How to fetch JSON from an API and count number of pigeons - json

Question

So I'm trying to get the number of pigeons from a JSON having this format. This JSON contains a lot of bird types and each one is defined by his color and last contact:
{
"url": "http://localhost:9001/",
"pigeons": [
{
"color": "white",
"lastContact": "2020-03-23T14:46:20.806Z"
},
{
"color": "grey",
"lastContact": "2020-03-23T14:46:20.807Z"
}
],
"parrots": [
{
"color": "green",
"lastContact": "2020-03-23T14:46:20.806Z"
}
]
}
Already made this piece of code that gets the JSON from the API, but since I don't have any experience in Go, can you guys help me to count the number of pigeons from here? I don't really care about the number of other bird types.
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"log"
"net/http"
"time"
)
type pigeons struct {
Number int `json:"something"`
}
func main() {
url := "http://localhost:9001"
birdsClient := http.Client{
Timeout: time.Second * 2, // Maximum of 2 secs
}
req, err := http.NewRequest(http.MethodGet, url, nil)
if err != nil {
log.Fatal(err)
}
res, getErr := birdsClient.Do(req)
if getErr != nil {
log.Fatal(getErr)
}
body, readErr := ioutil.ReadAll(res.Body)
if readErr != nil {
log.Fatal(readErr)
}
pigeons1 := pigeons{}
jsonErr := json.Unmarshal(body, &pigeons1)
if jsonErr != nil {
log.Fatal(jsonErr)
}
fmt.Println(pigeons1.Number)
}

Answer 1

In the JSON document that comes back, pigeons is an array and it looks like the length of that array is the number of pigeons. So if you unmarshal that into a struct that accepts and array for pigeons, you can get the length of it:
type pigeons struct {
Pigeons []interface{} `json:"pigeons"`
}
Above, you can unmarshal the pigeons field to an interface array because you don't care about the contents of the field. If you need to process contents, you need a separate struct and use the array of that. Then:
var p pigeons
json.Unmarshal(body, &p)
fmt.Printf("%d",len(p.Pigeons))