How can i get access to the error returned by the handler using a middleware?

[barata0]

Let´s suppose I want to log every error returned by the handlers
I believe the best way to do this is using a middleware and if there is an error log it.

Best I could think about is this:

		log.Printf("Error: %v", ctx.Context().Err())
	}

But ctx.Context.Err is nil.

[danielgtaylor]

@barata0 it depends on what you want to log exactly. I would suggest either a middleware or a transformer:

• Log HTTP status code, headers, response body, etc via a middleware. You can wrap http.ResponseWriter or huma.Context to store the status/headers/body and then read it after the operation completes.
• Get the error instance via a transformer before it is serialized to HTTP. You will have to check if the value is an error instance.

Another possibility is to use your own register function, something like:

func MyRegister[I, O any](api huma.API, op huma.Operation, handler func(context.Context, *I) (*O, error)) {
	huma.Register(api, op, func(ctx context.Context, input *I) (*O, error) {
		result, err := handler(ctx, input)
		if err != nil {
			// Do something here!
		}
		return result, err
	})
}

[shasderias]

Sorry for the cross-posts, I saw several variants of this question being asked and spent quite a bit of time trying to solve it for myself. It seems to me overriding huma.NewErrorWithContext although not possibly intended for this purpose, basically solves the problem.

ISTM that in huma.NewErrorWithContext, you have access to a huma.Context and the error returned by the handler, which should be good enough for most usecases (logging errors, hiding errors, transforming errors, etc.).

My original reply is here, and it comes with a little code snippet that demonstrates what I'm trying to say.

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