Introduction to Node.js: perspectives from a Drupal dev
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Transcript of Introduction to Node.js: perspectives from a Drupal dev
Introduction to Node.jsPerspectives from a Drupal dev
Mike Cantelon, Vancouver Drupal Users Group, Nov. 25, 2010
Thursday, November 25, 2010
I am:
A longtime PHP dev
Devop for The Georgia Straight
Experimenting with JS/SSJS and HTML5
http://mikecantelon.com
http://github.com/mcantelon
Thursday, November 25, 2010
WHY NODE.JS?
Thursday, November 25, 2010
wordsquared.com: Real-time HTML/JS Scrabble MMO
Thursday, November 25, 2010
The real-time web
Real-time applications are an interesting web subset
Examples: Twitter, Etherpad, games, monitoring
Real-time paradigm will spawn new types of apps
Thursday, November 25, 2010
Three barriers to real-time
Conventional languages can be slow
Conventional web servers can be slow
Conventional databases are slow
Thursday, November 25, 2010
Node.js eliminates two
Conventional languages can be slow
Conventional web servers can be slow
Conventional databases are slow
Thursday, November 25, 2010
http://www.slideshare.net/Vodafonedeveloper/nodejs-vs-phpapache
Node.js vs PHP/Apache
Thursday, November 25, 2010
So what exactly is Node.js?
Server-side Javascript (SSJS) implementation
“Asynchronous” (more on that later)
Built using V8 (JS engine used in Chrome Browser)
Thursday, November 25, 2010
Advantages over PHP
Javascript is a cleaner language
Asynchronous execution increases performance
Node.js is suitable for writing TCP/IP apps
Thursday, November 25, 2010
“Asynchronous”?
Also known as “event-based”
Think of it as defining actions triggered by events
CPU spends less time waiting around
Thursday, November 25, 2010
More benefits of SSJS
Requires less mental context switching for devs
Allows sharing of logic between client and server side
Server-side JQuery for screen scraping? Yes!
Thursday, November 25, 2010
What about that last barrier?
Conventional languages are slow
Conventional servers are slow
Conventional databases are slow
Thursday, November 25, 2010
MongoDB is one solution
MongoDB is generally faster than SQL databases
MongoDB queries are written in Javascript, not SQL
MongoDB works well with node.js
Thursday, November 25, 2010
And Drupal?
Drupal is great for managing content
Node.js has no killer CMS
Node.js can pull data from Drupal (details later)
Thursday, November 25, 2010
This looks conceptually like...
Thursday, November 25, 2010
SSJS HELLO WORLD
Thursday, November 25, 2010
Node.js isn’t hard to learn
Knowing Javascript is the hard part
Node.js is accessible
Express is a framework that makes Node.js easier
Thursday, November 25, 2010
Hello World in Node.js shell
var sys = require('sys');sys.puts('Hello world');
Thursday, November 25, 2010
Node.js server Hello World
var http = require('http');
http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n');}).listen(8124, "127.0.0.1");
Thursday, November 25, 2010
Hello World in Expressvar express = require('express');var app = express.createServer();
app.get('/', function(req, res){ res.send('Hello World');});
app.listen(8124);
Thursday, November 25, 2010
Why use Express?
Handles routing and redirection
Nice templating support
Provides sessions
Thursday, November 25, 2010
Express Templating Support
Supports EJS, HAML, SASS, Jade (HAML variant)
Extend with app-specific helper functions
Provides “partials” (subtemplates)
Thursday, November 25, 2010
app.get('/', function(req, res){ res.render('index.haml', { locals: { title: 'My Site' } });});
Templating Example
Thursday, November 25, 2010
SETTING UP NODE.JS
Thursday, November 25, 2010
Installing Node.js
OS X: build from source or brew install node
Linux: build from source
Build instructions at http://nodejs.org/#download
Thursday, November 25, 2010
Installing NPM
NPM lets you easily install node.js modules
OS X: brew install npm
Instructions for manual install:http://mikecantelon.com/npm
Thursday, November 25, 2010
Installing Express
npm install express
Now the command express will set up an example Express app for you
Thursday, November 25, 2010
Installing MongoDB
OS X: build from source or brew install mongodb
Linux: http://www.mongodb.org/display/DOCS/Quickstart+Unix
npm install mongodb
Thursday, November 25, 2010
DRUPAL -> NODE.JS
Thursday, November 25, 2010
Drupal as a datastore
One way Node.js and Drupal can work together is having Drupal be the storehouse for important content requiring long-term management
Thursday, November 25, 2010
Something like...
Thursday, November 25, 2010
Serve data, not just pages
For realtime apps you’re going to want to serve chunks of data to the browser rather than whole pages
Whole pages take longer to render and use more bandwidth to transmit
Leverage the browser as much as possible
Thursday, November 25, 2010
Serving a page...
1. Browser requests a URL2. Server grabs some data from a database and dresses it up as a page using a template.3. Whole page gets sent back to browser
Thursday, November 25, 2010
...vs Serving Data
1. Browser requests some data2. Server sends back data3. Browser templates data and outputs HTML into the existing page
Thursday, November 25, 2010
Where to serve data from
Pulling Drupal data directly to the browser is quick to implement, but puts more stress on your Drupal stack
The alternative is to pull Drupal data to node.js and cache using a datastore like MongoDB
Data can then be relayed via AJAX or Socket.io
Thursday, November 25, 2010
DRUPAL DATA SHARING
Thursday, November 25, 2010
Javascript For Data Sharing
JSON is the duct tape of the web
drupal_to_js turns any chunk of data into JSON
Drupal Views can output JSON via Views Datasource
Thursday, November 25, 2010
What JSON looks like
{ 'drupal': { 'language': 'PHP', 'license': 'GPL', 'developed_by': { 'individuals', 'organizations', 'companies' } }}
Thursday, November 25, 2010
Drupal pumping out JSON
Thursday, November 25, 2010
Example: RSS to JSON via Views
Thursday, November 25, 2010
What our example will do
Use the Aggregator module to pull data from an RSS feed (specifically “Drupal Planet”)
Use Views, via the Views JSON module, to publish the aggregator items as JSON data
Thursday, November 25, 2010
Install Views Datasource
Thursday, November 25, 2010
Add View
Thursday, November 25, 2010
Add Page Display and Path
Thursday, November 25, 2010
Add Paging
Thursday, November 25, 2010
Add Fields
Thursday, November 25, 2010
Set Style to JSON
Thursday, November 25, 2010
Set Feed/Category ID
Thursday, November 25, 2010
Save View and Check Path
Thursday, November 25, 2010
Demo use of Drupal/JSON...
[demo]
http://github.com/mcantelon/Drupalurk
Thursday, November 25, 2010
Hack for Paging (v6 beta2)
function mytheme_preprocess_views_views_json_style_simple(&$vars) { global $pager_total, $pager_page_array; $element = $vars['view']->pager['element']; $vars['rows']['pager'] = array( 'total' => $pager_total[$element], 'current' => $pager_page_array[$element] );}
http://gist.github.com/581974
Views Datasource needs theme tweak to make paging work
Stick the snippet below into your theme’s template.php
Thursday, November 25, 2010
Hack for Paging (v6 beta2)
This enables you to add &page=<page number starting at 0> to JSON calls
You can then implement your own JS paging
Thursday, November 25, 2010
Possible JSON View Uses
Pull front-page content
Pull content by taxonomy
Pull recent comments
Whatever else you can do with a view
Thursday, November 25, 2010
Pulling JSON into Node.js
var sys = require('sys'), rest = require('restler-aaronblohowiak'), item, node
rest.get('http://mikecantelon.com/jsontest/News') .addListener('complete', function(data) {
for(item in data.nodes) { node = data.nodes[item].node sys.puts(node.Title) sys.puts(node.Body) }})
http://gist.github.com/608741
restler module allows easy HTTP JSON requests
Thursday, November 25, 2010
TALKING TO MONGODB
Thursday, November 25, 2010
Things to remember
Can create databases and schema on-the-fly
Queries are Javascript
A “collection” is similar to an SQL DB’s “table”
MongoDB has a shell so easy to experiment
Thursday, November 25, 2010
Doing something to data
1. Open server DB connection2. Open database3. Open collection4. Do something to the collection
Thursday, November 25, 2010
Opening server DB connection
var mongo = require('mongodb');var port = mongo.Connection.DEFAULT_PORT;var db = new mongo.Db( 'classroom', new mongo.Server('localhost', port, {}), {});
Thursday, November 25, 2010
Opening database
db.open(function(err, db) { // stuff gets done in here});
Thursday, November 25, 2010
Opening a collection
db.collection( 'students', function(err, collection) { // collection operations here });
Thursday, November 25, 2010
Removing from a collection
collection.remove( function(err, collection) { // records are now gone! });
Thursday, November 25, 2010
Adding some records
// make four students with random agesvar names = ['Rick', 'Jane', 'Bob', 'Lisa'];
var index;for (index in names) { collection.insert({ 'name': (names[index]), 'age': Math.round(Math.random(4)*10)+18 });}
Thursday, November 25, 2010
Displaying data from records
// display namescollection.find({}, {}, function(err, cursor) { cursor.toArray( function(err, students) { var index; for(index in students) { sys.puts(students[index].name); }; } ); });
Thursday, November 25, 2010
DEPLOYING NODE.JS
Thursday, November 25, 2010
Node.js isn’t a daemon
Like PHP, node.js doesn’t run as a daemon
This means that naive deployment would require keeping a terminal open
There are a number of ways to deal with this...
Thursday, November 25, 2010
Upstart (Ubuntu/some other distros)
Make a config file for each app in /etc/init
Name config file my_app.conf and set as executable
Start app using: sudo start my_app
Thursday, November 25, 2010
Installing Upstart
Ubuntu: apt-get install upstart
Linux: http://upstart.ubuntu.com/download.html
Thursday, November 25, 2010
System V init script (the right way)
rc.local/custom script (quick and dirty)
Gnu screen (for temporary deployment)
No Upstart? (Centos/some other distros)
Thursday, November 25, 2010
Requires adding a line to /etc/rc.local and a script
Example line in rc.local triggers script at startup:su - mike -c "/home/mike/drupalchat/RUN.sh" &
Script should set NODE_PATH if you’re using npm
rc.local/custom script
Thursday, November 25, 2010
Example script
#!/bin/bashcd /home/mike/drupalchatexport NODE_PATH=/home/mike/root/usr/local/bin/node server.js
Thursday, November 25, 2010
Hotnode will restart node.js when you change a file
Start app with hotloading: hotnode my_app.js
Installation: npm install hotnode
Hotnode
Thursday, November 25, 2010
BONUS! WEBSOCKETS
Thursday, November 25, 2010
What are WebSockets?
WebSockets are an “HTML5” technology for two-way TCP/IP textual communication
Modern browsers, like Chrome and Firefox 4, offer a Javascript WebSockets interface
Thursday, November 25, 2010
Why not just use AJAX?
AJAX is a hack that uses HTTP for communication
HTTP request/response cycle has a lot of overhead
WebSockets increase speed, lessen bandwidth use
Thursday, November 25, 2010
Implementing with Socket.io
Socket.io is a client/server websocket solution, using Node.js for the server side
The client library tries WebSockets, but falls back to other mechanisms when talking to old browsers
Thursday, November 25, 2010
Questions? Ideas?
Thursday, November 25, 2010
Flickr Credits
http://www.flickr.com/photos/sidehike/459483568/http://www.flickr.com/photos/wysz/86758900/http://www.flickr.com/photos/generated/291537716/http://www.flickr.com/photos/gsfc/3720663082/http://www.flickr.com/photos/skreuzer/354316778/http://www.flickr.com/photos/ubookworm/455760111/http://www.flickr.com/photos/batega/1596898776/http://www.flickr.com/photos/batigolix/3778363253/http://www.flickr.com/photos/wwworks/4472384764/http://www.flickr.com/photos/19779889@N00/4398186065/http://www.flickr.com/photos/theplanetdotcom/4878809615/http://www.flickr.com/photos/estherase/177188677/
Thursday, November 25, 2010
Resources
Node.js, Express.js and MongoDBhttp://nodejs.org/http://expressjs.com/http://www.mongodb.org/
Socket.iohttp://socket.io/
This presentationhttp://mikecantelon.com/drupal-nodejs
Thursday, November 25, 2010