClient(app)

    response = client.post("/", json="bar")
    assert response.status_code == 200, response.text
    assert response.json() == "bar"

    response2 = client.post("/", json=[1, 2])
    assert response2.status_code == 200, response2.text
    assert response2.json() == [1, 2]


def test_is_bytes_sequence_annotation_union():
    # For coverage

Now as the end result is in a file `openapi.json`, you would modify the `package.json` to use that local file, for example:

```JSON  hl_lines="7"
{
  "name": "frontend-app",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "generate-client": "openapi-ts --input ./openapi.json --output ./src/client --client axios"
  },
  "author": "",
  "license": "",

```
https://www.external.org/events/invoices/2expen51ve
```

mit einem JSON-Body, der etwa Folgendes enthält:

```JSON
{
    "description": "Payment celebration",
    "paid": true
}
```

und sie würde eine Response von dieser *externen API* mit einem JSON-Body wie dem folgenden erwarten:

```JSON
{
    "ok": true
}
```

!!! tip "Tipp"

def test_valid():
    response = client.get("/items/valid")
    response.raise_for_status()
    assert response.json() == {"name": "valid", "price": 1.0, "owner_ids": None}


def test_coerce():
    response = client.get("/items/coerce")
    response.raise_for_status()
    assert response.json() == {"name": "coerce", "price": 1.0, "owner_ids": None}


def test_validlist():
    response = client.get("/items/validlist")

    response = client.get("/items/")
    assert response.status_code == 200
    assert response.json() == {
        "message": "Hello Items!",
        "params": {"q": None, "skip": 5, "limit": 10},
    }


def test_override_in_items_with_q():
    response = client.get("/items/?q=foo")
    assert response.status_code == 200
    assert response.json() == {
        "message": "Hello Items!",

    ```

=== "Python 3.8+"

    ```Python hl_lines="20"
    {!> ../../../docs_src/body_nested_models/tutorial006.py!}
    ```

Das wird einen JSON-Body erwarten (konvertieren, validieren, dokumentieren), wie:

```JSON hl_lines="11"
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": [
        "rock",
        "metal",

예를 들면, 위의 이 모델은 JSON "`object`" (혹은 파이썬 `dict`)을 다음과 같이 선언합니다:

```JSON
{
    "name": "Foo",
    "description": "선택적인 설명란",
    "price": 45.2,
    "tax": 3.5
}
```

...`description`과 `tax`는 (기본 값이 `None`으로 되어 있어) 선택적이기 때문에, 이 JSON "`object`"는 다음과 같은 상황에서도 유효합니다:

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

## 매개변수로서 선언하기

So, the frontend (that runs in the browser) would try to reach `/openapi.json` and wouldn't be able to get the OpenAPI schema.

Because we have a proxy with a path prefix of `/api/v1` for our app, the frontend needs to fetch the OpenAPI schema at `/api/v1/openapi.json`.

```mermaid
graph LR

browser("Browser")

# 直接返回响应

当你创建一个 **FastAPI** *路径操作* 时，你可以正常返回以下任意一种数据：`dict`，`list`，Pydantic 模型，数据库模型等等。

**FastAPI** 默认会使用 `jsonable_encoder` 将这些类型的返回值转换成 JSON 格式，`jsonable_encoder` 在 [JSON 兼容编码器](../tutorial/encoder.md){.internal-link target=_blank} 中有阐述。

然后，**FastAPI** 会在后台将这些兼容 JSON 的数据（比如字典）放到一个 `JSONResponse` 中，该 `JSONResponse` 会用来发送响应给客户端。

但是你可以在你的 *路径操作* 中直接返回一个 `JSONResponse`。

直接返回响应可能会有用处，比如返回自定义的响应头和 cookies。

## 返回 `Response`