【Question】How can I get my origin handler response in middleware

[LyunKi]

I want to add i18n capability for my application, I unify all errors to my server error enum which can be mapped to an error code.
All handlers return a Result<T,ServerError> like below

pub async fn register(
    Extension(ref db): Extension<DatabaseConnection>,
    Json(to_be_created): Json<CreateUser>,
) -> Result<CreateUserRsp, ServerError> {
  xxx
}

However, when I tried to log response in middleware ,I found all results returned by my handler will transform to Ok(Response(UnsyncBodyxxxx)) (Ok is 200,Err is 500 or others)

        let accept_language = req
            .headers()
            .get(header::ACCEPT_LANGUAGE)
            .map(HeaderValue::to_str)
            .map(|result| result.ok())
            .flatten()
            .map(ToString::to_string);
        let res_future = self.inner.call(req);
        Box::pin(res_future.inspect(|res| {
            dbg!(&res);
        }))

So if I want to get my origin SeverError and translate my error code by accept-language header, I will have to try to deserialize the HTTP body to ServerError.

is there a lifetime I can use to get my origin response before it becomes a response body?

[LyunKi]

finally, I struggled with nested futures and had to write like below...
body => bytes => str => struct => body .a little hard for me.

        Box::pin(async move {
            let result = res_future.await;
            let translation_config = TranslationConfig {
                accept_language,
                ..Default::default()
            };
            match result {
                Ok(response) if !response.status().is_success() => {
                    let body = response.into_body();
                    let body = hyper::body::to_bytes(body)
                        .await
                        .ok()
                        .and_then(|bytes| serde_json::from_slice(&bytes).ok())
                        .unwrap_or(TmpError::from(ServerError::InternalServerError))
                        .translate(translation_config);
                    Ok(body.into_response())
                }
                Ok(response) => Ok(response),
                Err(err) => Err(err),
            }
        })

[davidpdrsn]

Yeah you need to extract the things from your request that the error needs to be converted into a response