## `HTTPException` verwenden

Um HTTP-Responses mit Fehlern zum Client zurückzugeben, verwenden Sie `HTTPException`.

### `HTTPException` importieren

```Python hl_lines="1"
{!../../../docs_src/handling_errors/tutorial001.py!}
```

### Eine `HTTPException` in Ihrem Code auslösen

## Accessing the request body in an exception handler

!!! tip
    To solve this same problem, it's probably a lot easier to use the `body` in a custom handler for `RequestValidationError` ([Handling Errors](../tutorial/handling-errors.md#use-the-requestvalidationerror-body){.internal-link target=_blank}).

    But this example is still valid and it shows how to interact with the internal components.

    This is for client errors, invalid authentication, invalid data, etc. Not for server
    errors in your code.

    Read more about it in the
    [FastAPI docs for Handling Errors](https://fastapi.tiangolo.com/tutorial/handling-errors/).

    ## Example

    ```python
    from fastapi import FastAPI, HTTPException

    app = FastAPI()

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

Errors returned by [driver.Valuer] implementations are now wrapped for
improved error handling during operations like [DB.Query], [DB.Exec],

Таким же образом вы можете поднять исключение `HTTPException` или что-то подобное в завершающем коде, после `yield`.

Код выхода в зависимостях с `yield` выполняется *после* отправки ответа, поэтому [Обработчик исключений](../handling-errors.md#install-custom-exception-handlers){.internal-link target=_blank} уже будет запущен. В коде выхода (после `yield`) нет ничего, перехватывающего исключения, брошенные вашими зависимостями.

You can import it directly form `fastapi`:

```python
from fastapi import WebSocketDisconnect
```

::: fastapi.WebSocketDisconnect

## WebSockets - additional classes

Additional classes for handling WebSockets.

Provided directly by Starlette, but you can import it from `fastapi`:

```python
from fastapi.websockets import WebSocketDisconnect, WebSocketState
```

::: fastapi.websockets.WebSocketDisconnect

		return msg.ProtoReflect().Type(), nil
	}
	return typ, nil
}

// Wrapper is a wrapper around the Envoy ConfigDump
// It has extra helper functions for handling any/struct/marshal protobuf pain
type Wrapper struct {
	*admin.ConfigDump
}

// UnmarshalJSON is a custom unmarshaller to handle protobuf pain
func (w *Wrapper) UnmarshalJSON(b []byte) error {

## 使用 `yield` 和 `HTTPException` 的依赖项

您看到可以使用带有 `yield` 的依赖项，并且具有捕获异常的 `try` 块。

在 `yield` 后抛出 `HTTPException` 或类似的异常是很诱人的，但是**这不起作用**。

带有`yield`的依赖中的退出代码在响应发送之后执行，因此[异常处理程序](../handling-errors.md#install-custom-exception-handlers){.internal-link target=_blank}已经运行过。没有任何东西可以捕获退出代码（在`yield`之后）中的依赖抛出的异常。

所以，如果在`yield`之后抛出`HTTPException`，默认（或任何自定义）异常处理程序捕获`HTTPException`并返回HTTP 400响应的机制将不再能够捕获该异常。

Because this code is executed before the application **starts** taking requests, and right after it **finishes** handling requests, it covers the whole application **lifespan** (the word "lifespan" will be important in a second 😉).

👆 👀 👈 👆 💪 ⚙️ 🔗 ⏮️ `yield` & ✔️ `try` 🍫 👈 ✊ ⚠.

⚫️ 5️⃣📆 😋 🤚 `HTTPException` ⚖️ 🎏 🚪 📟, ⏮️ `yield`. ✋️ **⚫️ 🏆 🚫 👷**.

🚪 📟 🔗 ⏮️ `yield` 🛠️ *⏮️* 📨 📨, [⚠ 🐕‍🦺](../handling-errors.md#_4){.internal-link target=_blank} 🔜 ✔️ ⏪ 🏃. 📤 🕳 😽 ⚠ 🚮 👆 🔗 🚪 📟 (⏮️ `yield`).

, 🚥 👆 🤚 `HTTPException` ⏮️ `yield`, 🔢 (⚖️ 🙆 🛃) ⚠ 🐕‍🦺 👈 ✊ `HTTPException`Ⓜ & 📨 🇺🇸🔍 4️⃣0️⃣0️⃣ 📨 🏆 🚫 📤 ✊ 👈 ⚠ 🚫🔜.