when to use ruby on rails
DESCRIPTION
To advantages and disadvantages of the Ruby programming language and the Rails framework. Includes advise when to use it and comparisons to PHP.TRANSCRIPT
Contents• Ruby
– What is it?– Advantages– Disadvantages
• Rails– What is it?– Advantages– Disadvantages
• When to use it• Reusable best practices
Ruby Beach, Washington, U.S.Kevin Mc Neal
What is Ruby?
• A scripting language more powerful than
Perl and more object-oriented than Python.
• Invented in 1993 with inspiration from Perl, Phyton, Smalltalk, Eiffel, Ada, and Lisp.
• Designed for programmer productivity and joy instead of machine efficiency.
• Follows the principle of least surprise, the language should minimize confusion.
• It's easy to work with and to love Ruby.Yukihiro 'Matz' Matsumoto
Ruby's Architect
Ruby Advantages
• Elegant
• Powerful
• Readable
• Concise
Ruby and Diamond ringR. M. Rayner
class NewBowlingGame extends PHPSpec_Context{
private $_bowling = null;public function before(){
$this->_bowling = new Bowling;}
public function itShouldScore0ForGutterGame(){
for ($i=1; $i<=20; $i++) {$this->_bowling->hit(0);
} $this->spec($this->_bowling->score)->should->equal(0);}
}
describe Bowling dobefore(:each) do@bowling = Bowling.new
end
it "should score 0 for gutter game" do20.times { @bowling.hit(0) }@bowling.score.should == 0
endend
Ruby is Elegant
Ruby is Powerful
• Object-oriented (everything is an object)
• Dynamic (duck typing)
# Open Ruby's Time class and add a methodclass Timedef yesterdayself - 86400
endend
today = Time.now # => Thu Aug 14 16:51:50 +1200 2008yesterday = today.yesterday # => Wed Aug 13 16:51:50 +1200 2008
Ruby is Readable
• The code comments itself
• Leads to better naming practices
# An example example function for a photo camera programdef shutter_clickedcapture_image if @camera.on? and @camera.memory_available?
end
Ruby is Concise
• Very expressive language
• Less lines of code, higher productivity
-199.abs # 199"ruby is cool".length # 12"Your Mom".index("u") # 2"Nice Day!".downcase.split(//).sort.uniq.join # " !acdeiny"
say = "I love Ruby"say['love'] = "*love*"5.times { puts say }=> "I *love* Ruby" "I *love* Ruby" "I *love* Ruby" "I *love* Ruby" "I *love* Ruby"
Ruby Disadvantages
• Ruby is Slow
• Ruby is New
Ruby Fails Falls, Lookout Mountain, U.S.Oscar & L
Ruby is Slow
• About 10x slower than Java, 2x slower than PHP
All benchmarks, x64 Ubuntu, Intel Q6600 QuadComputer Language Benchmarks Game
Ruby is New
• Not many developers or customers
• No common IDE
– Most coders use the Mac text-editor Textmate
– IDEs: RadRails, RubyMine, 3rd Rail, Netbeans
• No common application server
– Passenger's Apache module has momentum
Evolution to web frameworks
Static Dynamic Integrated
From 1990 to 2009Time
Type of site
Tools
Business roleMarketing
• Brochure
• Advertising
Front office
• Communication
• Ordering
• Mailings
Back office
• Quotations
• Fulfillment
• Legacy systems
HTML editors:
Frontpage
Dreamweaver
PHP + MySQL:
Joomla
Drupal
Wordpress
Typo3
.Net
Sharepoint
Frameworks:
CakePHP (PHP)
Grails (Groovy)
Django (Phyton)
Ruby on Rails (Ruby)
Merb (Ruby)
Sanatra (Ruby)
What is ?
• Web application framework• Open Source (MIT license)• Based on a existing
application (Basecamp)• Provides common needs:
– Routing, sessions– Database storage– Business logic– Generate HTML/XML/CSS/Ajax– Testing
Creator of Ruby on RailsDavid Heinemeier Hansson
Who uses Rails
• Internally:
• Externally:
• style.mtv.com
• www.getsatisfaction.com
• www.basecamp.com
• www.yellowpages.com
• www.twitter.com
• www.yelloyello.nl
Rails Advantages
• Convention over configuration
• Don’t Repeat Yourself
• Object Relational Mapping
• Model View Controller
• Reuse of code
• Agile practices
• Security
Tay Rail Bridge, ScotlandRoss2085
Convention over Configuration
• Table and foreign key naming– Tables are multiples
(users, orders, etc.)
– Foreign key naming: user_id
• Default locations– MVC, Tests, Languages, Plugins
• Naming– Class names: CamelCase
– Files: lowercase_underscored.rb
Don’t repeat yourself
• Everything is defined in a single, unambiguous place
• Easier to find code– Only need to look once
– Can stop looking when found
– Well defined places for most items
• Much easier to maintain code– Faster to change
– Less inconsistency bugs
Model View Controller
• Model– Object relationships
(users, orders)
• Controller– Business logic
(perform a payment)
• View– Visual representation
(generate HTML/XML)
Model
• Contains validation and object methods
• Use 'fat' models and 'skinny' controllers to increase reuse of methods across controllers
class Order < ActiveRecord::Basehas_many :line_itemshas_one :userhas_one :email, :through => :user
validates_presence_of :uservalidates_numericality_of :amount
def purchaseself.purchase_time = Now
endend
View
• DSL languages
• Erb for ruby & html
• Haml improves on erb
• Textile for html
• Sass for css<div id='content'><div class='left column'><h2>Welcome to our site!</h2><p>
<%= print_information %></p>
</div><div class="right column"><%= render "sidebar" %>
</div></div>
#content.left.column%h2 Welcome to our site!%p= print_information
.right.column= render "sidebar"
Controller
• RESTful
– Better than SOAP
– Easy to understand
– Easy to debug
– Easy to cache
– Easy to prioritize
– No bottleneck
– HTML/XML/JSON
Method Resource Verb index /people GET show /people/12 GET create /people POST update /people/12 PUT delete /people/12 DELETE
GET /people/12.xml
def show@person =
Person.find(params[:id])respond_to do |wants|
wants.htmlwants.xml { render :xml
=> @person.to_xml }end
end
Object Relational Mapping
# Examples of finding recordsUser.find(:all)User.find(23).articlesUser.find_by_first_name('Johnny')User.order.find(:last).lines_items.count
Programming object Database row
#<User id: 1, login: "Sytse", email: "[email protected]", description: "<p>Sytse studied Management Science at the Universi...", avatar_id: 1, crypted_password: "b6675cab85b541a91e6d0
ORM Tools:-ActiveRecord-DataMapper-iBATIS
find
save
Re-use of code
• Gems and plugins, more then 1300
– For authentication, pagination, testing, etc.
• Git allows easy forking and merging
• Github website allows you to give back
• Acts as a portfolio
Agile practices
• Iterations (branch often, merge often)
• Test all the time (TDD, BDD)
Stories > Tests > Code > Continuous Integration
Story exampleFeature: Log-inIn order to view my profileAs a Registered memberI want to be required to log-in
Test exampleGiven /I am the registered member "quire"/ do@user = User.new({ :login => 'quire})@user.save!
end
Security
• Rails prevents SQL injection attacks– Attacher post in form: "some_title; DROP TABLE articles;"
– In bad code this can be injected:
"SELECT * FROM ARTICLES WHERE TITLE = $TITLE"
– Rails will be escape the input automatically:
@articles = Article.find(:all,
:conditions => [:title => params[:title]])
• Rails prevents Cross Site Scripting (XSS)– With html_escape in view: <%=h comment.body %>
Rails Disadvantages
• Rails is inefficient
• Rails is hard to deploy
Montparnesse 1895Jeff Mc Neill
Rails is inefficient
• Rails uses a lot of memory,
up to 150MB per instance
• Requires more application servers
• Where are your development constrains?
Resource Example application Rails
Man hours 2.200 hours / e22.000 1.000 hours / e10.000
Project duration 15 weeks of changes / e3.000 10 weeks / e2.000
Computing power 2 servers / e2.000 5 servers / e5.000
Total e27.000 e17.000
Rails is hard to deploy
• Harder than PHP, better with Passenger
• Lots of moving parts
– Rails, apps, gems, plugins
– Application server, webserver
• Deployment via scripts
– Via the Capistrano tool
– Easy to break something
• Deployment to multiple servers
When to use Ruby on Rails?
• New code base and DB
• High development speed
• Complex applications
• Web deployment
• Iterative projects
• Development is expensive
• Fixed price project
• Early adopter client/team
• Existing code and DB
• Low development speed
• Simple applications
• Client deployment
• Waterfall projects
• Deployment is expensive
• Hourly rate project
• Late majority client/team
Re-usable best practices
• Don't Repeat Yourself• 'Fat' model, 'skinny' controller• MVC framework
– CakePHP
• Integration testing– Selenium
• DSL's– Textile for markup
• Source code repository– GIT
• Project management– Github, Lighthouse, Basecamp
Recycle shirt by Brian Damage
Questions?
http://www.dosire.com/