My presentation from Ruby on Rails seminar in Varna at Varna Free University "Chernorizets Hrabar"

1. Защо Ruby и Rails ?
Радослав Станков
Ruby on Rails семинар – Варненски свободен университет 2010

2. Кой съм аз?
@rstankov
http://rstankov.com
http://blog.rstankov.com
http://github.com/rstankov

6. Ruby
Ruby е интерактивен,
обектно-ориентиран език за
програмиране.
Неготово мото е:
“Optimized for programmer happiness”

7. Ruby on Rails
Ruby on Rails е framework
за уеб приложения.
Неготово мото е:
“Web development doesn’t hurt”

8. Ruby
Създаден от японеца Юкихиро
Мацумото „Мац“.
Първата публична версия излиза
през 1995.
Версия 2.0 се очакава да излезе за
Коледа / не се казва коя /

10. private $_products = null;
public function getProducts($categoryId){
if ($this->_products === null){
$this->_products = Product::where(array(
'category_id' => $categoryId
));
}
return $this->products;
}

11. def products(category_id)
@products ||= Product.where({ :category_id => category_id })
end

12. def products(category_id)
@products ||= Product.where({ :category_id => category_id })
end

13. def products(category_id)
@products ||= Product.where({ :category_id => category_id })
end

14. def products(category_id)
@products ||= Product.where({ :category_id => category_id })
end

15. def products(category_id)
@products ||= Product.where({ :category_id => category_id })
end

16. def products(category_id)
@products ||= Product.where({ :category_id => category_id })
end

17. def products(category_id)
@products ||= Product.where( :category_id => category_id )
end

18. def products(category_id)
@products ||= Product.where :category_id => category_id
end

19. 5.times { puts "Ruby is cool!" }
5.times do
puts "Ruby is cool!"
end

20. File.open("some_file.txt") do |file|
file << "content"
end

21. [1,2,3,4].each { |value| puts value }
# => [1, 2, 3, 4]
[1,2,3,4].map { |value| value * value }
# => [1, 4, 9, 16]
[1,2,3,4].reduce { |a, b| a + b }
# => 10

22. def operate(value)
yield value
end
value = operate(5) { |v| v + 4 }
puts value # 9

23. class Person
attr_accessor :fist_name, :last_name
def initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
end
def full_name
"#{first_name} + #{last_name}"
end
end
me = Person.new("Radoslav", "Stankov")
puts me.full_name # Radoslav Stankov

24. class Person
attr_accessor :fist_name, :last_name
def initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
end
def full_name
first_name + " " + last_name
end
end
me = Person.new("Radoslav", "Stankov")
puts me.full_name # Radoslav Stankov

25. class Person
attr_accessor :fist_name, :last_name
def initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
end
def full_name
first_name + " " + last_name
end
end
me = Person.new("Radoslav", "Stankov")
puts me.full_name # Radoslav Stankov

26. class Person
attr_accessor :fist_name, :last_name
def initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
end
def full_name
first_name + " " + last_name
end
end
me = Person.new("Radoslav", "Stankov")
puts me.full_name # Radoslav Stankov

27. class Person
attr_accessor :fist_name, :last_name
def initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
end
def full_name
first_name + " " + last_name
end
end
me = Person.new("Radoslav", "Stankov")
puts me.full_name # Radoslav Stankov

28. class Person
def +(other_person)
# ...
end
end
person1 + person2

29. class Array
def first
self[0]
end
def second
self[1]
end
end
array = [1, 2, 3, 4]
array.first # 1
array.second # 2

30. class Numeric
def plus(x)
self + x
end
end
y = 5.plus(6)

31. Time.now - 2.days == 2.days.ago
1.month.ago + 45.days - 1.year

32. Ruby
• димично определяне на типа данните
• модули
• отворени класове
• блокове
• анонимни функции
• всяка операция връща резултат
• всичко е изпълним код
• изчистен синтаксис
• мета програмиране
• промяна на обектите по време на изпълнение
• вградени регулярни изрази

36. Ruby on Rails
Разработен от David
Heinemeier Hansson от 37
Signals.
Първата публична версия е
излиза през юли 2004.
Текущата стабилна версия
е 3.0.3

40. 37signals
Милиони клиенти ... по-малко от 37 служителя

46. MVC Архитектура

47. Начин на работа

67. Model
class Task < ActiveRecord::Base
belongs_to :user
has_many :comments
validates_presence_of :user, :text
validates_inclusion_of :status, :in => ["opened", "completed"]
attr_readonly :user_id
def editable?
status == "opened"
end
end

68. Model
class Task < ActiveRecord::Base
belongs_to :user
has_many :comments
validates_presence_of :user, :text
validates_inclusion_of :status, :in => ["opened", "completed"]
attr_readonly :user_id
def editable?
status == "opened"
end
end

69. Model
class Task < ActiveRecord::Base
belongs_to :user
has_many :comments
validates_presence_of :user, :text
validates_inclusion_of :status, :in => ["opened", "completed"]
attr_readonly :user_id
def editable?
status == "opened"
end
end

70. Model
class Task < ActiveRecord::Base
belongs_to :user
has_many :comments
validates_presence_of :user, :text
validates_inclusion_of :status, :in => ["opened", "completed"]
attr_readonly :user_id
def editable?
status == "opened"
end
end

71. Model
class Task < ActiveRecord::Base
belongs_to :user
has_many :comments
validates_presence_of :user, :text
validates_inclusion_of :status, :in => ["opened", "completed"]
attr_readonly :user_id
def editable?
status == "opened"
end
end

72. Controller
class TasksController < ApplicationController
def index
@tasks = Tasks.where(:status => "opened")
end
def show
@task = Task.find(params[:id])
end
def create
@task = current_user.tasks.build(params[:task])
if @task.save
redirect_to tasks_path
else
render :partial => "new"
end
end
end

73. Controller
class TasksController < ApplicationController
def index
@tasks = Tasks.where(:status => "opened")
end
def show
@task = Task.find(params[:id])
end
def create
@task = current_user.tasks.build(params[:task])
if @task.save
redirect_to tasks_path
else
render :partial => "new"
end
end
end

74. Controller
class TasksController < ApplicationController
def index
@tasks = Tasks.where(:status => "opened")
end
def show
@task = Task.find(params[:id])
end
def create
@task = current_user.tasks.build(params[:task])
if @task.save
redirect_to tasks_path
else
render :partial => "new"
end
end
end

75. Controller
class TasksController < ApplicationController
def index
@tasks = Tasks.where(:status => "opened")
end
def show
@task = Task.find(params[:id])
end
def create
@task = current_user.tasks.build(params[:task])
if @task.save
redirect_to tasks_path
else
render :partial => "new"
end
end
end

76. View
<%= form_for task do |form| %>
<%= render 'shared/error_messages', :target => form.object %>
<p>
<%= form.label :text %>
<%= form.text_area :text %>
</p>
<p>
<%= form.label :status %>
<%= form.select :status, Task.statuses %>
</p>
<div class="buttons">
<%= form.submit %> |
<% link_to "Cancel", task_path %>
</div>
<% end %>

77. Test Driven Development

78. Test Driven Development
1 Добавя се тест
... за несъществуващ код

79. Test Driven Development
1 Добавя се тест
... за несъществуващ код
2 Пише се код
... колкото само тестът да мине

80. Test Driven Development
1 Добавя се тест
... за несъществуващ код
2 Пише се код
... колкото само тестът да мине
3 Правят се подобрения
... подобрява се качеството на кода

81. Test Driven Development
1 Добавя се тест
... за несъществуващ код
2 Пише се код
... колкото само тестът да мине
3 Правят се подобрения
... подобрява се качеството на кода

82. describe Task do
it { should belong_to(:user) }
it { should have_many(:notes) }
it { should validate_presence_of(:user) }
it { should validate_presence_of(:text) }
describe "#editable?" do
it "returns true if task status is 'opened'" do
Task.new(:status => "opened").should be_editable
end
it "returns false if task status is 'rejected'" do
Task.new(:status => "rejected").should_not be_editable
end
it "returns false if task status is 'completed" do
Task.new(:status => "completed").should_not be_editable
end
end
end

83. Тесване на Controller
describe TasksController do
describe "GET 'show'" do
before { Task.should_recive(:find).with("1").and_return task }
before { get :show, :id => "1" }
it { should assign_to(:task).with(task) }
it { should render_temlate("show") }
end
end

84. Тестване на View
describe "tasks/show.html.erb" do
before do
assign :task, mock_model(Task, {
:id => 1,
:text => "task text"
})
render
end
it "renders task text" do
rendered.should contain("task text")
end
it "renders link for editing task" do
rendered.should have_selector('a[href="/tasks/1/edit"]')
end
end

86. Благодаря за вниманието
@rstankov