muxer.go

package main

import (
	"log"
	"net/http"
	"sync"
)

type Muxer struct {
	routes map[string]http.Handler
	moot   *sync.Mutex
}

func (m Muxer) HandleFunc(pat string, h http.HandlerFunc) {
	m.moot.Lock()
	defer m.moot.Unlock()
	m.routes[pat] = h
}

func (m Muxer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
	m.moot.Lock()
	defer m.moot.Unlock()
	if h, ok := m.routes[req.URL.Path]; ok {
		log.Printf("%s\t%s\n", req.Method, req.URL.Path)
		h.ServeHTTP(res, req)
		return
	}
	log.Printf("[404] %s\t%s\n", req.Method, req.URL.Path)
	http.NotFound(res, req)
}

func NewMuxer() Muxer {
	return Muxer{
		routes: map[string]http.Handler{},
		moot:   &sync.Mutex{},
	}
}

func main() {
	mux := NewMuxer()
	mux.HandleFunc("/hello", func(res http.ResponseWriter, req *http.Request) {
		res.Write([]byte("Hello, World!\n"))
	})
	mux.HandleFunc("/goodbye", func(res http.ResponseWriter, req *http.Request) {
		res.Write([]byte("Goodbye, World!\n"))
	})
	http.ListenAndServe(":3000", mux)
}