Speaking generally, it's more difficult to do much useful with that, because it's hard to do much more than route on the URL. You could prototype code that merely looks at the mentioned headers, but it's getting kinda silly at that point.
(I find that what I pay in using a static language like Go to manipulate JSON and having to use a tool like that often comes back to me pretty quickly when I take the tool output as a template and start turning all the structs into Real Objects (TM). The dynamic languages are pretty good at taking JSON and yielding a simple pile of dict/map/array/strings/numbers/etc., but if you want to get real objects back out of them the advantage over Go evaporates. Not because the dynamic languages make it "hard", but just because with one of these tools, both Go and the dynamic solutions are roughly as easy.)
