History of a change from Java to Ruby on Rails

1. Ruby on Rails sur vival guide
of an aged Java developer
or
how to get a project released without knowing the language
and neither the framework
Gian Carlo Pace - RubyDay - 10/06/2011 - Centro Congressi Milanofiori http://www.thinkgeek.com/gadgets/tools/a396/

2. Resilienza.
L'arte di risalire sulla barca rovesciata.

3. “Quando la vita rovescia la
nostra barca, alcuni affogano
altri lottano strenuamente
per risalirvi sopra.

4. Gli antichi connotavano il gesto
di tentare di risalire sulle
imbarcazioni rovesciate con il
verbo «resalio».

5. Forse il nome della qualità di chi
non perde mai la speranza e
continua a lottare contro le
av versità, la resilienza deriva
da qui.”
(Resisto Dunque Sono, Pietro Trabucchi - Casa editrice Corbaccio 2009)

6. me, myself and I

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10. history of a change

11. t wo teams
Coldfusion team Java Team

12. the remake
Java Team
Customer

13. The standby...
we must put in standby the
project you are working on
ok!
you’ll work on a new project
using Java, so you’ll get the
chance to learn it
good!
manager coldfusion team

14. fast prototype
...ah, a last comment. We need a
fast prototype for the project
to study the business in
advance!
!!!
!!!
manager coldfusion team

15. steep learning cur ve
confusion team
WTF

16. Java project kick off
Let’s start!
customer

17. different internal POV
SOA
iBatis JavaScript
GWT
JBoss Hibernate REST
Flex
HTML5 Spring
Glassfish BlazeDS
Java Team

18. time passes
Java Team
Flex BlazeDS Spring Hibernate Glassfish

19. time passes
B ad M ood
Java Team
Flex BlazeDS Spring Hibernate Glassfish

20. what should
we do?

21. when the going gets tough...
we need a BRAVE decision.
we need a technology switch!
...the meeting gets going!

22. technology selection

23. Ruby on Rails
Community
Libraries
Age
Books

24. Ruby on Rails
Community
Libraries
Age
Books

25. Ruby on Rails

26. Situation
Project esteemed 3 months Late of 1 month
Ruby Language unknown
Rails Framework unknown
Deadline unchanged
Customer waiting

27. Waltzing with Bears

28. Knowledge investment: books

29. Knowledge investment: a course

30. Installing Ruby: Windows

31. Ruby: MacOSX & Linux
https://rvm.beginrescueend.com
$ bash < <(curl -s https://rvm.beginrescueend.com/install/rvm)
$ rvm install 1.9.2
$ rvm use 1.9.2
$ ruby -v
ruby 1.9.2p0 (2010-08-18 revision 29036) [x86_64-darwin10.4.0]
$ which ruby
/Users/gicappa/.rvm/rubies/ruby-1.9.2-p0/bin/ruby

32. Ruby Virtual Machines
MRI/YARV (ruby) - http://www.ruby-lang.org/en/downloads/
Rubinius (rbx) - http://rubini.us/
JRuby (jruby) - http://www.jruby.org/
Ruby Enterprise Edition (ree) - http://www.rubyenterpriseedition.com/
MagLev (maglev) - http://maglev.gemstone.com/
IronRuby (ironruby) - http://www.ironruby.net/
MacRuby (macruby) - http://www.macruby.org/

33. Rails Installation
Usually run this as the root user:
# gem install rails

34. Rails Satisfaction
$ rails new blog
$ cd blog/
$ rake db:create
$ bundle install
$ rails server
=> Booting WEBrick
=> Rails 3.0.7 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2011-06-09 13:59:25] INFO WEBrick 1.3.1
[2011-06-09 13:59:25] INFO ruby 1.9.2 (2010-08-18) [x86_64-
darwin10.5.0]
[2011-06-09 13:59:25] INFO WEBrick::HTTPServer#start: pid=30347
port=3000

35. Rails Satisfaction

36. Rails Installation on Windows
"If you’re working on Windows, you should be aware that
the vast majority of Rails development is done in Unix
environments...”
“...If at all possible, we suggest that you install a Linux
virtual machine and use that for Rails development, instead
of using Windows."
(http://guides.rubyonrails.org/getting_started.html)

37. Ruby vs Java: similarities
Memory is managed for you via a garbage collector.
Objects are strongly typed.
There are public, private, and protected methods.
There are embedded doc tools (Ruby’s is called RDoc).

38. Ruby vs Java: differences
You don’t need to compile your code. You just run it directly.
All member variables are private. From the outside, you
access everything via methods.
Parentheses in method calls are usually optional and often
omitted.
Everything is an object.
There’s no static type checking.
Variable names are just labels. They don’t have a type
associated with them.
http://www.ruby-lang.org/en/documentation/ruby-from-other-languages/to-ruby-from-java/

39. Ruby Language: IRB
$ irb
irb(main):001:0> puts "Welcome rubyfriday!"
Welcome rubyfriday!
=> nil
irb(main):002:0>

40. Ruby Language: OO
“Metaprogramming Ruby” - Paolo Perrotta

41. Ruby Language: OO
irb(main):002:0> 3.times { puts "hi!" }
hi!
hi!
hi!
=> 3
irb(main):003:0> "hi there".split(" ")
=> ["hi", "there"]
irb(main):004:0>

42. Ruby Language :symbols
Symbols are constant names that you
don’t have to predeclare and that are
guaranteed to be unique.
NORTH = 1 :north
EAST = 2 :east
SOUTH = 3 :south
WEST = 4 :west

43. Ruby Language: code blocks
Code blocks are chunks of code you can
associate with method invocation almost
as if they were parameters

44. Ruby Language: code blocks
def call_block
puts “Start of method”
yield
yield
puts “End of method”
end
irb(main):008:0> call_block { puts 'In the block' }
Start of method
In the block
In the block
End of method
=> nil

45. Rails
Rails is a web application development
framework written in the Ruby language
DRY
Convention Over Configuration
RESTful Acrhitecture
MVC Pattern Based
ORM Based

46. Rails: bundler
Dependency manager
$ bundle install
Using rake (0.9.2)
Using abstract (1.0.0)
Using activesupport (3.0.7)
Using builder (2.1.2)
Using i18n (0.5.0)
Using activemodel (3.0.7)
...
Your bundle is complete! Use `bundle show [gemname]` to see where a
bundled gem is installed.
$

47. Rails: rake
rake means ruby make
$ rake -T
rake db:create # Create the database from config/
database.yml for the current Rails.env (use db:cre...
rake db:drop # Drops the database for the current
Rails.env (use db:drop:all to drop all databases)
rake db:fixtures:load # Load fixtures into the current
environment's database.
rake db:migrate # Migrate the database (options:
VERSION=x, VERBOSE=false).
rake db:migrate:status # Display status of migrations
...

48. Rails: MVC

49. Rails: generators
rails new MyProject
rails generate model MyModel attr:string
rails generate controller MyController
rails generate mailer SenderClass

50. Rails: generators
$ rails generate scaffold Post title:string body:text
invoke active_record
create db/migrate/20110609171958_create_posts.rb
create app/models/post.rb
invoke test_unit
create test/unit/post_test.rb
create test/fixtures/posts.yml
route resources :posts
invoke scaffold_controller
create app/controllers/posts_controller.rb
invoke erb
create app/views/posts
create app/views/posts/index.html.erb
create app/views/posts/edit.html.erb
create app/views/posts/show.html.erb
create app/views/posts/new.html.erb
create app/views/posts/_form.html.erb
invoke test_unit
...
invoke helper
...
invoke stylesheets
create public/stylesheets/scaffold.c

51. Rails: routes
$ rake routes
posts GET /posts(.:format) {:action=>"index", :controller=>"posts"}
POST /posts(.:format) {:action=>"create", :controller=>"posts"}
new_post GET /posts/new(.:format) {:action=>"new", :controller=>"posts"}
edit_post GET /posts/:id/edit(.:format) {:action=>"edit", :controller=>"posts"}
post GET /posts/:id(.:format) {:action=>"show", :controller=>"posts"}
PUT /posts/:id(.:format) {:action=>"update", :controller=>"posts"}
DELETE /posts/:id(.:format) {:action=>"destroy", :controller=>"posts"}

52. Rails: controller

53. Rails: view
erb = templating system

54. Rails: active record

55. Rails: active record
rake db:migrate

56. Rails: useful gems

57. Rails: authentication
Devise http://ruby-toolbox.com/
Authlogic

58. Rails: authorization
http://ruby-toolbox.com/
CanCan
declarative_authorization

59. Rails: file upload
paperclip
http://ruby-toolbox.com/
attachment_fu

60. Rails: misc
will_paginate
rufus-scheduler http://ruby-toolbox.com/
rmagick
EventMachine
formtastic
aws-s3
bitly
t witter_oauth

61. Rails: testing
test-unit
rspec http://ruby-toolbox.com/
cucumber
factory_girl
capybara
spork

62. Rails: deployment
http://ruby-toolbox.com/
capistrano

63. Rails: passenger

64. Project?

65. Work Hard

66. Production
Good job guys!
customer

67. What we achieved
Delivered working soft ware
On time
Starting a month LATER
Learning from scratch Ruby
Learning from scratch Rails

68. One team!
Rails team

69. Lesson learned
cohesion and mood matters
be resilient!

70. Thank You!

71. Q&A?