{!> ../../../docs_src/dependencies/tutorial008b.py!}
    ```

An alternative you could use to catch exceptions (and possibly also raise another `HTTPException`) is to create a [Custom Exception Handler](../handling-errors.md#install-custom-exception-handlers){.internal-link target=_blank}.

## Dependencies with `yield` and `except`

!!! note "Technical Details"
    Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded`.

    But when the form includes files, it is encoded as `multipart/form-data`. You'll read about handling files in the next chapter.

class WebSocketRecorder(
  private val name: String,
) : WebSocketListener() {
  private val events = LinkedBlockingQueue<Any>()
  private var delegate: WebSocketListener? = null

  /** Sets a delegate for handling the next callback to this listener. Cleared after invoked.  */
  fun setNextEventDelegate(delegate: WebSocketListener?) {
    this.delegate = delegate
  }

  override fun onOpen(
    webSocket: WebSocket,

  // When no rule matches the Pod failure, the default handling applies - the
  // counter of pod failures is incremented and it is checked against
  // the backoffLimit. At most 20 elements are allowed.
  // +listType=atomic
  repeated PodFailurePolicyRule rules = 1;
}

// PodFailurePolicyOnExitCodesRequirement describes the requirement for handling

// but will be re-emitted in their canonical form. (So always use canonical
// form, or don't diff.)
//
// This format is intended to make it difficult to use these numbers without
// writing some sort of special handling code in the hopes that that will
// cause implementors to also use a fixed point implementation.
//
// +protobuf=true
// +protobuf.embed=string
// +protobuf.options.marshal=false

http://hello%00

# Escaped numbers should be treated like IP addresses if they are.
# No special handling for IPv4 or IPv4-like URLs
http://%30%78%63%30%2e%30%32%35%30.01  s:http p:/ h:192.168.0.1
http://%30%78%63%30%2e%30%32%35%30.01%2e  s:http p:/ h:0xc0.0250.01.
http://192.168.0.257

# Invalid escaping should trigger the regular host error handling.
http://%3g%78%63%30%2e%30%32%35%30%2E.01

⏮️ 👈, 🌐 🏭 ⚛ 🎏.

✋️ ↩️ 👆 🔀 `GzipRequest.body`, 📨 💪 🔜 🔁 🗜 🕐❔ ⚫️ 📐 **FastAPI** 🕐❔ 💪.

## 🔐 📨 💪 ⚠ 🐕‍🦺

!!! tip
    ❎ 👉 🎏 ⚠, ⚫️ 🎲 📚 ⏩ ⚙️ `body` 🛃 🐕‍🦺 `RequestValidationError` ([🚚 ❌](../tutorial/handling-errors.md#requestvalidationerror){.internal-link target=_blank}).

    ✋️ 👉 🖼 ☑ & ⚫️ 🎦 ❔ 🔗 ⏮️ 🔗 🦲.

👥 💪 ⚙️ 👉 🎏 🎯 🔐 📨 💪 ⚠ 🐕‍🦺.

🌐 👥 💪 🍵 📨 🔘 `try`/`except` 🍫:

```Python hl_lines="13  15"

In most cases you would (and should) have a "termination proxy" handling HTTPS for you on top, this will depend on how you deploy your application, your provider might do this for you, or you might need to set it up yourself.

!!! tip

        * [Install custom exception handlers](https://fastapi.tiangolo.com/tutorial/handling-errors/#install-custom-exception-handlers).
        * [Override the default exception handlers](https://fastapi.tiangolo.com/tutorial/handling-errors/#override-the-default-exception-handlers).
        * [Re-use **FastAPI's** exception handlers](https://fastapi.tiangolo.com/tutorial/handling-errors/#re-use-fastapis-exception-handlers).

之后，所有处理逻辑都一样。

但因为改变了 `GzipRequest.body`，**FastAPI** 加载请求体时会自动解压。

## 在异常处理器中访问请求体

!!! tip "提示"

    为了解决同样的问题，在 `RequestValidationError` 的自定义处理器使用 `body`  （[处理错误](../tutorial/handling-errors.md#use-the-requestvalidationerror-body){.internal-link target=_blank}）可能会更容易。

    但本例仍然可行，而且本例展示了如何与内部组件进行交互。

同样也可以在异常处理器中访问请求体。

此时要做的只是处理 `try`/`except` 中的请求：

```Python hl_lines="13  15"