common/jwt_adapter/jwt_adapter.go

package jwt_adapter

import (
	"context"
	"fmt"
	"github.com/dgrijalva/jwt-go"
	"os"
	"strings"
	"time"
)

var publicKey = strings.Replace(`-----BEGIN PUBLIC KEY-----
	MIGeMA0GCSqGSIb3DQEBAQUAA4GMADCBiAKBgHgnvr7O2tiApjJfid1orFnIGm69
	80fZp+Lpbjo+NC/0whMFga2Biw5b1G2Q/B2u0tpO1Fs/E8z7Lv1nYfr5jx2S8x6B
	dA4TS2kB9Kf0wn0+7wSlyikHoKhbtzwXHZl17GsyEi6wHnsqNBSauyIWhpha8i+Y
	+3GyaOY536H47qyXAgMBAAE=
	-----END PUBLIC KEY-----`, "\t", "", -1)

const (
	DefaultAccessSecret = "awesomeAC"
	DefaultHeaderKey    = "Authorization"
)

var (
	//_            cookie.Cookie = new(JwtAdapter)
	accessSecret = publicKey
)

type JwtAdapter struct {
	jwt.StandardClaims
	Id string `json:"id"`
}

func init() {
	aS := os.Getenv("JWT_SECRET")
	if len(aS) != 0 {
		accessSecret = aS
	}
}

func Get(ctx context.Context) *JwtAdapter {
	if adapter, ok := ctx.Value(DefaultHeaderKey).(*JwtAdapter); ok {
		return adapter
	}

	return nil
}

func (receiver *JwtAdapter) SetUserID(ID string) {
	receiver.Id = ID
}

func (receiver *JwtAdapter) GetUserID() string {
	return receiver.Id
}

func (receiver *JwtAdapter) Validate() error {
	if err := receiver.Valid(); err != nil {
		return err
	}

	if !receiver.VerifyIssuer("pena-auth-service", true) {
		return fmt.Errorf("invalid issuer")
	}

	if !receiver.VerifyAudience("pena", true) {
		return fmt.Errorf("invalid audience")
	}

	return nil
}

func Decode(tokenString string) (*JwtAdapter, error) {
	token, err := jwt.ParseWithClaims(tokenString, &JwtAdapter{}, func(token *jwt.Token) (interface{}, error) {
		if _, ok := token.Method.(*jwt.SigningMethodRSA); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}
		return jwt.ParseRSAPublicKeyFromPEM([]byte(accessSecret))
	})

	if err != nil {
		return nil, err
	}

	claims, ok := token.Claims.(*JwtAdapter)
	if !ok && !token.Valid {
		return nil, fmt.Errorf("ErrorNoValidClaims")
	}

	if err := claims.Validate(); err != nil {
		return nil, err
	}

	return claims, nil
}

func Timestamp() int64 {
	return time.Now().UnixNano() / int64(time.Millisecond)
}

type ForCreate struct {
	PrivateKey []byte
	PublicKey  []byte
	Algorithm  *jwt.SigningMethodRSA
	ExpiresIn  time.Duration
	Issuer     string
	Audience   string
}

func Create(id string, forCreate ForCreate) (string, error) {
	privateKey, err := jwt.ParseRSAPrivateKeyFromPEM(forCreate.PrivateKey)
	if err != nil {
		return "", fmt.Errorf("failed to parse private key: %w", err)
	}

	now := time.Now().UTC()

	claims := jwt.MapClaims{
		"id":  id,
		"exp": now.Add(forCreate.ExpiresIn).Unix(),
		"aud": forCreate.Audience,
		"iss": forCreate.Issuer,
	}

	token, err := jwt.NewWithClaims(forCreate.Algorithm, claims).SignedString(privateKey)
	if err != nil {
		return "", fmt.Errorf("failed create jwt: %w", err)
	}

	return token, nil
}