from collections.abc import Callable
from typing import Annotated

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:

When a request contains invalid data, **FastAPI** internally raises a `RequestValidationError`.

And it also includes a default exception handler for it.

To override it, import the `RequestValidationError` and use it with `@app.exception_handler(RequestValidationError)` to decorate the exception handler.

The exception handler will receive a `Request` and the exception.

from fastapi import FastAPI, HTTPException
from fastapi.exception_handlers import (
    http_exception_handler,
    request_validation_exception_handler,
)
from fastapi.exceptions import RequestValidationError
from starlette.exceptions import HTTPException as StarletteHTTPException

app = FastAPI()


@app.exception_handler(StarletteHTTPException)
async def custom_http_exception_handler(request, exc):
    print(f"OMG! An HTTP error!: {repr(exc)}")

## 예외 핸들러에서 요청 바디 접근하기 { #accessing-the-request-body-in-an-exception-handler }

/// tip | 팁

같은 문제를 해결하려면 `RequestValidationError`에 대한 커스텀 핸들러에서 `body`를 사용하는 편이 아마 훨씬 더 쉽습니다([오류 처리하기](../tutorial/handling-errors.md#use-the-requestvalidationerror-body)).

하지만 이 예시도 여전히 유효하며, 내부 컴포넌트와 상호작용하는 방법을 보여줍니다.

///

같은 접근 방식을 사용해 예외 핸들러에서 요청 바디에 접근할 수도 있습니다.

from fastapi.encoders import jsonable_encoder
from fastapi.exceptions import RequestValidationError, WebSocketRequestValidationError
from fastapi.utils import is_body_allowed_for_status_code
from fastapi.websockets import WebSocket
from starlette.exceptions import HTTPException
from starlette.requests import Request
from starlette.responses import JSONResponse, Response
from starlette.status import WS_1008_POLICY_VIOLATION

/// 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)).

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

///

但由於我們修改了 `GzipRequest.body`，在 **FastAPI** 需要讀取本文時，請求本文會自動解壓縮。

## 在例外處理器中存取請求本文 { #accessing-the-request-body-in-an-exception-handler }

/// tip

要解決相同問題，使用針對 `RequestValidationError` 的自訂處理器來讀取 `body` 通常更簡單（[處理錯誤](../tutorial/handling-errors.md#use-the-requestvalidationerror-body)）。

但本範例仍然有效，並示範了如何與內部元件互動。

///

我們也可以用同樣的方法，在例外處理器中存取請求本文。

我們只需要在 `try`/`except` 區塊中處理請求即可：

## 例外ハンドラでのリクエストボディへのアクセス { #accessing-the-request-body-in-an-exception-handler }

/// tip | 豆知識

同じ問題を解決するには、`RequestValidationError` 用のカスタムハンドラで `body` を使う方がずっと簡単でしょう（[エラー処理](../tutorial/handling-errors.md#use-the-requestvalidationerror-body)）。

ただし、この例も有効で、内部コンポーネントとどのようにやり取りするかを示しています。

///

同じアプローチを使って、例外ハンドラ内でリクエストボディにアクセスすることもできます。

やることは、`try`/`except` ブロックの中でリクエストを処理するだけです：

        for err in self._errors:
            message += f"  {err}\n"
        message += self._format_endpoint_context()
        return message.rstrip()


class RequestValidationError(ValidationException):
    def __init__(
        self,
        errors: Sequence[Any],
        *,
        body: Any = None,
        endpoint_ctx: EndpointContext | None = None,
    ) -> None:

from fastapi.encoders import jsonable_encoder
from fastapi.exceptions import RequestValidationError
from fastapi.responses import JSONResponse
from pydantic import BaseModel

app = FastAPI()


@app.exception_handler(RequestValidationError)
async def validation_exception_handler(request: Request, exc: RequestValidationError):
    return JSONResponse(
        status_code=422,