Pass through error message and/or error description from response body

[r2DoesInc]

Is there an existing issue for this?

• I have searched the existing issues

Describe the problem to be solved

I have this setup as a default error handler on my k8s cluster, and it works great overall. My apis deployed on the cluster have a bit of an issue though.

When returning a 404 or something that this project is setup to respond for, my error content is ignored.

This turns my

{
    "error": "location_invalid",
    "message": "Given location either does not exist or is invalid."
}

Into

{
    "error": true,
    "code": "404",
    "message": "Not Found",
    "description": "The server can not find the requested page",
}

Suggest a solution

I propose modifying the error page to pull from the response body if it is provided

Something like

error-pages/internal/http/core/errorpage.go

Line 56 in b8f9608

props.Message = page.Message()

props.Message =  string(ctx.Request.Body.Peek(Message))

I dont know go, so not sure if thats how it would be implemented.

This could be configured behind a bool for ALLOW_ERROR_MESSAGE_PASSTHROUGH which would default to false to maintain consistency with prior behavior.

Additional context

No response

[Ruakij]

I was just looking into this too. I use Traefik as my Ingress, so maybe nginx handles things differently.
Unfortunately the error-middleware used to redirect to the error-page is a separate request and the original response is discarded. (see https://doc.traefik.io/traefik/middlewares/http/errorpages/)

There doesnt seem to be a way to only apply a middleware via a condition yet. So at this point i am unsure what options are left. A custom middleware should be able to do this i suppose.