}

```

但如果客户端请求 `http://example.com/items/bar`（`item_id` `「bar」` 不存在时），则会接收到 HTTP 状态码 - 404（「未找到」错误）及如下 JSON 响应结果：

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

```

!!! tip "提示"

    触发 `HTTPException` 时，可以用参数 `detail` 传递任何能转换为 JSON 的值，不仅限于 `str`。

    还支持传递 `dict`、`list` 等数据结构。

    **FastAPI** 能自动处理这些数据，并将之转换为 JSON。


## 添加自定义响应头

```

✋️ 🚥 👩‍💻 📨 `http://example.com/items/bar` (🚫-🚫 `item_id` `"bar"`), 👈 👩‍💻 🔜 📨 🇺🇸🔍 👔 📟 4️⃣0️⃣4️⃣ ("🚫 🔎" ❌), & 🎻 📨:

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

!!! tip
    🕐❔ 🙋‍♀ `HTTPException`, 👆 💪 🚶‍♀️ 🙆 💲 👈 💪 🗜 🎻 🔢 `detail`, 🚫 🕴 `str`.

    👆 💪 🚶‍♀️ `dict`, `list`, ♒️.

    👫 🍵 🔁 **FastAPI** & 🗜 🎻.

## 🚮 🛃 🎚

}
```

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。

    `dist`や`list`などを渡すことができます。

    これらは **FastAPI** によって自動的に処理され、JSONに変換されます。

## カスタムヘッダーの追加

            },
            "HTTPValidationError": {
                "title": "HTTPValidationError",
                "type": "object",
                "properties": {
                    "detail": {
                        "title": "Detail",
                        "type": "array",
                        "items": {
                            "$ref": "#/components/schemas/ValidationError"
                        }

Aus diesem Grund wird jetzt empfohlen, stattdessen `lifespan` wie oben erläutert zu verwenden.

## Technische Details

Nur ein technisches Detail für die neugierigen Nerds. 🤓

```

</div>

Then if you go to the URLs at `/openapi.json`, `/docs`, or `/redoc` you will just get a `404 Not Found` error like:

```JSON
{
    "detail": "Not Found"
}

            },
            "HTTPValidationError": {
                "title": "HTTPValidationError",
                "type": "object",
                "properties": {
                    "detail": {
                        "title": "Detail",
                        "type": "array",
                        "items": {
                            "$ref": "#/components/schemas/ValidationError"
                        }

* <a href="https://github.com/django/daphne" class="external-link" target="_blank">Daphne</a>: the ASGI server built for Django Channels.

## Server Machine and Server Program

There's a small detail about names to keep in mind. 💡

The word "**server**" is commonly used to refer to both the remote/cloud computer (the physical or virtual machine) and also the program that is running on that machine (e.g. Uvicorn).

可以提取如下当前用户数据：

```JSON
{
  "username": "johndoe",
  "email": "******@****.***",
  "full_name": "John Doe",
  "disabled": false,
  "hashed_password": "fakehashedsecret"
}
```

<img src="https://fastapi.tiangolo.com/img/tutorial/security/image06.png">

点击小锁图标，注销后，再执行同样的操作，则会得到 HTTP 401 错误：

```JSON
{
  "detail": "Not authenticated"
}
```

### 未激活用户

## Data validation

But if you go to the browser at <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>, you will see a nice HTTP error of:

```JSON
{
  "detail": [
    {
      "type": "int_parsing",
      "loc": [
        "path",
        "item_id"
      ],
      "msg": "Input should be a valid integer, unable to parse string as an integer",
      "input": "foo",