📍 feat: Preserve Deep Link Destinations Through the Auth Redirect Flow (#10275)

* added support for url query param persistance

* refactor: authentication redirect handling

- Introduced utility functions for managing login redirects, including `persistRedirectToSession`, `buildLoginRedirectUrl`, and `getPostLoginRedirect`.
- Updated `Login` and `AuthContextProvider` components to utilize these utilities for improved redirect logic.
- Refactored `useAuthRedirect` to streamline navigation to the login page while preserving intended destinations.
- Cleaned up the `StartupLayout` to remove unnecessary redirect handling, ensuring a more straightforward navigation flow.
- Added a new `redirect.ts` file to encapsulate redirect-related logic, enhancing code organization and maintainability.

* fix: enhance safe redirect validation logic

- Updated the `isSafeRedirect` function to improve validation of redirect URLs.
- Ensured that only safe relative paths are accepted, specifically excluding paths that lead to the login page.
- Refactored the logic to streamline the checks for valid redirect targets.

* test: add unit tests for redirect utility functions

- Introduced comprehensive tests for `isSafeRedirect`, `buildLoginRedirectUrl`, `getPostLoginRedirect`, and `persistRedirectToSession` functions.
- Validated various scenarios including safe and unsafe redirects, URL encoding, and session storage behavior.
- Enhanced test coverage to ensure robust handling of redirect logic and prevent potential security issues.

* chore: streamline authentication and redirect handling

- Removed unused `useLocation` import from `AuthContextProvider` and replaced its usage with `window.location` for better clarity.
- Updated `StartupLayout` to check for pending redirects before navigating to the new chat page, ensuring users are directed appropriately based on their session state.
- Enhanced unit tests for `useAuthRedirect` to verify correct handling of redirect parameters, including encoding of the current path and query parameters.

* test: add unit tests for StartupLayout redirect behavior

- Introduced a new test suite for the StartupLayout component to validate redirect logic based on authentication status and session storage.
- Implemented tests to ensure correct navigation to the new conversation page when authenticated without pending redirects, and to prevent navigation when a redirect URL parameter or session storage redirect is present.
- Enhanced coverage for scenarios where users are not authenticated, ensuring robust handling of redirect conditions.

---------

Co-authored-by: Vamsi Konakanchi <vamsi.k@trackmind.com>
Co-authored-by: Danny Avila <danny@librechat.ai>

client/src/utils/__tests__/redirect.test.ts

@@ -0,0 +1,197 @@
+import {
+  isSafeRedirect,
+  buildLoginRedirectUrl,
+  getPostLoginRedirect,
+  persistRedirectToSession,
+  SESSION_KEY,
+} from '../redirect';
+
+describe('isSafeRedirect', () => {
+  it('accepts a simple relative path', () => {
+    expect(isSafeRedirect('/c/new')).toBe(true);
+  });
+
+  it('accepts a path with query params and hash', () => {
+    expect(isSafeRedirect('/c/new?q=hello&submit=true#section')).toBe(true);
+  });
+
+  it('accepts a nested path', () => {
+    expect(isSafeRedirect('/dashboard/settings/profile')).toBe(true);
+  });
+
+  it('rejects an absolute http URL', () => {
+    expect(isSafeRedirect('https://evil.com')).toBe(false);
+  });
+
+  it('rejects an absolute http URL with path', () => {
+    expect(isSafeRedirect('https://evil.com/phishing')).toBe(false);
+  });
+
+  it('rejects a protocol-relative URL', () => {
+    expect(isSafeRedirect('//evil.com')).toBe(false);
+  });
+
+  it('rejects a bare domain', () => {
+    expect(isSafeRedirect('evil.com')).toBe(false);
+  });
+
+  it('rejects an empty string', () => {
+    expect(isSafeRedirect('')).toBe(false);
+  });
+
+  it('rejects /login to prevent redirect loops', () => {
+    expect(isSafeRedirect('/login')).toBe(false);
+  });
+
+  it('rejects /login with query params', () => {
+    expect(isSafeRedirect('/login?redirect_to=/c/new')).toBe(false);
+  });
+
+  it('rejects /login sub-paths', () => {
+    expect(isSafeRedirect('/login/2fa')).toBe(false);
+  });
+
+  it('rejects /login with hash', () => {
+    expect(isSafeRedirect('/login#foo')).toBe(false);
+  });
+
+  it('accepts the root path', () => {
+    expect(isSafeRedirect('/')).toBe(true);
+  });
+});
+
+describe('buildLoginRedirectUrl', () => {
+  const originalLocation = window.location;
+
+  beforeEach(() => {
+    Object.defineProperty(window, 'location', {
+      value: { pathname: '/c/abc123', search: '?model=gpt-4', hash: '#msg-5' },
+      writable: true,
+    });
+  });
+
+  afterEach(() => {
+    Object.defineProperty(window, 'location', { value: originalLocation, writable: true });
+  });
+
+  it('builds a login URL from explicit args', () => {
+    const result = buildLoginRedirectUrl('/c/new', '?q=hello', '');
+    expect(result).toBe('/login?redirect_to=%2Fc%2Fnew%3Fq%3Dhello');
+  });
+
+  it('encodes complex paths with query and hash', () => {
+    const result = buildLoginRedirectUrl('/c/new', '?q=hello&submit=true', '#section');
+    expect(result).toContain('redirect_to=');
+    const encoded = result.split('redirect_to=')[1];
+    expect(decodeURIComponent(encoded)).toBe('/c/new?q=hello&submit=true#section');
+  });
+
+  it('falls back to window.location when no args provided', () => {
+    const result = buildLoginRedirectUrl();
+    const encoded = result.split('redirect_to=')[1];
+    expect(decodeURIComponent(encoded)).toBe('/c/abc123?model=gpt-4#msg-5');
+  });
+
+  it('falls back to "/" when all location parts are empty', () => {
+    Object.defineProperty(window, 'location', {
+      value: { pathname: '', search: '', hash: '' },
+      writable: true,
+    });
+    const result = buildLoginRedirectUrl();
+    expect(result).toBe('/login?redirect_to=%2F');
+  });
+});
+
+describe('getPostLoginRedirect', () => {
+  beforeEach(() => {
+    sessionStorage.clear();
+  });
+
+  it('returns the redirect_to param when valid', () => {
+    const params = new URLSearchParams('redirect_to=%2Fc%2Fnew');
+    expect(getPostLoginRedirect(params)).toBe('/c/new');
+  });
+
+  it('falls back to sessionStorage when no URL param', () => {
+    sessionStorage.setItem(SESSION_KEY, '/c/abc123');
+    const params = new URLSearchParams();
+    expect(getPostLoginRedirect(params)).toBe('/c/abc123');
+  });
+
+  it('prefers URL param over sessionStorage', () => {
+    sessionStorage.setItem(SESSION_KEY, '/c/old');
+    const params = new URLSearchParams('redirect_to=%2Fc%2Fnew');
+    expect(getPostLoginRedirect(params)).toBe('/c/new');
+  });
+
+  it('clears sessionStorage after reading', () => {
+    sessionStorage.setItem(SESSION_KEY, '/c/abc123');
+    const params = new URLSearchParams();
+    getPostLoginRedirect(params);
+    expect(sessionStorage.getItem(SESSION_KEY)).toBeNull();
+  });
+
+  it('returns null when no redirect source exists', () => {
+    const params = new URLSearchParams();
+    expect(getPostLoginRedirect(params)).toBeNull();
+  });
+
+  it('rejects an absolute URL from params', () => {
+    const params = new URLSearchParams('redirect_to=https%3A%2F%2Fevil.com');
+    expect(getPostLoginRedirect(params)).toBeNull();
+  });
+
+  it('rejects a protocol-relative URL from params', () => {
+    const params = new URLSearchParams('redirect_to=%2F%2Fevil.com');
+    expect(getPostLoginRedirect(params)).toBeNull();
+  });
+
+  it('rejects an absolute URL from sessionStorage', () => {
+    sessionStorage.setItem(SESSION_KEY, 'https://evil.com');
+    const params = new URLSearchParams();
+    expect(getPostLoginRedirect(params)).toBeNull();
+  });
+
+  it('rejects /login redirect to prevent loops', () => {
+    const params = new URLSearchParams('redirect_to=%2Flogin');
+    expect(getPostLoginRedirect(params)).toBeNull();
+  });
+
+  it('rejects /login sub-path redirect', () => {
+    const params = new URLSearchParams('redirect_to=%2Flogin%2F2fa');
+    expect(getPostLoginRedirect(params)).toBeNull();
+  });
+
+  it('still clears sessionStorage even when target is unsafe', () => {
+    sessionStorage.setItem(SESSION_KEY, 'https://evil.com');
+    const params = new URLSearchParams();
+    getPostLoginRedirect(params);
+    expect(sessionStorage.getItem(SESSION_KEY)).toBeNull();
+  });
+});
+
+describe('persistRedirectToSession', () => {
+  beforeEach(() => {
+    sessionStorage.clear();
+  });
+
+  it('stores a valid relative path', () => {
+    persistRedirectToSession('/c/new?q=hello');
+    expect(sessionStorage.getItem(SESSION_KEY)).toBe('/c/new?q=hello');
+  });
+
+  it('rejects an absolute URL', () => {
+    persistRedirectToSession('https://evil.com');
+    expect(sessionStorage.getItem(SESSION_KEY)).toBeNull();
+  });
+
+  it('rejects a protocol-relative URL', () => {
+    persistRedirectToSession('//evil.com');
+    expect(sessionStorage.getItem(SESSION_KEY)).toBeNull();
+  });
+
+  it('rejects /login paths', () => {
+    persistRedirectToSession('/login?redirect_to=/c/new');
+    expect(sessionStorage.getItem(SESSION_KEY)).toBeNull();
+  });
+});