Node.js          Ruby on Rails          Python Django          PHP Laravel

WHAT IS / WHY NODE.JS?

• Server platform built on Chrome’s JavaScript V8 engine

• V8 is probably the fastest dynamic language interpreter around

• Node’s i/o facilities are really light weight

written by Ryan Dahl

DAWN OF ENTERPRISE JAVASCRIPT

Forrester Research:  Node.js is setting the stage for the “the biggest shift in enterprise development in more than a decade.”

CASE STUDY:   PAYPAL

• Enterprise applications built on Java

• Started a pilot project to evaluate Node

• Put 2 developers on the pilot vs 12 Java developers

• Ended up far exceeding everyone’s expectations

  • 7400 vs 18600 lines of code

  • Easier to read, easier to maintain

  • Created clean boundaries between UI, app logic and services

  • Node makes it easy to use the UI for experimentation

• 67 Node.js projects now in development in 18 months

CASE STUDY:  WALMART

• Black Friday traffic represents 70% of their annual website traffic

• Moved all their web servers over to Node

• Handled the Black Friday traffic without a hitch

• Now doubling their Node.js development team from 40 to 80 developers

OTHER ENTERPRISES

who made the move to Node

WHAT ENTERPRISES SAY

WHAT TO USE NODE FOR

• Ideal for building fast, scalable real-time applications

• Push technology over WebSockets
  (over port 80!)

• Handles two-way connections extremely well

WHAT ARE THE TOP USE CASES?

SAMPLE APPLICATIONS

• Chat server

• API on top of object store like MongoDB

• Queueing inputs to a db when receiving large amounts of concurrent data — such as real-time analytics

• Server-side proxy (like NGINX)

• Use Node stack for single page app dev

• Excellent for prototyping!

WHAT NOT TO USE NODE FOR

• CPU-intensive applications

• Server application that works with a relational DB

• Any application where a synchronous processing model is better suited

NODE.JS ARCHITECTURE

CALLBACK FUNCTIONS

• Creating asynchronous non-blocking code in Node is done with Callback functions

getStuff(inputParam, function(error, results) {
   if error is undefined
   do something with the results
}); 

NODE AS A WEB SERVER

• Built-in HTTP server

var http = require('http’);
var server = http.createServer(function(req, res) {
   res.write('Hello World') 
   res.end() 
});
 
server.listen(9000, function(){
   console.log('listening on port 9000') 
}); 

NODE MODULES

• Modules allow you to bring in external functionality into your Node app

• Modules can export variables, functions and objects

• Three main sources of Node modules

  • Node’s built-in modules — fs, http, os

  • Third party modules from npm

  • Creating your own modules

• Modules are a great way to organize your code

USING MODULES

• Create a function, make it available with either exports or module.exports

• Use it with require

// create module hello.js
var hello = function(){
   console.log('hello!') 
}; 
module.exports = hello;

// use the module in your main server file
var hello = require('./hello');
hello();
  

npmjs.org

USING MODULES

• Express.js

• Socket.io

• Jade

• Redis

• MongoDB

• Mongoose —
  MongoDB ORM

• Underscore

• Async

• Passport — auth

• Method-override

• Helmet — security

• Request — http client

• Restify — REST APIs

• Forever — keep Node server running

• Enables real-time bidirectional event-based communication
• Great for IM & chat apps, real-time analytics and concurrent document editing
• socket.io — 1.2 is available now

SOCKET.IO

SOCKET.IO SAMPLE APP

CHAT APP

code:   https://github.com/rauchg/chat-example/blob/master/index.js

SINATRA INSPIRED WEB APPLICATION FRAMEWORK FOR NODE

• Built-in HTTP server
• Request / response enhancements
• View support
• HTML & redirection helpers
• Ability to create robust APIs quickly & easily
• Model - View - Router architecture
• Does not hide any Node functions

EXPRESS.JS

written by T.J. Holowaychuck

SAMPLE EXPRESS.JS CODE

var express = require('express'); 
var app = express();  
 
app.get('/', function(req, res) {
   res.render("index"); 
}); 
 
app.get('*', function(req, res) {
   res.send("Page not found"); 
}); 
 
app.listen(3000, function() { 
   console.log("Listening on port 3000");
});

USING MIDDLEWARE WITH EXPRESS

• Intercept requests before it gets to any route
• Useful for authentication, validation, data parsing, session management and more

EXPRESS VIEW ENGINES

• Jade

• EJS

• Handlebars

• Swig

• Handlebars & Swig require a module

  • Consolidate.js,  Transformers

EXPRESS.JS EXAMPLE 

SIMPLE CMS APP

code:   https://github.com/markcalkins/nodesample

PROBLEMS WITH NODE & EXPRESS

• Callback hell

doAsync1(function () {
  doAsync2(function () {
    doAsync3(function () {
      doAsync4(function () {
    })
  })
})

SOLVING CALLBACK ISSUES

• async.js

• Q

• Promises (Node 0.12 supports ES6 promises)

• Generators (Node 0.11 supports ES6 generators)

• Koa.js — Express alternative with built-in generator support

• Strongloop article