package main

import (
    "encoding/json"
    "fmt"
    "log"
    "net/http"
)

type lego struct {
    Tagged    int `json:"width"`
    Thumbnail struct {
        URL   string //`json:"url"`
        Title string //`json:"title"`
    } //`json:"thumbnail"`
    ID []int //`json:"id"`
}

func main() {
    http.HandleFunc("/", index)
    http.ListenAndServe(":8080", nil)
}

func index(w http.ResponseWriter, req *http.Request) {
    var data lego
    unmrshl := `{"width":300,"thumbnail":{"url":"http://facebook.com","title":"facebook"},"id":[123,120,400,12045]}`
    err := json.Unmarshal([]byte(unmrshl), &data)
    if err != nil {
        log.Fatalln(err)
    }
    fmt.Fprintln(w, data.Tagged) //tagged
    for i, v := range data.ID {
        fmt.Fprintln(w, i, v)
    }
    fmt.Fprintln(w, data.Thumbnail.URL)
}