Introduction to node.js by Ran Mizrahi @ Reversim Summit
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The document is an introduction to Node.js, detailing its features as a server-side JavaScript platform designed for scalable, non-blocking I/O applications. It highlights the comparison between Apache and Nginx web servers, emphasizing the advantages of Node.js with its event-driven architecture. Additionally, it discusses popular frameworks and tools within the Node.js ecosystem, such as npm, Express, Socket.io, and Mongoose.
![TDD/BDD using Mocha and Expect.js
“Normal” test:
var expect = require('expect.js');
describe('Array', function() {
describe('#indexOf()', function() {
it('Expect -1 when the value is not present', function() {
var array = [1, 2, 3];
expect(array.indexOf(4)).to.be(-1);
});
});
});
Run it..
$ mocha --reporter spec
Array
#indexOf()
✓ Expect -1 when the value is not present
1 test complete (5 ms)
Monday, April 1, 13](https://image.slidesharecdn.com/introtonodejs-ranmizrahi-130401124831-phpapp02/85/Introduction-to-node-js-by-Ran-Mizrahi-Reversim-Summit-44-320.jpg)
Introduction to node.js by Ran Mizrahi @ Reversim Summit
- 1. Monday, April 1, 13
- 2. Introduction to node.js Ran Mizrahi (@ranm8) Open Source Dpt. Leader @ CodeOasis Monday, April 1, 13
- 3. About CodeOasis • CodeOasis specializes in cutting-edge web solutions. • Large variety of customers (from startups to enterprises). • Technologies we love: • PHP - Symfony2 and Drupal • node.js (-: • HTML5 • CSS3 • AngularJS • Our Microsoft department works with C#, WPF, etc. Monday, April 1, 13
- 4. What is node.js?? • Server-side JavaScript development platform. • Built on top of Chrome’s JavaScript runtime engine V8. • Aims for easy development of scalable, non-blocking I/O, real time and network applications. • Written in C/C++ and JavaScript. • CommonJS module system. • node.js is single-threaded and uses event-loop. Monday, April 1, 13
- 5. What is V8?? • V8 is Google Chrome's JavaScript runtime engine. • Implements ECMAScript specification (5th edition). • Standalone and can be embedded to any C++ application. • Compiles JavaScript to native machine code before executing it instead of interpreting. • Open sourced under the new BSD license. Monday, April 1, 13
- 6. We all love burgers! Monday, April 1, 13
- 7. We all love burgers! Monday, April 1, 13
- 8. Thread per Connection Burgers Restaurant Monday, April 1, 13
- 9. Thread per Connection Burgers Restaurant Monday, April 1, 13
- 10. Thread per Connection Burgers Restaurant Monday, April 1, 13
- 11. Monday, April 1, 13
- 12. Something is WRONG, we must do it BETTER!!! Monday, April 1, 13
- 13. Event-driven Burgers Restaurant Monday, April 1, 13
- 14. Event-driven Burgers Restaurant Monday, April 1, 13
- 15. Apache vs. NGINX Performance Requests per second: Monday, April 1, 13
- 16. Apache vs. NGINX Performance Memory usage: Monday, April 1, 13
- 17. Apache vs. NGINX Performance So, what is the big difference between Apache and Nginx? • Apache uses one thread per connection. • Hard to scale. • Resource expensive. • NGINX is single-threaded and uses event-loop for handling requests. • Easy to scale. • Lower resources consumption. Monday, April 1, 13
- 18. Blocking Code What is the software doing while it queries to the DB?!? var response = db.query('select * form users'); // use the result Monday, April 1, 13
- 19. Blocking Code What is the software doing while it queries to the DB?!? var response = db.query('select * form users'); // use the result In most cases, nothing (/: Monday, April 1, 13
- 20. Blocking Code What is the software doing while it queries to the DB?!? var response = db.query('select * form users'); // use the result In most cases, nothing (/: • Better software should handle I/O differently! It should multitask. • Other tasks should be performed while waiting.. Monday, April 1, 13
- 21. Non-blocking Code Non-blocking code: db.query('select * form users', function(result){ // Use the result }); Monday, April 1, 13
- 22. Non-blocking Code Non-blocking code: db.query('select * form users', function(result){ // Use the result }); This is how I/O should be handled in concurrency, when the DB will respond, the given function will be executed. Monday, April 1, 13
- 23. So, Why Isn’t Everyone Using Non-blocking I/O This what we learn: puts('Enter you name:'); var name = gets(); puts('Hello ' + name); Monday, April 1, 13
- 24. So, Why Isn’t Everyone Using Non-blocking I/O This what we learn: puts('Enter you name:'); var name = gets(); puts('Hello ' + name); Considered too complicated (:/ puts('Enter you name here:'); gets(function(name) { puts('Hello ' + name); }); Monday, April 1, 13
- 25. Why JavaScript?! JavaScript is designed specifically to be used with an event-loop: • Anonymous functions, closures. • Only one callback at a time. • I/O through DOM event callbacks. • Web developers already know JavaScript (Makes the learning curve much smaller). Monday, April 1, 13
- 26. The node.js project • Provides purely event-driven, non-blocking infrastructure to write high concurrency applications. • Uses JavaScript for easy development of asynchronies apps. • Open source and extendable module system. https://github.com/popular/starred Monday, April 1, 13
- 27. Some Examples Monday, April 1, 13
- 28. Hello Reversim Summit! setTimeout(function() { console.log('Reversim Summit!'); }, 2000); console.log('Hello'); • The program outputs “Hello”, then waits two seconds and outputs “Reversim Summit!”. • While waiting for the timeout to complete, node.js will keep adjusting other tasks. • Node exits automatically when nothing is left to do. Monday, April 1, 13
- 29. Streaming HTTP Server var http = require('http'); var server = http.createServer(function(request, response) { response.writeHead(200, { 'Content-Type': 'text/plain' }); setTimeout(function() { response.end('Reversim Summit!n'); }, 2000); response.write('Hellon'); }); server.listen(8000); Monday, April 1, 13
- 30. Streaming HTTP Server var http = require('http'); var server = http.createServer(function(request, response) { response.writeHead(200, { 'Content-Type': 'text/plain' }); setTimeout(function() { response.end('Reversim Summit!n'); }, 2000); response.write('Hellon'); }); server.listen(8000); Let’s benchmark that... and see the results.. Monday, April 1, 13
- 31. Streaming HTTP Server var http = require('http'); var server = http.createServer(function(request, response) { response.writeHead(200, { 'Content-Type': 'text/plain' }); setTimeout(function() { response.end('Reversim Summit!n'); }, 2000); response.write('Hellon'); }); server.listen(8000); Let’s benchmark that... and see the results.. 20 secs, with single thread is the result of non-blocking structure. Monday, April 1, 13
- 32. DNS Resolver var dns = require('dns'); console.log('resolving google.com...'); dns.resolve('google.com', function(error, addresses) { if (error) throw error; console.log('found: ' + addresses.join(', ')); }); Resolves “google.com” and outputs the result. Monday, April 1, 13
- 33. Common Frameworks and Tools Monday, April 1, 13
- 34. NPM (Node.js package manager) npm is a package and dependency manager for node.js. Some of npm features: • Easy installation and publishing of node.js modules. • Manages module dependancies. • Easy to use. • Works in both global and local scope. Monday, April 1, 13
- 35. NPM (Node.js package manager) npm usage: Installs package in the current local directory: $ npm install express Installs package globally $ npm install express -g Monday, April 1, 13
- 36. Express Express is a minimal and flexible node.js web framework, providing robust set of features for building web applications. Taken from http://expressjs.com Some of express features: • Robust routing. • Redirection helpers. • View rendering and partials support. • Built on top of connect. Monday, April 1, 13
- 37. Express Web Server example: var express = require('express'); var app = express.createServer(); app.get('/', function(request, response) { // Return JSON encoded response response.json({ code: 200, message: 'OK', payload: null }); }); • Creates new express HTTP server with route for path “/”. • Returns JSON formatted response. Monday, April 1, 13
- 38. Socket.IO Socket.IO aims to make real-time apps possible in every browser and mobile device, blurring the differences between transport mechanisms. Taken from http://socket.io Some of socket.io main features: • Supports multiple transport mechanisms (WebSocket, Flash and AJAX long-polling fallback, etc.). • Management of sockets rooms and namespaces. • Disconnections detection through heartbeats. • Reconnection support with buffering. Monday, April 1, 13
- 39. Socket.IO - Simple notification example Server: var io = require('socket.io').listen(3000); io.on('connection', function(socket) { var notification = { body: 'Hello Reversim Summit!' }; socket.emit('notification', notification, function(response) { console.log(response); }); }); Client: var socket = io.connect('http://localhost:3000'); socket.on('notification', function(data, callback) { console.log(data.body); callback('Hello to you too!'); }); Monday, April 1, 13
- 40. Mongoose Mongoose aims to provide elegant MongoDB object modeling (ODM) for node.js. Some of mongoose main features: • Allows creating DB schemas. • Management of sockets rooms and namespaces. • Disconnections detection through heartbeats. • Reconnection support with buffering. Monday, April 1, 13
- 41. Mongoose Mongoose cat document example: var mongoose = require('mongoose'); mongoose.connect('localhost', 'my_db'); var CatSchema = mongoose.Schema({ name: { required: true, default: 'My cat' } }); var Cat = mongoose.model('Cat', CatSchema); var kitty = new Cat({ name: 'Kati' }); kitty.save(function(err) { if (err) throw err; console.log('Saved!') }); Monday, April 1, 13
- 42. TDD/BDD using Mocha and Expect.js Mocha Mocha is a feature-rich JavaScript test frameworks running on node and the browser, making asynchronies tests easy. Main features: • Supports both TDD and BDD styles. • Both browser and node support. • Proper exit status for CI support. • Really easy async tests. • node.js debugger support. • Highly flexible, choose and join the pieces yourself (spy library, assertion library, etc.). Monday, April 1, 13
- 43. TDD/BDD using Mocha and Expect.js Expect.js Expect.js is a minimalistic assertion library based on should.js Main features: • BDD style. • Compatible with all test frameworks. • Both node.js and browser compatible. • Standalone assertion library. Monday, April 1, 13
- 44. TDD/BDD using Mocha and Expect.js “Normal” test: var expect = require('expect.js'); describe('Array', function() { describe('#indexOf()', function() { it('Expect -1 when the value is not present', function() { var array = [1, 2, 3]; expect(array.indexOf(4)).to.be(-1); }); }); }); Run it.. $ mocha --reporter spec Array #indexOf() ✓ Expect -1 when the value is not present 1 test complete (5 ms) Monday, April 1, 13
- 45. TDD/BDD using Mocha and Expect.js “Async” test: var expect = require('expect.js'); function asyncCall(val ,callback) { var prefix = ' - '; setTimeout(function() { var newString = val + prefix + 'OK'; callback(newString); }, 500); } describe('asyncCall', function() { it('Add suffix that prefixed with - to the given string', function(done) { var testVal = 'Foo'; asyncCall(testVal, function(response) { expect(response).to.contain(testVal + ' - OK'); done(); }); }); }); Let’s run it... Monday, April 1, 13
- 46. Use Case FXP • Real-time notifications, forum threads and posts. • 30,000 concurrency connections! • We started with version 0.4 )-: and moved to 0.6.. • Today, runs on one web server for serving all those concurrent connections.. Monday, April 1, 13
- 47. Thank you! Questions? Monday, April 1, 13