merge upstream/main

backend/internal/handler/auth_handler.go

@@ -15,14 +15,16 @@ type AuthHandler struct {
 	cfg         *config.Config
 	authService *service.AuthService
 	userService *service.UserService
+	settingSvc  *service.SettingService
 }
 
 // NewAuthHandler creates a new AuthHandler
-func NewAuthHandler(cfg *config.Config, authService *service.AuthService, userService *service.UserService) *AuthHandler {
+func NewAuthHandler(cfg *config.Config, authService *service.AuthService, userService *service.UserService, settingService *service.SettingService) *AuthHandler {
 	return &AuthHandler{
 		cfg:         cfg,
 		authService: authService,
 		userService: userService,
+		settingSvc:  settingService,
 	}
 }
 

backend/internal/handler/auth_linuxdo_oauth.go

+package handler
+
+import (
+	"context"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"log"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	infraerrors "github.com/Wei-Shaw/sub2api/internal/pkg/errors"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/oauth"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/response"
+	"github.com/Wei-Shaw/sub2api/internal/service"
+
+	"github.com/gin-gonic/gin"
+	"github.com/imroc/req/v3"
+	"github.com/tidwall/gjson"
+)
+
+const (
+	linuxDoOAuthCookiePath        = "/api/v1/auth/oauth/linuxdo"
+	linuxDoOAuthStateCookieName   = "linuxdo_oauth_state"
+	linuxDoOAuthVerifierCookie    = "linuxdo_oauth_verifier"
+	linuxDoOAuthRedirectCookie    = "linuxdo_oauth_redirect"
+	linuxDoOAuthCookieMaxAgeSec   = 10 * 60 // 10 minutes
+	linuxDoOAuthDefaultRedirectTo = "/dashboard"
+	linuxDoOAuthDefaultFrontendCB = "/auth/linuxdo/callback"
+
+	linuxDoOAuthMaxRedirectLen      = 2048
+	linuxDoOAuthMaxFragmentValueLen = 512
+	linuxDoOAuthMaxSubjectLen       = 64 - len("linuxdo-")
+)
+
+type linuxDoTokenResponse struct {
+	AccessToken  string `json:"access_token"`
+	TokenType    string `json:"token_type"`
+	ExpiresIn    int64  `json:"expires_in"`
+	RefreshToken string `json:"refresh_token,omitempty"`
+	Scope        string `json:"scope,omitempty"`
+}
+
+type linuxDoTokenExchangeError struct {
+	StatusCode          int
+	ProviderError       string
+	ProviderDescription string
+	Body                string
+}
+
+func (e *linuxDoTokenExchangeError) Error() string {
+	if e == nil {
+		return ""
+	}
+	parts := []string{fmt.Sprintf("token exchange status=%d", e.StatusCode)}
+	if strings.TrimSpace(e.ProviderError) != "" {
+		parts = append(parts, "error="+strings.TrimSpace(e.ProviderError))
+	}
+	if strings.TrimSpace(e.ProviderDescription) != "" {
+		parts = append(parts, "error_description="+strings.TrimSpace(e.ProviderDescription))
+	}
+	return strings.Join(parts, " ")
+}
+
+// LinuxDoOAuthStart 启动 LinuxDo Connect OAuth 登录流程。
+// GET /api/v1/auth/oauth/linuxdo/start?redirect=/dashboard
+func (h *AuthHandler) LinuxDoOAuthStart(c *gin.Context) {
+	cfg, err := h.getLinuxDoOAuthConfig(c.Request.Context())
+	if err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	state, err := oauth.GenerateState()
+	if err != nil {
+		response.ErrorFrom(c, infraerrors.InternalServer("OAUTH_STATE_GEN_FAILED", "failed to generate oauth state").WithCause(err))
+		return
+	}
+
+	redirectTo := sanitizeFrontendRedirectPath(c.Query("redirect"))
+	if redirectTo == "" {
+		redirectTo = linuxDoOAuthDefaultRedirectTo
+	}
+
+	secureCookie := isRequestHTTPS(c)
+	setCookie(c, linuxDoOAuthStateCookieName, encodeCookieValue(state), linuxDoOAuthCookieMaxAgeSec, secureCookie)
+	setCookie(c, linuxDoOAuthRedirectCookie, encodeCookieValue(redirectTo), linuxDoOAuthCookieMaxAgeSec, secureCookie)
+
+	codeChallenge := ""
+	if cfg.UsePKCE {
+		verifier, err := oauth.GenerateCodeVerifier()
+		if err != nil {
+			response.ErrorFrom(c, infraerrors.InternalServer("OAUTH_PKCE_GEN_FAILED", "failed to generate pkce verifier").WithCause(err))
+			return
+		}
+		codeChallenge = oauth.GenerateCodeChallenge(verifier)
+		setCookie(c, linuxDoOAuthVerifierCookie, encodeCookieValue(verifier), linuxDoOAuthCookieMaxAgeSec, secureCookie)
+	}
+
+	redirectURI := strings.TrimSpace(cfg.RedirectURL)
+	if redirectURI == "" {
+		response.ErrorFrom(c, infraerrors.InternalServer("OAUTH_CONFIG_INVALID", "oauth redirect url not configured"))
+		return
+	}
+
+	authURL, err := buildLinuxDoAuthorizeURL(cfg, state, codeChallenge, redirectURI)
+	if err != nil {
+		response.ErrorFrom(c, infraerrors.InternalServer("OAUTH_BUILD_URL_FAILED", "failed to build oauth authorization url").WithCause(err))
+		return
+	}
+
+	c.Redirect(http.StatusFound, authURL)
+}
+
+// LinuxDoOAuthCallback 处理 OAuth 回调：创建/登录用户，然后重定向到前端。
+// GET /api/v1/auth/oauth/linuxdo/callback?code=...&state=...
+func (h *AuthHandler) LinuxDoOAuthCallback(c *gin.Context) {
+	cfg, cfgErr := h.getLinuxDoOAuthConfig(c.Request.Context())
+	if cfgErr != nil {
+		response.ErrorFrom(c, cfgErr)
+		return
+	}
+
+	frontendCallback := strings.TrimSpace(cfg.FrontendRedirectURL)
+	if frontendCallback == "" {
+		frontendCallback = linuxDoOAuthDefaultFrontendCB
+	}
+
+	if providerErr := strings.TrimSpace(c.Query("error")); providerErr != "" {
+		redirectOAuthError(c, frontendCallback, "provider_error", providerErr, c.Query("error_description"))
+		return
+	}
+
+	code := strings.TrimSpace(c.Query("code"))
+	state := strings.TrimSpace(c.Query("state"))
+	if code == "" || state == "" {
+		redirectOAuthError(c, frontendCallback, "missing_params", "missing code/state", "")
+		return
+	}
+
+	secureCookie := isRequestHTTPS(c)
+	defer func() {
+		clearCookie(c, linuxDoOAuthStateCookieName, secureCookie)
+		clearCookie(c, linuxDoOAuthVerifierCookie, secureCookie)
+		clearCookie(c, linuxDoOAuthRedirectCookie, secureCookie)
+	}()
+
+	expectedState, err := readCookieDecoded(c, linuxDoOAuthStateCookieName)
+	if err != nil || expectedState == "" || state != expectedState {
+		redirectOAuthError(c, frontendCallback, "invalid_state", "invalid oauth state", "")
+		return
+	}
+
+	redirectTo, _ := readCookieDecoded(c, linuxDoOAuthRedirectCookie)
+	redirectTo = sanitizeFrontendRedirectPath(redirectTo)
+	if redirectTo == "" {
+		redirectTo = linuxDoOAuthDefaultRedirectTo
+	}
+
+	codeVerifier := ""
+	if cfg.UsePKCE {
+		codeVerifier, _ = readCookieDecoded(c, linuxDoOAuthVerifierCookie)
+		if codeVerifier == "" {
+			redirectOAuthError(c, frontendCallback, "missing_verifier", "missing pkce verifier", "")
+			return
+		}
+	}
+
+	redirectURI := strings.TrimSpace(cfg.RedirectURL)
+	if redirectURI == "" {
+		redirectOAuthError(c, frontendCallback, "config_error", "oauth redirect url not configured", "")
+		return
+	}
+
+	tokenResp, err := linuxDoExchangeCode(c.Request.Context(), cfg, code, redirectURI, codeVerifier)
+	if err != nil {
+		description := ""
+		var exchangeErr *linuxDoTokenExchangeError
+		if errors.As(err, &exchangeErr) && exchangeErr != nil {
+			log.Printf(
+				"[LinuxDo OAuth] token exchange failed: status=%d provider_error=%q provider_description=%q body=%s",
+				exchangeErr.StatusCode,
+				exchangeErr.ProviderError,
+				exchangeErr.ProviderDescription,
+				truncateLogValue(exchangeErr.Body, 2048),
+			)
+			description = exchangeErr.Error()
+		} else {
+			log.Printf("[LinuxDo OAuth] token exchange failed: %v", err)
+			description = err.Error()
+		}
+		redirectOAuthError(c, frontendCallback, "token_exchange_failed", "failed to exchange oauth code", singleLine(description))
+		return
+	}
+
+	email, username, subject, err := linuxDoFetchUserInfo(c.Request.Context(), cfg, tokenResp)
+	if err != nil {
+		log.Printf("[LinuxDo OAuth] userinfo fetch failed: %v", err)
+		redirectOAuthError(c, frontendCallback, "userinfo_failed", "failed to fetch user info", "")
+		return
+	}
+
+	// 安全考虑：不要把第三方返回的 email 直接映射到本地账号（可能与本地邮箱用户冲突导致账号被接管）。
+	// 统一使用基于 subject 的稳定合成邮箱来做账号绑定。
+	if subject != "" {
+		email = linuxDoSyntheticEmail(subject)
+	}
+
+	jwtToken, _, err := h.authService.LoginOrRegisterOAuth(c.Request.Context(), email, username)
+	if err != nil {
+		// 避免把内部细节泄露给客户端；给前端保留结构化原因与提示信息即可。
+		redirectOAuthError(c, frontendCallback, "login_failed", infraerrors.Reason(err), infraerrors.Message(err))
+		return
+	}
+
+	fragment := url.Values{}
+	fragment.Set("access_token", jwtToken)
+	fragment.Set("token_type", "Bearer")
+	fragment.Set("redirect", redirectTo)
+	redirectWithFragment(c, frontendCallback, fragment)
+}
+
+func (h *AuthHandler) getLinuxDoOAuthConfig(ctx context.Context) (config.LinuxDoConnectConfig, error) {
+	if h != nil && h.settingSvc != nil {
+		return h.settingSvc.GetLinuxDoConnectOAuthConfig(ctx)
+	}
+	if h == nil || h.cfg == nil {
+		return config.LinuxDoConnectConfig{}, infraerrors.ServiceUnavailable("CONFIG_NOT_READY", "config not loaded")
+	}
+	if !h.cfg.LinuxDo.Enabled {
+		return config.LinuxDoConnectConfig{}, infraerrors.NotFound("OAUTH_DISABLED", "oauth login is disabled")
+	}
+	return h.cfg.LinuxDo, nil
+}
+
+func linuxDoExchangeCode(
+	ctx context.Context,
+	cfg config.LinuxDoConnectConfig,
+	code string,
+	redirectURI string,
+	codeVerifier string,
+) (*linuxDoTokenResponse, error) {
+	client := req.C().SetTimeout(30 * time.Second)
+
+	form := url.Values{}
+	form.Set("grant_type", "authorization_code")
+	form.Set("client_id", cfg.ClientID)
+	form.Set("code", code)
+	form.Set("redirect_uri", redirectURI)
+	if cfg.UsePKCE {
+		form.Set("code_verifier", codeVerifier)
+	}
+
+	r := client.R().
+		SetContext(ctx).
+		SetHeader("Accept", "application/json")
+
+	switch strings.ToLower(strings.TrimSpace(cfg.TokenAuthMethod)) {
+	case "", "client_secret_post":
+		form.Set("client_secret", cfg.ClientSecret)
+	case "client_secret_basic":
+		r.SetBasicAuth(cfg.ClientID, cfg.ClientSecret)
+	case "none":
+	default:
+		return nil, fmt.Errorf("unsupported token_auth_method: %s", cfg.TokenAuthMethod)
+	}
+
+	resp, err := r.SetFormDataFromValues(form).Post(cfg.TokenURL)
+	if err != nil {
+		return nil, fmt.Errorf("request token: %w", err)
+	}
+	body := strings.TrimSpace(resp.String())
+	if !resp.IsSuccessState() {
+		providerErr, providerDesc := parseOAuthProviderError(body)
+		return nil, &linuxDoTokenExchangeError{
+			StatusCode:          resp.StatusCode,
+			ProviderError:       providerErr,
+			ProviderDescription: providerDesc,
+			Body:                body,
+		}
+	}
+
+	tokenResp, ok := parseLinuxDoTokenResponse(body)
+	if !ok || strings.TrimSpace(tokenResp.AccessToken) == "" {
+		return nil, &linuxDoTokenExchangeError{
+			StatusCode: resp.StatusCode,
+			Body:       body,
+		}
+	}
+	if strings.TrimSpace(tokenResp.TokenType) == "" {
+		tokenResp.TokenType = "Bearer"
+	}
+	return tokenResp, nil
+}
+
+func linuxDoFetchUserInfo(
+	ctx context.Context,
+	cfg config.LinuxDoConnectConfig,
+	token *linuxDoTokenResponse,
+) (email string, username string, subject string, err error) {
+	client := req.C().SetTimeout(30 * time.Second)
+	authorization, err := buildBearerAuthorization(token.TokenType, token.AccessToken)
+	if err != nil {
+		return "", "", "", fmt.Errorf("invalid token for userinfo request: %w", err)
+	}
+
+	resp, err := client.R().
+		SetContext(ctx).
+		SetHeader("Accept", "application/json").
+		SetHeader("Authorization", authorization).
+		Get(cfg.UserInfoURL)
+	if err != nil {
+		return "", "", "", fmt.Errorf("request userinfo: %w", err)
+	}
+	if !resp.IsSuccessState() {
+		return "", "", "", fmt.Errorf("userinfo status=%d", resp.StatusCode)
+	}
+
+	return linuxDoParseUserInfo(resp.String(), cfg)
+}
+
+func linuxDoParseUserInfo(body string, cfg config.LinuxDoConnectConfig) (email string, username string, subject string, err error) {
+	email = firstNonEmpty(
+		getGJSON(body, cfg.UserInfoEmailPath),
+		getGJSON(body, "email"),
+		getGJSON(body, "user.email"),
+		getGJSON(body, "data.email"),
+		getGJSON(body, "attributes.email"),
+	)
+	username = firstNonEmpty(
+		getGJSON(body, cfg.UserInfoUsernamePath),
+		getGJSON(body, "username"),
+		getGJSON(body, "preferred_username"),
+		getGJSON(body, "name"),
+		getGJSON(body, "user.username"),
+		getGJSON(body, "user.name"),
+	)
+	subject = firstNonEmpty(
+		getGJSON(body, cfg.UserInfoIDPath),
+		getGJSON(body, "sub"),
+		getGJSON(body, "id"),
+		getGJSON(body, "user_id"),
+		getGJSON(body, "uid"),
+		getGJSON(body, "user.id"),
+	)
+
+	subject = strings.TrimSpace(subject)
+	if subject == "" {
+		return "", "", "", errors.New("userinfo missing id field")
+	}
+	if !isSafeLinuxDoSubject(subject) {
+		return "", "", "", errors.New("userinfo returned invalid id field")
+	}
+
+	email = strings.TrimSpace(email)
+	if email == "" {
+		// LinuxDo Connect 的 userinfo 可能不提供 email。为兼容现有用户模型（email 必填且唯一），使用稳定的合成邮箱。
+		email = linuxDoSyntheticEmail(subject)
+	}
+
+	username = strings.TrimSpace(username)
+	if username == "" {
+		username = "linuxdo_" + subject
+	}
+
+	return email, username, subject, nil
+}
+
+func buildLinuxDoAuthorizeURL(cfg config.LinuxDoConnectConfig, state string, codeChallenge string, redirectURI string) (string, error) {
+	u, err := url.Parse(cfg.AuthorizeURL)
+	if err != nil {
+		return "", fmt.Errorf("parse authorize_url: %w", err)
+	}
+
+	q := u.Query()
+	q.Set("response_type", "code")
+	q.Set("client_id", cfg.ClientID)
+	q.Set("redirect_uri", redirectURI)
+	if strings.TrimSpace(cfg.Scopes) != "" {
+		q.Set("scope", cfg.Scopes)
+	}
+	q.Set("state", state)
+	if cfg.UsePKCE {
+		q.Set("code_challenge", codeChallenge)
+		q.Set("code_challenge_method", "S256")
+	}
+
+	u.RawQuery = q.Encode()
+	return u.String(), nil
+}
+
+func redirectOAuthError(c *gin.Context, frontendCallback string, code string, message string, description string) {
+	fragment := url.Values{}
+	fragment.Set("error", truncateFragmentValue(code))
+	if strings.TrimSpace(message) != "" {
+		fragment.Set("error_message", truncateFragmentValue(message))
+	}
+	if strings.TrimSpace(description) != "" {
+		fragment.Set("error_description", truncateFragmentValue(description))
+	}
+	redirectWithFragment(c, frontendCallback, fragment)
+}
+
+func redirectWithFragment(c *gin.Context, frontendCallback string, fragment url.Values) {
+	u, err := url.Parse(frontendCallback)
+	if err != nil {
+		// 兜底：尽力跳转到默认页面，避免卡死在回调页。
+		c.Redirect(http.StatusFound, linuxDoOAuthDefaultRedirectTo)
+		return
+	}
+	if u.Scheme != "" && !strings.EqualFold(u.Scheme, "http") && !strings.EqualFold(u.Scheme, "https") {
+		c.Redirect(http.StatusFound, linuxDoOAuthDefaultRedirectTo)
+		return
+	}
+	u.Fragment = fragment.Encode()
+	c.Header("Cache-Control", "no-store")
+	c.Header("Pragma", "no-cache")
+	c.Redirect(http.StatusFound, u.String())
+}
+
+func firstNonEmpty(values ...string) string {
+	for _, v := range values {
+		v = strings.TrimSpace(v)
+		if v != "" {
+			return v
+		}
+	}
+	return ""
+}
+
+func parseOAuthProviderError(body string) (providerErr string, providerDesc string) {
+	body = strings.TrimSpace(body)
+	if body == "" {
+		return "", ""
+	}
+
+	providerErr = firstNonEmpty(
+		getGJSON(body, "error"),
+		getGJSON(body, "code"),
+		getGJSON(body, "error.code"),
+	)
+	providerDesc = firstNonEmpty(
+		getGJSON(body, "error_description"),
+		getGJSON(body, "error.message"),
+		getGJSON(body, "message"),
+		getGJSON(body, "detail"),
+	)
+
+	if providerErr != "" || providerDesc != "" {
+		return providerErr, providerDesc
+	}
+
+	values, err := url.ParseQuery(body)
+	if err != nil {
+		return "", ""
+	}
+	providerErr = firstNonEmpty(values.Get("error"), values.Get("code"))
+	providerDesc = firstNonEmpty(values.Get("error_description"), values.Get("error_message"), values.Get("message"))
+	return providerErr, providerDesc
+}
+
+func parseLinuxDoTokenResponse(body string) (*linuxDoTokenResponse, bool) {
+	body = strings.TrimSpace(body)
+	if body == "" {
+		return nil, false
+	}
+
+	accessToken := strings.TrimSpace(getGJSON(body, "access_token"))
+	if accessToken != "" {
+		tokenType := strings.TrimSpace(getGJSON(body, "token_type"))
+		refreshToken := strings.TrimSpace(getGJSON(body, "refresh_token"))
+		scope := strings.TrimSpace(getGJSON(body, "scope"))
+		expiresIn := gjson.Get(body, "expires_in").Int()
+		return &linuxDoTokenResponse{
+			AccessToken:  accessToken,
+			TokenType:    tokenType,
+			ExpiresIn:    expiresIn,
+			RefreshToken: refreshToken,
+			Scope:        scope,
+		}, true
+	}
+
+	values, err := url.ParseQuery(body)
+	if err != nil {
+		return nil, false
+	}
+	accessToken = strings.TrimSpace(values.Get("access_token"))
+	if accessToken == "" {
+		return nil, false
+	}
+	expiresIn := int64(0)
+	if raw := strings.TrimSpace(values.Get("expires_in")); raw != "" {
+		if v, err := strconv.ParseInt(raw, 10, 64); err == nil {
+			expiresIn = v
+		}
+	}
+	return &linuxDoTokenResponse{
+		AccessToken:  accessToken,
+		TokenType:    strings.TrimSpace(values.Get("token_type")),
+		ExpiresIn:    expiresIn,
+		RefreshToken: strings.TrimSpace(values.Get("refresh_token")),
+		Scope:        strings.TrimSpace(values.Get("scope")),
+	}, true
+}
+
+func getGJSON(body string, path string) string {
+	path = strings.TrimSpace(path)
+	if path == "" {
+		return ""
+	}
+	res := gjson.Get(body, path)
+	if !res.Exists() {
+		return ""
+	}
+	return res.String()
+}
+
+func truncateLogValue(value string, maxLen int) string {
+	value = strings.TrimSpace(value)
+	if value == "" || maxLen <= 0 {
+		return ""
+	}
+	if len(value) <= maxLen {
+		return value
+	}
+	value = value[:maxLen]
+	for !utf8.ValidString(value) {
+		value = value[:len(value)-1]
+	}
+	return value
+}
+
+func singleLine(value string) string {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return ""
+	}
+	return strings.Join(strings.Fields(value), " ")
+}
+
+func sanitizeFrontendRedirectPath(path string) string {
+	path = strings.TrimSpace(path)
+	if path == "" {
+		return ""
+	}
+	if len(path) > linuxDoOAuthMaxRedirectLen {
+		return ""
+	}
+	// 只允许同源相对路径（避免开放重定向）。
+	if !strings.HasPrefix(path, "/") {
+		return ""
+	}
+	if strings.HasPrefix(path, "//") {
+		return ""
+	}
+	if strings.Contains(path, "://") {
+		return ""
+	}
+	if strings.ContainsAny(path, "\r\n") {
+		return ""
+	}
+	return path
+}
+
+func isRequestHTTPS(c *gin.Context) bool {
+	if c.Request.TLS != nil {
+		return true
+	}
+	proto := strings.ToLower(strings.TrimSpace(c.GetHeader("X-Forwarded-Proto")))
+	return proto == "https"
+}
+
+func encodeCookieValue(value string) string {
+	return base64.RawURLEncoding.EncodeToString([]byte(value))
+}
+
+func decodeCookieValue(value string) (string, error) {
+	raw, err := base64.RawURLEncoding.DecodeString(value)
+	if err != nil {
+		return "", err
+	}
+	return string(raw), nil
+}
+
+func readCookieDecoded(c *gin.Context, name string) (string, error) {
+	ck, err := c.Request.Cookie(name)
+	if err != nil {
+		return "", err
+	}
+	return decodeCookieValue(ck.Value)
+}
+
+func setCookie(c *gin.Context, name string, value string, maxAgeSec int, secure bool) {
+	http.SetCookie(c.Writer, &http.Cookie{
+		Name:     name,
+		Value:    value,
+		Path:     linuxDoOAuthCookiePath,
+		MaxAge:   maxAgeSec,
+		HttpOnly: true,
+		Secure:   secure,
+		SameSite: http.SameSiteLaxMode,
+	})
+}
+
+func clearCookie(c *gin.Context, name string, secure bool) {
+	http.SetCookie(c.Writer, &http.Cookie{
+		Name:     name,
+		Value:    "",
+		Path:     linuxDoOAuthCookiePath,
+		MaxAge:   -1,
+		HttpOnly: true,
+		Secure:   secure,
+		SameSite: http.SameSiteLaxMode,
+	})
+}
+
+func truncateFragmentValue(value string) string {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return ""
+	}
+	if len(value) > linuxDoOAuthMaxFragmentValueLen {
+		value = value[:linuxDoOAuthMaxFragmentValueLen]
+		for !utf8.ValidString(value) {
+			value = value[:len(value)-1]
+		}
+	}
+	return value
+}
+
+func buildBearerAuthorization(tokenType, accessToken string) (string, error) {
+	tokenType = strings.TrimSpace(tokenType)
+	if tokenType == "" {
+		tokenType = "Bearer"
+	}
+	if !strings.EqualFold(tokenType, "Bearer") {
+		return "", fmt.Errorf("unsupported token_type: %s", tokenType)
+	}
+
+	accessToken = strings.TrimSpace(accessToken)
+	if accessToken == "" {
+		return "", errors.New("missing access_token")
+	}
+	if strings.ContainsAny(accessToken, " \t\r\n") {
+		return "", errors.New("access_token contains whitespace")
+	}
+	return "Bearer " + accessToken, nil
+}
+
+func isSafeLinuxDoSubject(subject string) bool {
+	subject = strings.TrimSpace(subject)
+	if subject == "" || len(subject) > linuxDoOAuthMaxSubjectLen {
+		return false
+	}
+	for _, r := range subject {
+		switch {
+		case r >= '0' && r <= '9':
+		case r >= 'a' && r <= 'z':
+		case r >= 'A' && r <= 'Z':
+		case r == '_' || r == '-':
+		default:
+			return false
+		}
+	}
+	return true
+}
+
+func linuxDoSyntheticEmail(subject string) string {
+	subject = strings.TrimSpace(subject)
+	if subject == "" {
+		return ""
+	}
+	return "linuxdo-" + subject + service.LinuxDoConnectSyntheticEmailDomain
+}

backend/internal/handler/auth_linuxdo_oauth_test.go

+package handler
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSanitizeFrontendRedirectPath(t *testing.T) {
+	require.Equal(t, "/dashboard", sanitizeFrontendRedirectPath("/dashboard"))
+	require.Equal(t, "/dashboard", sanitizeFrontendRedirectPath(" /dashboard "))
+	require.Equal(t, "", sanitizeFrontendRedirectPath("dashboard"))
+	require.Equal(t, "", sanitizeFrontendRedirectPath("//evil.com"))
+	require.Equal(t, "", sanitizeFrontendRedirectPath("https://evil.com"))
+	require.Equal(t, "", sanitizeFrontendRedirectPath("/\nfoo"))
+
+	long := "/" + strings.Repeat("a", linuxDoOAuthMaxRedirectLen)
+	require.Equal(t, "", sanitizeFrontendRedirectPath(long))
+}
+
+func TestBuildBearerAuthorization(t *testing.T) {
+	auth, err := buildBearerAuthorization("", "token123")
+	require.NoError(t, err)
+	require.Equal(t, "Bearer token123", auth)
+
+	auth, err = buildBearerAuthorization("bearer", "token123")
+	require.NoError(t, err)
+	require.Equal(t, "Bearer token123", auth)
+
+	_, err = buildBearerAuthorization("MAC", "token123")
+	require.Error(t, err)
+
+	_, err = buildBearerAuthorization("Bearer", "token 123")
+	require.Error(t, err)
+}
+
+func TestLinuxDoParseUserInfoParsesIDAndUsername(t *testing.T) {
+	cfg := config.LinuxDoConnectConfig{
+		UserInfoURL: "https://connect.linux.do/api/user",
+	}
+
+	email, username, subject, err := linuxDoParseUserInfo(`{"id":123,"username":"alice"}`, cfg)
+	require.NoError(t, err)
+	require.Equal(t, "123", subject)
+	require.Equal(t, "alice", username)
+	require.Equal(t, "linuxdo-123@linuxdo-connect.invalid", email)
+}
+
+func TestLinuxDoParseUserInfoDefaultsUsername(t *testing.T) {
+	cfg := config.LinuxDoConnectConfig{
+		UserInfoURL: "https://connect.linux.do/api/user",
+	}
+
+	email, username, subject, err := linuxDoParseUserInfo(`{"id":"123"}`, cfg)
+	require.NoError(t, err)
+	require.Equal(t, "123", subject)
+	require.Equal(t, "linuxdo_123", username)
+	require.Equal(t, "linuxdo-123@linuxdo-connect.invalid", email)
+}
+
+func TestLinuxDoParseUserInfoRejectsUnsafeSubject(t *testing.T) {
+	cfg := config.LinuxDoConnectConfig{
+		UserInfoURL: "https://connect.linux.do/api/user",
+	}
+
+	_, _, _, err := linuxDoParseUserInfo(`{"id":"123@456"}`, cfg)
+	require.Error(t, err)
+
+	tooLong := strings.Repeat("a", linuxDoOAuthMaxSubjectLen+1)
+	_, _, _, err = linuxDoParseUserInfo(`{"id":"`+tooLong+`"}`, cfg)
+	require.Error(t, err)
+}
+
+func TestParseOAuthProviderErrorJSON(t *testing.T) {
+	code, desc := parseOAuthProviderError(`{"error":"invalid_client","error_description":"bad secret"}`)
+	require.Equal(t, "invalid_client", code)
+	require.Equal(t, "bad secret", desc)
+}
+
+func TestParseOAuthProviderErrorForm(t *testing.T) {
+	code, desc := parseOAuthProviderError("error=invalid_request&error_description=Missing+code_verifier")
+	require.Equal(t, "invalid_request", code)
+	require.Equal(t, "Missing code_verifier", desc)
+}
+
+func TestParseLinuxDoTokenResponseJSON(t *testing.T) {
+	token, ok := parseLinuxDoTokenResponse(`{"access_token":"t1","token_type":"Bearer","expires_in":3600,"scope":"user"}`)
+	require.True(t, ok)
+	require.Equal(t, "t1", token.AccessToken)
+	require.Equal(t, "Bearer", token.TokenType)
+	require.Equal(t, int64(3600), token.ExpiresIn)
+	require.Equal(t, "user", token.Scope)
+}
+
+func TestParseLinuxDoTokenResponseForm(t *testing.T) {
+	token, ok := parseLinuxDoTokenResponse("access_token=t2&token_type=bearer&expires_in=60")
+	require.True(t, ok)
+	require.Equal(t, "t2", token.AccessToken)
+	require.Equal(t, "bearer", token.TokenType)
+	require.Equal(t, int64(60), token.ExpiresIn)
+}
+
+func TestSingleLineStripsWhitespace(t *testing.T) {
+	require.Equal(t, "hello world", singleLine("hello\r\nworld"))
+	require.Equal(t, "", singleLine("\n\t\r"))
+}

backend/internal/handler/dto/mappers.go

@@ -85,6 +85,8 @@ func GroupFromServiceShallow(g *service.Group) *Group {
 		ImagePrice1K:     g.ImagePrice1K,
 		ImagePrice2K:     g.ImagePrice2K,
 		ImagePrice4K:     g.ImagePrice4K,
+		ClaudeCodeOnly:   g.ClaudeCodeOnly,
+		FallbackGroupID:  g.FallbackGroupID,
 		CreatedAt:        g.CreatedAt,
 		UpdatedAt:        g.UpdatedAt,
 		AccountCount:     g.AccountCount,
@@ -280,6 +282,7 @@ func usageLogFromServiceBase(l *service.UsageLog, account *AccountSummary) *Usag
 		FirstTokenMs:          l.FirstTokenMs,
 		ImageCount:            l.ImageCount,
 		ImageSize:             l.ImageSize,
+		UserAgent:             l.UserAgent,
 		CreatedAt:             l.CreatedAt,
 		User:                  UserFromServiceShallow(l.User),
 		APIKey:                APIKeyFromService(l.APIKey),

backend/internal/handler/dto/settings.go

@@ -17,6 +17,11 @@ type SystemSettings struct {
 	TurnstileSiteKey             string `json:"turnstile_site_key"`
 	TurnstileSecretKeyConfigured bool   `json:"turnstile_secret_key_configured"`
 
+	LinuxDoConnectEnabled                bool   `json:"linuxdo_connect_enabled"`
+	LinuxDoConnectClientID               string `json:"linuxdo_connect_client_id"`
+	LinuxDoConnectClientSecretConfigured bool   `json:"linuxdo_connect_client_secret_configured"`
+	LinuxDoConnectRedirectURL            string `json:"linuxdo_connect_redirect_url"`
+
 	SiteName     string `json:"site_name"`
 	SiteLogo     string `json:"site_logo"`
 	SiteSubtitle string `json:"site_subtitle"`
@@ -50,5 +55,6 @@ type PublicSettings struct {
 	APIBaseURL          string `json:"api_base_url"`
 	ContactInfo         string `json:"contact_info"`
 	DocURL              string `json:"doc_url"`
+	LinuxDoOAuthEnabled bool   `json:"linuxdo_oauth_enabled"`
 	Version             string `json:"version"`
 }

backend/internal/handler/dto/types.go

@@ -52,6 +52,10 @@ type Group struct {
 	ImagePrice2K *float64 `json:"image_price_2k"`
 	ImagePrice4K *float64 `json:"image_price_4k"`
 
+	// Claude Code 客户端限制
+	ClaudeCodeOnly  bool   `json:"claude_code_only"`
+	FallbackGroupID *int64 `json:"fallback_group_id"`
+
 	CreatedAt time.Time `json:"created_at"`
 	UpdatedAt time.Time `json:"updated_at"`
 
@@ -180,6 +184,9 @@ type UsageLog struct {
 	ImageCount int     `json:"image_count"`
 	ImageSize  *string `json:"image_size"`
 
+	// User-Agent
+	UserAgent *string `json:"user_agent"`
+
 	CreatedAt time.Time `json:"created_at"`
 
 	User         *User             `json:"user,omitempty"`

backend/internal/handler/gateway_handler.go

@@ -96,6 +96,9 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 	reqModel := parsedReq.Model
 	reqStream := parsedReq.Stream
 
+	// 设置 Claude Code 客户端标识到 context（用于分组限制检查）
+	SetClaudeCodeClientContext(c, body)
+
 	// 验证 model 必填
 	if reqModel == "" {
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "model is required")
@@ -229,7 +232,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 					h.handleConcurrencyError(c, err, "account", streamStarted)
 					return
 				}
-				if err := h.gatewayService.BindStickySession(c.Request.Context(), sessionKey, account.ID); err != nil {
+				if err := h.gatewayService.BindStickySession(c.Request.Context(), apiKey.GroupID, sessionKey, account.ID); err != nil {
 					log.Printf("Bind sticky session failed: %v", err)
 				}
 			}
@@ -357,7 +360,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 				h.handleConcurrencyError(c, err, "account", streamStarted)
 				return
 			}
-			if err := h.gatewayService.BindStickySession(c.Request.Context(), sessionKey, account.ID); err != nil {
+			if err := h.gatewayService.BindStickySession(c.Request.Context(), apiKey.GroupID, sessionKey, account.ID); err != nil {
 				log.Printf("Bind sticky session failed: %v", err)
 			}
 		}
@@ -683,6 +686,9 @@ func (h *GatewayHandler) CountTokens(c *gin.Context) {
 		return
 	}
 
+	// 设置 Claude Code 客户端标识到 context（用于分组限制检查）
+	SetClaudeCodeClientContext(c, body)
+
 	// 验证 model 必填
 	if parsedReq.Model == "" {
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "model is required")

backend/internal/handler/gateway_helper.go

@@ -2,6 +2,7 @@ package handler
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"math/rand"
 	"net/http"
@@ -13,6 +14,26 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
+// claudeCodeValidator is a singleton validator for Claude Code client detection
+var claudeCodeValidator = service.NewClaudeCodeValidator()
+
+// SetClaudeCodeClientContext 检查请求是否来自 Claude Code 客户端，并设置到 context 中
+// 返回更新后的 context
+func SetClaudeCodeClientContext(c *gin.Context, body []byte) {
+	// 解析请求体为 map
+	var bodyMap map[string]any
+	if len(body) > 0 {
+		_ = json.Unmarshal(body, &bodyMap)
+	}
+
+	// 验证是否为 Claude Code 客户端
+	isClaudeCode := claudeCodeValidator.Validate(c.Request, bodyMap)
+
+	// 更新 request context
+	ctx := service.SetClaudeCodeClient(c.Request.Context(), isClaudeCode)
+	c.Request = c.Request.WithContext(ctx)
+}
+
 // 并发槽位等待相关常量
 //
 // 性能优化说明：

backend/internal/handler/gemini_v1beta_handler.go

@@ -203,6 +203,10 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
 
 	// 3) select account (sticky session based on request body)
 	parsedReq, _ := service.ParseGatewayRequest(body)
+
+	// 设置 Claude Code 客户端标识到 context（用于分组限制检查）
+	SetClaudeCodeClientContext(c, body)
+
 	sessionHash := h.gatewayService.GenerateSessionHash(parsedReq)
 	sessionKey := sessionHash
 	if sessionHash != "" {
@@ -262,7 +266,7 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
 				googleError(c, http.StatusTooManyRequests, err.Error())
 				return
 			}
-			if err := h.gatewayService.BindStickySession(c.Request.Context(), sessionKey, account.ID); err != nil {
+			if err := h.gatewayService.BindStickySession(c.Request.Context(), apiKey.GroupID, sessionKey, account.ID); err != nil {
 				log.Printf("Bind sticky session failed: %v", err)
 			}
 		}

backend/internal/handler/openai_gateway_handler.go

@@ -206,7 +206,7 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 				h.handleConcurrencyError(c, err, "account", streamStarted)
 				return
 			}
-			if err := h.gatewayService.BindStickySession(c.Request.Context(), sessionHash, account.ID); err != nil {
+			if err := h.gatewayService.BindStickySession(c.Request.Context(), apiKey.GroupID, sessionHash, account.ID); err != nil {
 				log.Printf("Bind sticky session failed: %v", err)
 			}
 		}

backend/internal/handler/setting_handler.go

@@ -42,6 +42,7 @@ func (h *SettingHandler) GetPublicSettings(c *gin.Context) {
 		APIBaseURL:          settings.APIBaseURL,
 		ContactInfo:         settings.ContactInfo,
 		DocURL:              settings.DocURL,
+		LinuxDoOAuthEnabled: settings.LinuxDoOAuthEnabled,
 		Version:             h.version,
 	})
 }

backend/internal/pkg/antigravity/client.go

@@ -5,8 +5,11 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
+	"log"
+	"net"
 	"net/http"
 	"net/url"
 	"strings"
@@ -22,10 +25,10 @@ func resolveHost(urlStr string) string {
 	return parsed.Host
 }
 
-// NewAPIRequest 创建 Antigravity API 请求（v1internal 端点）
-func NewAPIRequest(ctx context.Context, action, accessToken string, body []byte) (*http.Request, error) {
+// NewAPIRequestWithURL 使用指定的 base URL 创建 Antigravity API 请求（v1internal 端点）
+func NewAPIRequestWithURL(ctx context.Context, baseURL, action, accessToken string, body []byte) (*http.Request, error) {
 	// 构建 URL，流式请求添加 ?alt=sse 参数
-	apiURL := fmt.Sprintf("%s/v1internal:%s", BaseURL, action)
+	apiURL := fmt.Sprintf("%s/v1internal:%s", baseURL, action)
 	isStream := action == "streamGenerateContent"
 	if isStream {
 		apiURL += "?alt=sse"
@@ -53,11 +56,15 @@ func NewAPIRequest(ctx context.Context, action, accessToken string, body []byte)
 		req.Host = host
 	}
 
-	// 注意：requestType 已在 JSON body 的 V1InternalRequest 中设置，不需要 HTTP Header
-
 	return req, nil
 }
 
+// NewAPIRequest 使用默认 URL 创建 Antigravity API 请求（v1internal 端点）
+// 向后兼容：仅使用默认 BaseURL
+func NewAPIRequest(ctx context.Context, action, accessToken string, body []byte) (*http.Request, error) {
+	return NewAPIRequestWithURL(ctx, BaseURL, action, accessToken, body)
+}
+
 // TokenResponse Google OAuth token 响应
 type TokenResponse struct {
 	AccessToken  string `json:"access_token"`
@@ -164,6 +171,38 @@ func NewClient(proxyURL string) *Client {
 	}
 }
 
+// isConnectionError 判断是否为连接错误（网络超时、DNS 失败、连接拒绝）
+func isConnectionError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	// 检查超时错误
+	var netErr net.Error
+	if errors.As(err, &netErr) && netErr.Timeout() {
+		return true
+	}
+
+	// 检查连接错误（DNS 失败、连接拒绝）
+	var opErr *net.OpError
+	if errors.As(err, &opErr) {
+		return true
+	}
+
+	// 检查 URL 错误
+	var urlErr *url.Error
+	return errors.As(err, &urlErr)
+}
+
+// shouldFallbackToNextURL 判断是否应切换到下一个 URL
+// 仅连接错误和 HTTP 429 触发 URL 降级
+func shouldFallbackToNextURL(err error, statusCode int) bool {
+	if isConnectionError(err) {
+		return true
+	}
+	return statusCode == http.StatusTooManyRequests
+}
+
 // ExchangeCode 用 authorization code 交换 token
 func (c *Client) ExchangeCode(ctx context.Context, code, codeVerifier string) (*TokenResponse, error) {
 	params := url.Values{}
@@ -272,6 +311,7 @@ func (c *Client) GetUserInfo(ctx context.Context, accessToken string) (*UserInfo
 }
 
 // LoadCodeAssist 获取账户信息，返回解析后的结构体和原始 JSON
+// 支持 URL fallback：sandbox → daily → prod
 func (c *Client) LoadCodeAssist(ctx context.Context, accessToken string) (*LoadCodeAssistResponse, map[string]any, error) {
 	reqBody := LoadCodeAssistRequest{}
 	reqBody.Metadata.IDEType = "ANTIGRAVITY"
@@ -281,40 +321,65 @@ func (c *Client) LoadCodeAssist(ctx context.Context, accessToken string) (*LoadC
 		return nil, nil, fmt.Errorf("序列化请求失败: %w", err)
 	}
 
-	url := BaseURL + "/v1internal:loadCodeAssist"
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, strings.NewReader(string(bodyBytes)))
-	if err != nil {
-		return nil, nil, fmt.Errorf("创建请求失败: %w", err)
+	// 获取可用的 URL 列表
+	availableURLs := DefaultURLAvailability.GetAvailableURLs()
+	if len(availableURLs) == 0 {
+		availableURLs = BaseURLs // 所有 URL 都不可用时，重试所有
 	}
-	req.Header.Set("Authorization", "Bearer "+accessToken)
-	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("User-Agent", UserAgent)
 
-	resp, err := c.httpClient.Do(req)
-	if err != nil {
-		return nil, nil, fmt.Errorf("loadCodeAssist 请求失败: %w", err)
-	}
-	defer func() { _ = resp.Body.Close() }()
+	var lastErr error
+	for urlIdx, baseURL := range availableURLs {
+		apiURL := baseURL + "/v1internal:loadCodeAssist"
+		req, err := http.NewRequestWithContext(ctx, http.MethodPost, apiURL, strings.NewReader(string(bodyBytes)))
+		if err != nil {
+			lastErr = fmt.Errorf("创建请求失败: %w", err)
+			continue
+		}
+		req.Header.Set("Authorization", "Bearer "+accessToken)
+		req.Header.Set("Content-Type", "application/json")
+		req.Header.Set("User-Agent", UserAgent)
+
+		resp, err := c.httpClient.Do(req)
+		if err != nil {
+			lastErr = fmt.Errorf("loadCodeAssist 请求失败: %w", err)
+			if shouldFallbackToNextURL(err, 0) && urlIdx < len(availableURLs)-1 {
+				DefaultURLAvailability.MarkUnavailable(baseURL)
+				log.Printf("[antigravity] loadCodeAssist URL fallback: %s -> %s", baseURL, availableURLs[urlIdx+1])
+				continue
+			}
+			return nil, nil, lastErr
+		}
 
-	respBodyBytes, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, nil, fmt.Errorf("读取响应失败: %w", err)
-	}
+		respBodyBytes, err := io.ReadAll(resp.Body)
+		_ = resp.Body.Close() // 立即关闭，避免循环内 defer 导致的资源泄漏
+		if err != nil {
+			return nil, nil, fmt.Errorf("读取响应失败: %w", err)
+		}
 
-	if resp.StatusCode != http.StatusOK {
-		return nil, nil, fmt.Errorf("loadCodeAssist 失败 (HTTP %d): %s", resp.StatusCode, string(respBodyBytes))
-	}
+		// 检查是否需要 URL 降级
+		if shouldFallbackToNextURL(nil, resp.StatusCode) && urlIdx < len(availableURLs)-1 {
+			DefaultURLAvailability.MarkUnavailable(baseURL)
+			log.Printf("[antigravity] loadCodeAssist URL fallback (HTTP %d): %s -> %s", resp.StatusCode, baseURL, availableURLs[urlIdx+1])
+			continue
+		}
 
-	var loadResp LoadCodeAssistResponse
-	if err := json.Unmarshal(respBodyBytes, &loadResp); err != nil {
-		return nil, nil, fmt.Errorf("响应解析失败: %w", err)
-	}
+		if resp.StatusCode != http.StatusOK {
+			return nil, nil, fmt.Errorf("loadCodeAssist 失败 (HTTP %d): %s", resp.StatusCode, string(respBodyBytes))
+		}
 
-	// 解析原始 JSON 为 map
-	var rawResp map[string]any
-	_ = json.Unmarshal(respBodyBytes, &rawResp)
+		var loadResp LoadCodeAssistResponse
+		if err := json.Unmarshal(respBodyBytes, &loadResp); err != nil {
+			return nil, nil, fmt.Errorf("响应解析失败: %w", err)
+		}
+
+		// 解析原始 JSON 为 map
+		var rawResp map[string]any
+		_ = json.Unmarshal(respBodyBytes, &rawResp)
+
+		return &loadResp, rawResp, nil
+	}
 
-	return &loadResp, rawResp, nil
+	return nil, nil, lastErr
 }
 
 // ModelQuotaInfo 模型配额信息
@@ -339,6 +404,7 @@ type FetchAvailableModelsResponse struct {
 }
 
 // FetchAvailableModels 获取可用模型和配额信息，返回解析后的结构体和原始 JSON
+// 支持 URL fallback：sandbox → daily → prod
 func (c *Client) FetchAvailableModels(ctx context.Context, accessToken, projectID string) (*FetchAvailableModelsResponse, map[string]any, error) {
 	reqBody := FetchAvailableModelsRequest{Project: projectID}
 	bodyBytes, err := json.Marshal(reqBody)
@@ -346,38 +412,63 @@ func (c *Client) FetchAvailableModels(ctx context.Context, accessToken, projectI
 		return nil, nil, fmt.Errorf("序列化请求失败: %w", err)
 	}
 
-	apiURL := BaseURL + "/v1internal:fetchAvailableModels"
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, apiURL, strings.NewReader(string(bodyBytes)))
-	if err != nil {
-		return nil, nil, fmt.Errorf("创建请求失败: %w", err)
+	// 获取可用的 URL 列表
+	availableURLs := DefaultURLAvailability.GetAvailableURLs()
+	if len(availableURLs) == 0 {
+		availableURLs = BaseURLs // 所有 URL 都不可用时，重试所有
 	}
-	req.Header.Set("Authorization", "Bearer "+accessToken)
-	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("User-Agent", UserAgent)
 
-	resp, err := c.httpClient.Do(req)
-	if err != nil {
-		return nil, nil, fmt.Errorf("fetchAvailableModels 请求失败: %w", err)
-	}
-	defer func() { _ = resp.Body.Close() }()
+	var lastErr error
+	for urlIdx, baseURL := range availableURLs {
+		apiURL := baseURL + "/v1internal:fetchAvailableModels"
+		req, err := http.NewRequestWithContext(ctx, http.MethodPost, apiURL, strings.NewReader(string(bodyBytes)))
+		if err != nil {
+			lastErr = fmt.Errorf("创建请求失败: %w", err)
+			continue
+		}
+		req.Header.Set("Authorization", "Bearer "+accessToken)
+		req.Header.Set("Content-Type", "application/json")
+		req.Header.Set("User-Agent", UserAgent)
+
+		resp, err := c.httpClient.Do(req)
+		if err != nil {
+			lastErr = fmt.Errorf("fetchAvailableModels 请求失败: %w", err)
+			if shouldFallbackToNextURL(err, 0) && urlIdx < len(availableURLs)-1 {
+				DefaultURLAvailability.MarkUnavailable(baseURL)
+				log.Printf("[antigravity] fetchAvailableModels URL fallback: %s -> %s", baseURL, availableURLs[urlIdx+1])
+				continue
+			}
+			return nil, nil, lastErr
+		}
 
-	respBodyBytes, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, nil, fmt.Errorf("读取响应失败: %w", err)
-	}
+		respBodyBytes, err := io.ReadAll(resp.Body)
+		_ = resp.Body.Close() // 立即关闭，避免循环内 defer 导致的资源泄漏
+		if err != nil {
+			return nil, nil, fmt.Errorf("读取响应失败: %w", err)
+		}
 
-	if resp.StatusCode != http.StatusOK {
-		return nil, nil, fmt.Errorf("fetchAvailableModels 失败 (HTTP %d): %s", resp.StatusCode, string(respBodyBytes))
-	}
+		// 检查是否需要 URL 降级
+		if shouldFallbackToNextURL(nil, resp.StatusCode) && urlIdx < len(availableURLs)-1 {
+			DefaultURLAvailability.MarkUnavailable(baseURL)
+			log.Printf("[antigravity] fetchAvailableModels URL fallback (HTTP %d): %s -> %s", resp.StatusCode, baseURL, availableURLs[urlIdx+1])
+			continue
+		}
 
-	var modelsResp FetchAvailableModelsResponse
-	if err := json.Unmarshal(respBodyBytes, &modelsResp); err != nil {
-		return nil, nil, fmt.Errorf("响应解析失败: %w", err)
-	}
+		if resp.StatusCode != http.StatusOK {
+			return nil, nil, fmt.Errorf("fetchAvailableModels 失败 (HTTP %d): %s", resp.StatusCode, string(respBodyBytes))
+		}
 
-	// 解析原始 JSON 为 map
-	var rawResp map[string]any
-	_ = json.Unmarshal(respBodyBytes, &rawResp)
+		var modelsResp FetchAvailableModelsResponse
+		if err := json.Unmarshal(respBodyBytes, &modelsResp); err != nil {
+			return nil, nil, fmt.Errorf("响应解析失败: %w", err)
+		}
+
+		// 解析原始 JSON 为 map
+		var rawResp map[string]any
+		_ = json.Unmarshal(respBodyBytes, &rawResp)
+
+		return &modelsResp, rawResp, nil
+	}
 
-	return &modelsResp, rawResp, nil
+	return nil, nil, lastErr
 }

backend/internal/pkg/antigravity/oauth.go

@@ -32,17 +32,79 @@ const (
 		"https://www.googleapis.com/auth/cclog " +
 		"https://www.googleapis.com/auth/experimentsandconfigs"
 
-	// API 端点
-	// 优先使用 sandbox daily URL，配额更宽松
-	BaseURL = "https://daily-cloudcode-pa.sandbox.googleapis.com"
-
 	// User-Agent（模拟官方客户端）
 	UserAgent = "antigravity/1.104.0 darwin/arm64"
 
 	// Session 过期时间
 	SessionTTL = 30 * time.Minute
+
+	// URL 可用性 TTL（不可用 URL 的恢复时间）
+	URLAvailabilityTTL = 5 * time.Minute
 )
 
+// BaseURLs 定义 Antigravity API 端点，按优先级排序
+// fallback 顺序: sandbox → daily → prod
+var BaseURLs = []string{
+	"https://daily-cloudcode-pa.sandbox.googleapis.com", // sandbox
+	"https://daily-cloudcode-pa.googleapis.com",         // daily
+	"https://cloudcode-pa.googleapis.com",               // prod
+}
+
+// BaseURL 默认 URL（保持向后兼容）
+var BaseURL = BaseURLs[0]
+
+// URLAvailability 管理 URL 可用性状态（带 TTL 自动恢复）
+type URLAvailability struct {
+	mu          sync.RWMutex
+	unavailable map[string]time.Time // URL -> 恢复时间
+	ttl         time.Duration
+}
+
+// DefaultURLAvailability 全局 URL 可用性管理器
+var DefaultURLAvailability = NewURLAvailability(URLAvailabilityTTL)
+
+// NewURLAvailability 创建 URL 可用性管理器
+func NewURLAvailability(ttl time.Duration) *URLAvailability {
+	return &URLAvailability{
+		unavailable: make(map[string]time.Time),
+		ttl:         ttl,
+	}
+}
+
+// MarkUnavailable 标记 URL 临时不可用
+func (u *URLAvailability) MarkUnavailable(url string) {
+	u.mu.Lock()
+	defer u.mu.Unlock()
+	u.unavailable[url] = time.Now().Add(u.ttl)
+}
+
+// IsAvailable 检查 URL 是否可用
+func (u *URLAvailability) IsAvailable(url string) bool {
+	u.mu.RLock()
+	defer u.mu.RUnlock()
+	expiry, exists := u.unavailable[url]
+	if !exists {
+		return true
+	}
+	return time.Now().After(expiry)
+}
+
+// GetAvailableURLs 返回可用的 URL 列表（保持优先级顺序）
+func (u *URLAvailability) GetAvailableURLs() []string {
+	u.mu.RLock()
+	defer u.mu.RUnlock()
+
+	now := time.Now()
+	result := make([]string, 0, len(BaseURLs))
+	for _, url := range BaseURLs {
+		expiry, exists := u.unavailable[url]
+		if !exists || now.After(expiry) {
+			result = append(result, url)
+		}
+	}
+	return result
+}
+
 // OAuthSession 保存 OAuth 授权流程的临时状态
 type OAuthSession struct {
 	State        string    `json:"state"`

backend/internal/pkg/ctxkey/ctxkey.go

@@ -7,4 +7,6 @@ type Key string
 const (
 	// ForcePlatform 强制平台（用于 /antigravity 路由），由 middleware.ForcePlatform 设置
 	ForcePlatform Key = "ctx_force_platform"
+	// IsClaudeCodeClient 是否为 Claude Code 客户端，由中间件设置
+	IsClaudeCodeClient Key = "ctx_is_claude_code_client"
 )

backend/internal/pkg/geminicli/constants.go

@@ -27,10 +27,9 @@ const (
 	// https://www.googleapis.com/auth/generative-language.retriever (often with cloud-platform).
 	DefaultAIStudioScopes = "https://www.googleapis.com/auth/cloud-platform https://www.googleapis.com/auth/generative-language.retriever"
 
-	// DefaultScopes for Google One (personal Google accounts with Gemini access)
-	// Only used when a custom OAuth client is configured. When using the built-in Gemini CLI client,
-	// Google One uses DefaultCodeAssistScopes (same as code_assist) because the built-in client
-	// cannot request restricted scopes like generative-language.retriever or drive.readonly.
+	// DefaultGoogleOneScopes (DEPRECATED, no longer used)
+	// Google One now always uses the built-in Gemini CLI client with DefaultCodeAssistScopes.
+	// This constant is kept for backward compatibility but is not actively used.
 	DefaultGoogleOneScopes = "https://www.googleapis.com/auth/cloud-platform https://www.googleapis.com/auth/generative-language.retriever https://www.googleapis.com/auth/drive.readonly https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile"
 
 	// GeminiCLIRedirectURI is the redirect URI used by Gemini CLI for Code Assist OAuth.

backend/internal/pkg/geminicli/oauth.go

@@ -185,13 +185,9 @@ func EffectiveOAuthConfig(cfg OAuthConfig, oauthType string) (OAuthConfig, error
 				effective.Scopes = DefaultAIStudioScopes
 			}
 		case "google_one":
-			// Google One uses built-in Gemini CLI client (same as code_assist)
-			// Built-in client can't request restricted scopes like generative-language.retriever
-			if isBuiltinClient {
-				effective.Scopes = DefaultCodeAssistScopes
-			} else {
-				effective.Scopes = DefaultGoogleOneScopes
-			}
+			// Google One always uses built-in Gemini CLI client (same as code_assist)
+			// Built-in client can't request restricted scopes like generative-language.retriever or drive.readonly
+			effective.Scopes = DefaultCodeAssistScopes
 		default:
 			// Default to Code Assist scopes
 			effective.Scopes = DefaultCodeAssistScopes

backend/internal/pkg/geminicli/oauth_test.go

@@ -23,14 +23,14 @@ func TestEffectiveOAuthConfig_GoogleOne(t *testing.T) {
 			wantErr:      false,
 		},
 		{
-			name: "Google One with custom client",
+			name: "Google One always uses built-in client (even if custom credentials passed)",
 			input: OAuthConfig{
 				ClientID:     "custom-client-id",
 				ClientSecret: "custom-client-secret",
 			},
 			oauthType:    "google_one",
 			wantClientID: "custom-client-id",
-			wantScopes:   DefaultGoogleOneScopes,
+			wantScopes:   DefaultCodeAssistScopes, // Uses code assist scopes even with custom client
 			wantErr:      false,
 		},
 		{

backend/internal/repository/account_repo.go

@@ -886,6 +886,11 @@ func (r *accountRepository) BulkUpdate(ctx context.Context, ids []int64, updates
 		args = append(args, *updates.Status)
 		idx++
 	}
+	if updates.Schedulable != nil {
+		setClauses = append(setClauses, "schedulable = $"+itoa(idx))
+		args = append(args, *updates.Schedulable)
+		idx++
+	}
 	// JSONB 需要合并而非覆盖，使用 raw SQL 保持旧行为。
 	if len(updates.Credentials) > 0 {
 		payload, err := json.Marshal(updates.Credentials)

backend/internal/repository/api_key_repo.go

@@ -325,6 +325,8 @@ func groupEntityToService(g *dbent.Group) *service.Group {
 		ImagePrice2K:        g.ImagePrice2k,
 		ImagePrice4K:        g.ImagePrice4k,
 		DefaultValidityDays: g.DefaultValidityDays,
+		ClaudeCodeOnly:      g.ClaudeCodeOnly,
+		FallbackGroupID:     g.FallbackGroupID,
 		CreatedAt:           g.CreatedAt,
 		UpdatedAt:           g.UpdatedAt,
 	}

backend/internal/repository/gateway_cache.go

@@ -2,6 +2,7 @@ package repository
 
 import (
 	"context"
+	"fmt"
 	"time"
 
 	"github.com/Wei-Shaw/sub2api/internal/service"
@@ -18,17 +19,23 @@ func NewGatewayCache(rdb *redis.Client) service.GatewayCache {
 	return &gatewayCache{rdb: rdb}
 }
 
-func (c *gatewayCache) GetSessionAccountID(ctx context.Context, sessionHash string) (int64, error) {
-	key := stickySessionPrefix + sessionHash
+// buildSessionKey 构建 session key，包含 groupID 实现分组隔离
+// 格式: sticky_session:{groupID}:{sessionHash}
+func buildSessionKey(groupID int64, sessionHash string) string {
+	return fmt.Sprintf("%s%d:%s", stickySessionPrefix, groupID, sessionHash)
+}
+
+func (c *gatewayCache) GetSessionAccountID(ctx context.Context, groupID int64, sessionHash string) (int64, error) {
+	key := buildSessionKey(groupID, sessionHash)
 	return c.rdb.Get(ctx, key).Int64()
 }
 
-func (c *gatewayCache) SetSessionAccountID(ctx context.Context, sessionHash string, accountID int64, ttl time.Duration) error {
-	key := stickySessionPrefix + sessionHash
+func (c *gatewayCache) SetSessionAccountID(ctx context.Context, groupID int64, sessionHash string, accountID int64, ttl time.Duration) error {
+	key := buildSessionKey(groupID, sessionHash)
 	return c.rdb.Set(ctx, key, accountID, ttl).Err()
 }
 
-func (c *gatewayCache) RefreshSessionTTL(ctx context.Context, sessionHash string, ttl time.Duration) error {
-	key := stickySessionPrefix + sessionHash
+func (c *gatewayCache) RefreshSessionTTL(ctx context.Context, groupID int64, sessionHash string, ttl time.Duration) error {
+	key := buildSessionKey(groupID, sessionHash)
 	return c.rdb.Expire(ctx, key, ttl).Err()
 }