With Go (golang) how can I Unmarshal data into a struct, and then call specific fields from the struct?

I'm trying to do an API request to get some information from steams public API (this is mainly for learning Go and just learning how to deal with Json / API requests) I have gotten this code so far:

package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"strconv"
)
type SteamAPI struct {
APIKey string
}
type GetAppNews struct {
AppNews struct {
AppId     int `json:"appid"`
NewsItems []struct {
Gid           int    `json:"gid"`
Title         string `json:"title"`
Url           string `json:"url"`
IsExternalUrl bool   `json:"is_external_url"`
Author        string `json:"author"`
Contents      string `json:"contents"`
Feedlabel     string `json:"feedlabel"`
Date          int    `json:"date"`
} `json:"newsitems"`
} `json:"appnews"`
}
type JsonResponse map[string]GetAppNews
func (s SteamAPI) GetNewsForApp(appid, count, maxlength int) error {
sAppid := strconv.Itoa(appid)
sCount := strconv.Itoa(count)
sMaxlength := strconv.Itoa(maxlength)
resp, err := http.Get("http://api.steampowered.com/ISteamNews/GetNewsForApp/v0002/?appid=" + sAppid + "&count=" + sCount + "&maxlength=" + sMaxlength + "&format=json")
if err != nil {
return err
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return err
}
var jsonReturn JsonResponse
json.Unmarshal(body, &jsonReturn)
fmt.Println(jsonReturn)
return nil
}
func main() {
Tester := SteamAPI{""}
Tester.GetNewsForApp(440, 3, 300)
}

Things seem to work, alright, I guess but its not formatting it the way I would expect it to Unmarshal. It prints out like this:

map[appnews:{{0 []}}]

You can click here to see exactly what the format of the JSON response looks like, if anybody could tell me what I have done wrong with my struct, in the end I expect to be able to go something like:

fmt.Println(blah["appnews"]["appid"]) and it would return 440.

Thats all I really got to go off of, if you need anymore specific information let me know! Thanks for the help!

The data fits the struct just fine, no need for map[string]GetAppNews.

type JsonResponse map[string]GetAppNews should just be GetAppNews.

<kbd>playground</kbd>