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Agenda

• [Demo] DESIS Hackathon app
• Node.js
• Express.js
• Web Sockets
• Mongo DB

Disclaimer: I am not an expert in any of these.

Node.js

• Platform built on Chrome's JavaScript runtime (V8) for easily building fast, scalable network applications.
• Event driven "Server Side" JavaScript
• Non-blocking I/O. Async model.
  • Event loop
  • libev, libeio
• Authored by Ryan Dahl. Sponsored by Joyent
• Alternatives: Twisted for Python, Event Machine for Ruby

Node.js - Getting Started

• Installation
  • Using Installers - Mac, Linux and Windows
  • using Package Managers - Mac and Linux
  • Build from source - Mac and Linux
• node REPL
• Hello World
• Diving into Node.js #shamelessplug

Node.js - Concurrency

• I/O bound vs CPU bound
• Everything is asynchronous except your code
• Non-blocking I/O. Async model.
  • Event loop
  • libev, libeio
• Single stack environment
• Multi-processor concurrency?
  • child_process.fork()
  • For load balancing, use cluster module
• Ref: Node.js from Enterprise Java Perspective

Node.js - Globals

• global
• process
• console
• require()
• require.resolve()
• require.cache
• require.extensions [array]
• __filename, __dirname
• module, exports
• setTimeout, clearTimeout
• setInterval, clearInterval

Node.js - Modules

• Each file is a module
  • Core Modules (fs, os, http)
  • File Modules
• Module extensions (.js, .json, .node)
• Module resolution
• Cycles
• Module caching
• Node Package Manager - npm
• Modules wiki

Node.js - Frameworks

• Express.js
• Flatiron
• Derby
• Many more...

Express.js

• High performance, high class web development for Node.js
• Built on top of Connect
• Installation via npm
• Project template generation
• Features
  • Robust routing
  • View rendering (Jade)
  • Environment based configuration (NODE_ENV)
  • Settings - Internal & arbitary settings
  • Session support
  • Middleware

Web Sockets

The Awesome 'Socket.io'

• WebSocket-compatible server and client with fallback for legacy browsers
• Storing data associated with a client
• Namespace restriction
• Acknowledgements are possible
• Multiple transports and fallback
• More info: socket.io | Github

Socket.io - Browser Support

• WebSocket
• Adobe® Flash® Socket
• AJAX long polling
• AJAX multipart streaming
• Forever Iframe
• JSONP Polling

• Internet Explorer 5.5+
• Safari 3+
• Google Chrome 4+
• Firefox 3+
• Opera 10.61+

mongo DB {name:"mongo", type: "DB"}

• Document Oriented Storage
• Full Index Support
• Replication & High Availability
• Auto Sharding
• Querying
• Map/Reduce
• Fast In-Place updates