building-websocket-server

# Building WebSocket Server ## Overview Build scalable WebSocket servers for real-time bidirectional communication using the `ws` library, Socket.IO, or native framework WebSocket support. Handle connection lifecycle management, room/channel subscriptions, message broadcasting, heartbeat keepalive, and horizontal scaling with Redis pub/sub adapters. ## Prerequisites - Node.js 18+ with `ws` or `socket.io`, or Python 3.10+ with `websockets` or FastAPI WebSocket, or Go with `gorilla/websocket` - Redis for horizontal scaling with pub/sub adapter (Socket.IO Redis adapter, or manual pub/sub) - Load balancer configured for WebSocket upgrade (sticky sessions or proper `Upgrade` header forwarding) - JWT or session-based authentication for connection handshake - Monitoring for active connection counts and message throughput ## Instructions 1. Examine existing HTTP server configuration using Read and Grep to determine the framework and identify where WebSocket upgrade handling integrates. 2. Create a WebSocket server instance attached to the existing HTTP server, configuring the upgrade path (e.g., `/ws`, `/socket.io`) and allowed origins. 3. Implement connection authentication by validating JWT tokens or session cookies during the WebSocket handshake `upgrade` event, rejecting unauthorized connections before protocol switch. 4. Build a connection registry that tracks active clients with metadata (user ID, subscribed channels, connection time) for targeted message delivery. 5. Def...