JWT Tokens using jwt-go

jwt.go

package components

import (
	"crypto/rsa"
	jwt "github.com/dgrijalva/jwt-go"
	"io/ioutil"
	"log"
	"time"
)

const (
	privKeyPath = "keys/key.rsa"     // openssl genrsa -out key.rsa 2048
	pubKeyPath  = "keys/key.rsa.pub" // openssl rsa -in key.rsa -pubout > key.rsa.pub
)

var (
	verifyKey *rsa.PublicKey
	signKey   *rsa.PrivateKey
)

func init() {
	signBytes, err := ioutil.ReadFile(privKeyPath)
	fatal(err)

	signKey, err = jwt.ParseRSAPrivateKeyFromPEM(signBytes)
	fatal(err)

	verifyBytes, err := ioutil.ReadFile(pubKeyPath)
	fatal(err)

	verifyKey, err = jwt.ParseRSAPublicKeyFromPEM(verifyBytes)
	fatal(err)
}

func fatal(err error) {
	if err != nil {
		log.Fatal(err)
	}
}

func NewToken(userId int) string {
	// create a signer for rsa 256
	t := jwt.New(jwt.GetSigningMethod("RS256"))

	// set claims
	t.Claims["user"] = userId
	t.Claims["iat"] = time.Now().Unix()
	t.Claims["exp"] = time.Now().Add(time.Second * 3600 * 24).Unix()

	token, err := t.SignedString(signKey)
	if err != nil {
		return ""
	}

	return token
}

func ValidateToken(token string) bool {
	t, err := jwt.Parse(token, func(token *jwt.Token) (interface{}, error) {
		return verifyKey, nil
	})

	if err == nil && t.Valid {
		return true
	}
	return false
}