OSCON 2011 - Node.js Tutorial

Node.js WorkshopTom Hughes-CroucherChief Evangelist / Node Tech Lead@sh1mmertom@joyent.com

Overview• Introduction• Why Server-Side JavaScript?• What is Node?• Using Node• Understanding Node• Node Ecosystem• Programming Style• More Complex applications• Deploying Node apps to the cloud

Introduction• Tom Hughes-Croucher• Chief Evangelist at Joyent• Node.js core contributor• Author of "Up and Running with Node.js"

Scalable Server-Side Code with JavaScriptNode Up and Running Tom Hughes-Croucher

Major update this week

Why Server-Side JavaScript?

JavaScriptprogrammers 3>2>1

Massive Code base of jQuery and other JS libraries

Laziness or “I’m sickof writing stuff twice”I could have said efficiency, but I think we allsecretly long to sit around in our underwear.

ProgressiveEnhancement is free*Remember WWCD (What Would Crockford Do) *close enough

TL;DR:SSJS is Awesome Like a Unicorn riding a Narwhal

If SSJS is so awesomewhy is it "new"?

1. Professionalism

“Yahoo!s corporate motto is: Dont be eval().“

2. JavaScript Runtimes

Runtimes• V8 (Google), C++• Spider Monkey (Mozilla), C++• Rhino (Mozilla), Java

V8 Spider MonkeyJavaScript Performance

8xSep 08! Mar 11!

Anatomy of SSJS

Node { !

Runtime != Browser

No DOM(By default, anyway)

Summary• Beneﬁts of SSJS • Lots of JavaScript expertise • Lots of web code in JS libraries • Write once, run anywhere • Progressive Enhancement• Why SSJS happened now • Professionalism in JavaScript • New generation of JavaScript runtimes

What is Node?

Node• JavaScript programming environment• Uses V8 runtime• Event Driven• Non-blocking libraries• Supports CommonJS module format• Supports C/C++ based add-ons

Woah! Overload.

1. Its JavaScript

See Above.

2. Its Fast

concurrency=300, Smaller is Better 400 300response time (ms) server nginx 200 thin tornado node_buffer 100 24 26 28 210 212 214 216 218 response size (bytes)

3. Its easy to extend

Modules in JSAdd-ons in C

4. Node is _not_ Rails/ Django/etc

Node is bare-bone to the metal

However, the Nodecommunity are making Rails/Django/etc

5. Node is young

Stable is "stable"Unstable moves fast

Using Node

Using Node• Part 1. Installation• Part 2. Basics• Part 3. Getting stuck in

Part 1. Installation

Navea.k.a the easy way

Enki:~ $ wget -q http://github.com/isaacs/nave/raw/master/nave.shEnki:~ $ chmod 755 nave.shEnki:~ $ ./nave.sh install latest

Nave• Installs and versions Node• Allows Node shells with speciﬁc versions• Allows you to get latest <-- Stable• May add unstable option in future

Manual Installation

Go to http://nodejs.org/#downloadand get the URL of the current stable release

Enki:~ $ wget -q http://nodejs.org/dist/node-v0.4.10.tar.gzEnki:~ $ tar xzf node-v0.4.10.tar.gzEnki:~ $ cd node-v0.4.10Enki:~/node-v0.4.10 $

Local or system?

Enki:~/node-v0.4.10 $ mkdir ~/localEnki:~/node-v0.4.10 $ ./configure --prefix=~/localChecking for program g++ or c++ : /usr/bin/g++Checking for program cpp : /usr/bin/cpp...Checking for fdatasync(2) with c++ : noconfigure finished successfully (3.466s)

Enki:~/node-v0.4.10 $ makeWaf: Entering directory `/Users/sh1mmer/node-v0.4.10/buildDEST_OS: darwinDEST_CPU: x86Parallel Jobs: 1[ 1/69] cc: deps/libeio/eio.c -> build/default/deps/libeio/eio_1.o/usr/bin/gcc -rdynamic -D_GNU_SOURCE -DHAVE_CONFIG_H=1-DEV_MULTIPLICITY=0 -pthread -g -O3 -DHAVE_OPENSSL=1 -DX_STACKSIZE=65536 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -DHAVE_FDATASYNC=0 -DPLATFORM="darwin" -DNDEBUG -Idefault/deps/libeio -I../deps/libeio -Idefault -I.. ../deps/libeio/eio.c -c -o default/deps/libeio/eio_1.o...

Enki:~/node-v0.4.10 $ make installWaf: Entering directory `/Users/sh1mmer/node-v0.4.10/buildDEST_OS: darwinDEST_CPU: x86Parallel Jobs: 1* installing build/default/config.h as /Users/sh1mmer/local/include/node/config.h* installing build/default/node as /Users/sh1mmer/local/bin/node* installing build/default/src/node_config.h as /Users/sh1mmer/local/include/node/node_config.hWaf: Leaving directory `/Users/sh1mmer/node-v0.4.10/buildinstall finished successfully (0.373s)Enki:~/node-v0.4.7 $

Enki:~/node-v0.4.10 $ echo $PATH/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/local/git/bin:/Users/croucher/Code/narwhal/bin:/opt/local/bin:/usr/local/git/bin:/Users/sh1mmer/binEnki:~/node-v0.4.10 $ node -v-bash: node: command not foundEnki:~/node-v0.4.10 $ echo PATH=~/local/bin:$PATH>> ~/.proﬁleEnki:~/node-v0.4.10 $ node -vv0.4.10

System

Enki:~/node-v0.4.10 $ ./conﬁgure...Enki:~/node-v0.4.10 $ make...Enki:~/node-v0.4.10 $ sudo make install...Enki:~/node-v0.4.10 $ node -vv0.4.7Enki:~/node-v0.4.10 $

Exercise• Get Node head from Github using Git• Install to ~/node

Part 2. Basics

node-replInteractive JavaScript terminal

$Enki:~ $ node

$Enki:~ $ node>3>2>1false> true == 1true> true === 1false

> console.log(Hello World);Hello World> .help.clear Break, and also clear the local context..exit Exit the prompt.help Show repl options> .clearClearing context...> .exitEnki:~ $

Enki:~ $ node> var foo = "bar";> foo;bar> .clearClearing context...> fooReferenceError: foo is not deﬁned at [object Context]:1:1 at Interface.<anonymous> (repl:98:19) at Interface.emit (events:27:15) at Interface._ttyWrite (readline:295:12) at Interface.write (readline:132:30) at Stream.<anonymous> (repl:79:9) at Stream.emit (events:27:15) at IOWatcher.callback (net:489:16)

var http = require(http);http.createServer(function (req, res) { res.writeHead(200, {Content-Type: text/plain}); res.end(Hello Worldn);}).listen(8124, "127.0.0.1");console.log(Server running at http://127.0.0.1:8124/);

var http = require(http);//include the http library

http.createServer(function (req, res) {}).listen(8124, "127.0.0.1");//create an http server//when ‘stuff’ happens call this anonymous function//listen on port 8124 of the IP 127.0.0.1

http.createServer(function (req, res) { res.writeHead(200, {Content-Type: text/plain}); res.end(Hello Worldn);})//when ‘stuff’ happens my function ﬁres//I get a request object and a response object//I write to the response object header//HTTP status 200 and content-type ‘text/plain’//close the response with the body://Hello World

console.log(Server running at http://127.0.0.1:8124/);//write Server is running at http://127.0.0.1:8124///to the console

Interactive Debugging

Enki:~/Code/node-examples $ node --debughelloworld.jsdebugger listening on port 5858Server running at http://127.0.0.1:8124/

Enki:~ $ npm install node-inspectornode-inspector@0.1.8 ./node_modules/node-inspector websocket-server@1.4.04 paperboy@0.0.2Enki:~ $ node-inspectorvisit http://0.0.0.0:8080/debug?port=5858 to startdebugging

Exercises• Modify the HTTP server to return the text "Im learning Node"• Change the HTTP response to HTML and return your text in an HTML page• Return the User-Agent string from the browser as part of your HTML page• Return different textual responses to 2 (or more) browsers

Part 3. Getting Stuck In

HTTP Client

var http = require(http);var request = http.request({host: www.google.com,port: 80, path: /, method:GET});request.on(response, function (response) { console.log(STATUS: + response.statusCode); console.log(HEADERS: +JSON.stringify(response.headers)); response.setEncoding(utf8); response.on(data, function (chunk) { console.log(BODY: + chunk); });

Streaming API

write(data) write(data) DestinationRequest end() (google.com) response(headers) data(chunk) data(chunk) Response data(chunk) end()

Exercise• Fetch the NYTimes.com and output the contents to the console• Create a web server • Create an HTTP client • POST data to your web server • Output the POST data to console

Events

object.on(event, function() { //stuff} );

EventEmitter

EventEmitter• manage "event handlers" • list of functions to be called per event• provide mechanism to trigger events

var util = require(util), EE = require(events).EventEmitter;util.inherits(MyClass, EE);var myObj = new MyClass();//nb using ﬁrst class functionsmyObj.on(something, function);

exports.inherits = function (ctor, superCtor) { ctor.super_ = superCtor; ctor.prototype = Object.create(superCtor.prototype, { constructor: { value: ctor, enumerable: false } });};

More than just core

CommonJS Modules

Library format for SSJS

math.jsexports.add = function() { var sum = 0, i = 0, args = arguments, l = args.length; while (i < l) { sum += args[i++]; } return sum;};increment.jsvar add = require(math).add;exports.increment = function(val) { return add(val, 1);};var inc = require(increment).increment;var a = 1;inc(a); // 2

Protipexports.awesome = function() { //yay my code is awesomesauce};var exports.fail = function() { //exports is a global //by redeclaring it as //a local variable //your code _will_ fail};

Exercise• Create a CommonJS module called "ﬁsh" • Provide functions to: • swim • mouth breath • ﬂop around• Import your module into a node project• Call the various functions

Node PackageManager (NPM)

NPM is written inJavaScript for Node

Enki:~ $ cat `which npm`#!/usr/bin/env node;(function () { // wrapper in case were in module_context modevar log = require("../lib/utils/log")log.waitForConﬁg()log.info("ok", "it worked if it ends with")var fs = require("../lib/utils/graceful-fs") , path = require("path") , sys = require("../lib/utils/sys") , npm = require("../npm") , ini = require("../lib/utils/ini") , rm = require("../lib/utils/rm-rf")

Enki:~/Code/node(master) $ npm install expressexpress@2.3.11 ../../node_modules/express mime@1.2.2 connect@1.4.2 qs@0.1.0Enki:~/Code/node(master) $

Yay. Easy.

Install instructions https://github.com/isaacs/npm

Express.js

Sinatra Style MVC framework

var app = require(express).createServer();app.get(/, function(req, res){ res.send(hello world);});app.listen(3000);

HTTP Verb Oriented

Middleware

app.use(express.bodyParser());app.use(express.cookieParser());app.post(/, function(req, res){ // Perhaps we posted several items with a form // (use the bodyParser() middleware for this) var items = req.body.items; console.log(items); res.send(logging);});

Templating

Exercise• Create an Express server• Serve two different pages based on value of the HTTP Get param "page"• Create a redirect from /old to /new• Set a cookie on the client

Express in depth

Routes• Routes are based on verbs • GET • POST • PUT • DELETE • ALL (not a real verb, but obvious)

Simple routes

app.get(‘/’, function(req,res) { res.send(‘hello root’);});

Routes with variables

app.get(‘/user/:id’, function(req,res) { res.send(‘hello ‘ + req.params.id);});

Optional ﬂags in routes

app.get(‘/:filename?’, function(req,res) { if(req.params.filename) { res.send(req.params.filename); } else { res.send(‘root’); }});

Regex as routes

app.get(///, function(req, res) { //like using ‘/’ ? res.send(‘/’);});

app.get(/^/d+/?$/, function(req,res) { res.send(‘matches a number’);});

app.get(/^/(.+)/?$/, function(req,res) { //note translation of %23, etc res.send(‘Got: ’ + req.params[0]); //also captures become an array});

Using regex todeﬁne parameters

app.get(‘/index.:format((html|json))’,function(req,res) { res.send(Got: + req.params.format);});

app.get(/:id(d+), function(req,res) { //only digits, right? res.send(req.params.id);});

app.get(/:id(d+), function(req,res) { //escape your in strings res.send(req.params.id);});

Routing magic: Router.jsfunction normalizePath(path, keys) { path = path .concat(/?) .replace(//(/g, (?:/) .replace(/(/)?(.)?:(w+)(?:((.*?)))?(?)?/g, function(_, slash, format, key,capture, optional){ keys.push(key); slash = slash || ; return + (optional ? : slash) + (?: + (optional ? slash : ) + (format || ) + (capture || ([^/]+?)) + ) + (optional || ); }) .replace(/([/.])/g, $1) .replace(/*/g, (.+)); return new RegExp(^ + path + $, i);}

Routing magic• If . before :variable? then . is also optional• If ? is not after a variable then only the previous character is affected• / at the end of URLs automatically optional• * Can be used as a wildcard in routes• Includes when end of URL is optional e.g. /app/e?• Regex can be used any place in a route string e.g. /app/(d)r?

Exercises• Create an express app with routes that capture / /products and /services• Create a route that captures the product ID after /product/ e.g. /product/abc12 and returns it in the response• Use a regular expression to restrict the ID parameter to 3 letter followed by 3-5 numbers• Create a route using a regex that matches the entire route

Passing Control• Routes are actually stacked middleware• You can pass control between routes• The next() function calls the next matching route

app.get(/users/:id, function(req, res, next){ var id = req.params.id; if (checkPermission(id)) { // show private page } else { next(); }});app.get(/users/:id, function(req, res){ // show public user page});

Passing Control• next() is a function of router (and deﬁned in the closure containing the route)• router will grab routes in the order they were declared• e.g. since/* will match everything so it should be the last route!• router doesnt care about verbs so you can use all() to operate on all verbs/routes and then use next() to pass to get(), put(), etc

Exercises• Create a simple check for correct product IDs if not pass control to a route showing a custom error page• Use app.all() to check user permission before showing (mock-up) edit controls on a web site

Middleware

Its a pattern

req, resnext()next()next()

req, resnext()next() Dispatchernext() req res

req, res, next

var express = require(express), app = express.createServer();var middleware = function (req, res, next) { req.foo = bar; next();};app.use(middleware);app.get(/, function(req, res) { res.send(req.foo);

Connect middleware (Renamed express.* for convenience)• logger • proﬁler• bodyParser • responseTime• cookieParser • basicAuth• session • favicon• static • vhost• errorHandler

var express = require(express), app = express.createServer();app.use(express.logger());app.use(express.bodyParser());app.use(express.cookieParser());app.use(app.router);app.use(express.static(__dirname + /images));app.use(express.errorHandler());app.get(/, function(req, res) { res.send(<html><img src="/image.png"></html);});app.listen(9003);

Ordering matters

Router uses "internalmiddleware"

var express = require(express), app = express.createServer();var middleware = function (req, res, next) { req.foo = bar; next();};app.get(/, middleware, function(req, res) { res.send(req.foo);});

var a, b, c, d;a = b = c = d = function(req,res,next) { next();}var set1 = [a,b];var set2 = [c,d];var all = [set1, set2];app.get(/set1, set1, function(req,res) { res.send(output);});app.get(/set2, [c,d], function(req,res) { res.send(output);});app.get(/all, all, function(req,res) { res.send(output);});

Middleware factories

Middleware are just functions

var a, b, c, d;a = b = c = d = function(req,res,next) { next();}var set1 = [a,b];var set2 = [c,d];var all = [set1, set2];app.get(/set1, set1, function(req,res) { res.send(output);});app.get(/set2, [c,d], function(req,res) { res.send(output);});app.get(/all, all, function(req,res) { res.send(output);});

Exercise• Create a middleware to detect mobile phone browsers and attach a boolean to req• Create an express app that serves up links to an image using staticProvider• Modify Profiler to profile your app and write each profile to a log file• Create a middleware factory that sets the HTTP Expires header based on roles

Error handling

app.error(function(err, req, res, next){ if (err instanceof NotFound) { res.render(404.jade); } else { next(err); }});

View Rendering

app.get(/, function(req, res){ res.render(index.ejs, { title: Falsy Demo });});

Enki:~/Code/express-demo $ tree. app.js lib public views index.ejs layout.ejs layout1.ejs partials stylesheet.ejs4 directories, 5 ﬁlesEnki:~/Code/express-demo $

Dont forget to installnpm install ejsnpm install jade

layout.ejs<!DOCTYPE html><html lang="en"> <head> <meta charset="utf-8"> <title><%= title %></title> </head> <body> <%- body %> </body></html>

• layout is a framework unless you turn it off• body is a special variable for layout referring to the ﬁle speciﬁed

app.set(view engine, ejs);app.get(/, function(req,res) { res.render(index, { title:Falsy Demo});});

//globalapp.set(view options), { layout: false;});//or per routeres.render(index, {layout: false});

Partial views

View Partials• Repeating elements• Take a collection• Iterate over the collection• "Built in" variables for managing collections

layout.ejs<!DOCTYPE html><html lang="en"> <head> <meta charset="utf-8"> <%- partial(stylesheet, stylesheets) %> <title><%= title %></title> </head> <body> <h1><%= header %></h1> <%- body %> </body></html>

partials/stylesheet.ejs<link rel="stylesheet" type="text/css" href="<%-stylesheet %>">

res.render(index, { locals: {title: title, header: header, content: content, stylesheets: [/public/style.css] }, });

Exercises• Create an express server that use jade, haml, ejs to render an index page• Create a public folder and include ﬁle from it (CSS, images, etc) in your layout• Create a route for /blog/id to accept only digits• Make a fake database (array) of blog posts and use a middleware to validate each id is valid• Create a view for the /blog/id show the correct post• Use a view partial to a preview of each blog post on the index page

Questions

http://sugyan.no.de	224
http://www.oscon.com	164
http://lanyrd.com	123
http://www.nitinkatkam.com	25
http://tweetedtimes.com	14
http://twitter.com	13
http://localhost	5
https://twitter.com	5
http://fasoulas.posterous.com	4
http://staging.conferize.com	3
http://tenkao.tumblr.com	3
http://us-w1.rockmelt.com	2
http://blog.fasoulas.com	2
http://www.techgig.com	2
http://posterous.com	1
http://a0.twimg.com	1
http://115.112.206.134	1
http://www.onlydoo.com	1

OSCON 2011 - Node.js Tutorial

by Tom Hughes-Croucher

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