Socket.IO

• cross browser (including IE6)
• Real-time and bi-directional persistent connection (WebSocket)
• Wworking for https and cross-domain (if use webSocket or JSONP)
• Authentication . Cookie & Session . Cookie does not cross domain, use SSL + Access Token instead
• Use Nginx for loading Balancing.
• Configurations . Store(default: memoryStore, single process only) . transports(default: websocket, htmlfile, xhr-polling, jsonp-polling) . authorization (default: false)
• Socket.IO primarily use WebSocket, but can fallback to other methods lik AJAX Long polling, JSONP polling In addition to 1-to-1 communication as in WebSocket, it enables broadcasting to multiple nodes

modules

• Redis
• Socket.io
• isomorphic-fetch
• node-jsonwebtoken

Q&A

• Pub/Sub or Message Queue

Processing flow

1. in browser, when React Component is rendered, in componentDidMount fires a socket.emit,
2. in server, socket.on is triggered and does redis publish
3. in server, redis.on does redis-stuff (hgetall…)
4. in server, redis.on fires socket.emit() to pass/broadcast data to browser.
5. in browser, socket.on is triggered to process the data, and render the components.

Reference

• Forever Iframe
• XMLHttpRequest Long Polling
• Cometed
• Websocket