node.js workshop

the re-nodening

Presented by Shubhra Kar / @shubhrakar

Agenda

  • Why node.js?
  • Node JavaScript Runtime Basics
  • Routing and templating with Express
  • Persistence Options
  • Realtime Apps with Socket.io
  • Sharing Code and Culture with the Client with Browserify
  • Further Reading

doing is for doers

  • This is a workshop for DOers
  • Lots of live code
  • Lots of hands-on experimentation

why might I want to use node?

JavaScript Everywhere

  • Code reuse (minimal)
  • Same programming culture on client and server
  • Lots of JavaScript programmers

Vibrant Community

  • 60,000+ packages on npm
  • Top corporate sponsors
  • Huge wealth of JS code

Sweet Spots

  • Real-time/high concurrency apps (I/O Bound)
  • API tier for single-page apps and rich clients (iOS, Android)
  • Service orchestration
  • Working with document (JSON-style) databases

Not So Sweet Spots (For Now)

  • Simple CRUD Apps (Frameworks not as good)
  • Not as fast as some for CPU-intensive stuff

node.js basics

What is node.js?

  • v8 JavaScript runtime
  • Event driven
  • Non-blocking standard libraries
  • Most APIs speak Streams
  • Extensible via C/C++ add-ons
  • Provides a package manager and module system for JS/native extensions

What node is not

  • A framework like Django or Rails
  • A new programming language

Interactive Mode

  • Great for quick tests
  • [Demo - node console]

Standard libraries

  • Async by default
  • Low level
  • HTTP is first class citizen
  • [Demo - hello world]

Developing and Debugging

  • Lots of different choices
  • nodemon (faster cycles)
  • node-inspector (step-through debugging)
  • [Demo - supervisor and debugging]

CommonJS Modules

  • Prevents pollution of the global scope
  • Two Styles of module development
  • [Demo - your own local modules]

npm

  • node's package manager (ruby gems)
  • handles and resolves dependencies (Bundler)
  • ~60,000 modules available today (easy to publish)
  • [Demo - npm init and shameless plug]

Challenge One

and

Challenge Two

get the code

Routing and templating with express

Express at a high level

  • Based on Connect (a bit like Rack)
  • De facto standard framework of node web apps
  • Minimalistic, unopinionated
  • Supports a variety of middleware
  • Alternatives: hapi, restify, geddy, koa

Routes

  • Respond to HTTP requests with a callback
  • Supports variable placement in routes
  • Easy to serve JSON
  • [Demo - some basic routing and HTTP testing in Chrome]

Middleware

  • Some useful built in middleware (like bodyParser)
  • Useful for preprocessing requests
  • Authentication/Authorization
  • [Demo - some simple middleware, and how to use it]

Challenge Three

Persistence

Popular node.js options

  • SQL libraries supported, but not especially popular
  • Best community support is around Postgres (JSON column)
  • Document stores more popular, good fit for JS
  • MongoDB or CouchDB are popular primary durable data stores
  • redis is popular for fast, in-memory data storage

Mongoose

Mongoose Concepts: Schema

  • MongoDB by default enforces no data format
  • Mongoose does with the "Schema" object
  • Schema: define data types, validation, instance, and "static" functions

Mongoose Concepts: Model

  • Representation of a MongoDB document
  • Synthesized from a Schema
  • You use the Model to actually create, query, and modify documents

Hosted MongoDB

Challenge Four

Real time apps with socket.io

Socket.io at a high level

  • Thin wrapper around WebSockets
  • Works in tandem with an HTTP Server
  • Documentation: less than awesome, wiki is better than site

Key Features

  • Client/Server Push
  • Broadcast
  • Client "session" information
  • Message namespaces
  • Plain ol' WebSockets API as well

Challenge Five

Sharing Code and Culture with Browserify

What is Browserify?

  • node-style require in the browser!
  • self-contained node module environment
  • use local, core, or npm-installed modules

Why would I want to use Browserify?

  • Helps you write modular code on the client
  • no futzing with client-side script loading
  • share client and server code
  • Have the same code style, package management, and module system as server! Why have two different paradigms?

Fun Browserify Features

  • Provides browser shims for lots of node core
  • can provide modules with alternate entry points when used by browserify
  • Source Maps

Challenge Six

Further Reading

Moving To Production

VPS Options

  • Have had good experiences with Linode
  • Use the Node KO stack script
  • More info
  • Also hear good things about Digital Ocean

PaaS Options

  • Heroku
  • Nodejitsu
  • AppFog
  • Red Hat OpenShift

Streams

More Exercises and Reinforcement

@shubhrakar

skar@strongloop.com