Intro to Node

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

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

Meet Nodevar http = require(http);//Node function called each time a new HTTP request arrivesfunction 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 processvar 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 NodeJavaScript is ubiquitous

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

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

Bad Node ScenariosBehavior Application• Large HTTP response sizes • Static file servers, reporting tools• CRUD • Blogs, CMS• Transaction-heavy systems • 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 Tells Node and NPM what packages are required readme.txt web/ Root of your actual application server.js The main entry point for your application views/ index.html models/ post.js User-defined module for handling persistence helpers/ timestamp.js User-defined module for other stuff test/ Directory for unit tests route-test.js post-test.js node_modules/ Output directory for all NPM installationsC:[projectroot]> node web/server.jsNode server listenening on port 3000 in development mode

Event Loop + Workers

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/listexports.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 optionfor 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 azureSource @ 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/

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Intro to Node

by Aaron Stannard

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