feat: 로그인 끊김/실패 시 복구 UX 개선

apps/web/messages/en-US.json

@@ -296,5 +296,25 @@
     "report-error-button": "Report Error",
     "ranking-error-title": "Unable to load ranking information",
     "ranking-error-description": "Please try again later"
+  },
+  "Auth": {
+    "sessionExpiredTitle": "Your session has expired",
+    "sessionExpiredDescription": "Please sign in again for security.\nYou'll return to your previous page after signing in.",
+    "sessionExpiredAction": "Sign in again",
+    "desktopTitle": "Connect desktop app",
+    "desktopDescription": "The GitAnimals desktop app is requesting GitHub authentication.\nYou'll return to the desktop app once you sign in.",
+    "desktopContinueButton": "Continue with GitHub",
+    "desktopAuthenticatedMessage": "Returning to the desktop app…",
+    "desktopLoadingMessage": "Please wait a moment…",
+    "desktopErrorBanner": "Something went wrong while signing in. Please try again.",
+    "desktopInvalidTitle": "Invalid request",
+    "desktopInvalidDescription": "The redirect_uri is out of the allowed range or a required parameter is missing.",
+    "errorTitle": "Sign in failed",
+    "errorDescriptionDefault": "You can try again or go back to the home page.",
+    "errorDescriptionAccessDenied": "Access was denied. Please try again.",
+    "errorDescriptionCredentials": "Account verification failed. Please try again in a moment.",
+    "errorRetryDesktop": "Retry desktop connection",
+    "errorRetryDefault": "Sign in again",
+    "errorGoHome": "Back to home"
   }
 }

apps/web/messages/ko-KR.json

@@ -297,5 +297,25 @@
     "report-error-button": "오류 보고하기",
     "ranking-error-title": "랭킹 정보를 불러올 수 없습니다",
     "ranking-error-description": "잠시 후 다시 시도해주세요"
+  },
+  "Auth": {
+    "sessionExpiredTitle": "세션이 만료되었어요",
+    "sessionExpiredDescription": "보안을 위해 다시 로그인이 필요해요.\n로그인 후 이전 페이지로 자동 이동합니다.",
+    "sessionExpiredAction": "다시 로그인",
+    "desktopTitle": "데스크톱 앱 연결",
+    "desktopDescription": "GitAnimals 데스크톱 앱이 GitHub 계정 인증을 요청했어요.\n로그인하면 데스크톱 앱으로 자동 복귀해요.",
+    "desktopContinueButton": "GitHub으로 계속하기",
+    "desktopAuthenticatedMessage": "데스크톱 앱으로 이동하고 있어요…",
+    "desktopLoadingMessage": "잠시만 기다려주세요…",
+    "desktopErrorBanner": "로그인 중 문제가 발생했어요. 다시 시도해주세요.",
+    "desktopInvalidTitle": "잘못된 요청",
+    "desktopInvalidDescription": "redirect_uri가 허용 범위를 벗어났거나 필수 파라미터가 누락되었습니다.",
+    "errorTitle": "로그인에 실패했어요",
+    "errorDescriptionDefault": "다시 시도하거나 처음으로 돌아갈 수 있어요.",
+    "errorDescriptionAccessDenied": "접근이 거부되었어요. 다시 시도해주세요.",
+    "errorDescriptionCredentials": "계정 인증에 실패했어요. 잠시 후 다시 시도해주세요.",
+    "errorRetryDesktop": "데스크톱 연결 다시 시도",
+    "errorRetryDefault": "다시 로그인",
+    "errorGoHome": "처음으로"
   }
 }

apps/web/src/apis/interceptor.ts

@@ -1,5 +1,5 @@
 import { cache } from 'react';
-import { getSession, signOut } from 'next-auth/react';
+import { getSession } from 'next-auth/react';
 import {
   setRenderRequestInterceptor,
   setRenderResponseInterceptor,
@@ -11,6 +11,7 @@ import type { AxiosError, AxiosInstance, AxiosResponse, InternalAxiosRequestConf
 
 import { getServerAuth } from '@/auth';
 import type { ApiErrorScheme } from '@/exceptions/type';
+import { triggerSessionExpired } from '@/utils/sessionExpired';
 
 // Server path: request-scoped memoization via React cache(). Deduped within a
 // single render (one JWT decode instead of one per outbound request), and never
@@ -32,6 +33,11 @@ let cachedSession: CachedSession | null = null;
 let sessionPromise: Promise<string | null> | null = null;
 const CACHE_DURATION = 5 * 60 * 1000; // 5 minutes
 
+export const clearSessionCache = () => {
+  cachedSession = null;
+  sessionPromise = null;
+};
+
 const getAccessToken = async (): Promise<string | null> => {
   if (typeof window === 'undefined') {
     return getServerAccessToken();
@@ -83,27 +89,15 @@ export const interceptorResponseFulfilled = (res: AxiosResponse) => {
 };
 
 // Response interceptor
-// Latch so a burst of concurrent 401s triggers at most one signOut (which then
-// redirects/reloads and resets this module).
-let isSigningOut = false;
-
 export const interceptorResponseRejected = async (error: AxiosError<ApiErrorScheme>) => {
   if (error?.response?.status === 401) {
-    if (typeof window === 'undefined') {
-      // Server: surface as a domain exception (unchanged).
-      throw new CustomException('TOKEN_EXPIRED', 'token expired and sign out success');
-    }
-
-    // Client: only sign out an actually-authenticated session whose backend
-    // token expired. A 401 while logged out (e.g. a background query to an
-    // authed endpoint like /inboxes) must NOT trigger signOut — that loops:
-    // signOut → session refetch → re-render → re-query → 401 → signOut → …
-    const session = await getSession();
-    if (session?.user?.accessToken && !isSigningOut) {
-      isSigningOut = true;
-      signOut();
-      throw new CustomException('TOKEN_EXPIRED', 'token expired and sign out success');
+    // 캐시 무효화는 환경과 무관하게 먼저 수행 — 만료된 토큰 재사용 방지.
+    clearSessionCache();
+    // 복구 UX(세션 만료 다이얼로그)는 클라이언트에서만 띄운다.
+    if (typeof window !== 'undefined') {
+      triggerSessionExpired(window.location.pathname + window.location.search);
     }
+    throw new CustomException('TOKEN_EXPIRED', 'token expired');
   }
 
   // TODO: 403 처리

apps/web/src/app/[locale]/auth/desktop/page.tsx

@@ -2,6 +2,8 @@
 
 import { useEffect } from 'react';
 import { useSearchParams } from 'next/navigation';
+import { useTranslations } from 'next-intl';
+import { Button } from '@gitanimals/ui-tailwind';
 
 import { login } from '@/components/AuthButton';
 import { buildDesktopCallbackUrl, isValidDesktopRedirect } from '@/constants/desktopAuth';
@@ -16,43 +18,60 @@ export default function DesktopAuthPage() {
   const params = useSearchParams();
   const redirectUri = params.get('redirect_uri');
   const state = params.get('state');
+  const errorCode = params.get('error');
+  const t = useTranslations('Auth');
 
   const { status, data } = useClientSession();
 
   const isValid = isValidDesktopRedirect(redirectUri) && !!state;
 
   useEffect(() => {
     if (!isValid) return;
-
     if (status === 'authenticated' && data?.user?.accessToken) {
       window.location.replace(buildDesktopCallbackUrl(redirectUri!, data.user.accessToken, state!));
-    } else if (status === 'unauthenticated') {
-      login(
-        `/auth/desktop?redirect_uri=${encodeURIComponent(redirectUri!)}&state=${encodeURIComponent(state!)}`,
-      );
     }
   }, [status, isValid, redirectUri, state, data?.user?.accessToken]);
 
   if (!isValid) {
     return (
       <div className={pageRootClass}>
         <div className={cardClass}>
-          <h1 className="glyph28-bold text-white mobile:glyph24-bold">잘못된 요청</h1>
-          <p className="glyph16-regular text-center text-white">
-            redirect_uri가 허용 범위를 벗어났거나 필수 파라미터가 누락되었습니다.
-          </p>
+          <h1 className="glyph28-bold text-white mobile:glyph24-bold">{t('desktopInvalidTitle')}</h1>
+          <p className="glyph16-regular text-center text-white-75">{t('desktopInvalidDescription')}</p>
         </div>
       </div>
     );
   }
 
-  const message =
-    status === 'authenticated' ? '데스크톱 앱으로 이동합니다…' : '로그인으로 이동합니다…';
+  const handleLogin = () => {
+    login(`/auth/desktop?redirect_uri=${encodeURIComponent(redirectUri!)}&state=${encodeURIComponent(state!)}`);
+  };
 
   return (
     <div className={pageRootClass}>
       <div className={cardClass}>
-        <p className="glyph20-regular text-white">{message}</p>
+        <h1 className="glyph28-bold text-white mobile:glyph24-bold">{t('desktopTitle')}</h1>
+
+        {errorCode && (
+          <div className="w-full rounded-[8px] bg-[rgba(255,75,75,0.15)] px-[16px] py-[12px] text-center glyph14-regular text-white">
+            {t('desktopErrorBanner')}
+          </div>
+        )}
+
+        {status === 'loading' && <p className="glyph20-regular text-white-75">{t('desktopLoadingMessage')}</p>}
+
+        {status === 'authenticated' && (
+          <p className="glyph20-regular text-white-75">{t('desktopAuthenticatedMessage')}</p>
+        )}
+
+        {status === 'unauthenticated' && (
+          <>
+            <p className="whitespace-pre-line text-center glyph16-regular text-white-75">{t('desktopDescription')}</p>
+            <Button variant="primary" size="m" onClick={handleLogin}>
+              {t('desktopContinueButton')}
+            </Button>
+          </>
+        )}
       </div>
     </div>
   );

apps/web/src/app/[locale]/auth/error/page.tsx

@@ -0,0 +1,77 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { useRouter, useSearchParams } from 'next/navigation';
+import { useTranslations } from 'next-intl';
+import { Button } from '@gitanimals/ui-tailwind';
+
+import { login } from '@/components/AuthButton';
+import { LOCAL_STORAGE_KEY } from '@/constants/storage';
+
+const DESKTOP_CALLBACK_HINTS = ['/auth/desktop', 'redirect_uri='];
+
+const isDesktopCallback = (value: string | null): value is string => {
+  if (!value) return false;
+  return DESKTOP_CALLBACK_HINTS.some((hint) => value.includes(hint));
+};
+
+const pageRootClass =
+  'flex min-h-screen flex-col items-center justify-center p-[24px] text-white bg-[linear-gradient(180deg,#000_0%,#004875_38.51%,#005B93_52.46%,#006FB3_73.8%,#0187DB_100%)] mobile:p-[16px]';
+const cardClass =
+  'flex w-fit min-w-[520px] max-w-full flex-col items-center gap-[16px] rounded-[16px] bg-white-10 p-[40px] backdrop-blur-[7px] mobile:min-w-full mobile:bg-[rgba(255,255,255,0.08)] mobile:px-[16px] mobile:py-[24px]';
+
+export default function AuthErrorPage() {
+  const params = useSearchParams();
+  const router = useRouter();
+  const t = useTranslations('Auth');
+
+  const errorCode = params.get('error');
+  const [savedCallbackUrl, setSavedCallbackUrl] = useState<string | null>(null);
+
+  useEffect(() => {
+    setSavedCallbackUrl(localStorage.getItem(LOCAL_STORAGE_KEY.callbackUrl));
+  }, []);
+
+  const isDesktopFlow = isDesktopCallback(savedCallbackUrl);
+
+  const description = (() => {
+    switch (errorCode) {
+      case 'AccessDenied':
+        return t('errorDescriptionAccessDenied');
+      case 'CredentialsSignin':
+        return t('errorDescriptionCredentials');
+      default:
+        return t('errorDescriptionDefault');
+    }
+  })();
+
+  const handleRetry = () => {
+    if (isDesktopFlow && savedCallbackUrl) {
+      router.replace(savedCallbackUrl);
+      return;
+    }
+    login('/mypage');
+  };
+
+  const handleGoHome = () => {
+    router.replace('/');
+  };
+
+  return (
+    <main className={pageRootClass}>
+      <section className={cardClass}>
+        <h1 className="glyph28-bold text-white mobile:glyph24-bold">{t('errorTitle')}</h1>
+        <p className="whitespace-pre-line text-center glyph16-regular text-white-75">{description}</p>
+        {errorCode && <p className="glyph14-regular text-white-50">code: {errorCode}</p>}
+        <div className="mt-[8px] flex flex-wrap justify-center gap-[12px]">
+          <Button variant="primary" size="m" onClick={handleRetry}>
+            {isDesktopFlow ? t('errorRetryDesktop') : t('errorRetryDefault')}
+          </Button>
+          <Button variant="secondary" size="m" onClick={handleGoHome}>
+            {t('errorGoHome')}
+          </Button>
+        </div>
+      </section>
+    </main>
+  );
+}

apps/web/src/components/AuthButton.tsx

@@ -11,8 +11,10 @@ import { COOKIE_KEY, LOCAL_STORAGE_KEY } from '@/constants/storage';
 /**
  * client용 로그인 함수
  */
-export const login = (callbackUrl: string = '/mypage') => {
-  localStorage.setItem(LOCAL_STORAGE_KEY.callbackUrl, callbackUrl);
+export const login = (callbackUrl?: string) => {
+  // 인자가 없으면(예: 헤더 로그인 버튼) 미들웨어가 심어둔 딥링크 복귀 경로를 우선 사용한다.
+  const target = callbackUrl ?? localStorage.getItem(LOCAL_STORAGE_KEY.callbackUrl) ?? '/mypage';
+  localStorage.setItem(LOCAL_STORAGE_KEY.callbackUrl, target);
 
   // cookie set (client)
   const currentLocale = window.location.pathname.split('/')[1];

apps/web/src/components/Global/GlobalComponent.tsx

@@ -4,13 +4,17 @@ import { createPortal } from 'react-dom';
 import { Toaster } from 'sonner';
 
 import FeedBack from './FeedbackForm';
+import { LoginCallbackWatcher } from './LoginCallbackWatcher';
+import { SessionExpiredDialog } from './SessionExpiredDialog';
 import { DialogComponent } from './useDialog';
 
 function GlobalComponent() {
   return createPortal(
     <>
       <FeedBack />
       <DialogComponent />
+      <SessionExpiredDialog />
+      <LoginCallbackWatcher />
       <Toaster
         position="top-center"
         toastOptions={{

apps/web/src/components/Global/LoginCallbackWatcher.tsx

@@ -0,0 +1,31 @@
+'use client';
+
+import { useEffect } from 'react';
+import { useSearchParams } from 'next/navigation';
+
+import { LOCAL_STORAGE_KEY } from '@/constants/storage';
+
+// 보호 라우트에서 미들웨어가 홈으로 되돌릴 때 실어 보낸 `?callbackUrl` 을 캡처해
+// localStorage 에 저장한다. 사용자가 로그인하면 login()/LoginButton 이 이 값을 읽어
+// 원래 목적지로 자동 복귀시킨다. (useSearchParams 구독으로 클라 네비게이션 유입도 감지)
+export function LoginCallbackWatcher() {
+  const searchParams = useSearchParams();
+
+  useEffect(() => {
+    const callbackUrl = searchParams.get('callbackUrl');
+    if (!callbackUrl) return;
+
+    // open-redirect 방지: 외부 절대 URL(`//`, `https://…`)은 무시하고 앱 내부 경로만 허용.
+    const isInternalPath = callbackUrl.startsWith('/') && !callbackUrl.startsWith('//');
+    if (isInternalPath) {
+      localStorage.setItem(LOCAL_STORAGE_KEY.callbackUrl, callbackUrl);
+    }
+
+    const params = new URLSearchParams(searchParams.toString());
+    params.delete('callbackUrl');
+    const query = params.toString();
+    window.history.replaceState(null, '', window.location.pathname + (query ? `?${query}` : ''));
+  }, [searchParams]);
+
+  return null;
+}

apps/web/src/components/Global/SessionExpiredDialog.tsx

@@ -0,0 +1,38 @@
+'use client';
+
+import { useTranslations } from 'next-intl';
+import { Button, Dialog } from '@gitanimals/ui-tailwind';
+import { useAtomValue } from 'jotai';
+
+import { login } from '@/components/AuthButton';
+import { sessionExpiredAtom } from '@/utils/sessionExpired';
+
+export function SessionExpiredDialog() {
+  const { open, callbackUrl } = useAtomValue(sessionExpiredAtom);
+  const t = useTranslations('Auth');
+
+  const handleLogin = () => {
+    login(callbackUrl ?? '/mypage');
+  };
+
+  return (
+    <Dialog open={open}>
+      <Dialog.Content
+        isShowClose={false}
+        onEscapeKeyDown={(e) => e.preventDefault()}
+        onPointerDownOutside={(e) => e.preventDefault()}
+        onInteractOutside={(e) => e.preventDefault()}
+      >
+        <Dialog.Title className="text-left glyph20-regular">{t('sessionExpiredTitle')}</Dialog.Title>
+        <Dialog.Description className="w-full text-left glyph16-regular text-white-75">
+          {t('sessionExpiredDescription')}
+        </Dialog.Description>
+        <div className="flex w-full justify-end gap-[8px]">
+          <Button onClick={handleLogin} variant="primary" size="m">
+            {t('sessionExpiredAction')}
+          </Button>
+        </div>
+      </Dialog.Content>
+    </Dialog>
+  );
+}