maternal-app/PUSH_NOTIFICATIONS_IMPLEMENTATION.md

Push Notifications Implementation Summary

Status: ✅ COMPLETED (Backend + Frontend Integration Ready) Date: October 8, 2025 Implementation Type: Web Push (VAPID) - No Firebase/OneSignal dependency

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🎯 Overview

We successfully implemented a streamlined, fully local Web Push notification system for ParentFlow using the Web Push Protocol with VAPID keys. This allows browser-based push notifications without relying on third-party services like Firebase or OneSignal.

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📦 Backend Implementation

1. Database Schema ✅

Table: push_subscriptions (Already exists in production)

CREATE TABLE push_subscriptions (
  id uuid PRIMARY KEY DEFAULT uuid_generate_v4(),
  user_id varchar(20) NOT NULL,
  endpoint text NOT NULL UNIQUE,
  p256dh text NOT NULL,
  auth text NOT NULL,
  user_agent text,
  device_type varchar(20),
  browser varchar(50),
  is_active boolean DEFAULT true,
  last_error text,
  failed_attempts integer DEFAULT 0,
  last_success_at timestamp,
  created_at timestamp DEFAULT now(),
  updated_at timestamp DEFAULT now()
);

Indexes:

• idx_push_subs_user_id on user_id
• idx_push_subs_active on is_active (WHERE is_active = true)
• unique_endpoint on endpoint

2. TypeORM Entity ✅

File: src/database/entities/push-subscription.entity.ts

Features:

• Relationship with User entity (CASCADE delete)
• Tracks device type, browser, and subscription health
• Automatic timestamps (created_at, updated_at)

3. Push Service ✅

File: src/modules/push/push.service.ts

Key Features:

• VAPID configuration from environment variables
• Subscribe/unsubscribe management
• Send push notifications to individual users or groups
• Automatic error handling (404/410 = deactivate, retries for 5xx)
• User agent parsing for device/browser detection
• Statistics and cleanup utilities

Main Methods:

- getPublicVapidKey(): string
- subscribe(userId, subscriptionData, userAgent): PushSubscription
- unsubscribe(userId, endpoint): void
- sendToUser(userId, payload): {sent, failed}
- sendToUsers(userIds[], payload): {sent, failed}
- sendTestNotification(userId): void
- cleanupInactiveSubscriptions(daysOld): number
- getStatistics(userId?): Statistics

4. Push Controller ✅

File: src/modules/push/push.controller.ts

REST API Endpoints:

Method	Endpoint	Description
GET	/api/v1/push/vapid-public-key	Get VAPID public key for frontend
POST	/api/v1/push/subscriptions	Subscribe to push notifications
GET	/api/v1/push/subscriptions	Get user's active subscriptions
DELETE	/api/v1/push/subscriptions?endpoint=...	Unsubscribe from push
POST	/api/v1/push/test	Send test notification
GET	/api/v1/push/statistics	Get push statistics

Authentication: All endpoints require JWT authentication (JwtAuthGuard)

5. Push Module ✅

File: src/modules/push/push.module.ts

Wired into main AppModule and exports PushService for use by other modules.

6. Notifications Integration ✅

Updated: src/modules/notifications/notifications.service.ts

Features:

• Automatic push notification when creating notifications
• Intelligent URL routing based on notification type
• Smart notifications (feeding, sleep, diaper reminders) now trigger push
• Medication reminders trigger push
• Anomaly detection triggers push

Integration Flow:

createNotification()
  → Save to DB
  → sendPushNotification()
  → PushService.sendToUser()
  → markAsSent/markAsFailed

7. Environment Configuration ✅

File: maternal-app-backend/.env

# Push Notifications (Web Push - VAPID)
PUSH_NOTIFICATIONS_ENABLED=true
VAPID_PUBLIC_KEY=BErlB-L0pDfv1q3W0SHs3ZXqyFi869OScpt5wJ2aNu2KKbLxLj4a-YO6SyuAamjRG_cqY65yt2agyXdMdy2wEXI
VAPID_PRIVATE_KEY=Rg47clL1z4wSpsBTx4yIOIHHX9qh1W5TyBZwBfPIesk
VAPID_SUBJECT=mailto:hello@parentflow.com
PUSH_DEFAULT_TTL=86400
PUSH_BATCH_SIZE=100

Security: Keep VAPID_PRIVATE_KEY secret. Never expose in logs or client-side code.

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🌐 Frontend Implementation

1. Service Worker ✅

File: maternal-web/public/push-sw.js

Features:

• Listens for push events
• Shows notifications with custom icons, badges, and data
• Handles notification clicks (focus existing window or open new)
• Tracks notification dismissals
• Test notification support

Event Handlers:

• push - Receive and display notifications
• notificationclick - Handle user clicks, navigate to URLs
• notificationclose - Track dismissals
• message - Handle messages from the app

2. Push Utilities ✅

File: maternal-web/lib/push-notifications.ts

Utility Functions:

- isPushNotificationSupported(): boolean
- getNotificationPermission(): NotificationPermission
- requestNotificationPermission(): Promise<NotificationPermission>
- getVapidPublicKey(token): Promise<string>
- registerPushServiceWorker(): Promise<ServiceWorkerRegistration>
- subscribeToPush(token): Promise<PushSubscription>
- savePushSubscription(subscription, token): Promise<void>
- getPushSubscription(): Promise<PushSubscription | null>
- unsubscribeFromPush(token): Promise<void>
- isPushSubscribed(): Promise<boolean>
- sendTestPushNotification(token): Promise<void>
- getPushStatistics(token): Promise<any>
- showLocalTestNotification(): Promise<void>

Key Features:

• Browser compatibility checks
• VAPID key base64 conversion
• Service worker registration
• Subscription management
• Backend API integration

3. UI Component ✅

File: maternal-web/components/PushNotificationToggle.tsx

Features:

• Toggle switch to enable/disable push notifications
• Permission status display
• Error handling and user feedback
• Test notification button
• Loading states
• Dark mode support
• Responsive design

Component States:

• Unsupported browser warning
• Permission denied message
• Subscribed confirmation with test button
• Loading indicator

Usage:

import PushNotificationToggle from '@/components/PushNotificationToggle';

// In settings page
<PushNotificationToggle />

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🔧 Testing Guide

Backend Testing

1. Get VAPID Public Key:

curl http://localhost:3020/api/v1/push/vapid-public-key

2. Subscribe (requires auth token):

curl -X POST http://localhost:3020/api/v1/push/subscriptions \
  -H "Authorization: Bearer YOUR_JWT_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "endpoint": "https://fcm.googleapis.com/fcm/send/...",
    "keys": {
      "p256dh": "...",
      "auth": "..."
    }
  }'

3. Send Test Notification:

curl -X POST http://localhost:3020/api/v1/push/test \
  -H "Authorization: Bearer YOUR_JWT_TOKEN"

4. Get Statistics:

curl http://localhost:3020/api/v1/push/statistics \
  -H "Authorization: Bearer YOUR_JWT_TOKEN"

Frontend Testing

1. Open Web App: Navigate to http://maternal.noru1.ro

2. Go to Settings: Find the Push Notification Toggle component

3. Enable Notifications:

   • Click the toggle switch
   • Grant permission when prompted
   • Wait for confirmation

4. Test Notification:

   • Click "Send Test Notification" button
   • Check browser notifications

5. Test Full Flow:

   • Create a feeding/sleep/diaper activity
   • Wait for reminder notification (based on patterns)
   • Check notification appears

Browser Compatibility Testing

Test on:

• ✅ Chrome (Desktop & Mobile)
• ✅ Firefox (Desktop & Mobile)
• ✅ Edge (Desktop)
• ✅ Safari (iOS 16.4+ PWA only - must be installed to home screen)

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📊 Notification Flow

1. User Action (e.g., feeding activity)
   ↓
2. NotificationsService detects pattern
   ↓
3. createNotification() called
   ↓
4. Notification saved to DB
   ↓
5. sendPushNotification() triggered
   ↓
6. PushService.sendToUser() sends to all user's devices
   ↓
7. Web Push sends to browser
   ↓
8. Service Worker receives push event
   ↓
9. Service Worker shows notification
   ↓
10. User clicks notification
   ↓
11. Service Worker navigates to URL

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🔒 Security Considerations

VAPID Keys

• ✅ Private key stored in .env (never committed to git)
• ✅ Public key safe to expose to frontend
• ✅ Subject configured as mailto: contact email

Authentication

• ✅ All push endpoints require JWT authentication
• ✅ Users can only manage their own subscriptions
• ✅ Endpoint validation prevents injection attacks

Data Privacy

• ✅ Subscription endpoints hashed in logs
• ✅ User agent data stored for analytics only
• ✅ Inactive subscriptions auto-cleaned after 90 days
• ✅ Cascade delete when user is deleted

Rate Limiting

• ⚠️ TODO: Add rate limiting to push endpoints
• Recommended: 10 requests/minute per user for subscribe/unsubscribe
• Recommended: 100 notifications/day per user

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📈 Monitoring & Maintenance

Database Cleanup

Run periodic cleanup (recommended: daily cron job):

-- Delete inactive subscriptions older than 90 days
DELETE FROM push_subscriptions
WHERE is_active = false
AND updated_at < NOW() - INTERVAL '90 days';

Or use the service method:

await pushService.cleanupInactiveSubscriptions(90);

Statistics Monitoring

const stats = await pushService.getStatistics();
// Returns:
// {
//   totalSubscriptions: 150,
//   activeSubscriptions: 142,
//   inactiveSubscriptions: 8,
//   byBrowser: { chrome: 100, firefox: 30, safari: 12 },
//   byDeviceType: { mobile: 90, desktop: 50, tablet: 10 }
// }

Error Monitoring

Check push subscription errors:

SELECT user_id, endpoint, last_error, failed_attempts
FROM push_subscriptions
WHERE is_active = false
AND last_error IS NOT NULL
ORDER BY updated_at DESC
LIMIT 20;

---

🚀 Deployment Checklist

Production Deployment

• Generate production VAPID keys (npx web-push generate-vapid-keys)
• Add VAPID keys to production .env
• Set VAPID_SUBJECT to production email (mailto:support@parentflow.com)
• Enable HTTPS (required for Web Push)
• Test on all major browsers
• Set up monitoring for failed push deliveries
• Configure rate limiting
• Set up cleanup cron job
• Test notification appearance on mobile devices
• Verify service worker registration on production domain

Environment Variables (Production)

PUSH_NOTIFICATIONS_ENABLED=true
VAPID_PUBLIC_KEY=<production-public-key>
VAPID_PRIVATE_KEY=<production-private-key>
VAPID_SUBJECT=mailto:support@parentflow.com
PUSH_DEFAULT_TTL=86400
PUSH_BATCH_SIZE=100

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🎨 Customization Guide

Notification Appearance

Edit in maternal-web/public/push-sw.js:

const options = {
  body: data.body,
  icon: '/icons/icon-192x192.png',  // Change app icon
  badge: '/icons/icon-72x72.png',    // Change badge icon
  vibrate: [200, 100, 200],          // Customize vibration pattern
  tag: data.tag || 'default',
  data: data.data || {},
  requireInteraction: false,         // Set true for persistent notifications
};

Notification URLs

Edit URL routing in notifications.service.ts:

private getNotificationUrl(notification: Notification): string {
  switch (notification.type) {
    case NotificationType.FEEDING_REMINDER:
      return `/children/${notification.childId}/activities`;
    // Add custom routes here
  }
}

Notification Triggers

Add custom notification triggers in notifications.service.ts:

async createCustomNotification(userId: string, childId: string) {
  await this.createNotification(
    userId,
    NotificationType.CUSTOM,
    'Custom Title',
    'Custom Message',
    {
      childId,
      priority: NotificationPriority.HIGH,
      metadata: { customData: 'value' }
    }
  );
}

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🐛 Troubleshooting

Common Issues

Issue: "Push notifications not supported" Solution: Ensure HTTPS is enabled. Service Workers require secure context.

Issue: "Permission denied" Solution: User must manually reset permissions in browser settings.

Issue: "Subscription failed" Solution: Check VAPID public key is correctly fetched from backend.

Issue: "Notifications not appearing" Solution: Check browser notification settings, ensure service worker is registered.

Issue: "Push fails with 404/410" Solution: Subscription is invalid/expired. System auto-deactivates these.

Issue: "iOS not receiving notifications" Solution: On iOS, app must be installed as PWA (Add to Home Screen).

Debug Logs

Browser Console:

// Check service worker registration
navigator.serviceWorker.getRegistrations().then(console.log);

// Check current subscription
navigator.serviceWorker.ready.then(reg =>
  reg.pushManager.getSubscription().then(console.log)
);

// Check notification permission
console.log(Notification.permission);

Backend Logs:

# Check push service logs
tail -f /tmp/backend-dev.log | grep "\[Push\]"

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📚 References

• Web Push Notifications Guide
• VAPID Protocol
• Service Worker API
• Push API
• web-push NPM Package

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✅ Completion Status

Backend ✅

• Database schema (already existed)
• PushSubscription entity
• PushService implementation
• PushController with REST endpoints
• PushModule integration
• NotificationsService integration
• Environment configuration
• VAPID keys generated

Frontend ✅

• Service Worker (push-sw.js)
• Push utilities library
• PushNotificationToggle component
• Browser compatibility checks
• Error handling

Testing 🔄

• Backend compilation successful
• Backend running on port 3020
• End-to-end push notification test
• Multi-device testing
• Browser compatibility testing

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🎉 Next Steps

1. Test End-to-End Flow:

   • Log in to web app
   • Enable push notifications in settings
   • Send test notification
   • Create activities and verify smart notifications

2. Production Deployment:

   • Generate production VAPID keys
   • Update environment variables
   • Deploy to production
   • Test on production domain

3. Monitoring Setup:

   • Set up error tracking for failed push sends
   • Configure cleanup cron job
   • Set up analytics for notification engagement

4. Documentation:

   • Add push notification docs to user guide
   • Create admin documentation for monitoring
   • Update API documentation

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Implementation Complete! 🚀 The push notification system is ready for testing and deployment.