Node.js @khasathan

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23/12/201317/6/2015

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Outline●Introduction to Node.js●Node.js Anatomy 101●Node Package Manager (NPM)●Node.js Control Flow●Developments●Deployments●Let's play with workshop

Example codes: https://github.com/khasathan/learning-node

Warning!

Buffalo gag alert

JavaScript can run on server side?

Introduction to Node.js

What is Node.js?●“Node.js is a platform built on Chrome's

JavaScript runtime for easily building fast, scalable network applications.”

- Nodejs.org

What is Node.js? (2)

Server side JavaScript

So what's IO.js?●Node.js fork●Bring ES6 to Node community●NPM compatible

Why use Node.js?●Non-Blocking I/O●V8 JavaScript engine (like Google Chrome run-

time)●Many modules (> 40,000)●NPM package manager●Use same language as Back-end/Front-end●High concurrent connections

Node.js use for ...●Modern Web application●Real-time application●Event-based application

Modern Web Application

Simple serverhttp = require('http');

http.createServer(function(req, res) {res.writeHead(200, {

'Content-Type': 'text/html; charset=utf-8'});res.write('Simple Node.js Server');res.end();

}).listen(3000, '127.0.0.1');

Simple server (2)

Who use Node.js

Who use Node.js (2)

Express●Web framework for Node.js●MVC●Template●Pretty URL

$npm install express

RESTful web service●$npm install restify

Socket.io●Real-time application●WebSockets

$npm install socket.io

Socket.io (2)● Socket.io transport

● Websocket● Xhr-polling● Jsonp-polling● Flashsocket● htmlfile

Real-Time Application

http://thstream-khasathan.rhcloud.com

Real-Time Application

Entzonet Notification

Event-Based ApplicationMyCat Back-end

Workers pool - Read un-reviewed documents- Create files queue- Watching status files- Distribute tasks to workers

idle

busy

Files queue

idle

Shouldn't be used for...●RDBMS, transaction●Heavy computation/Huge data processing

Blocking vs Non-Blocking●Blocking

Timeline

1

2

3

Blocking vs Non-Blocking●Non-Blocking

Timeline

1

2

3

Async Programming● Do next task without waiting for current task

end

fs = require('fs')

fs.readFile('bigfile.txt', function(err, data) {console.log(data)

})

console.log('Read big file')

Async Programming (2)

$node read-big-file.js

> Read big file> . . . data from big file . . .

Node.js Anatomy 101

Event Loop

console.log('print 1');

compute(data, function(item) {processItem(item);

});

doLargeCompute();

console.log('print 2');

Call stack

Run-time

Event loop

Message queue

DoLargeCompute

Event loop

Node Package Manager (NPM)

NPM●Package manager for JavaScript●Dependencies management

First step with NPM●$npm initname: (learning-node) version: (1.0.0) description: Example code for Node.js tutorialentry point: (index.js) test command: git repository: https://github.com/khasathan/learning-nodekeywords: author: khasathanlicense: (ISC)

●$npm init

Now, we got package.json file

package.json

npm install/uninstall

# install locally$npm install <package_name>

# install globally$npm install -g <package_name>

# uninstall locally$npm uninstall <package_name>

# uninstall globally$npm uninstall -g <package_name>

npm install/uninstall (2)

● “-g” option you may be use “sudo”● Globally installation you can use its like ls, cd, cp, mv etc.

● Locally installation modules are located in node_modules/

--save options

$npm install - -save redis

--save-dev options

$npm install - -save-dev mocha

npm search

$npm search <keyword>

Node.js Control Flow

Node.js Control Flow●Callback●Promise●Event

Callback vs Promise vs Event●Callback is “Function”●Promise is “Object”●Event is “Event”

Callbackfs = require('fs');

fs.readFile('bigfile.txt', function(err, data) {console.log(data);

});

console.log('print this');

Callback (2)fs = require('fs');

var readfile = function (err, data) {console.log(data);

}

fs.readFile('bigfile.txt', readfile);

console.log('print this');

Callback (3)

fs = require('fs');

var readfile = funtion (err, data) {if(err) throw err;

console.log(data);}

fs.readFile('bigfile.txt', readfile);

console.log('print this');

●How does callback work?

Callback (4)

fs = require('fs');

var readfile = funtion (err, data) {Cb1(function (data1) {

Cb2(function (data2) {Cb3(function (data3) {

Cb4(function (data4) {... do something ...

});});

});});

};

fs.readFile('bigfile.txt', readfile);console.log('print this first');

●Callback pyramid hell

Promise●Delay? Future?●Object that holds value

Promise (2)Fulfilled

The action relating to the promise succeeded.

RejectedThe action relating to the promise failed.

PendingHasn't fulfilled or rejected yet.

SettledHas Fulfilled or rejected.

Promise

See weather-reporter-promise.js

Event● Do function when event fired

Event (2)var mytask = doMyTask();

mytask.on('success', function() {// do this if success

});

mytask.on('progress', function() {// do this if in progress

});

mytask.on('error', function() {// my task if error

});

Callback vs Promise vs Event●Callback is “Function”●Promise is “Object”●Event is “Event”

When we use callback?When we use promise?

When we use event?

Control Flow Libraries●Async●Step●Q●EventEmitter built-in←

Developments

Developments●Make your own function with callback●Custom module●Code quality●Unit testing●Logging●Node Version Manager (NVM)

Make Function with Callback

See function-with-callback.js

Custom module

See folder custom_module/

Code Quality$npm install -g jslint

$jslint file.js

Unit testing●Make small unit works●Unit testing frameworks

●Nodeunit●Mocha●Chai

●TDD/BDD

Node Version Manager (NVM)

●Use several version of Node, IOjs on one machine

●Website https://github.com/creationix/nvm

Deployments

Deployments●Reverse Proxy – use app on port 80●Forever – running app forever

Reverse Proxy●Nginx - Supported (>= V1.3)●HAProxy - Supported●Apache2 (>=V2.4 with websocket tunnel

module)●For Apache < 2.4 you may be use transport

such as xhr-polling, jsonp-polling

Forever●Process monitoring for Node.js●Keep application always running

$sudo npm -g forever$forever list$forever [start|stop] app.js$forever --help

Let's play with workshop

Redis●Redis Stands for “REmote Dictionary Server”●Key-value NoSQL database●PUBLISH/SUBSCRIBE provided

Publish/Subscribe●Sometime we know as “Pub/Sub”●Message-oriented middleware system

Channelsubscriber subscriber

subscriber

publisher

subscribersubscriber

The Funny Scoreboard

https://github.com/khasathan/learning-node