feat(web): add same-origin SPA authentication

apps/web/src/lib/api.spec.ts

@@ -0,0 +1,57 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { api } from './api';
+
+describe('api', () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it('fetches the supplied relative path with credentials and a JSON body', async () => {
+    const fetchMock = vi.fn<typeof fetch>();
+    fetchMock.mockResolvedValue(
+      new Response(JSON.stringify({ ok: true }), {
+        status: 200,
+        headers: { 'Content-Type': 'application/json' },
+      }),
+    );
+    vi.stubGlobal('fetch', fetchMock);
+
+    await expect(
+      api<{ ok: boolean }>('/api/projects', {
+        method: 'POST',
+        body: { name: 'Mosaic' },
+      }),
+    ).resolves.toEqual({ ok: true });
+
+    expect(fetchMock).toHaveBeenCalledOnce();
+    expect(fetchMock).toHaveBeenCalledWith(
+      '/api/projects',
+      expect.objectContaining({
+        method: 'POST',
+        credentials: 'include',
+        body: JSON.stringify({ name: 'Mosaic' }),
+        headers: expect.objectContaining({
+          Accept: 'application/json',
+          'Content-Type': 'application/json',
+        }),
+      }),
+    );
+  });
+
+  it('throws the gateway JSON error with its statusCode', async () => {
+    const fetchMock = vi.fn<typeof fetch>();
+    fetchMock.mockResolvedValue(
+      new Response(JSON.stringify({ statusCode: 403, message: 'Forbidden' }), {
+        status: 403,
+        headers: { 'Content-Type': 'application/json' },
+      }),
+    );
+    vi.stubGlobal('fetch', fetchMock);
+
+    await expect(api('/api/admin/users')).rejects.toMatchObject({
+      name: 'Error',
+      message: 'Forbidden',
+      statusCode: 403,
+    });
+  });
+});

apps/web/src/lib/api.ts

@@ -1,5 +1,3 @@
-const GATEWAY_URL = process.env['NEXT_PUBLIC_GATEWAY_URL'] ?? 'http://localhost:14242';
-
 export interface ApiRequestInit extends Omit<RequestInit, 'body'> {
   body?: unknown;
 }
@@ -25,7 +23,7 @@ export async function api<T>(path: string, init?: ApiRequestInit): Promise<T> {
     headers['Content-Type'] = 'application/json';
   }
 
-  const res = await fetch(`${GATEWAY_URL}${path}`, {
+  const res = await fetch(path, {
     credentials: 'include',
     ...rest,
     headers,

apps/web/src/lib/auth-client.spec.ts

@@ -0,0 +1,29 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+describe('auth client origin contract', () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    vi.resetModules();
+  });
+
+  it('uses the same-origin BetterAuth mount at /api/auth', async () => {
+    const fetchMock = vi.fn<typeof fetch>();
+    fetchMock.mockResolvedValue(
+      new Response(JSON.stringify({ session: null, user: null }), {
+        status: 200,
+        headers: { 'Content-Type': 'application/json' },
+      }),
+    );
+    vi.stubGlobal('fetch', fetchMock);
+
+    const { authClient } = await import('./auth-client');
+    await authClient.getSession();
+
+    expect(fetchMock).toHaveBeenCalledOnce();
+    const firstCall = fetchMock.mock.calls.at(0);
+    expect(firstCall).toBeDefined();
+    const requestURL = new URL(String(firstCall?.[0]), window.location.origin);
+    expect(requestURL.origin).toBe(window.location.origin);
+    expect(requestURL.pathname).toBe('/api/auth/get-session');
+  });
+});

apps/web/src/lib/auth-client.ts

@@ -1,8 +1,9 @@
 import { createAuthClient } from 'better-auth/react';
 import { adminClient, genericOAuthClient } from 'better-auth/client/plugins';
 
+// The gateway and BetterAuth client both use /api/auth. Omitting baseURL keeps
+// every browser request on the current origin in development and production.
 export const authClient = createAuthClient({
-  baseURL: process.env['NEXT_PUBLIC_GATEWAY_URL'] ?? 'http://localhost:14242',
   plugins: [adminClient(), genericOAuthClient()],
 });
 

apps/web/src/lib/auth-redirect.spec.ts

@@ -0,0 +1,25 @@
+import { describe, expect, it } from 'vitest';
+import { resolveAuthCallbackURL } from './auth-redirect';
+
+const CURRENT_ORIGIN = 'https://mosaic.example';
+
+describe('resolveAuthCallbackURL', () => {
+  it('preserves a canonical same-origin path with search and hash', () => {
+    expect(resolveAuthCallbackURL('/projects?view=active#current', CURRENT_ORIGIN)).toBe(
+      '/projects?view=active#current',
+    );
+  });
+
+  it.each([
+    null,
+    'chat',
+    '//evil.example',
+    '/\\evil.example',
+    '/\n//evil.example',
+    '/\r//evil.example',
+    '/\t//evil.example',
+    'https://evil.example/phish',
+  ])('falls back to chat for an unsafe callback target %#', (candidate) => {
+    expect(resolveAuthCallbackURL(candidate, CURRENT_ORIGIN)).toBe('/chat');
+  });
+});

apps/web/src/lib/auth-redirect.ts

@@ -0,0 +1,21 @@
+const DEFAULT_AUTH_CALLBACK_URL = '/chat';
+
+/**
+ * Return a canonical same-origin path for post-auth navigation.
+ *
+ * Parsing before comparing origins rejects protocol-relative URLs, backslash
+ * variants, and control characters that the WHATWG parser normalizes away.
+ */
+export function resolveAuthCallbackURL(candidate: string | null, currentOrigin: string): string {
+  if (!candidate?.startsWith('/')) return DEFAULT_AUTH_CALLBACK_URL;
+
+  try {
+    const expectedOrigin = new URL(currentOrigin).origin;
+    const resolved = new URL(candidate, expectedOrigin);
+    if (resolved.origin !== expectedOrigin) return DEFAULT_AUTH_CALLBACK_URL;
+
+    return `${resolved.pathname}${resolved.search}${resolved.hash}`;
+  } catch {
+    return DEFAULT_AUTH_CALLBACK_URL;
+  }
+}

apps/web/src/lib/socket.spec.ts

@@ -0,0 +1,52 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+const { ioMock } = vi.hoisted(() => ({
+  ioMock: vi.fn(),
+}));
+
+vi.mock('socket.io-client', () => ({
+  io: ioMock,
+}));
+
+import { destroySocket, getSocket } from './socket';
+
+describe('chat socket', () => {
+  let disconnectHandler: (() => void) | undefined;
+
+  beforeEach(() => {
+    disconnectHandler = undefined;
+    ioMock.mockReset();
+
+    const mockSocket = {
+      on: vi.fn((event: string, handler: () => void) => {
+        if (event === 'disconnect') disconnectHandler = handler;
+        return mockSocket;
+      }),
+      offAny: vi.fn(() => mockSocket),
+      disconnect: vi.fn(() => mockSocket),
+    };
+
+    ioMock.mockReturnValue(mockSocket);
+  });
+
+  afterEach(() => {
+    destroySocket();
+  });
+
+  it('creates one same-origin /chat namespace socket until it disconnects', () => {
+    const first = getSocket();
+    const second = getSocket();
+
+    expect(first).toBe(second);
+    expect(ioMock).toHaveBeenCalledOnce();
+    expect(ioMock).toHaveBeenCalledWith('/chat', {
+      withCredentials: true,
+      autoConnect: false,
+      transports: ['websocket', 'polling'],
+    });
+
+    disconnectHandler?.();
+    getSocket();
+    expect(ioMock).toHaveBeenCalledTimes(2);
+  });
+});

apps/web/src/lib/socket.ts

@@ -1,12 +1,10 @@
 import { io, type Socket } from 'socket.io-client';
 
-const GATEWAY_URL = process.env['NEXT_PUBLIC_GATEWAY_URL'] ?? 'http://localhost:14242';
-
 let socket: Socket | null = null;
 
 export function getSocket(): Socket {
   if (!socket) {
-    socket = io(`${GATEWAY_URL}/chat`, {
+    socket = io('/chat', {
       withCredentials: true,
       autoConnect: false,
       transports: ['websocket', 'polling'],

apps/web/src/lib/sso-providers.test.ts

@@ -1,48 +0,0 @@
-import { afterEach, describe, expect, it, vi } from 'vitest';
-import { getEnabledSsoProviders, getSsoProvider } from './sso-providers';
-
-describe('sso-providers', () => {
-  afterEach(() => {
-    vi.unstubAllEnvs();
-  });
-
-  it('returns the enabled providers in login button order', () => {
-    vi.stubEnv('NEXT_PUBLIC_WORKOS_ENABLED', 'true');
-    vi.stubEnv('NEXT_PUBLIC_KEYCLOAK_ENABLED', 'true');
-
-    expect(getEnabledSsoProviders()).toEqual([
-      {
-        id: 'workos',
-        buttonLabel: 'Continue with WorkOS',
-        description: 'Enterprise SSO via WorkOS',
-        enabled: true,
-        href: '/auth/provider/workos',
-      },
-      {
-        id: 'keycloak',
-        buttonLabel: 'Continue with Keycloak',
-        description: 'Enterprise SSO via Keycloak',
-        enabled: true,
-        href: '/auth/provider/keycloak',
-      },
-    ]);
-  });
-
-  it('marks disabled providers without exposing them in the enabled list', () => {
-    vi.stubEnv('NEXT_PUBLIC_WORKOS_ENABLED', 'true');
-    vi.stubEnv('NEXT_PUBLIC_KEYCLOAK_ENABLED', 'false');
-
-    expect(getEnabledSsoProviders().map((provider) => provider.id)).toEqual(['workos']);
-    expect(getSsoProvider('keycloak')).toEqual({
-      id: 'keycloak',
-      buttonLabel: 'Continue with Keycloak',
-      description: 'Enterprise SSO via Keycloak',
-      enabled: false,
-      href: '/auth/provider/keycloak',
-    });
-  });
-
-  it('returns null for unknown providers', () => {
-    expect(getSsoProvider('authentik')).toBeNull();
-  });
-});

apps/web/src/lib/sso-providers.ts

@@ -1,53 +0,0 @@
-export type SsoProviderId = 'workos' | 'keycloak';
-
-export interface SsoProvider {
-  id: SsoProviderId;
-  buttonLabel: string;
-  description: string;
-  enabled: boolean;
-  href: string;
-}
-
-const PROVIDER_METADATA: Record<SsoProviderId, Omit<SsoProvider, 'enabled' | 'href'>> = {
-  workos: {
-    id: 'workos',
-    buttonLabel: 'Continue with WorkOS',
-    description: 'Enterprise SSO via WorkOS',
-  },
-  keycloak: {
-    id: 'keycloak',
-    buttonLabel: 'Continue with Keycloak',
-    description: 'Enterprise SSO via Keycloak',
-  },
-};
-
-export function getEnabledSsoProviders(): SsoProvider[] {
-  return (Object.keys(PROVIDER_METADATA) as SsoProviderId[])
-    .map((providerId) => getSsoProvider(providerId))
-    .filter((provider): provider is SsoProvider => provider?.enabled === true);
-}
-
-export function getSsoProvider(providerId: string): SsoProvider | null {
-  if (!isSsoProviderId(providerId)) {
-    return null;
-  }
-
-  return {
-    ...PROVIDER_METADATA[providerId],
-    enabled: isSsoProviderEnabled(providerId),
-    href: `/auth/provider/${providerId}`,
-  };
-}
-
-function isSsoProviderId(value: string): value is SsoProviderId {
-  return value === 'workos' || value === 'keycloak';
-}
-
-function isSsoProviderEnabled(providerId: SsoProviderId): boolean {
-  switch (providerId) {
-    case 'workos':
-      return process.env['NEXT_PUBLIC_WORKOS_ENABLED'] === 'true';
-    case 'keycloak':
-      return process.env['NEXT_PUBLIC_KEYCLOAK_ENABLED'] === 'true';
-  }
-}