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 = `