You nave import the github.com/gorilla/mux in your controller or middleware, when you receive the r *http.Request, and use it the same away
something like that
import (
"github.com/gorilla/mux"
)
func Get(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
vars := mux.Vars(r)
id := vars["id"]
}