Rails by example
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The document discusses the fundamentals of Ruby on Rails, including data types, class definitions, and coding conventions. It outlines key frameworks and concepts such as RESTful architecture, optional parameters, and how to structure Rails applications. Additionally, it provides examples of method usage, partials, and rapid development principles in the context of building web applications.
![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]](https://image.slidesharecdn.com/railsbyexample-100608152109-phpapp02/85/Rails-by-example-5-320.jpg)
![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"]](https://image.slidesharecdn.com/railsbyexample-100608152109-phpapp02/85/Rails-by-example-6-320.jpg)
![Code blocks
[1,2,3,5,7].select {|x| x.even?}
# => [2]](https://image.slidesharecdn.com/railsbyexample-100608152109-phpapp02/85/Rails-by-example-11-320.jpg)
![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](https://image.slidesharecdn.com/railsbyexample-100608152109-phpapp02/85/Rails-by-example-12-320.jpg)
![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](https://image.slidesharecdn.com/railsbyexample-100608152109-phpapp02/85/Rails-by-example-13-320.jpg)
Rails by example
- 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
- 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
- 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
- 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)
Editor's Notes
- #4: Symbol can be seen as a constant without any overhead. Used for indexing, as key, etc.
- #33: Greatly increases readability!
- #34: Greatly increases readability!
- #35: Greatly increases readability!
- #36: Greatly increases readability!
- #37: Greatly increases readability!
- #38: Greatly increases readability!
- #39: Greatly increases readability!
- #40: Greatly increases readability!
- #41: Greatly increases readability!
- #42: Greatly increases readability!
- #43: I have been doing Ruby on Rails for about six weeks now; time for a quick introduction! This is not intended as a be-all-and-end-all presentation; I point out the things I find interesting or surprising. Image: http://shakti.trincoll.edu/~dmerrick/images/ruby.png