CAPTCHAと2FAを実装

internal/service/totp_service.go

@@ -0,0 +1,71 @@
+package service
+
+import (
+	"bytes"
+	"encoding/base64"
+	"fmt"
+	"image/png"
+	"net/url"
+
+	"github.com/pquerna/otp"
+	totplib "github.com/pquerna/otp/totp"
+)
+
+type TOTPService struct{}
+
+func NewTOTPService() *TOTPService {
+	return &TOTPService{}
+}
+
+type TOTPSetupData struct {
+	Secret     string
+	QRCodeB64  string
+	OTPAuthURL string
+}
+
+func (s *TOTPService) GenerateSecret(email, issuer string) (*TOTPSetupData, error) {
+	key, err := totplib.Generate(totplib.GenerateOpts{
+		Issuer:      issuer,
+		AccountName: email,
+	})
+	if err != nil {
+		return nil, err
+	}
+	return s.buildSetupData(key)
+}
+
+func (s *TOTPService) SetupDataFromSecret(secret, email, issuer string) (*TOTPSetupData, error) {
+	otpURL := fmt.Sprintf("otpauth://totp/%s:%s?secret=%s&issuer=%s",
+		url.PathEscape(issuer),
+		url.PathEscape(email),
+		url.QueryEscape(secret),
+		url.QueryEscape(issuer),
+	)
+	key, err := otp.NewKeyFromURL(otpURL)
+	if err != nil {
+		return nil, err
+	}
+	return s.buildSetupData(key)
+}
+
+func (s *TOTPService) buildSetupData(key *otp.Key) (*TOTPSetupData, error) {
+	img, err := key.Image(200, 200)
+	if err != nil {
+		return nil, err
+	}
+
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, img); err != nil {
+		return nil, err
+	}
+
+	return &TOTPSetupData{
+		Secret:     key.Secret(),
+		QRCodeB64:  base64.StdEncoding.EncodeToString(buf.Bytes()),
+		OTPAuthURL: key.URL(),
+	}, nil
+}
+
+func (s *TOTPService) Validate(secret, code string) bool {
+	return totplib.Validate(code, secret)
+}