radio stream generator in go

hi.go

package hi

import (
	"crypto/md5"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"strconv"
	"strings"
	"time"
)

// Httpbin represents network connection information
type Httpbin struct {
	IP string `json:"origin"`
}

// GenIP will retrive current ip address by httpbin service
func GenIP() string {
	res, err := http.Get("https://httpbin.org/ip")
	if err != nil {
		fmt.Println(err.Error())
		return ""
	}
	defer res.Body.Close()
	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		fmt.Println(err.Error())
		return ""
	}
	model := Httpbin{}
	json.Unmarshal(body, &model)
	return model.IP
}

// GenToken will generate token with path, timestamp, ip and suffix key
func GenToken(path string, timestamp int64, ip string, suffixKey string) string {
	secret := "radio@himediaservice#t"
	var builder strings.Builder
	fmt.Fprint(&builder, path)
	fmt.Fprint(&builder, strconv.FormatInt(timestamp, 10))
	fmt.Fprint(&builder, ip)
	fmt.Fprint(&builder, secret)
	fmt.Fprint(&builder, suffixKey)
	source := builder.String()
	hash := md5.New()
	hash.Write([]byte(source))
	hashInBase64 := base64.StdEncoding.EncodeToString(hash.Sum(nil))
	step1 := strings.Replace(hashInBase64, "+", "-", -1)
	step2 := strings.Replace(step1, "/", "_", -1)
	return strings.Replace(step2, "=", "", -1)
}

// GenStreamURL will generate radio stream resource url
func GenStreamURL(channel string) string {
	entry := "https://radio-hichannel.cdn.hinet.net"
	now := time.Now()
	timestamp := now.Unix()
	path := fmt.Sprintf("/live/pool/hich-%s/ra-hls/", channel)
	ip := GenIP()
	expire1 := timestamp + (5 * 60)
	expire2 := expire1 + (8 * 60 * 60)
	token1 := GenToken(path, expire1, ip, "1")
	token2 := GenToken(path, expire2, ip, "2")
	params := fmt.Sprintf("token1=%s&token2=%s&expire1=%d&expire2=%d", token1, token2, expire1, expire2)
	return fmt.Sprintf("%s%sindex.m3u8?%s", entry, path, params)
	// return fmt.Sprintf("%s%shich-%s-audio_track=128000.m3u8?%s", entry, path, channel, params)
}