This is a Keynote slide about the "Getting started with Rails

1. ROR Lab. Season 2
- The 3rd Round -
Getting Started
with Rails (3)
July 21, 2012
Hyoseong Choi
ROR Lab.

2. A Blog Project
Post
ny
on
a
m
separate form nested form
e
to form_for
to
ne
m
an
o
y
Comment Tag
form_for fields_for
ROR Lab.

3. Adding
a Second Model
Class Database
Comment ORM
comments
singular
plural
ROR Lab.

4. Adding
a Second Model
Model Class Database Table
Comment Active
Record
comments
object record
attributes fields
ROR Lab.

5. Generating
a Model
$ rails generate model Comment
commenter:string
body:text
post:references
generate scaffold
generate model
generate controller
generate migration
ROR Lab.

6. Generating
a Model
$ rails generate model Comment
commenter:string
body:text
Migration file
Model Class : db/migrate/xxxx_create_comment.rb
: app/models/comment.rb
Comment Comments
belongs_to :post post_id :integer
post:references
ROR Lab.

7. Generating
a Model
class Comment < ActiveRecord::Base
belongs_to :post
end
Model class file
@comment.post
class CreateComments < ActiveRecord::Migration
def change
create_table :comments do |t|
t.string :commenter
t.text :body
t.references :post
t.timestamps Migration file
end
add_index :comments, :post_id
end
end
$ rake db:migrate
ROR Lab.

8. Associating
Models
Parent Model Relation Child Model
has_many
Post Comment
belongs_to
app/models/post.rb app/models/comment.rb
ROR Lab.

9. Associating
Models
class Post < ActiveRecord::Base
attr_accessible :content, :name, :title
validates :name, :presence => true
validates :title, :presence => true,
:length => { :minimum => 5 }
has_many :comments
end
app/models/post.rb
Automatic behavior :
@post.comments
ROR Lab.

10. Adding a Route
config/routes.rb
resources :posts do
resources :comments
end
ROR Lab.

11. Generating
a Controller
$ rails generate controller Comments
ROR Lab.

12. app/views/posts/show.html.erb
A post
<p id="notice"><%= notice %></p>
<p>
<b>Name:</b>
<%= @post.name %>
</p>
<p>
<b>Title:</b> comments:
<%= @post.title %>
</p>
<p>
<b>Content:</b>
<%= @post.content %>
</p> submit
<h2>Add a comment:</h2>
<%= form_for([@post, @post.comments.build]) do |f| %>
<div class="field">
<%= f.label :commenter %><br />
<%= f.text_field :commenter %>
</div>
<div class="field">
<%= f.label :body %><br />
<%= f.text_area :body %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
<%= link_to 'Edit Post', edit_post_path(@post) %> |
<%= link_to 'Back to Posts', posts_path %> |
ROR Lab.

13. app/views/posts/show.html.erb
A post
<p id="notice"><%= notice %></p>
<p>
<b>Name:</b>
<%= @post.name %>
</p>
<p>
<b>Title:</b> comments:
<%= @post.title %>
</p>
<p>
<b>Content:</b>
<%= @post.content %>
</p> submit
<h2>Add a comment:</h2>
<%= form_for([@post, @post.comments.build]) do |f| %>
<div class="field">
<%= f.label :commenter %><br />
<%= f.text_field :commenter %>
</div>
<div class="field">
<%= f.label :body %><br />
<%= f.text_area :body %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
<%= link_to 'Edit Post', edit_post_path(@post) %> |
<%= link_to 'Back to Posts', posts_path %> |
ROR Lab.

14. app/views/posts/show.html.erb
A post
<p id="notice"><%= notice %></p>
<p>
<b>Name:</b>
<%= @post.name %>
</p>
<p>
<b>Title:</b> comments:
<%= @post.title %>
</p>
<p>
<b>Content:</b>
<%= @post.content %>
</p> submit
<h2>Add a comment:</h2>
<%= form_for([@post, @post.comments.build]) do |f| %>
<div class="field">
<%= f.label :commenter %><br />
<%= f.text_field :commenter %>
</div>
<div class="field">
<%= f.label :body %><br />
<%= f.text_area :body %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
<%= link_to 'Edit Post', edit_post_path(@post) %> |
<%= link_to 'Back to Posts', posts_path %> |
ROR Lab.

15. Creating
a Comment
$ rails generate controller Comments
create destroy
/app/controllers/comments_controller.rb
class CommentsController < ApplicationController
def create
@post = Post.find(params[:post_id])
@comment = @post.comments.create(params[:comment])
redirect_to post_path(@post)
end
end
ROR Lab.

16. Creating
a Comment
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %>
</p>
<p>
comments:
<b>Comment:</b>
<%= comment.body %>
</p>
<% end %>
submit
ROR Lab.

17. Creating
a Comment
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %>
</p>
<p>
comments:
<b>Comment:</b>
<%= comment.body %>
</p>
<% end %>
submit
ROR Lab.

18. Refactoring
• Getting long and awkward
• Using “partials” to clean up
ROR Lab.

19. Refactoring
Rendering Partial Collections
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %> comments:
</p>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<% end %>
submit
ROR Lab.

20. Refactoring
Rendering Partial Collections
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %> comments:
</p>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<% end %>
submit
ROR Lab.

21. Refactoring
Rendering Partial Collections
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %> comments:
</p>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<% end %>
submit
ROR Lab.

22. Refactoring
Rendering Partial Collections
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %> comments:
</p>
_comment.html.erb
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<% end %>
submit
app/views/comments/_comment.html.erb
ROR Lab.

23. Refactoring
Rendering Partial Collections
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %> comments:
</p>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<% end %>
submit
app/views/comments/_comment.html.erb
ROR Lab.

24. Refactoring
Rendering Partial Collections
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %> comments:
</p>
<%= render :partial => “comments/comment” %>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<% end %>
submit
app/views/comments/_comment.html.erb
ROR Lab.

25. Refactoring
Rendering Partial Collections
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %> comments:
</p>
<%= render :partial => “comments/comment” %>
@post.comments %>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<% end %>
submit
app/views/comments/_comment.html.erb
ROR Lab.

26. Refactoring
Rendering Partial Collections
/app/views/posts/show.html.erb
A post
<h2>Comments</h2>
<% @post.comments.each do |comment| %>
<p>
<b>Commenter:</b>
<%= comment.commenter %> comments:
</p>
<%= render :partial => “comments/comment” %>
@post.comments %>
<p>
<b>Comment:</b>
<%= comment.body %>
</p> local variable,
<% end %> comment
submit
app/views/comments/_comment.html.erb
ROR Lab.

27. Refactoring
Rendering a Partial Form
/app/views/posts/show.html.erb
A post
<%= form_for([@post, @post.comments.build]) do |f| %>
<div class="field">
<%= f.label :commenter %><br />
<%= f.text_field :commenter %>
</div>
<div class="field"> comments:
<%= f.label :body %><br />
<%= f.text_area :body %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
submit
app/views/comments/_form.html.erb
ROR Lab.

28. Refactoring
Rendering a Partial Form
/app/views/posts/show.html.erb
A post
<%= form_for([@post, @post.comments.build]) do |f| %>
<div class="field">
<%= f.label :commenter %><br />
<%= f.text_field :commenter %>
</div>
<div class="field"> comments:
<%= f.label :body %><br />
<%= f.text_area :body %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
submit
app/views/comments/_form.html.erb
ROR Lab.

29. app/views/posts/show.html.erb
A post
<p id="notice"><%= notice %></p>
<p>
<b>Name:</b>
<%= @post.name %>
</p>
<p>
<b>Title:</b> comments:
<%= @post.title %>
</p>
<p>
<b>Content:</b>
<%= @post.content %>
</p> submit
<h2>Add a comment:</h2>
<%= form_for([@post, @post.comments.build]) do |f| %>
<div class="field">
<%= f.label :commenter %><br />
<%= f.text_field :commenter %>
</div>
<div class="field">
<%= f.label :body %><br />
<%= f.text_area :body %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
<%= link_to 'Edit Post', edit_post_path(@post) %> |
<%= link_to 'Back to Posts', posts_path %> |
ROR Lab.

30. app/views/posts/show.html.erb
A post
<p id="notice"><%= notice %></p>
<p>
<b>Name:</b>
<%= @post.name %>
</p>
<p>
<b>Title:</b> comments:
<%= @post.title %>
</p>
<p>
<b>Content:</b>
<%= @post.content %>
</p> submit
<h2>Add a comment:</h2>
<%= form_for([@post, @post.comments.build]) do |f| %>
<div class="field">
<%= f.label :commenter %><br />
<%= f.text_field :commenter %>
</div>
<div class="field">
<%= f.label :body %><br />
<%= f.text_area :body %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
<%= link_to 'Edit Post', edit_post_path(@post) %> |
<%= link_to 'Back to Posts', posts_path %> |
ROR Lab.

31. app/views/posts/show.html.erb
A post
<p id="notice"><%= notice %></p>
<p>
<b>Name:</b>
<%= @post.name %>
</p>
<p>
<b>Title:</b> comments:
<%= @post.title %>
</p>
<p>
<b>Content:</b>
<%= @post.content %>
</p> submit
<h2>Comments</h2>
<h2>Add a comment:</h2>
<% @post.comments.each do |comment| %>
<%= form_for([@post, @post.comments.build]) do |f| %>
<%= render “comments/comment” %>
<div class="field">
<% end %>
<%= f.label :commenter %><br />
<%= f.text_field :commenter %>
or
</div>
<div class="field">
<h2>Comments</h2>
<%= f.label :body %><br />
<%= render @post.comments %>
<%= f.text_area :body %>
</div>
<div class="actions">
<h2>Add a comment:</h2>
<%= f.submit %>
<%= render "comments/form" %>
</div>
<% end %>
<%= link_to 'Edit Post', edit_post_path(@post) %> |
<%= link_to 'Back to Posts', posts_path %> |
ROR Lab.

32. Deleting
Comments
app/views/comments/_comment.html.erb
<p>
<b>Commenter:</b>
<%= comment.commenter %>
</p>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<p>
<%= link_to 'Destroy Comment', [comment.post, comment],
:confirm => 'Are you sure?',
:method => :delete %>
</p>
DELETE /posts/:post_id/comments/:id
ROR Lab.

33. Deleting
Comments
app/views/comments/_comment.html.erb
<p>
<b>Commenter:</b>
<%= comment.commenter %>
</p>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<p>
<%= link_to 'Destroy Comment', [comment.post, comment],
:confirm => 'Are you sure?',
:method => :delete %>
</p>
DELETE /posts/:post_id/comments/:id
ROR Lab.

34. Deleting
Comments
DELETE /posts/:post_id/comments/:id
<p>
<b>Commenter:</b>
<%= comment.commenter %>
</p>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<p>
<%= link_to 'Destroy Comment', [comment.post, comment],
:confirm => 'Are you sure?',
:method => :delete %>
</p>
ROR Lab.

35. Deleting
Comments
DELETE /posts/:post_id/comments/:id
<p>
<b>Commenter:</b>
<%= comment.commenter %>
</p>
<p>
<b>Comment:</b>
<%= comment.body %>
</p>
<p>
<%= link_to 'Destroy Comment', [comment.post, comment],
:confirm => 'Are you sure?',
:method => :delete %>
</p>
ROR Lab.

36. Deleting
Comments
DELETE /posts/:post_id/comments/:id
$ rake routes
post_comments GET /posts/:post_id/comments(.:format) comments#index
POST /posts/:post_id/comments(.:format) comments#create
new_post_comment GET /posts/:post_id/comments/new(.:format) comments#new
edit_post_comment GET /posts/:post_id/comments/:id/edit(.:format) comments#edit
post_comment GET /posts/:post_id/comments/:id(.:format) comments#show
PUT /posts/:post_id/comments/:id(.:format) comments#update
DELETE /posts/:post_id/comments/:id(.:format) comments#destroy
posts GET /posts(.:format) posts#index
POST /posts(.:format) posts#create
new_post GET /posts/new(.:format) posts#new
edit_post GET /posts/:id/edit(.:format) posts#edit
post GET /posts/:id(.:format) posts#show
PUT /posts/:id(.:format) posts#update
DELETE /posts/:id(.:format) posts#destroy
ROR Lab.

37. Deleting
Comments
DELETE /posts/:post_id/comments/:id
$ rake routes
post_comments GET /posts/:post_id/comments(.:format) comments#index
POST /posts/:post_id/comments(.:format) comments#create
new_post_comment GET /posts/:post_id/comments/new(.:format) comments#new
edit_post_comment GET /posts/:post_id/comments/:id/edit(.:format) comments#edit
post_comment GET /posts/:post_id/comments/:id(.:format) comments#show
PUT /posts/:post_id/comments/:id(.:format) comments#update
DELETE /posts/:post_id/comments/:id(.:format) comments#destroy
posts GET /posts(.:format) posts#index
POST /posts(.:format) posts#create
new_post GET /posts/new(.:format) posts#new
edit_post GET /posts/:id/edit(.:format) posts#edit
post GET /posts/:id(.:format) posts#show
PUT /posts/:id(.:format) posts#update
DELETE /posts/:id(.:format) posts#destroy
ROR Lab.

38. Deleting
Comments
class CommentsController < ApplicationController
def create
@post = Post.find(params[:post_id])
@comment = @post.comments.create(params[:comment])
redirect_to post_path(@post)
end
def destroy
@post = Post.find(params[:post_id])
@comment = @post.comments.find(params[:id])
@comment.destroy
redirect_to post_path(@post)
end
end
ROR Lab.

39. Deleting
Comments
class CommentsController < ApplicationController
def create
@post = Post.find(params[:post_id])
@comment = @post.comments.create(params[:comment])
redirect_to post_path(@post)
end
def destroy
@post = Post.find(params[:post_id])
@comment = @post.comments.find(params[:id])
@comment.destroy
redirect_to post_path(@post)
end
end
ROR Lab.

40. Deleting
Assoc. Objects
class Post < ActiveRecord::Base
attr_accessible :content, :name, :title
validates :name, :presence => true
validates :title, :presence => true,
:length => { :minimum => 5 }
has_many :comments, :dependent => :destroy
app/models/post.rb
ROR Lab.

41. Deleting
Assoc. Objects
class Post < ActiveRecord::Base
attr_accessible :content, :name, :title
validates :name, :presence => true
validates :title, :presence => true,
:length => { :minimum => 5 }
has_many :comments, :dependent => :destroy
app/models/post.rb
Other options: :dependent => :destroy
:dependent => :delete
:dependent => :nullify
ROR Lab.

42. Security
A very simple HTTP authentication system
class PostsController < ApplicationController
http_basic_authenticate_with
:name => "dhh",
:password => "secret",
:except => [:index, :show]
# GET /posts
# GET /posts.json
def index
@posts = Post.all
respond_to do |format|
ROR Lab.

43. Security
A very simple HTTP authentication system
class PostsController < ApplicationController
http_basic_authenticate_with
:name => "dhh",
:password => "secret",
:except => [:index, :show]
# GET /posts
# GET /posts.json
def index
@posts = Post.all
respond_to do |format|
ROR Lab.

44. Security
A very simple HTTP authentication system
class CommentsController < ApplicationController
http_basic_authenticate_with
:name => "dhh",
:password => "secret",
:only => :destroy
def create
@post = Post.find(params[:post_id])
ROR Lab.

45. Security
A very simple HTTP authentication system
class CommentsController < ApplicationController
http_basic_authenticate_with
:name => "dhh",
:password => "secret",
:only => :destroy
def create
@post = Post.find(params[:post_id])
ROR Lab.

46. Security
A very simple HTTP authentication system
ROR Lab.

47. Live Demo
Creating a project ~ First model, Post
ROR Lab.

48. 감사합니다.

49.
ROR Lab.