package main
import (
    "flag"
    "log"
    "net/http"
    "text/template"
)
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=300x300cht=qrchoe=UTF-8chl={{urlquery .}}" />
br>
{{html .}}
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>