Is this a bug in 4? Don't see the headers sent by the browser on error

[mamcx]

I need to return different response depending if the server is called as API or the browser. In 3 I do:

//check if the request comes from the browser or API request...
pub fn is_ui_request(headers: &HeaderMap) -> bool {
    dbg!(headers);
    match headers.get("Content-Type") {
        Some(t) => {
            let tt = t.to_str().unwrap_or("");
            !tt.contains("application/json")
        }
        None => true,
    }
}

fn error_page<B>(
    res: dev::ServiceResponse<B>,
    headers: &HeaderMap,
) -> Result<ErrorHandlerResponse<B>> {
    let status = res.status();
    let json_err = res.response();
    let company = get_req_company(res.request());
    error!(?status, ?company, error = ?json_err.error());

    let status = res.status();
    let headers = res.headers();
    let json_err = res.response();
    let company = get_req_company(res.request());
    error!(?status, ?company, error = ?json_err.error());
    let error = json_err
        .error()
        .map(...);

    // Return an Error 500 page or a JSON?
    if is_ui_request(headers) {
        let page = match admin::error_page(company, status, PageError::Err(error)) {
            Ok(page) => page,
            Err(err) => HttpResponse::InternalServerError().body(format!("{}", err)),
        };
        Ok(ErrorHandlerResponse::Response(
            res.into_response(page.into_body()),
        ))
    } else {
        error!(?status);
        Ok(ErrorHandlerResponse::Response(res))
    }
}

But with the change to 4, I don't get the full headers. I get now this (note how this send json without nobody I see changing it):

headers = HeaderMap {
    inner: {
        "content-type": Value {
            inner: [
                "application/json",
            ],
        },
        "vary": Value {
            inner: [
                "accept-encoding",
            ],
        },
        "content-encoding": Value {
            inner: [
                "gzip",
            ],
        },
    },
}

This is what firefox send:

GET /manager/zone/edit/001?search= HTTP/1.1
Host: vincorte.localhost:5000
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:98.0) Gecko/20100101 Firefox/98.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://vincorte.localhost:5000/manager/zone/
Connection: keep-alive

The code on 4 is:

fn error_handlers<B: 'static>() -> ErrorHandlers<B> {
    ErrorHandlers::new()
        .handler(StatusCode::INTERNAL_SERVER_ERROR, error_page)
        .handler(StatusCode::NOT_FOUND, error_page)
}

fn error_page<B>(res: ServiceResponse<B>) -> Result<ErrorHandlerResponse<B>> {
    let status = res.status();
    let headers = res.headers();
    let json_err = res.response();
    let company = get_req_company(res.request());
    error!(?status, ?company, error = ?json_err.error());
    let error = json_err
        .error()
        .map(...);

    let response = if is_ui_request(headers) {
        match admin::error_page(company, status, PageError::Err(error)) {
            Ok(page) => page,
            Err(err) => HttpResponse::InternalServerError().body(err.to_string()),
        }
    } else {
        error!(?status);
        HttpResponse::build(status)
            .content_type(ContentType::json())
            .json(error)
    };

    let (req, res) = res.into_parts();

    let res = ServiceResponse::new(req, response)
        .map_into_boxed_body()
        .map_into_right_body();

    Ok(ErrorHandlerResponse::Response(res))
}

[robjtede]

I don't get the full headers

Sounds like you're trying to retain the headers from the original response. But see that you're creating brand new responses in both cases UI/API. You'll need to use a method that either modifies the original response or moves the headers to the new response.

Of course, I can't run this code because there's too much application-specific stuff going on. If I'm wrong about what you're trying to do here then see if you can reduce the sample to something I'd be able to run.

[mamcx]

The problem, is not clear how get the original headers. In the impl for ResponseError, it have not access to the request, not way to call the "parent" implementation.