feat: 0.0.1

internal/auth/jwt_maker.go

@@ -0,0 +1,128 @@
+package auth
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/FernandoJVideira/simple_bank/internal/config"
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/google/uuid"
+)
+
+// JWTMaker is a JSON Web Token maker
+type JWTMaker struct {
+	secretKey string
+	config    config.Config
+}
+
+func NewJWTClaims(payload *Payload, config config.Config) jwt.Claims {
+	return &jwt.MapClaims{
+		"iat":  jwt.NewNumericDate(payload.IssuedAt),
+		"iss":  config.TokenISS,
+		"exp":  jwt.NewNumericDate(payload.ExpiredAt),
+		"nbf":  jwt.NewNumericDate(payload.IssuedAt),
+		"aud":  []string{config.TokenAUD},
+		"sub":  payload.Username,
+		"role": payload.Role,
+		"jti":  payload.ID.String(),
+	}
+}
+
+// NewJWTMaker creates a new JWTMaker
+
+func NewJWTMaker(config config.Config) (Maker, error) {
+	if len(config.TokenKey) < config.MinTokenSize {
+		return nil, fmt.Errorf("invalid key size: must be at least %d characters", config.MinTokenSize)
+	}
+	return &JWTMaker{secretKey: config.TokenKey, config: config}, nil
+}
+
+func (maker *JWTMaker) CreateToken(username string, role string, duration time.Duration) (string, *Payload, error) {
+	payload, err := NewPayload(username, role, duration)
+	if err != nil {
+		return "", nil, err
+	}
+
+	jwtToken := jwt.NewWithClaims(jwt.SigningMethodHS256, NewJWTClaims(payload, maker.config))
+
+	signedString, err := jwtToken.SignedString([]byte(maker.secretKey))
+
+	return signedString, payload, err
+}
+
+func (maker *JWTMaker) VerifyToken(token string) (*Payload, error) {
+	payloadClaims := jwt.MapClaims{}
+	keyFunc := func(token *jwt.Token) (any, error) {
+		_, ok := token.Method.(*jwt.SigningMethodHMAC)
+		if !ok {
+			return nil, ErrInvalidToken
+		}
+		return []byte(maker.secretKey), nil
+	}
+
+	jwtToken, err := jwt.ParseWithClaims(token, payloadClaims, keyFunc)
+	if err != nil {
+		if errors.Is(err, jwt.ErrTokenExpired) {
+			return nil, ErrExpiredToken
+		} else if errors.Is(err, ErrInvalidToken) {
+			return nil, ErrInvalidToken
+		} else {
+			return nil, err
+		}
+	}
+
+	payloadClaims, ok := jwtToken.Claims.(jwt.MapClaims)
+	if !ok {
+		return nil, ErrInvalidToken
+	}
+
+	payload, err := parseTypes(payloadClaims)
+	if err != nil {
+		return nil, err
+	}
+
+	return payload, nil
+}
+
+func parseTypes(claims jwt.MapClaims) (*Payload, error) {
+	// Safe type assertions with error checking
+	jti, ok := claims["jti"].(string)
+	if !ok {
+		return nil, ErrInvalidToken
+	}
+
+	id, err := uuid.Parse(jti)
+	if err != nil {
+		return nil, ErrInvalidToken
+	}
+
+	username, ok := claims["sub"].(string)
+	if !ok {
+		return nil, ErrInvalidToken
+	}
+
+	role, ok := claims["role"].(string)
+	if !ok {
+		return nil, ErrInvalidToken
+	}
+
+	// Parse numeric dates
+	nbf, ok := claims["nbf"].(float64)
+	if !ok {
+		return nil, ErrInvalidToken
+	}
+
+	exp, ok := claims["exp"].(float64)
+	if !ok {
+		return nil, ErrInvalidToken
+	}
+
+	return &Payload{
+		ID:        id,
+		Username:  username,
+		Role:      role,
+		IssuedAt:  time.Unix(int64(nbf), 0),
+		ExpiredAt: time.Unix(int64(exp), 0),
+	}, nil
+}