feat: 增加邀请码注册功能

backend/cmd/jwtgen/main.go

@@ -33,7 +33,7 @@ func main() {
 	}()
 
 	userRepo := repository.NewUserRepository(client, sqlDB)
-	authService := service.NewAuthService(userRepo, cfg, nil, nil, nil, nil, nil)
+	authService := service.NewAuthService(userRepo, nil, cfg, nil, nil, nil, nil, nil)
 
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()

backend/cmd/server/wire_gen.go

@@ -43,6 +43,7 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 		return nil, err
 	}
 	userRepository := repository.NewUserRepository(client, db)
+	redeemCodeRepository := repository.NewRedeemCodeRepository(client)
 	settingRepository := repository.NewSettingRepository(client)
 	settingService := service.NewSettingService(settingRepository, configConfig)
 	redisClient := repository.ProvideRedis(configConfig)
@@ -61,24 +62,23 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	apiKeyService := service.NewAPIKeyService(apiKeyRepository, userRepository, groupRepository, userSubscriptionRepository, apiKeyCache, configConfig)
 	apiKeyAuthCacheInvalidator := service.ProvideAPIKeyAuthCacheInvalidator(apiKeyService)
 	promoService := service.NewPromoService(promoCodeRepository, userRepository, billingCacheService, client, apiKeyAuthCacheInvalidator)
-	authService := service.NewAuthService(userRepository, configConfig, settingService, emailService, turnstileService, emailQueueService, promoService)
+	authService := service.NewAuthService(userRepository, redeemCodeRepository, configConfig, settingService, emailService, turnstileService, emailQueueService, promoService)
 	userService := service.NewUserService(userRepository, apiKeyAuthCacheInvalidator)
+	subscriptionService := service.NewSubscriptionService(groupRepository, userSubscriptionRepository, billingCacheService)
+	redeemCache := repository.NewRedeemCache(redisClient)
+	redeemService := service.NewRedeemService(redeemCodeRepository, userRepository, subscriptionService, redeemCache, billingCacheService, client, apiKeyAuthCacheInvalidator)
 	secretEncryptor, err := repository.NewAESEncryptor(configConfig)
 	if err != nil {
 		return nil, err
 	}
 	totpCache := repository.NewTotpCache(redisClient)
 	totpService := service.NewTotpService(userRepository, secretEncryptor, totpCache, settingService, emailService, emailQueueService)
-	authHandler := handler.NewAuthHandler(configConfig, authService, userService, settingService, promoService, totpService)
+	authHandler := handler.NewAuthHandler(configConfig, authService, userService, settingService, promoService, redeemService, totpService)
 	userHandler := handler.NewUserHandler(userService)
 	apiKeyHandler := handler.NewAPIKeyHandler(apiKeyService)
 	usageLogRepository := repository.NewUsageLogRepository(client, db)
 	usageService := service.NewUsageService(usageLogRepository, userRepository, client, apiKeyAuthCacheInvalidator)
 	usageHandler := handler.NewUsageHandler(usageService, apiKeyService)
-	redeemCodeRepository := repository.NewRedeemCodeRepository(client)
-	subscriptionService := service.NewSubscriptionService(groupRepository, userSubscriptionRepository, billingCacheService)
-	redeemCache := repository.NewRedeemCache(redisClient)
-	redeemService := service.NewRedeemService(redeemCodeRepository, userRepository, subscriptionService, redeemCache, billingCacheService, client, apiKeyAuthCacheInvalidator)
 	redeemHandler := handler.NewRedeemHandler(redeemService)
 	subscriptionHandler := handler.NewSubscriptionHandler(subscriptionService)
 	announcementRepository := repository.NewAnnouncementRepository(client)

backend/internal/domain/constants.go

@@ -36,6 +36,7 @@ const (
 	RedeemTypeBalance      = "balance"
 	RedeemTypeConcurrency  = "concurrency"
 	RedeemTypeSubscription = "subscription"
+	RedeemTypeInvitation   = "invitation"
 )
 
 // PromoCode status constants

backend/internal/handler/admin/redeem_handler.go

@@ -29,7 +29,7 @@ func NewRedeemHandler(adminService service.AdminService) *RedeemHandler {
 // GenerateRedeemCodesRequest represents generate redeem codes request
 type GenerateRedeemCodesRequest struct {
 	Count        int     `json:"count" binding:"required,min=1,max=100"`
-	Type         string  `json:"type" binding:"required,oneof=balance concurrency subscription"`
+	Type         string  `json:"type" binding:"required,oneof=balance concurrency subscription invitation"`
 	Value        float64 `json:"value" binding:"min=0"`
 	GroupID      *int64  `json:"group_id"`                                    // 订阅类型必填
 	ValidityDays int     `json:"validity_days" binding:"omitempty,max=36500"` // 订阅类型使用，默认30天，最大100年

backend/internal/handler/admin/setting_handler.go

@@ -49,6 +49,7 @@ func (h *SettingHandler) GetSettings(c *gin.Context) {
 		EmailVerifyEnabled:                   settings.EmailVerifyEnabled,
 		PromoCodeEnabled:                     settings.PromoCodeEnabled,
 		PasswordResetEnabled:                 settings.PasswordResetEnabled,
+		InvitationCodeEnabled:                settings.InvitationCodeEnabled,
 		TotpEnabled:                          settings.TotpEnabled,
 		TotpEncryptionKeyConfigured:          h.settingService.IsTotpEncryptionKeyConfigured(),
 		SMTPHost:                             settings.SMTPHost,
@@ -98,6 +99,7 @@ type UpdateSettingsRequest struct {
 	EmailVerifyEnabled    bool `json:"email_verify_enabled"`
 	PromoCodeEnabled      bool `json:"promo_code_enabled"`
 	PasswordResetEnabled  bool `json:"password_reset_enabled"`
+	InvitationCodeEnabled bool `json:"invitation_code_enabled"`
 	TotpEnabled           bool `json:"totp_enabled"` // TOTP 双因素认证
 
 	// 邮件服务设置
@@ -291,6 +293,7 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 		EmailVerifyEnabled:          req.EmailVerifyEnabled,
 		PromoCodeEnabled:            req.PromoCodeEnabled,
 		PasswordResetEnabled:        req.PasswordResetEnabled,
+		InvitationCodeEnabled:       req.InvitationCodeEnabled,
 		TotpEnabled:                 req.TotpEnabled,
 		SMTPHost:                    req.SMTPHost,
 		SMTPPort:                    req.SMTPPort,
@@ -370,6 +373,7 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 		EmailVerifyEnabled:                   updatedSettings.EmailVerifyEnabled,
 		PromoCodeEnabled:                     updatedSettings.PromoCodeEnabled,
 		PasswordResetEnabled:                 updatedSettings.PasswordResetEnabled,
+		InvitationCodeEnabled:                updatedSettings.InvitationCodeEnabled,
 		TotpEnabled:                          updatedSettings.TotpEnabled,
 		TotpEncryptionKeyConfigured:          h.settingService.IsTotpEncryptionKeyConfigured(),
 		SMTPHost:                             updatedSettings.SMTPHost,

backend/internal/handler/auth_handler.go

@@ -20,17 +20,19 @@ type AuthHandler struct {
 	userService   *service.UserService
 	settingSvc    *service.SettingService
 	promoService  *service.PromoService
+	redeemService *service.RedeemService
 	totpService   *service.TotpService
 }
 
 // NewAuthHandler creates a new AuthHandler
-func NewAuthHandler(cfg *config.Config, authService *service.AuthService, userService *service.UserService, settingService *service.SettingService, promoService *service.PromoService, totpService *service.TotpService) *AuthHandler {
+func NewAuthHandler(cfg *config.Config, authService *service.AuthService, userService *service.UserService, settingService *service.SettingService, promoService *service.PromoService, redeemService *service.RedeemService, totpService *service.TotpService) *AuthHandler {
 	return &AuthHandler{
 		cfg:           cfg,
 		authService:   authService,
 		userService:   userService,
 		settingSvc:    settingService,
 		promoService:  promoService,
+		redeemService: redeemService,
 		totpService:   totpService,
 	}
 }
@@ -42,6 +44,7 @@ type RegisterRequest struct {
 	VerifyCode     string `json:"verify_code"`
 	TurnstileToken string `json:"turnstile_token"`
 	PromoCode      string `json:"promo_code"`      // 注册优惠码
+	InvitationCode string `json:"invitation_code"` // 邀请码
 }
 
 // SendVerifyCodeRequest 发送验证码请求
@@ -87,7 +90,7 @@ func (h *AuthHandler) Register(c *gin.Context) {
 		}
 	}
 
-	token, user, err := h.authService.RegisterWithVerification(c.Request.Context(), req.Email, req.Password, req.VerifyCode, req.PromoCode)
+	token, user, err := h.authService.RegisterWithVerification(c.Request.Context(), req.Email, req.Password, req.VerifyCode, req.PromoCode, req.InvitationCode)
 	if err != nil {
 		response.ErrorFrom(c, err)
 		return
@@ -346,6 +349,67 @@ func (h *AuthHandler) ValidatePromoCode(c *gin.Context) {
 	})
 }
 
+// ValidateInvitationCodeRequest 验证邀请码请求
+type ValidateInvitationCodeRequest struct {
+	Code string `json:"code" binding:"required"`
+}
+
+// ValidateInvitationCodeResponse 验证邀请码响应
+type ValidateInvitationCodeResponse struct {
+	Valid     bool   `json:"valid"`
+	ErrorCode string `json:"error_code,omitempty"`
+}
+
+// ValidateInvitationCode 验证邀请码（公开接口，注册前调用）
+// POST /api/v1/auth/validate-invitation-code
+func (h *AuthHandler) ValidateInvitationCode(c *gin.Context) {
+	// 检查邀请码功能是否启用
+	if h.settingSvc == nil || !h.settingSvc.IsInvitationCodeEnabled(c.Request.Context()) {
+		response.Success(c, ValidateInvitationCodeResponse{
+			Valid:     false,
+			ErrorCode: "INVITATION_CODE_DISABLED",
+		})
+		return
+	}
+
+	var req ValidateInvitationCodeRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		response.BadRequest(c, "Invalid request: "+err.Error())
+		return
+	}
+
+	// 验证邀请码
+	redeemCode, err := h.redeemService.GetByCode(c.Request.Context(), req.Code)
+	if err != nil {
+		response.Success(c, ValidateInvitationCodeResponse{
+			Valid:     false,
+			ErrorCode: "INVITATION_CODE_NOT_FOUND",
+		})
+		return
+	}
+
+	// 检查类型和状态
+	if redeemCode.Type != service.RedeemTypeInvitation {
+		response.Success(c, ValidateInvitationCodeResponse{
+			Valid:     false,
+			ErrorCode: "INVITATION_CODE_INVALID",
+		})
+		return
+	}
+
+	if redeemCode.Status != service.StatusUnused {
+		response.Success(c, ValidateInvitationCodeResponse{
+			Valid:     false,
+			ErrorCode: "INVITATION_CODE_USED",
+		})
+		return
+	}
+
+	response.Success(c, ValidateInvitationCodeResponse{
+		Valid: true,
+	})
+}
+
 // ForgotPasswordRequest 忘记密码请求
 type ForgotPasswordRequest struct {
 	Email          string `json:"email" binding:"required,email"`

backend/internal/handler/dto/settings.go

@@ -6,6 +6,7 @@ type SystemSettings struct {
 	EmailVerifyEnabled          bool `json:"email_verify_enabled"`
 	PromoCodeEnabled            bool `json:"promo_code_enabled"`
 	PasswordResetEnabled        bool `json:"password_reset_enabled"`
+	InvitationCodeEnabled       bool `json:"invitation_code_enabled"`
 	TotpEnabled                 bool `json:"totp_enabled"`                   // TOTP 双因素认证
 	TotpEncryptionKeyConfigured bool `json:"totp_encryption_key_configured"` // TOTP 加密密钥是否已配置
 
@@ -63,6 +64,7 @@ type PublicSettings struct {
 	EmailVerifyEnabled          bool   `json:"email_verify_enabled"`
 	PromoCodeEnabled            bool   `json:"promo_code_enabled"`
 	PasswordResetEnabled        bool   `json:"password_reset_enabled"`
+	InvitationCodeEnabled       bool   `json:"invitation_code_enabled"`
 	TotpEnabled                 bool   `json:"totp_enabled"` // TOTP 双因素认证
 	TurnstileEnabled            bool   `json:"turnstile_enabled"`
 	TurnstileSiteKey            string `json:"turnstile_site_key"`

backend/internal/handler/setting_handler.go

@@ -36,6 +36,7 @@ func (h *SettingHandler) GetPublicSettings(c *gin.Context) {
 		EmailVerifyEnabled:          settings.EmailVerifyEnabled,
 		PromoCodeEnabled:            settings.PromoCodeEnabled,
 		PasswordResetEnabled:        settings.PasswordResetEnabled,
+		InvitationCodeEnabled:       settings.InvitationCodeEnabled,
 		TotpEnabled:                 settings.TotpEnabled,
 		TurnstileEnabled:            settings.TurnstileEnabled,
 		TurnstileSiteKey:            settings.TurnstileSiteKey,

backend/internal/server/api_contract_test.go

@@ -600,7 +600,7 @@ func newContractDeps(t *testing.T) *contractDeps {
 	settingService := service.NewSettingService(settingRepo, cfg)
 
 	adminService := service.NewAdminService(userRepo, groupRepo, &accountRepo, proxyRepo, apiKeyRepo, redeemRepo, nil, nil, nil, nil)
-	authHandler := handler.NewAuthHandler(cfg, nil, userService, settingService, nil, nil)
+	authHandler := handler.NewAuthHandler(cfg, nil, userService, settingService, nil, nil, nil)
 	apiKeyHandler := handler.NewAPIKeyHandler(apiKeyService)
 	usageHandler := handler.NewUsageHandler(usageService, apiKeyService)
 	adminSettingHandler := adminhandler.NewSettingHandler(settingService, nil, nil, nil)

backend/internal/server/routes/auth.go

@@ -32,6 +32,10 @@ func RegisterAuthRoutes(
 		auth.POST("/validate-promo-code", rateLimiter.LimitWithOptions("validate-promo", 10, time.Minute, middleware.RateLimitOptions{
 			FailureMode: middleware.RateLimitFailClose,
 		}), h.Auth.ValidatePromoCode)
+		// 邀请码验证接口添加速率限制：每分钟最多 10 次（Redis 故障时 fail-close）
+		auth.POST("/validate-invitation-code", rateLimiter.LimitWithOptions("validate-invitation", 10, time.Minute, middleware.RateLimitOptions{
+			FailureMode: middleware.RateLimitFailClose,
+		}), h.Auth.ValidateInvitationCode)
 		// 忘记密码接口添加速率限制：每分钟最多 5 次（Redis 故障时 fail-close）
 		auth.POST("/forgot-password", rateLimiter.LimitWithOptions("forgot-password", 5, time.Minute, middleware.RateLimitOptions{
 			FailureMode: middleware.RateLimitFailClose,

backend/internal/service/auth_service.go

@@ -30,6 +30,8 @@ var (
 	ErrEmailVerifyRequired    = infraerrors.BadRequest("EMAIL_VERIFY_REQUIRED", "email verification is required")
 	ErrRegDisabled            = infraerrors.Forbidden("REGISTRATION_DISABLED", "registration is currently disabled")
 	ErrServiceUnavailable     = infraerrors.ServiceUnavailable("SERVICE_UNAVAILABLE", "service temporarily unavailable")
+	ErrInvitationCodeRequired = infraerrors.BadRequest("INVITATION_CODE_REQUIRED", "invitation code is required")
+	ErrInvitationCodeInvalid  = infraerrors.BadRequest("INVITATION_CODE_INVALID", "invalid or used invitation code")
 )
 
 // maxTokenLength 限制 token 大小，避免超长 header 触发解析时的异常内存分配。
@@ -47,6 +49,7 @@ type JWTClaims struct {
 // AuthService 认证服务
 type AuthService struct {
 	userRepo          UserRepository
+	redeemRepo        RedeemCodeRepository
 	cfg               *config.Config
 	settingService    *SettingService
 	emailService      *EmailService
@@ -58,6 +61,7 @@ type AuthService struct {
 // NewAuthService 创建认证服务实例
 func NewAuthService(
 	userRepo UserRepository,
+	redeemRepo RedeemCodeRepository,
 	cfg *config.Config,
 	settingService *SettingService,
 	emailService *EmailService,
@@ -67,6 +71,7 @@ func NewAuthService(
 ) *AuthService {
 	return &AuthService{
 		userRepo:          userRepo,
+		redeemRepo:        redeemRepo,
 		cfg:               cfg,
 		settingService:    settingService,
 		emailService:      emailService,
@@ -78,11 +83,11 @@ func NewAuthService(
 
 // Register 用户注册，返回token和用户
 func (s *AuthService) Register(ctx context.Context, email, password string) (string, *User, error) {
-	return s.RegisterWithVerification(ctx, email, password, "", "")
+	return s.RegisterWithVerification(ctx, email, password, "", "", "")
 }
 
-// RegisterWithVerification 用户注册（支持邮件验证和优惠码），返回token和用户
-func (s *AuthService) RegisterWithVerification(ctx context.Context, email, password, verifyCode, promoCode string) (string, *User, error) {
+// RegisterWithVerification 用户注册（支持邮件验证、优惠码和邀请码），返回token和用户
+func (s *AuthService) RegisterWithVerification(ctx context.Context, email, password, verifyCode, promoCode, invitationCode string) (string, *User, error) {
 	// 检查是否开放注册（默认关闭：settingService 未配置时不允许注册）
 	if s.settingService == nil || !s.settingService.IsRegistrationEnabled(ctx) {
 		return "", nil, ErrRegDisabled
@@ -93,6 +98,26 @@ func (s *AuthService) RegisterWithVerification(ctx context.Context, email, passw
 		return "", nil, ErrEmailReserved
 	}
 
+	// 检查是否需要邀请码
+	var invitationRedeemCode *RedeemCode
+	if s.settingService != nil && s.settingService.IsInvitationCodeEnabled(ctx) {
+		if invitationCode == "" {
+			return "", nil, ErrInvitationCodeRequired
+		}
+		// 验证邀请码
+		redeemCode, err := s.redeemRepo.GetByCode(ctx, invitationCode)
+		if err != nil {
+			log.Printf("[Auth] Invalid invitation code: %s, error: %v", invitationCode, err)
+			return "", nil, ErrInvitationCodeInvalid
+		}
+		// 检查类型和状态
+		if redeemCode.Type != RedeemTypeInvitation || redeemCode.Status != StatusUnused {
+			log.Printf("[Auth] Invitation code invalid: type=%s, status=%s", redeemCode.Type, redeemCode.Status)
+			return "", nil, ErrInvitationCodeInvalid
+		}
+		invitationRedeemCode = redeemCode
+	}
+
 	// 检查是否需要邮件验证
 	if s.settingService != nil && s.settingService.IsEmailVerifyEnabled(ctx) {
 		// 如果邮件验证已开启但邮件服务未配置，拒绝注册
@@ -153,6 +178,14 @@ func (s *AuthService) RegisterWithVerification(ctx context.Context, email, passw
 		return "", nil, ErrServiceUnavailable
 	}
 
+	// 标记邀请码为已使用（如果使用了邀请码）
+	if invitationRedeemCode != nil {
+		if err := s.redeemRepo.Use(ctx, invitationRedeemCode.ID, user.ID); err != nil {
+			// 邀请码标记失败不影响注册，只记录日志
+			log.Printf("[Auth] Failed to mark invitation code as used for user %d: %v", user.ID, err)
+		}
+	}
+
 	// 应用优惠码（如果提供且功能已启用）
 	if promoCode != "" && s.promoService != nil && s.settingService != nil && s.settingService.IsPromoCodeEnabled(ctx) {
 		if err := s.promoService.ApplyPromoCode(ctx, user.ID, promoCode); err != nil {

backend/internal/service/auth_service_register_test.go

@@ -115,6 +115,7 @@ func newAuthService(repo *userRepoStub, settings map[string]string, emailCache E
 
 	return NewAuthService(
 		repo,
+		nil, // redeemRepo
 		cfg,
 		settingService,
 		emailService,
@@ -152,7 +153,7 @@ func TestAuthService_Register_EmailVerifyEnabledButServiceNotConfigured(t *testi
 	}, nil)
 
 	// 应返回服务不可用错误，而不是允许绕过验证
-	_, _, err := service.RegisterWithVerification(context.Background(), "user@test.com", "password", "any-code", "")
+	_, _, err := service.RegisterWithVerification(context.Background(), "user@test.com", "password", "any-code", "", "")
 	require.ErrorIs(t, err, ErrServiceUnavailable)
 }
 
@@ -164,7 +165,7 @@ func TestAuthService_Register_EmailVerifyRequired(t *testing.T) {
 		SettingKeyEmailVerifyEnabled:  "true",
 	}, cache)
 
-	_, _, err := service.RegisterWithVerification(context.Background(), "user@test.com", "password", "", "")
+	_, _, err := service.RegisterWithVerification(context.Background(), "user@test.com", "password", "", "", "")
 	require.ErrorIs(t, err, ErrEmailVerifyRequired)
 }
 
@@ -178,7 +179,7 @@ func TestAuthService_Register_EmailVerifyInvalid(t *testing.T) {
 		SettingKeyEmailVerifyEnabled:  "true",
 	}, cache)
 
-	_, _, err := service.RegisterWithVerification(context.Background(), "user@test.com", "password", "wrong", "")
+	_, _, err := service.RegisterWithVerification(context.Background(), "user@test.com", "password", "wrong", "", "")
 	require.ErrorIs(t, err, ErrInvalidVerifyCode)
 	require.ErrorContains(t, err, "verify code")
 }

backend/internal/service/domain_constants.go

@@ -38,6 +38,7 @@ const (
 	RedeemTypeBalance      = domain.RedeemTypeBalance
 	RedeemTypeConcurrency  = domain.RedeemTypeConcurrency
 	RedeemTypeSubscription = domain.RedeemTypeSubscription
+	RedeemTypeInvitation   = domain.RedeemTypeInvitation
 )
 
 // PromoCode status constants
@@ -75,6 +76,7 @@ const (
 	SettingKeyEmailVerifyEnabled    = "email_verify_enabled"    // 是否开启邮件验证
 	SettingKeyPromoCodeEnabled      = "promo_code_enabled"      // 是否启用优惠码功能
 	SettingKeyPasswordResetEnabled  = "password_reset_enabled"  // 是否启用忘记密码功能（需要先开启邮件验证）
+	SettingKeyInvitationCodeEnabled = "invitation_code_enabled" // 是否启用邀请码注册
 
 	// 邮件服务设置
 	SettingKeySMTPHost     = "smtp_host"      // SMTP服务器地址

backend/internal/service/redeem_service.go

@@ -126,7 +126,8 @@ func (s *RedeemService) GenerateCodes(ctx context.Context, req GenerateCodesRequ
 		return nil, errors.New("count must be greater than 0")
 	}
 
-	if req.Value <= 0 {
+	// 邀请码类型不需要数值，其他类型需要
+	if req.Type != RedeemTypeInvitation && req.Value <= 0 {
 		return nil, errors.New("value must be greater than 0")
 	}
 
@@ -139,6 +140,12 @@ func (s *RedeemService) GenerateCodes(ctx context.Context, req GenerateCodesRequ
 		codeType = RedeemTypeBalance
 	}
 
+	// 邀请码类型的 value 设为 0
+	value := req.Value
+	if codeType == RedeemTypeInvitation {
+		value = 0
+	}
+
 	codes := make([]RedeemCode, 0, req.Count)
 	for i := 0; i < req.Count; i++ {
 		code, err := s.GenerateRandomCode()
@@ -149,7 +156,7 @@ func (s *RedeemService) GenerateCodes(ctx context.Context, req GenerateCodesRequ
 		codes = append(codes, RedeemCode{
 			Code:   code,
 			Type:   codeType,
-			Value:  req.Value,
+			Value:  value,
 			Status: StatusUnused,
 		})
 	}

backend/internal/service/setting_service.go

@@ -62,6 +62,7 @@ func (s *SettingService) GetPublicSettings(ctx context.Context) (*PublicSettings
 		SettingKeyEmailVerifyEnabled,
 		SettingKeyPromoCodeEnabled,
 		SettingKeyPasswordResetEnabled,
+		SettingKeyInvitationCodeEnabled,
 		SettingKeyTotpEnabled,
 		SettingKeyTurnstileEnabled,
 		SettingKeyTurnstileSiteKey,
@@ -99,6 +100,7 @@ func (s *SettingService) GetPublicSettings(ctx context.Context) (*PublicSettings
 		EmailVerifyEnabled:          emailVerifyEnabled,
 		PromoCodeEnabled:            settings[SettingKeyPromoCodeEnabled] != "false", // 默认启用
 		PasswordResetEnabled:        passwordResetEnabled,
+		InvitationCodeEnabled:       settings[SettingKeyInvitationCodeEnabled] == "true",
 		TotpEnabled:                 settings[SettingKeyTotpEnabled] == "true",
 		TurnstileEnabled:            settings[SettingKeyTurnstileEnabled] == "true",
 		TurnstileSiteKey:            settings[SettingKeyTurnstileSiteKey],
@@ -141,6 +143,7 @@ func (s *SettingService) GetPublicSettingsForInjection(ctx context.Context) (any
 		EmailVerifyEnabled          bool   `json:"email_verify_enabled"`
 		PromoCodeEnabled            bool   `json:"promo_code_enabled"`
 		PasswordResetEnabled        bool   `json:"password_reset_enabled"`
+		InvitationCodeEnabled       bool   `json:"invitation_code_enabled"`
 		TotpEnabled                 bool   `json:"totp_enabled"`
 		TurnstileEnabled            bool   `json:"turnstile_enabled"`
 		TurnstileSiteKey            string `json:"turnstile_site_key,omitempty"`
@@ -161,6 +164,7 @@ func (s *SettingService) GetPublicSettingsForInjection(ctx context.Context) (any
 		EmailVerifyEnabled:          settings.EmailVerifyEnabled,
 		PromoCodeEnabled:            settings.PromoCodeEnabled,
 		PasswordResetEnabled:        settings.PasswordResetEnabled,
+		InvitationCodeEnabled:       settings.InvitationCodeEnabled,
 		TotpEnabled:                 settings.TotpEnabled,
 		TurnstileEnabled:            settings.TurnstileEnabled,
 		TurnstileSiteKey:            settings.TurnstileSiteKey,
@@ -188,6 +192,7 @@ func (s *SettingService) UpdateSettings(ctx context.Context, settings *SystemSet
 	updates[SettingKeyEmailVerifyEnabled] = strconv.FormatBool(settings.EmailVerifyEnabled)
 	updates[SettingKeyPromoCodeEnabled] = strconv.FormatBool(settings.PromoCodeEnabled)
 	updates[SettingKeyPasswordResetEnabled] = strconv.FormatBool(settings.PasswordResetEnabled)
+	updates[SettingKeyInvitationCodeEnabled] = strconv.FormatBool(settings.InvitationCodeEnabled)
 	updates[SettingKeyTotpEnabled] = strconv.FormatBool(settings.TotpEnabled)
 
 	// 邮件服务设置（只有非空才更新密码）
@@ -286,6 +291,15 @@ func (s *SettingService) IsPromoCodeEnabled(ctx context.Context) bool {
 	return value != "false"
 }
 
+// IsInvitationCodeEnabled 检查是否启用邀请码注册功能
+func (s *SettingService) IsInvitationCodeEnabled(ctx context.Context) bool {
+	value, err := s.settingRepo.GetValue(ctx, SettingKeyInvitationCodeEnabled)
+	if err != nil {
+		return false // 默认关闭
+	}
+	return value == "true"
+}
+
 // IsPasswordResetEnabled 检查是否启用密码重置功能
 // 要求：必须同时开启邮件验证
 func (s *SettingService) IsPasswordResetEnabled(ctx context.Context) bool {
@@ -401,6 +415,7 @@ func (s *SettingService) parseSettings(settings map[string]string) *SystemSettin
 		EmailVerifyEnabled:           emailVerifyEnabled,
 		PromoCodeEnabled:             settings[SettingKeyPromoCodeEnabled] != "false", // 默认启用
 		PasswordResetEnabled:         emailVerifyEnabled && settings[SettingKeyPasswordResetEnabled] == "true",
+		InvitationCodeEnabled:        settings[SettingKeyInvitationCodeEnabled] == "true",
 		TotpEnabled:                  settings[SettingKeyTotpEnabled] == "true",
 		SMTPHost:                     settings[SettingKeySMTPHost],
 		SMTPUsername:                 settings[SettingKeySMTPUsername],

backend/internal/service/settings_view.go

@@ -5,6 +5,7 @@ type SystemSettings struct {
 	EmailVerifyEnabled    bool
 	PromoCodeEnabled      bool
 	PasswordResetEnabled  bool
+	InvitationCodeEnabled bool
 	TotpEnabled           bool // TOTP 双因素认证
 
 	SMTPHost               string
@@ -65,6 +66,7 @@ type PublicSettings struct {
 	EmailVerifyEnabled    bool
 	PromoCodeEnabled      bool
 	PasswordResetEnabled  bool
+	InvitationCodeEnabled bool
 	TotpEnabled           bool // TOTP 双因素认证
 	TurnstileEnabled      bool
 	TurnstileSiteKey      string

frontend/src/api/admin/settings.ts

@@ -14,6 +14,7 @@ export interface SystemSettings {
   email_verify_enabled: boolean
   promo_code_enabled: boolean
   password_reset_enabled: boolean
+  invitation_code_enabled: boolean
   totp_enabled: boolean // TOTP 双因素认证
   totp_encryption_key_configured: boolean // TOTP 加密密钥是否已配置
   // Default settings
@@ -72,6 +73,7 @@ export interface UpdateSettingsRequest {
   email_verify_enabled?: boolean
   promo_code_enabled?: boolean
   password_reset_enabled?: boolean
+  invitation_code_enabled?: boolean
   totp_enabled?: boolean // TOTP 双因素认证
   default_balance?: number
   default_concurrency?: number

frontend/src/api/auth.ts

@@ -164,6 +164,24 @@ export async function validatePromoCode(code: string): Promise<ValidatePromoCode
   return data
 }
 
+/**
+ * Validate invitation code response
+ */
+export interface ValidateInvitationCodeResponse {
+  valid: boolean
+  error_code?: string
+}
+
+/**
+ * Validate invitation code (public endpoint, no auth required)
+ * @param code - Invitation code to validate
+ * @returns Validation result
+ */
+export async function validateInvitationCode(code: string): Promise<ValidateInvitationCodeResponse> {
+  const { data } = await apiClient.post<ValidateInvitationCodeResponse>('/auth/validate-invitation-code', { code })
+  return data
+}
+
 /**
  * Forgot password request
  */
@@ -229,6 +247,7 @@ export const authAPI = {
   getPublicSettings,
   sendVerifyCode,
   validatePromoCode,
+  validateInvitationCode,
   forgotPassword,
   resetPassword
 }

frontend/src/i18n/locales/en.ts

@@ -265,6 +265,13 @@ export default {
     promoCodeAlreadyUsed: 'You have already used this promo code',
     promoCodeValidating: 'Promo code is being validated, please wait',
     promoCodeInvalidCannotRegister: 'Invalid promo code. Please check and try again or clear the promo code field',
+    invitationCodeLabel: 'Invitation Code',
+    invitationCodePlaceholder: 'Enter invitation code',
+    invitationCodeRequired: 'Invitation code is required',
+    invitationCodeValid: 'Invitation code is valid',
+    invitationCodeInvalid: 'Invalid or used invitation code',
+    invitationCodeValidating: 'Validating invitation code...',
+    invitationCodeInvalidCannotRegister: 'Invalid invitation code. Please check and try again',
     linuxdo: {
       signIn: 'Continue with Linux.do',
       orContinue: 'or continue with email',
@@ -1899,6 +1906,8 @@ export default {
       balance: 'Balance',
       concurrency: 'Concurrency',
       subscription: 'Subscription',
+      invitation: 'Invitation',
+      invitationHint: 'Invitation codes are used to restrict user registration. They are automatically marked as used after use.',
       unused: 'Unused',
       used: 'Used',
       columns: {
@@ -1945,6 +1954,7 @@ export default {
         balance: 'Balance',
         concurrency: 'Concurrency',
         subscription: 'Subscription',
+        invitation: 'Invitation',
         // Admin adjustment types (created when admin modifies user balance/concurrency)
         admin_balance: 'Balance (Admin)',
         admin_concurrency: 'Concurrency (Admin)'
@@ -2896,6 +2906,8 @@ export default {
         emailVerificationHint: 'Require email verification for new registrations',
         promoCode: 'Promo Code',
         promoCodeHint: 'Allow users to use promo codes during registration',
+        invitationCode: 'Invitation Code Registration',
+        invitationCodeHint: 'When enabled, users must enter a valid invitation code to register',
         passwordReset: 'Password Reset',
         passwordResetHint: 'Allow users to reset their password via email',
         totp: 'Two-Factor Authentication (2FA)',

frontend/src/i18n/locales/zh.ts

@@ -262,6 +262,13 @@ export default {
     promoCodeAlreadyUsed: '您已使用过此优惠码',
     promoCodeValidating: '优惠码正在验证中，请稍候',
     promoCodeInvalidCannotRegister: '优惠码无效，请检查后重试或清空优惠码',
+    invitationCodeLabel: '邀请码',
+    invitationCodePlaceholder: '请输入邀请码',
+    invitationCodeRequired: '请输入邀请码',
+    invitationCodeValid: '邀请码有效',
+    invitationCodeInvalid: '邀请码无效或已被使用',
+    invitationCodeValidating: '正在验证邀请码...',
+    invitationCodeInvalidCannotRegister: '邀请码无效，请检查后重试',
     linuxdo: {
       signIn: '使用 Linux.do 登录',
       orContinue: '或使用邮箱密码继续',
@@ -2022,6 +2029,7 @@ export default {
         balance: '余额',
         concurrency: '并发数',
         subscription: '订阅',
+        invitation: '邀请码',
         // 管理员在用户管理页面调整余额/并发时产生的记录
         admin_balance: '余额（管理员）',
         admin_concurrency: '并发数（管理员）'
@@ -2030,6 +2038,8 @@ export default {
       balance: '余额',
       concurrency: '并发数',
       subscription: '订阅',
+      invitation: '邀请码',
+      invitationHint: '邀请码用于限制用户注册，使用后自动标记为已使用。',
       allTypes: '全部类型',
       allStatus: '全部状态',
       unused: '未使用',
@@ -3049,6 +3059,8 @@ export default {
         emailVerificationHint: '新用户注册时需要验证邮箱',
         promoCode: '优惠码',
         promoCodeHint: '允许用户在注册时使用优惠码',
+        invitationCode: '邀请码注册',
+        invitationCodeHint: '开启后，用户注册时需要填写有效的邀请码',
         passwordReset: '忘记密码',
         passwordResetHint: '允许用户通过邮箱重置密码',
         totp: '双因素认证 (2FA)',