For a demo to some colleagues, I created a Ruby on Rails demonstration. This presentation is used to show concepts, and illustrate the case. See http://changelos.com/2010/06/08/demoing-ruby-on-rails/ for the full story.

1. Ruby on Rails

2. Ruby
(shorter now)

3. Everything is an object
1.class # => Fixnum
'a'.class # => String
:z.class # => Symbol
class Foo
end
Foo.class # => Class
Foo.new.class # => Foo

4. Dynamically typed
def do_stuff(thing)
thing.do_the_stuff
end
class TheThing
def do_the_stuff
puts "Stuff was done!"
end
end
do_stuff(TheThing.new)

5. Arrays
Array.new # => []
Array.new(3) # => [nil, nil, nil]
[] # => []
a = [1,2,3] # => [1, 2, 3]
a[0] = 'one' # => "one"
a # => ["one", 2, 3]
a[-1] # => 3
a[1..2] # => [2, 3]

6. Hashes
Hash.new # => {}
{} # => {}
h = {1 => "one", 2 => "two"}
h[1] # => "one"
h["1"] # => nil
h[:one] = "einz" # => "einz"
h[:one] # => "einz"
h.keys # => [1, 2, :one]
h.values # => ["one", "two", "einz"]

7. Classes

8. Classes
class Pet
attr_accessor :name
def initialize(name)
@name = name
end
def sit!
puts "Wuff"
end
end

9. Naming conventions
CamelCased # Classes, modules
with_underscores # methods, local variables
@instance_variable
@@class_variable
$GLOBAL_VARIABLE

10. Code blocks

11. Code blocks
[1,2,3,5,7].select {|x| x.even?}
# => [2]

12. Code blocks
[1,2,3,5,7].select {|x| x.even?}
# => [2]
def do_random_nr_of_times &block
nr = rand(10)
for i in 1..nr
yield
end
end

13. Code blocks
[1,2,3,5,7].select {|x| x.even?}
# => [2]
def do_random_nr_of_times &block
nr = rand(10)
for i in 1..nr
yield
end
end
do_random_nr_of_times { puts "bla" }
# bla
# bla
# bla
# => 1..3

14. Optional language

15. Optional language
def my_method(data, options = {})
# ...
end

16. Optional language
def my_method(data, options = {})
# ...
end
# Full signature
my_method("bla", {:option => 'value', :two => 2})

17. Optional language
def my_method(data, options = {})
# ...
end
# Full signature
my_method("bla", {:option => 'value', :two => 2})
# The last parameter a hash? implicit.
my_method("bla", :option => 'value', :two => 2)

18. Optional language
def my_method(data, options = {})
# ...
end
# Full signature
my_method("bla", {:option => 'value', :two => 2})
# The last parameter a hash? implicit.
my_method("bla", :option => 'value', :two => 2)
# Parentheses are optional
my_method "bla", :option => 'value', :two => 2

19. Optional language
def my_method(data, options = {})
# ...
end
# Full signature
my_method("bla", {:option => 'value', :two => 2})
# The last parameter a hash? implicit.
my_method("bla", :option => 'value', :two => 2)
# Parentheses are optional
my_method "bla", :option => 'value', :two => 2
# As long as its unambiguous, it's OK

20. Ruby on Rails

21. Our case: a webshop

22. Our case: a webshop

23. What has rails built?

24. What has rails built?
• config
• db
• public
• script
• test

25. REST in Rails

26. REST in Rails
# Listing # Reading
# GET /things # GET /things/1
def index def show

27. REST in Rails
# Listing # Reading
# GET /things # GET /things/1
def index def show
# Creating # Updating
# GET /things/new # GET /things/1/edit
def new def edit
# POST /things # PUT /things/1
def create def update

28. REST in Rails
# Listing # Reading
# GET /things # GET /things/1
def index def show
# Creating # Updating
# GET /things/new # GET /things/1/edit
def new def edit
# POST /things # PUT /things/1
def create def update
# Deleting
# DELETE /things/1
# Actually: POST /things/1 with :destroy = true
def destroy

29. Layouts

30. Layouts

31. Filters

32. The Shop controller

33. Partials
/things/_my_partial.html.erb
<div id="my_div">
<p>Hello, <%= person %>!</p>
</div>

34. Partials
/things/_my_partial.html.erb
<div id="my_div">
<p>Hello, <%= person %>!</p>
</div>
<%= render
:partial => 'my_partial',
:locals => {:person => 'angelo'} %>

35. Partials

36. Partials

37. The Cart

38. The Cart

39. REST in Rails
# Listing # Reading
# GET /things # GET /things/1
def index def show
# Creating # Updating
# GET /things/new # GET /things/1/edit
def new def edit
# POST /things # PUT /things/1
def create def update
# Deleting
# DELETE /things/1
# Actually: POST /things/1 with :destroy = true
def destroy

40. REST in Rails
# Listing # Reading
# GET /things # GET /things/1
def index def show
# Creating # Updating
# GET /things/new # GET /things/1/edit
def new def edit
# POST /things # PUT /things/1
def create def update
# Deleting
# DELETE /things/1
# Actually: POST /things/1 with :destroy = true
def destroy

41. Line and Order

42. What was all that?

43. What was all that?
• Convention over configuration

44. What was all that?
• Convention over configuration
• Mixed languages as necessary

45. What was all that?
• Convention over configuration
• Mixed languages as necessary
• Rapid development

46. Resources
http://pragprog.com/
titles/rails2

47. Resources
http://www.railscasts.com

48. What haven’t I talked

49. What haven’t I talked
• AJAX-y things

50. What haven’t I talked
• AJAX-y things
• Testing (RSpec)