middleware.go

package main

import (
	"fmt"
	"time"
	"net/http"
)

func chain(handleFuncs ...func(w http.ResponseWriter, r *http.Request)) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		for _, fn := range handleFuncs {
			fn(w, r)
		}
	}
}

func log(w http.ResponseWriter, r *http.Request) {
	t := time.Now()
	fmt.Printf("%s - - [%s]", r.RemoteAddr, t)
}

func index(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "hello, world!")
}

func main() {
	http.HandleFunc("/", chain(log, index))
	http.ListenAndServe(":4093", nil)
}