Node.js

Created by Maksym Tarasenko

Agenda

Node Basics
Express.js
Mongo/Mongoose
SOCKET.IO

Node Basics: What is node?

v8 javascript engine
Event drivin
Non-blocking standart libraries
C\C++ adons
NPM

Node Basics: JavaScript Everywhere

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

Node Basics: Vibrant Community

340,000+ packages on npm
Top corporate sponsors
Huge wealth of JS code

Node Basics: 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

Event Loop

Modules

Prevents pollution of the global scope
Module structure
module.exports
Caching

Modules: require


						var module1 = require('module1');
						var module1 = require('./node_modules/module1/index.js');
						var module2 = require('./module2');
						var module3 = require('../module3');

Modules:


						exports.log = function(msg) {
							console.log(msg);
						}

						module.exports = function Loger() {
							this.log = function(msg) {
								console.log(msg);
							}
						};

NPM

package.json
npm init
npm install
npm publish

package.json (1)

{
	"name": "3_npm_test",
	"version": "1.0.0",
	"description": "test package",
	"main": "main.js",
	"scripts": {
		"test": "echo \"Error: no test\" && exit 1",
		"runMain": "node main.js"
	}
}

package.json (2)

{
	"repository": {
		"type": "git",
		"url": "git+https://github.com/itmoh/node-mentoring.git"
	},
	"keywords": [
		"node"
	],
	"author": "maxim tarasenko",
	"license": "ISC",
	"bugs": {
		"url": "https://github.com/itmoh/node-mentoring/issues"
	},
	"homepage": "https://github.com/itmoh/node-mentoring#readme"
}

Some Commands

npm init
npm install [--save] [--save-dev] [-g]
npm run some_command
npm adduser
npm publish
npm version

test_1

Acync Code

Node-style
Promises (Q)
Async
Generators(ES6)

Node-style


						var someModule = require('./some_module');
						someModule.sum({ x: 1, y: 2 }, function(err, result) {
							if (err) {
								console.log(err);
								return;
							}
							console.log(result);
						});

Promises (Q)


						var someModule = require('./some_module');
						var qSum = Q.denodeify(someModule.sum);
						Q({ x: 1, y: 2 })
							.then(qSum)
							.then(function(result) {
								console.log(result);
							})
							.catch(function(error) {
								console.log(error);
							});

Async


						var async = require('async');
						var someModule = require('./some_module');
						async.waterfall([
							function(callback) {
								callback(null, { x: 1, y: 2 });
							},
							someModule.sum,
							function(result, callback) {
								console.log(result);
							},
						], function (err, result) {
							console.log(err);
						});

Generators(ES6)


						var Q = require('Q');
						var co = require('co');
						var someModule = require('./some_module');
						var qSum = Q.denodeify(someModule.sum);
						function* test() {
							try {
								var result = yield qSum({x: 1, y: 2});
								console.log(result);
							} catch(err) {
								console.log(err);
							}
						};
						co(test);

Streams

Events
fs
http
stream-adventure

Events


						var EventEmitter = require('events');
						var emitter = new EventEmitter();
						var listener = (arg) => {console.log(arg);};
						emitter.on('test', listener);
						setTimeout(function() {
							emitter.emit('test', 'Hello world');
							emitter.removeListener('test', listener);
							emitter.emit('test', 'Hello world');
						}, 1000);

fs + http


						var http = require('http'),
						fs = require('fs');
						http.createServer(function(request, response) {
							if (req.method === 'POST') {
								fs.readFile('./data.csv', 'utf-8', function(err, data) {
									response.end(data);
								});
							} else res.end('send me a POST\n');
						}).listen(3000);

test_2

Development & Debug

nodemon, pm2
node-inspector

Express.js

Middleware
Routing
Templating

Middleware concept


						var express = require('express');
						var app = express();
						app.use(bodyParser.json());
						app.use(function (req, res, next) {
							console.log('Time:', Date.now());
							next();
						});
						app.get('/user', function(req, res) {
							res.send('hello user');
						});
						app.listen(3000, function () {
							console.log('Example app listening on port 3000!');
						});

Routing

Respond to HTTP requests with a callback
Supports variable placement in routes
Easy to serve JSON
Routing filter types

Routing


						app.get('/', function (req, res) {});
						app.post('/:id', function (req, res) {});

						var express = require('express');
						var router = express.Router();
						router.put(/\/abc|\/xyz/, function (req, res) {}});
						router.delete(['/', '/:id'], function (req, res) {});

Templating


						app.set('view engine', 'ejs');
						app.locals.title = 'My App';
						app.get('/', function (req, res) {
							res.locals.someText = 'test';
							res.render('test', { message: 'Hello there!'});;
						});

test_3

MongoDB Basics

DataBase
Collection
Document
Field

Create


					db.unicorns
						.insert({
							name: 'Aurora', 
							dob: new Date(1992,2,13,7,47), 
							loves: ['carrot','papaya'], 
							weight: 600, 
							gender: 'm', 
							vampires: 63
						});

Find


						db.unicorns.find({gender: 'm', weight: {$gt: 700}})
						db.unicorns.find({gender: {$ne: 'f'}, weight: {$gte: 701}})
						//$lt, $lte, $gt, $gte, $ne, $or
						db.unicorns.find({
							gender: 'f', 
							$or: [
								{loves: 'apple'}, 
								{loves: 'orange'}, 
								{weight: {$lt: 500}}
							]})
						//Projection
						db.unicorns.find({vampires: {$exists: false}}, { name:1, _id: 0})
							.skip(2)
							.limit(5)
							.sort({name:1})

update


						db.unicorns.insert({})
						db.unicorns.insert([{}, {}])
						db.unicorns.update(
							{gender: 'm'},// selector
							{
								$set: {loves: "grape"},
								$currentDate: {dob: true}
							},//update
							{
								multi: true,
								upsert: true
							}
						)
						// remove all
						db.unicorns.remove({})
						// remove match condition
						db.unicorns.remove({type: "food"})
						// remove match condition only one
						db.unicorns.remove({type: "food"}, 1)

ORM-way: Mongoose

SCHEMA
MODEL
Fields types

Connection


						var mongoose = require('mongoose');
						mongoose.connect('mongodb://localhost/test');
						var db = mongoose.connection;
						mongoose.Promise = require('q').Promise;
						db.on('error', function(err) {
							console.error('connection error:', err));
						});
						db.once('open', function (callback) {
							console.log('connected');
						});

MODEL


						var mongoose = require('mongoose');
						var Schema = mongoose.Schema;
						var RolesSchema = new Schema({
							role: {
								type: String,
								required: true
							},
							date: {type: Date, default: Date.now},
							members: [{ type: String }]
						}, {collection: 'roles'});
						module.exports = mongoose.model('Roles', RolesSchema);

MODEL


						RolesSchema.methods.findAllMembersRoles = function () {
							return this.model('Roles').find({members: this.members});
						}
						RolesSchema.statics.findByName = function (name) {
							return this.find({role: new RegExp(name, 'i')});
						}
						RolesSchema.virtual('membersAll')
							.get(function () {
								return this.members.join(',');
							})
							.set(function (members) {
								var membersArray = members.split(',');
								this.members = membersArray;
							});

Work with model: Save


						var newModel = new model({
							role: 'dev',
							members: ['user1', 'user3']
						});

						newModel.save(function (err) {
							if (err) return handleError(err);
							saved!
						});
						newModel.save()
							.then()
							.catch()

Work with model: Find


						model.find({role: 'dev'})
							.skip(skip)
							.limit(limit)
						
						model.findById(id)
							.then(function (modelInstance) {
								var updatedInstance = _.extend(modelInstance, req.body);
								return updatedInstance.save();
							})

Work with model: Find


						model.remove({role: 'dev'})

						model.update({
								role: 'dev'
							}, {
								$set: {members: ['user2']}
							})

test_4

REALTIME

Periodic Polling
Long Polling
Forever Frame
WebSockets

SOCKET.IO


						var io = require('socket.io')(8080);
						io.on('connection', function (socket) {
							socket.emit('greet', {
								hello: 'world'
							});
							socket.on('message', function (from, msg) {
								console.log('message by ', from, ' saying ', msg);
							});
							socket.on('disconnect', function () {
								socket.emit('user disconnected');
							});
						});

SOCKET.IO


						<script src "/socket.io/socket.io.js"></script>
						<script>
							var socket = io('http://localhost:8080');
							socket.on('greet', function (data) {
								console.log(data);
								socket.emit('message', 'user', 'hello');
							});
						</script>

BROADCAST & VOLATILE


						var io = require('socket.io')(8080);
						io.on('connection', function (socket) {
							socket.broadcast.emit('new user connected');
						});
						var io = require('socket.io')(8080);
						io.on('connection', function (socket) {
							var tweets = setInterval(function () {
								getCatsTweets(function (tweet) {
								socket.volatile.emit('cats tweet', tweet);
								});
							}, 100);
							socket.on('disconnect', function () {
								clearInterval(tweets);
							});
						});

Node.js

Agenda

Node Basics: What is node?

Node Basics: JavaScript Everywhere

Node Basics: Vibrant Community

Node Basics: Sweet Spots

Event Loop

Event Loop

Event Loop

Event Loop

Event Loop

Modules

Modules: require

Modules:

NPM

package.json (1)

package.json (2)

Some Commands

test_1

Acync Code

Node-style

Promises (Q)

Async

Generators(ES6)

Streams

Events

fs + http

test_2

Development & Debug

Express.js

Middleware concept

Routing

Routing

Templating

test_3

MongoDB Basics

Create

Find

update

ORM-way: Mongoose

Connection

MODEL

MODEL

Work with model: Save

Work with model: Find

Work with model: Find

test_4

REALTIME

SOCKET.IO

SOCKET.IO

BROADCAST & VOLATILE

Questions?