Intro to Node

Intro to Node.JS
By Aaron Stannard
Startup Developer Evangelist, Microsoft Corporation

Examples from Today’s Talk
https://github.com/Aaronontheweb/introtonode

Meet Node
var http = require('http');
//Node function called each time a new HTTP request arrives
function onRequest(req, res){
res.writeHead(200, {'Content-Type':'text/plain'});
res.end('Hello ' + req.connection.remoteAddress + '!');
/* Write the IP addresses of our connecting client to console */
console.log('Incoming connection from ' +
req.connection.remoteAddress);
}
//Listen for connections on the port provided by the host process
var server = http.createServer(onRequest).listen(process.env.PORT);

What Is Node?
• Server Side JavaScript
• Asynchronous Web Framework
• Evented I/O Model

What Is Node?
Network I/O Libraries
+
+
=

What Makes Node Special?
• Uses the familiar JavaScript programming
model to enable server-side development
• Buries the pain of working with async /
parallel programming
• No Blocking I/O
• Can handle large concurrent loads more easily
than other technologies
• Not a silver bullet

Why Node
JavaScript is ubiquitous

Why Node
Traditional Platforms
• Things you need for
concurrent web
programming:
– Locks
– Threads / Thread Pools
– Thread Management
– Inter-Thread Communication
– Callbacks + Enclosures + Sync
to Blocking Calls
Node
• Things you need for
concurrent web
programming:
– Callbacks + Enclosures
Which looks
simpler?

Good Node Scenarios
Behavior
• High request volume, low
response-sizes
• Pub / Sub
• Real-time applications
Application
• Online games, message
passing services
• Social networks, content-
syndication services
• Chat, real-time games

Bad Node Scenarios
Behavior
• Large HTTP response sizes
• CRUD
• Transaction-heavy systems
Application
• Static file servers, reporting
tools
• Blogs, CMS
• E-Commerce

Node Concepts
• What Do Node Projects Look Like?
• Event Loop & Workers
• HTTP as a First Class Citizen
• Callbacks and Functions as Objects
• Modules & Packages

Structure of a Node Project
/projectroot/
package.json
readme.txt
web/
server.js
views/
index.html
models/
post.js
helpers/
timestamp.js
test/
route-test.js
post-test.js
node_modules/
C:[projectroot]> node web/server.js
Node server listenening on port 3000 in development mode
Tells Node and NPM what packages are required
The main entry point for your application
User-defined module for handling persistence
User-defined module for other stuff
Root of your actual application
Directory for unit tests
Output directory for all NPM installations

HTTP
• HTTP is a first class citizen
• Request Object
– Holds properties about the client
– Holds session state
– Passes client-data to request handlers
• Response Object
– Holds the HTTP response stream
– Can be written in chunks

Callbacks and Functions as Objects
// HTTP GET /app/list
exports.listapps = function(req, res){
var pageTitle = req.session.userName + "'s Apps";
appProvider.getAppsForUser(req.session.userName,
function(error, userApps){
if(error){
console.log(error.message);
return res.redirect('/');
}
res.render('list_apps', {locals:{title: pageTitle,
apps:userApps}})
});
}

Modules & Packages
• Including a built-in module
var http = require('http');
• Including your own module
[timestamp.js] exports.currentTime = function(){…}
[server.js] var timestamp = require(‘./helpers/timestamp');
[server.js] console.log(timestamp.currentTime());
• Node Package Manager (NPM)
[Commandline] C:> npm install express
[server.js] var express = require(‘express’);

Microsoft & Node
Microsoft wants Windows Azure to be an option
for developers regardless of stack
=>

Node on Windows Azure
• IISNode
• Windows Azure Node PowerShell Cmdlets
• Windows Azure Node SDK
• Cloud9 IDE

IISNode
• Hosts Node applications in IIS as native
modules
• Automatically manages life-cycle of node.exe
• Can load-balance multiple node.exe processes

Azure / Node Powershell Cmdlets
• Create new Azure Services
• Add Node Web and Worker Roles
• Deploy to Azure Emulator
• Import Publish Settings
• Deploy to Azure (Production / Staging)
• Source @ Github

Windows Azure SDK
• Loads Storage Settings from Web.config
• Azure Tables
• Azure Blobs
• Azure Queues
[console] C:> npm install azure
Source @ Github

Cloud9 IDE
• Browser-based IDE
• Deploys to Windows Azure
• Only way to deploy without Windows Vista / 7

Popular Node Frameworks and Tools
• Express (MVC)
• Connect
• Socket.IO
• Unit Testing:
– Assert (built-in)
– Nodeunit

Further Reference
• NodeBeginner.org - Used this to teach myself
Node when I was first getting started.
• NodeJS.org - Official Node Homepage
• Github.com/WindowsAzure – Azure bits

About Me
• Aaron Stannard
– Twitter: @Aaronontheweb
– Github: @Aaronontheweb
– Blog: http://www.aaronstannard.com/

Intro to Node

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