Method extractExpiration

credentials/jwt/file_reader.go:91–118

extractExpiration parses the JWT token to extract the expiration time.

(token string)

// extractExpiration parses the JWT token to extract the expiration time.
func (r *jwtFileReader) extractExpiration(token string) (time.Time, error) {
	claimsRaw, ok := extractClaimsRaw(token)
	if !ok {
		return time.Time{}, fmt.Errorf("expected 3 parts in token")
	}
	payloadBytes, err := base64.RawURLEncoding.DecodeString(claimsRaw)
	if err != nil {
		return time.Time{}, fmt.Errorf("decode error: %v", err)
	}

	var claims jwtClaims
	if err := json.Unmarshal(payloadBytes, &claims); err != nil {
		return time.Time{}, fmt.Errorf("unmarshal error: %v", err)
	}

	if claims.Exp == 0 {
		return time.Time{}, fmt.Errorf("no expiration claims")
	}

	expTime := time.Unix(claims.Exp, 0)

	// Check if token is already expired.
	if expTime.Before(time.Now()) {
		return time.Time{}, fmt.Errorf("expired token")
	}

	return expTime, nil
}