[Golang] Get Instagram User Information From HTML Source

package main

import (
      "encoding/json"
      "fmt"
      "io/ioutil"
      "net/http"
      "regexp"
      "strings"
)

type sharedData struct {
      EntryData struct {
              ProfilePage []struct {
                      GraphQL struct {
                              User IGUser `json:"user"`
                      } `json:"graphql"`
              } `json:"ProfilePage"`
      } `json:"entry_data"`
}

type IGUser struct {
      Biography     string `json:"biography"`
      Id            string `json:"id"`
      Username      string `json:"username"`
      ProfilePicUrl string `json:"profile_pic_url"`
}

func getSource(username string) (b []byte, err error) {
      resp, err := http.Get("https://www.instagram.com/" + username + "/")
      if err != nil {
              return
      }
      defer resp.Body.Close()

      return ioutil.ReadAll(resp.Body)
}

func getJsonStr(b []byte) string {
      pattern := regexp.MustCompile(`<script type="text\/javascript">window\._sharedData = (.*?);<\/script>`)
      m := string(pattern.Find(b))
      m1 := strings.TrimPrefix(m, `<script type="text/javascript">window._sharedData = `)
      return strings.TrimSuffix(m1, `;</script>`)
}

func decodeJsonString(s string) (user IGUser, err error) {
      d := sharedData{}
      err = json.Unmarshal([]byte(s), &d)
      user = d.EntryData.ProfilePage[0].GraphQL.User
      return
}

func main() {
      b, err := getSource("instagram")
      if err != nil {
              panic(err)
      }

      jsonStr := getJsonStr(b)
      user, err := decodeJsonString(jsonStr)
      if err != nil {
              panic(err)
      }
      fmt.Println(user)
}