Migrate from Ably to Socket.IO for unlimited concurrent users

[Copilot]

Removes Ably dependency (200 user limit, $29-299/month) and completes migration to Socket.IO (unlimited users, $0). Infrastructure and client code already in place; this PR removes legacy code and hardens security.

Changes

Dependencies

• Removed ably package and 30 dependencies
• Deleted lib/ably.ts and backend/utils/ably-server.ts

Security

• Enhanced CSP in backend/middleware/security.ts with URL validation and WebSocket support
• Removed Ably CDN references
• Updated SECURITY_AUDIT_REPORT.md - marked API key exposure as resolved

Documentation

• Added DEPLOYMENT_CHECKLIST.md and MIGRATION_COMPLETE.md
• Updated cost analysis and architecture diagrams

Security Improvement

Before:

// ❌ Client-exposed API key
const ably = new Ably.Realtime({ 
  key: process.env.NEXT_PUBLIC_ABLY_CLIENT_KEY 
});

After:

// ✅ No API keys needed, server-side auth only
const socket = getSocketClient(); // WebSocket to same origin

Impact

• Cost: $0 vs $29-299/month
• Scale: Unlimited vs 200 concurrent users
• Security: No exposed API keys
• Latency: 20-50ms vs 50-100ms (same-server WebSocket)

Deployment Notes

Remove from production .env:

ABLY_API_KEY
NEXT_PUBLIC_ABLY_CLIENT_KEY

Vercel has limited WebSocket support - consider Railway/Render/DigitalOcean for production.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• fonts.googleapis.com
  • Triggering command: /usr/local/bin/node /home/REDACTED/work/QuestEd/QuestEd/node_modules/next/dist/compiled/jest-worker/processChild.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

feat: Migrate from Ably to Socket.IO for unlimited concurrent users

🚀 Major Migration: Ably → Socket.IO

Objective

Complete migration from Ably (200 user limit, $29+/month) to Socket.IO (unlimited users, $0 forever) while maintaining 100% feature parity.

✅ What Changed

Infrastructure

• ✅ Installed Socket.IO (socket.io + socket.io-client)
• ✅ Created custom Next.js server with Socket.IO integration (server.ts)
• ✅ Implemented room-based pub/sub architecture
• ✅ Added global instance persistence for hot reload compatibility

Backend

• ✅ /backend/socketServer.ts - Socket.IO server initialization with CORS
• ✅ /backend/utils/socket-server.ts - Server-side publishing utilities
• ✅ Event relays: leaderboard-update, live-test-update, answer-submitted

Client Library

• ✅ /lib/socket.ts - Complete Socket.IO client with Ably-compatible API
• ✅ All functions: subscribe/publish for tests, quizzes, materials, announcements
• ✅ Auto-reconnection, WebSocket + polling fallback

API Routes (8 files updated)

• ✅ Materials: /api/teacher/materials/*
• ✅ Announcements: /api/teacher/announcements/*
• ✅ Quick Quiz: /api/quick-quiz/join, /api/quick-quiz/[id]/start
• ✅ Classroom invites: /api/teacher/classrooms/[id]/invite

Client Components (8 files updated)

• ✅ Student test page: Real-time leaderboard
• ✅ Teacher live page: Real-time control
• ✅ Quick quiz: Host page, take page, live page
• ✅ Materials & Announcements pages
• ✅ NotificationBell component

Configuration

• ✅ Updated .env.example - Removed Ably, added Socket.IO docs
• ✅ Updated next.config.mjs - Removed Ably env vars
• ✅ Updated package.json - Scripts use tsx server.ts
• ✅ Updated install.sh - Removed Ably setup instructions

Documentation

• ✅ /docs/SOCKET_IO_MIGRATION.md - Complete migration guide
• ✅ /docs/FEATURE_PARITY_AUDIT.md - 100% parity verification
• ✅ /docs/SOCKET_IO_SECURITY_AUDIT.md - Comprehensive security audit
• ✅ Updated README.md - Highlighted unlimited users benefit

🎯 Feature Parity: 100%

Feature	Ably (Before)	Socket.IO (After)	Status
Live test broadcasting	✓	✓	✅ 100%
Real-time leaderboards	✓	✓	✅ 100%
Quick quiz participants	✓	✓	✅ 100%
Answer submissions	✓	✓	✅ 100%
Materials notifications	✓	✓	✅ 100%
Announcements	✓	✓	✅ 100%
Classroom invites	✓	✓	✅ 100%
User notifications	✓	✓	✅ 100%
Test/quiz completion	✓	✓	✅ 100%

🔒 Security Audit Results

Status: ✅ PASSED - Production Ready

• ✅ Zero Ably dependencies in active code
• ✅ No API keys required or exposed
• ✅ Secure WebSocket connections with CORS
• ✅ Room-based data isolation working
• ✅ Server-side validation enforced
• ✅ Authentication still required (JWT)
• ✅ No sensitive data in broadcasts

Security Score: A (Production Ready)

💰 Benefits

Metric	Ably (Before)	Socket.IO (After)	Improvement
Concurrent Users	200 (free tier)	Unlimited	♾️
Monthly Cost	$0-29+	$0 Forever	100% savings
Latency	50-100ms	20-50ms	50% faster
Control	Limited (SaaS)	Full	100% control
Scalability	Pay-per-use	Unlimited	∞

🧪 Testing Results

All features tested and verified working:

Quick Quiz Flow ✅

1. Create quiz → Join with code → Host sees participant instantly
2. Start quiz → Participants notified in real-time
3. Answer questions → Host sees answers live
4. Leaderboard updates → Position changes animate
5. Complete quiz → Results page working

Live Test Flow ✅

1. Create live test → Students join
2. Answer questions → Real-time score updates
3. Leaderboard updates → Position tracking working
4. Teacher ends test → Students redirected

Classroom Features ✅

1. Upload material → Students notified instantly
2. Create announcement → Real-time broadcast
3. Invite student → Bell notification working

📋 Commits in This PR

feat: migrate from Ably to Socket.IO for unlimited concurrent users
docs: update README and add Socket.IO migration documentation  
fix: restore missing real-time features for 100% Ably parity
fix: Socket.IO global persistence for API routes hot reload
docs: add comprehensive security audit + remove Ably references

🔧 Breaking Changes

None. This is a drop-in replacement. Users will not notice any difference except:

• ✅ Faster real-time updates
• ✅ No more 200 user limit warnings
• ✅ Same exact user experience

🚀 Deployment

Requirements:

• No new environment variables needed (Socket.IO uses same server)
• Optional: NEXT_PUBLIC_SOCKET_URL for separate API server

Compatible Platforms:

• ✅ Railway (recommended)
• ✅ Render
• ✅ DigitalOcean
• ✅ AWS EC2
• ⚠️ Vercel (...

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Project	Deployment	Preview	Comments	Updated (UTC)
quest-ed	Ready	Preview	Comment	Nov 3, 2025 6:37pm