Go web server example with support for URL matching on regular expressions

main.go

package main

import (
	"net/http"
	"regexp"
)

type route struct {
	pattern *regexp.Regexp
	handler http.Handler
}

// RegexpHandler bla bla
type RegexpHandler struct {
	routes []*route
}

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

// HandleFunc bla bla
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)
}

func handleDigits(res http.ResponseWriter, req *http.Request) {
	res.Write([]byte("Digits in the URL\n"))
}

func handleStrings(res http.ResponseWriter, req *http.Request) {
	res.Write([]byte("Strings in the URL\n"))
}

func main() {
	handler := &RegexpHandler{}

	reg1, _ := regexp.Compile("/foo-\\d+")
	handler.HandleFunc(reg1, handleDigits)

	reg2, _ := regexp.Compile("/foo-\\w+")
	handler.HandleFunc(reg2, handleStrings)

	http.ListenAndServe(":3000", handler)
}