EffectiveGo-7-A Web Server

Parts of Effective Go

一个`Web`服务器

package main

import (
	"flag"
	"html/template"
	"log"
	"net/http"
)

var addr = flag.String("addr", ":1718", "http service address") // Q=17, R=18
var templ = template.Must(template.New("qr").Parse(templateStr))

func main() {
	flag.Parse()
	http.Handle("/", http.HandlerFunc(QR))
	err := http.ListenAndServe(*addr, nil)
	if err != nil {
		log.Fatal("ListenAndServe:", err)
	}
}

func QR(w http.ResponseWriter, req *http.Request) {
	templ.Execute(w, req.FormValue("s"))
}

const templateStr = `
<html>
  <head>
    <title>QR Link Generator</title>
  </head>
  <body>
    {{if .}}
      <img src="http://chart.apis.google.com/chart?chs=300x300&cht=qr&choe=UTF-8&chl={{.}}"/>
      <br>
    {{.}}
      <br>
      <br>
    {{end}}
    <form action="/" name=f method="GET">
      <input maxLength=1024 size=70 name=s value="" title="Text to QR Encode">
      <input type=submit value="Show QR" name=qr>
    </form>
  </body>
</html>
`

调用 http://chart.apis.google.com 来生成二维码QR码

一个Web服务器

一个`Web`服务器