Node.js: Building a RESTful API

Nikos Kampitakis

Stavros Bastakis

September 10, 2015

Heraklion

Who is who

Stavros Bastakis:

• Web developer @ AdScience
• Three months of professional Node.js experience
• PHP background

Nikos Kampitakis:

• Software developer @ imgZine
• Founder @ webtrails
• One year of professional Node.js experience
• PHP previous years

What is Node.js

Node.js is

• a runtime environment
• for developing server-side web applications
• using Javascript
• open-source & cross-platform
• uses an event-driven & non-blocking I/O model 

How it works

Pitfalls

• CPU-intensive operations
• Exceptions bubbling up to the core event-loop
• Callback hell

Why Node.js (1/3)

• Asynchronous, event-driven
• Powered by V8. JavaScript not interpreted but compiled
• Performance in data-intensive operations
  • Fact 1. PayPal reported: double the number of requests per-second and reduced response time by 35% or 200 milliseconds.
  • Fact 2. On Black Friday the WalMart servers didn’t go over 1% CPU utilisation and the team did a deploy with 200,000,000 users online

Why Node.js (2/3)

• Unified API: Node.js combined with a browser, a document DB (mongodb) and JSON offers a unified JavaScript development stack.
• Even same libraries server and client side (see moment.js)
• Isomorphic (aka Universal) development
• One large pool of modules (npm) VS modules per platform
• Start with a small collection of modules and build up as you go VS large monolithic frameworks

Why Node.js (3/3)

• Built-in support for package management using the NPM tool that comes by default with every Node.js installation
• Large and fast-evolving community creates great modules/projects
• Shorter development cycles
• Developers love it!

The Callback Hell

• What is a callback function?
• Used for asynchronous calls

Example

Async lib to the rescue

async.series([
    function(callback){
        // do some stuff ...
        callback(null, 'one');
    },
    function(callback){
        // do some more stuff ...
        callback(null, 'two');
    }
],
// optional callback
function(err, results){
    // results is now equal to ['one', 'two']
});

• Async is a utility module which provides straight-forward, powerful functions for working with asynchronous JavaScript.
• Async provides around 20 functions that include the usual 'functional' suspects (map, reduce,filter, each…) as well as some common patterns for asynchronous control flow (parallel,series, waterfall…).
• Example:

Usefull node modules

• Express - web framework for Node.js
   
• Request - make HTTP calls easily from your Node.js app
   
• Lodash - toolkit of Javascript functions for manipulating objects and collections
   
• Moment - Full featured library for manipulating dates
   
• Passport - authentication middleware for Node.js
   
• Want more..?
  http://www.npmjs.com

RESTful API

Project: Task list

• GET /tasks : list all the tasks
• POST /tasks : create new task
• GET /tasks/{task_id} : get a task
• PUT /tasks/{task_id} : edit a task
• DELETE /tasks/{task_id} : delete a task

Postman

Postman is a Chrome Addon that helps us build, test, and document our APIs faster. It provides en easy way to build and store requests and a nice interface to check the responses.

Node Inspector

Node Inspector is a debugger interface for Node.js applications that uses the Blink Developer Tools (formerly WebKit Web Inspector).

$ npm install -g node-inspector

$ nodemon --debug app.js

$ node-inspector app.js

Related topics

• Template engines: Handlebars - Jade - Swig
• MongoDB
• Promises

Thank you!

Nikos Kampitakis

@kabitakis

gr.linkedin.com/in/kabitakis

nikos@webtrails.gr

Stavros Mpastakis

@sstauross

linkedin.com: Stavros Bastakis

staurosmpa@gmail.com