# Nginx Configuration for Flask-SocketIO with WebSocket Support

This document provides the required Nginx configuration to properly proxy WebSocket connections for the Markov Economics application.

## Required Nginx Configuration

```nginx
server {
    listen 80;
    server_name markov.elpatron.me;
    
    # Optional: Redirect HTTP to HTTPS
    return 301 https://$server_name$request_uri;
}

server {
    listen 443 ssl http2;
    server_name markov.elpatron.me;
    
    # SSL configuration (adjust paths as needed)
    ssl_certificate /path/to/cert.pem;
    ssl_certificate_key /path/to/private.key;
    
    # WebSocket proxy settings
    location /socket.io/ {
        proxy_pass http://127.0.0.1:5000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        
        # WebSocket specific timeouts
        proxy_read_timeout 86400;
        proxy_send_timeout 86400;
        proxy_connect_timeout 60;
        
        # Disable buffering for real-time communication
        proxy_buffering off;
        proxy_cache off;
    }
    
    # Regular HTTP traffic
    location / {
        proxy_pass http://127.0.0.1:5000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        
        # Standard timeouts
        proxy_read_timeout 30;
        proxy_send_timeout 30;
        proxy_connect_timeout 10;
    }
}
```

## Critical Configuration Points

1. **WebSocket Upgrade Headers**: The `Upgrade` and `Connection` headers are essential for WebSocket handshake
2. **HTTP Version**: Must use HTTP/1.1 for WebSocket support
3. **Extended Timeouts**: WebSocket connections need longer timeouts than regular HTTP
4. **Disable Buffering**: Real-time communication requires immediate data flow
5. **Separate Location Blocks**: Socket.IO traffic should be handled separately from regular HTTP traffic

## Testing the Configuration

After applying the configuration:

1. Restart Nginx: `sudo nginx -t && sudo systemctl reload nginx`
2. Check browser console for connection messages
3. Test the debug endpoint: https://markov.elpatron.me/debug
4. Run the distribution test: Open browser console and type `testDistributionChart()`

## Troubleshooting

If WebSocket connections still fail:
- Check Nginx error logs: `sudo tail -f /var/log/nginx/error.log`
- Verify the application is accessible directly: `curl http://127.0.0.1:5000/health`
- Test WebSocket connection manually with tools like `wscat`
- Ensure firewall allows WebSocket traffic

## Alternative: Fallback to Polling Only

If WebSocket cannot be made to work, the application will automatically fall back to HTTP polling, which should work with any standard HTTP proxy configuration.