first-web-server.go

package main

import (
	"flag"
	"fmt"
	"log"
	"net/http"
)

var listenOn = "127.0.0.1:8888"

func helloHandler(w http.ResponseWriter, r *http.Request) {
	log.Printf("%#v", r)
	fmt.Fprint(w, "hello world")
}

func init() {
	flag.StringVar(&listenOn, "listen", listenOn, "The address to listen on for web requests")
}

func main() {
	flag.Parse()
	http.HandleFunc("/hello", helloHandler)
	log.Fatal(http.ListenAndServe(listenOn, nil))
}