Is it possible to forward headers in the unified Gateway?

[Ashwin Madavan]

I would like to forward authentication headers from my unified GraphQL gateway to my backend gRPC services. Normally, I would register a request middleware in Nautilus. Will this library translate the HTTP headers to gRPC metadata?

[Adrian Shum]

For this particular purpose without changing the library, you may try inject HTTP request header using metadata.NewOutgoingContext, through a HTTP middleware:

func authForwardHandler(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		next.ServeHTTP(w, r.WithContext(
			metadata.NewOutgoingContext(r.Context(), map[string][]string{
				"authorization": {r.Header.Get("Authorization")},
			}),
		))
		return
	})
}
...
mux.Handle("/graphql", authForwardHandler(handler.NewDefaultServer(...))