In some cases, I want to backward compatibility with old API. So I should use redirect to redirect old URL to the new one.

And I think the http code 307 and 308 would be better.

But grails redirect is only support 301 and 302 for now: https://docs.grails.org/latest/ref/Controllers/redirect.html

So I think it's better to make possible to redirect with 307 and 308.