feat: WebSocket presence tracking with page_focus and presence_update

Made-with: Cursor

backend/utils/websocket-manager.js

@@ -32,6 +32,8 @@ class WebSocketManager {
     const clientInfo = {
       authenticated: false,
       userId: null,
+      adminName: null,
+      currentPage: null,
       subscribedSessions: new Set(),
       lastPing: Date.now()
     };
@@ -96,6 +98,15 @@ class WebSocketManager {
         clientInfo.lastPing = Date.now();
         this.send(ws, { type: 'pong' });
         break;
+
+      case 'page_focus':
+        if (!clientInfo.authenticated) {
+          this.sendError(ws, 'Not authenticated');
+          return;
+        }
+        clientInfo.currentPage = message.page || null;
+        this.broadcastPresence();
+        break;
         
       default:
         this.sendError(ws, `Unknown message type: ${message.type}`);
@@ -117,7 +128,13 @@ class WebSocketManager {
       
       if (clientInfo) {
         clientInfo.authenticated = true;
-        clientInfo.userId = decoded.role; // 'admin' for now
+        clientInfo.userId = decoded.role;
+        clientInfo.adminName = decoded.name || null;
+
+        if (!decoded.name) {
+          this.sendError(ws, 'Token missing admin identity, please re-login', 'auth_error');
+          return;
+        }
         
         this.send(ws, {
           type: 'auth_success',
@@ -283,9 +300,31 @@ class WebSocketManager {
       
       this.clients.delete(ws);
       console.log('[WebSocket] Client disconnected and cleaned up');
+      this.broadcastPresence();
     }
   }
 
+  broadcastPresence() {
+    const admins = [];
+    this.clients.forEach((info) => {
+      if (info.authenticated && info.adminName && info.currentPage) {
+        admins.push({ name: info.adminName, page: info.currentPage });
+      }
+    });
+
+    const message = {
+      type: 'presence_update',
+      timestamp: new Date().toISOString(),
+      admins
+    };
+
+    this.clients.forEach((info, ws) => {
+      if (info.authenticated && ws.readyState === ws.OPEN) {
+        this.send(ws, message);
+      }
+    });
+  }
+
   /**
    * Start heartbeat to detect dead connections
    */

tests/api/named-admins.test.js

@@ -125,3 +125,103 @@ describe('POST /api/auth/login — named admins', () => {
     expect(res.status).toBe(401);
   });
 });
+
+const WebSocket = require('ws');
+const jwt = require('jsonwebtoken');
+const http = require('http');
+
+describe('WebSocket presence', () => {
+  let server, wsUrl;
+
+  beforeAll((done) => {
+    process.env.ADMIN_KEY = 'test-admin-key';
+    process.env.ADMIN_CONFIG_PATH = '/tmp/nonexistent-admins.json';
+    jest.resetModules();
+    const { app } = require('../../backend/server');
+    const { WebSocketManager, setWebSocketManager } = require('../../backend/utils/websocket-manager');
+
+    server = http.createServer(app);
+    const wsManager = new WebSocketManager(server);
+    setWebSocketManager(wsManager);
+
+    server.listen(0, () => {
+      const port = server.address().port;
+      wsUrl = `ws://localhost:${port}/api/sessions/live`;
+      done();
+    });
+  });
+
+  afterAll((done) => {
+    server.close(done);
+  });
+
+  function makeToken(name) {
+    return jwt.sign({ role: 'admin', name }, process.env.JWT_SECRET, { expiresIn: '1h' });
+  }
+
+  function connectAndAuth(name) {
+    return new Promise((resolve) => {
+      const ws = new WebSocket(wsUrl);
+      ws.on('open', () => {
+        ws.send(JSON.stringify({ type: 'auth', token: makeToken(name) }));
+      });
+      ws.on('message', (data) => {
+        const msg = JSON.parse(data.toString());
+        if (msg.type === 'auth_success') {
+          resolve(ws);
+        }
+      });
+    });
+  }
+
+  function waitForMessage(ws, type) {
+    return new Promise((resolve) => {
+      const handler = (data) => {
+        const msg = JSON.parse(data.toString());
+        if (msg.type === type) {
+          ws.off('message', handler);
+          resolve(msg);
+        }
+      };
+      ws.on('message', handler);
+    });
+  }
+
+  test('page_focus triggers presence_update with admin name and page', async () => {
+    const ws1 = await connectAndAuth('Alice');
+    const ws2 = await connectAndAuth('Bob');
+
+    const presencePromise = waitForMessage(ws2, 'presence_update');
+
+    ws1.send(JSON.stringify({ type: 'page_focus', page: '/history' }));
+
+    const msg = await presencePromise;
+    expect(msg.admins).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({ name: 'Alice', page: '/history' })
+      ])
+    );
+
+    ws1.close();
+    ws2.close();
+  });
+
+  test('disconnect removes admin from presence', async () => {
+    const ws1 = await connectAndAuth('Alice');
+    const ws2 = await connectAndAuth('Bob');
+
+    ws1.send(JSON.stringify({ type: 'page_focus', page: '/picker' }));
+    ws2.send(JSON.stringify({ type: 'page_focus', page: '/picker' }));
+
+    await new Promise(r => setTimeout(r, 100));
+
+    const presencePromise = waitForMessage(ws2, 'presence_update');
+    ws1.close();
+
+    const msg = await presencePromise;
+    const names = msg.admins.map(a => a.name);
+    expect(names).not.toContain('Alice');
+
+    ws2.close();
+  });
+});