Golang Implement for Generate "FastlyCDN" URL Token Validation.

main.go

package main

import (
	"crypto/hmac"
	"crypto/sha1"
	"encoding/base64"
	"encoding/hex"
	"io"
	"strconv"
	"time"

	"github.com/gin-gonic/gin"
)

var (
	secret_key      string            = base64.StdEncoding.EncodeToString([]byte("YOUR KEY HERE"))
	authorize_table map[string]string = map[string]string{
		"test": "123.mp4",
	}
)

func main() {

	r := gin.Default()

	//Serve Media File, /serveMedia/this_is_hash
	r.GET("/serveMedia/:hash", func(c *gin.Context) {
		filepath := authorize_table[c.Param("hash")]
		c.File(filepath)
	})

	//Show the 10 min exp link with token
	r.GET("/generateMediaUrl", func(c *gin.Context) {
		//simulate hash
		hash := "kfskfoksdokfpsd"

		//add hash with filename to table
		authorize_table[hash] = "./1.mp4"

		//build token
		ru := "/serveMedia/" + hash
		urltoken := generateToken(ru, makeExpTime())
		c.String(200, ru+"?token="+urltoken)
	})

	r.GET("/removeFile", func(c *gin.Context) {
		//simulate hash
		hash := "kfskfoksdokfpsd"

		//delete file in table
		delete(authorize_table, hash)
		c.JSON(200, "good")
	})

	r.Run(":80")

}

func makeExpTime() int64 {
	t := time.Now().Local().Add(
		time.Hour*time.Duration(0) +
			time.Minute*time.Duration(10) + //after 10 minute
			time.Second*time.Duration(0))

	return t.Unix()
}

func generateToken(urlpath string, expTime int64) string {
	base64data, _ := base64.StdEncoding.DecodeString(secret_key)
	timestamp := strconv.FormatInt(expTime, 10)
	unsigndata := urlpath + timestamp

	//sha1
	h := hmac.New(sha1.New, base64data)
	io.WriteString(h, unsigndata)
	signdata := h.Sum(nil)
	strTypeSignData := hex.EncodeToString(signdata)

	//token format
	token := timestamp + "_" + strTypeSignData
	return token
}