Como consumir a API de CNPJ em Go?

1go mod init exemplo-apifordevs
2# net/http e encoding/json fazem parte da biblioteca padrão.

1$env:AFD_PUBLIC_KEY="afd_test_pk_..."
2$env:AFD_SECRET_KEY="seu_segredo_de_desenvolvimento"
3$env:AFD_PROJECT_ID="proj_..."

1export AFD_PUBLIC_KEY="afd_test_pk_..."
2export AFD_SECRET_KEY="seu_segredo_de_desenvolvimento"
3export AFD_PROJECT_ID="proj_..."

1package main
2
3import (
4  "crypto/rand"
5  "encoding/hex"
6  "encoding/json"
7  "fmt"
8  "net/http"
9  "os"
10  "time"
11)
12func env(key string) string {
13  value := os.Getenv(key); if value == "" { panic("Configure " + key) }; return value
14}
15func read(client *http.Client, request *http.Request) map[string]interface{} {
16  response, err := client.Do(request); if err != nil { panic(err) }; defer response.Body.Close()
17  var payload map[string]interface{}
18  if err := json.NewDecoder(response.Body).Decode(&payload); err != nil { panic(err) }
19  if response.StatusCode >= 400 || payload["success"] != true {
20    codes := []interface{}{}
21    if errors, ok := payload["errors"].([]interface{}); ok {
22      for _, raw := range errors { if e, ok := raw.(map[string]interface{}); ok { codes = append(codes, e["code"]) } }
23    }
24    panic(fmt.Sprintf("HTTP %d codes=%v Retry-After=%s", response.StatusCode, codes, response.Header.Get("Retry-After")))
25  }
26  return payload
27}
28func main() {
29  client := &http.Client{Timeout: 30 * time.Second}
30  key := make([]byte, 16); if _, err := rand.Read(key); err != nil { panic(err) }
31  ping, err := http.NewRequest("GET", "https://api.apifordevs.com/api/v1/ping/billable?dev_mode=true", nil); if err != nil { panic(err) }
32  ping.SetBasicAuth(env("AFD_PUBLIC_KEY"), env("AFD_SECRET_KEY"))
33  ping.Header.Set("X-Project-Id", env("AFD_PROJECT_ID"))
34  ping.Header.Set("Idempotency-Key", hex.EncodeToString(key))
35  fmt.Println(read(client, ping))
36  cnpj, err := http.NewRequest("GET", "https://api.apifordevs.com/api/v1/cnpj/00000000007951", nil); if err != nil { panic(err) }
37  fmt.Println(read(client, cnpj)["data"].([]interface{})[0])
38}

1go run main.go