Use dynamic route with URL parameters

[jorgebay]

Resolves #92 .

With this patch, a route with the pattern /graphql/:keyspace is always created and the keyspace is obtained from the url path.

[mpenick]

What do you think about providing a small interface to leverage routers libraries?

type RouteHandler interface {
	KeyspaceRoute(pattern string) string
	Keyspace(r *http.Request) string
}

type httpRouterHandler struct { }

func NewHttpRouterHandler() httpRouterHandler {
	return httpRouterHandler{}
}

func (h httpRouterHandler) KeyspaceRoute(pattern string) string {
	return path.Join(pattern, ":keyspace")
}

func (h httpRouterHandler) Keyspace(r *http.Request) string {
	params := httprouter.ParamsFromContext(r.Context())
	return params.ByName("keyspace")
}

Full patch: 1eaa7ca (updated)

[jorgebay]

What do you think about providing a small interface to leverage routers libraries?

My only concern is that it requires more code from endpoint route user pov. For cloud, if they decide to switch to mux it will involve implementing this interface vs changing a setting.

[mpenick]

That would also work with gorilla/mux:

type gorillaMuxHandler struct { }

func NewHttpRouterHandler() gorillaMuxHandler {
	return gorillaMuxHandler{}
}

func (h gorillaMuxHandler) KeyspaceRoute(pattern string) string {
	return path.Join(pattern, "{keyspace}")
}

func (h gorillaMuxHandler) Keyspace(r *http.Request) string {
  vars := mux.Vars(r)
  return vars["keyspace"]
}

[mpenick]

What do you think about providing a small interface to leverage routers libraries?

My only concern is that it requires more code from endpoint route user pov. For cloud, if they decide to switch to mux it will involve implementing this interface vs changing a setting.

It ends up being a very small amount of stateless code and using a regex doesn't leverage the router's capabilities so we end up double parsing the url.

[jorgebay]

I think exposing less API surface for cloud integration and simple settings are a plus, even at the cost of being less extensible and parsing the url ourselves, but I don't have strong feelings about it.

I'll rebase this and address the lock optimization.

[jorgebay]

Done! Feel free to push the RouteHandler interface directly to this branch.

[mpenick]

Secret option C: Because we're not leveraging the URL templating in either router, meaning we don't need to have the syntax :keyspace or {keyspace}. What about having no option at all?

We know that keyspace is the last segment in the pattern: /some/pattern/<keyspace>. Why not just split that off using something like path.Base()?

[jorgebay]

Secret option C

Interesting... I'm not sure I understand how routers would match the path without a router-based expression like {param} or :param? afaik, there's no built way to do that in http package,.