nslookup go api endpoint

nslookupapi.go

package main

import (
    "fmt"
    "github.com/julienschmidt/httprouter"
    "github.com/miekg/dns"
    "net/http"
    "encoding/json"
    "log"
)

type Status struct {
  Name string
  Free string
}

func Index(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
  fmt.Fprint(w, "Welcome!\n")
}

func Lookup(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
  target := ps.ByName("name")
  server := "8.8.8.8"
  free := "false"

  c := dns.Client{}
  m := dns.Msg{}
  m.SetQuestion(target+".", dns.TypeNS)
  res, _, err := c.Exchange(&m, server+":53")
  if err != nil {
    log.Printf("%s", err)
    free = "unknown"
  } else {
    // log.Printf("Took %v", t)
    if len(res.Answer) == 0 {
      free = "true"
      log.Printf("No results for %s", target)
    }
    /* for _, ans := range res.Answer {
      NSrecord := ans.(*dns.NS)
      log.Printf("%s", NSrecord.Ns)
    } */
  }

  status := Status{target, free}

  js, err := json.Marshal(status)
  if err != nil {
    http.Error(w, err.Error(), http.StatusInternalServerError)
    return
  }

  w.Header().Set("Content-Type", "application/json")
  w.Write(js)
}

func main() {
    router := httprouter.New()
    router.GET("/", Index)
    router.GET("/free/:name", Lookup)

    log.Fatal(http.ListenAndServe(":80", router))
}