json_handling2.go

func uploadHandler(w http.ResponseWriter, r *http.Request) {

	var m map[string]interface{}

	body, err := ioutil.ReadAll(r.Body)

	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// fmt.Println(string(body))

  // json.Unmarshal(b, &t) => decode the byte array into a type
	if err = json.Unmarshal(body, &m); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// json.Marshal(m) => encode the object m as a byte array containing its json representation.
	jsonStr, err := json.Marshal(m)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	fmt.Fprintln(w, string(jsonStr))
}