Course Outline

🔹 Day 1: Foundations of Real-Time Communication

Session 1: Real-Time Web – Concepts & Use Cases

• Evolution of real-time web: polling → long polling → WebSockets
• Common use cases: chat apps, live dashboards, multiplayer games, collaborative tools
• Overview of transport protocols (HTTP, TCP, UDP)

Session 2: Introduction to WebSockets

• What are WebSockets? Full-duplex, persistent connections
• WebSocket lifecycle: handshake, open, message, close
• WebSocket API in the browser

Session 3: Building Your First WebSocket App

• Setting up a WebSocket server (Node.js + ws package)
• Writing a client to connect and send/receive messages
• Message handling and broadcasting

Lab Activities:

• Build a simple real-time chat app using vanilla WebSockets
• Monitor connection lifecycle and debug messages
• Handle JSON-based message protocols

🔹 Day 2: Real-Time Frameworks & Messaging Patterns

Session 1: Using Socket.IO for Robust Real-Time Apps

• Why Socket.IO? Features beyond native WebSockets
• Rooms, namespaces, reconnection, and broadcasting
• Server-side setup and client integration

Session 2: Real-Time Messaging Patterns

• One-to-one, one-to-many, many-to-many
• Publish/subscribe pattern
• Handling user presence and status

Session 3: Real-Time Error Handling and Reconnection

• Dealing with disconnects, retries, and fallbacks
• Timeout strategies and heartbeat/ping-pong mechanisms
• Middleware and authentication for Socket.IO

Lab Activities:

• Create a collaborative whiteboard app with Socket.IO
• Implement rooms and private messaging
• Add user presence indicators and reconnection logic

🔹 Day 3: Advanced Topics, Security & Deployment

Session 1: Scaling WebSockets for Production

• Horizontal scaling challenges
• Redis Pub/Sub with Socket.IO for multi-instance apps
• Load balancing and sticky sessions

Session 2: Security & WebSocket Best Practices

• Securing WebSocket connections (wss://, origin checks)
• Authentication using JWT or session cookies
• Rate limiting and DoS protection

Session 3: Alternative Real-Time Tech (Bonus)

• Server-Sent Events (SSE) vs WebSockets
• Introduction to WebRTC for peer-to-peer communication
• Integrating real-time updates with frontend frameworks (React/Vue)

Lab Activities:

• Secure WebSocket communication with HTTPS and token auth
• Scale an app using Redis adapter and test across multiple tabs
• Optional: Add real-time notifications with SSE