handler.go

package main

import (
    "net/http"
    "regexp"
)
type route struct {
    pattern *regexp.Regexp
    handler http.Handler
}

type RegexpHandler struct {
    routes []*route
}

func (h *RegexpHandler) Handler(pattern *regexp.Regexp, handler http.Handler) {
    h.routes = append(h.routes, &route{pattern, handler})
}

func (h *RegexpHandler) HandleFunc(pattern *regexp.Regexp, handler func(http.ResponseWriter, *http.Request)) {
    h.routes = append(h.routes, &route{pattern, http.HandlerFunc(handler)})
}

func (h *RegexpHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    for _, route := range h.routes {
        if route.pattern.MatchString(r.URL.Path) {
            route.handler.ServeHTTP(w, r)
            return
        }
    }
    // no pattern matched; send 404 response
    http.NotFound(w, r)
}