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Week 5 - Controllers

Review of named routes

$ rake routes
    books GET    /books(.:format)          books#index
          POST   /books(.:format)          books#create
 new_book GET    /books/new(.:format)      books#new
edit_book GET    /books/:id/edit(.:format) books#edit
     book GET    /books/:id(.:format)      books#show
          PUT    /books/:id(.:format)      books#update
          DELETE /books/:id(.:format)      books#destroy
$ bundle exec rails c
Loading development environment (Rails 3.2.17)
2.0.0-p247 :001 > app.books_path
 => "/books"
2.0.0-p247 :002 > book = Book.first
  Book Load (0.2ms)  SELECT "books".* FROM "books" LIMIT 1
 => #<Book id: 5, name: "The Bible", pages: 2500, created_at: "2014-03-04 02:26:32", updated_at: "2014-03-04 02:26:32">
2.0.0-p247 :003 > app.book_path(book)
 => "/books/5"
2.0.0-p247 :004 > app.edit_book_path(book)
 => "/books/5/edit"
2.0.0-p247 :005 > helper.link_to "Edit", app.edit_book_path(book)
 => "<a href=\"/books/5/edit\">Edit</a>"
2.0.0-p247 :005 > helper.link_to "Show", app.book_path(book)
 => "<a href=\"/books/5\">Show</a>"
2.0.0-p247 :005 > app.polymorphic_path(book)
 => "/books/5"
2.0.0-p247 :006 > exit

Anywhere you use book_path, you can just pass in the object

  • app/controllers/books_controller.rb

    class BooksController < ApplicationController
  def index
    @books = Book.all
  end

  def show
    @book = Book.find params[:id]
  end

  def new
    @book = Book.new
  end

  def create
    @book = Book.new params[:book]
    @book.save
    redirect_to @book #Changed
  end

  def edit
    @book = Book.find params[:id]
  end

  def update
    @book = Book.find params[:id]
    @book.update_attributes params[:book]
    redirect_to @book # Changed
  end

  def destroy
    @book = Book.find params[:id]
    @book.destroy
    redirect_to books_path
  end
end

  • app/views/index.html.erb

    <h1>Books</h1>
<%= link_to "New Book", new_book_path %>

<table>
  <tr>
    <th>Name</th>
    <th>Pages</th>
  </tr>
  <% @books.each do |book| %>
  <tr>
    <!-- changed -->
    <td><%= link_to book.name, book %></td>
    <td><%= book.pages %></td>
  </tr>
  <% end %>
</table>

  • app/views/show.html.erb

    <h1><%= @book.name %></h1>

<%= link_to "Edit", edit_book_path(@book) %> |
<!-- Changed book_path(@book) to @book -->
<%= link_to "Delete", @book, method: :delete, data:{confirm: "Are you sure?"} %>
<p>Pages: <%= @book.pages %></p>

<%= link_to "All Books", books_path %>

Adding a Book summary field (Alexii)

  1. Create a migration

    $ rails generate migration add_summary_to_books summary:text

  2. Show migration file. Talk about why text instead of string

  3. Migrate the database

    $ rake db:migrate
==  AddSummaryToBooks: migrating ==============================================
-- add_column(:books, :summary, :text)
   -> 0.0008s
==  AddSummaryToBooks: migrated (0.0009s) =====================================

  4. Show rollback functionality

    $ rake db:rollback
==  AddSummaryToBooks: reverting ==============================================
-- remove_column("books", :summary)
   -> 0.0246s
==  AddSummaryToBooks: reverted (0.0248s) =====================================

$ rake db:migrate
==  AddSummaryToBooks: migrating ==============================================
-- add_column(:books, :summary, :text)
   -> 0.0008s
==  AddSummaryToBooks: migrated (0.0009s) =====================================

  5. Restart the server bundle exec rails s

  6. Update app/views/books/_form.html.erb

    <%= form_for @book do |f| %>
  <div>
    <%= f.label :name %>
    <%= f.text_field :name %>
  </div>
  <div>
    <%= f.label :pages %>
    <%= f.text_field :pages %>
  </div>
  <div>
    <%= f.label :summary %>
    <%= f.text_area :summary %>
  </div>
  <%= f.submit %>
<% end %>

  7. Try to submit, see Mass assignment security error

  8. Update app/models/book.rb

    class Book < ActiveRecord::Base
  attr_accessible :name, :pages, :summary
end

  9. Render summary on app/models/show.html.erb

    <h1><%= @book.name %></h1>

<%= link_to "Edit", edit_book_path(@book) %>
<%= link_to "Delete", @book, method: :delete %>

<p>Pages: <%= @book.pages %></p>

<%= @book.summary %>

<%= link_to "Back to all books", books_path %>

  10. Use simple_format view helper to include line breaks

    <h1><%= @book.name %></h1>

<%= link_to "Edit", edit_book_path(@book) %>
<%= link_to "Delete", @book, method: :delete %>

<p>Pages: <%= @book.pages %></p>

<p><%= simple_format @book.summary %></p>

<%= link_to "Back to all books", books_path %>

Associations

See slides

Adding reviews

  1. Generate review model

    $ rails generate model review name:string rating:integer body:text book:belongs_to

  2. Show migration and model

  3. Migrate the database

    $ rake db:migrate

  4. Create some reviews

    $ bundle exec rails c
Loading development environment (Rails 3.2.17)
2.0.0-p247 :001 > review = Review.new name: "Joe Smith", rating: 4, body: "Cool Cat!"
 => #<Review id: nil, name: "Joe Smith", rating: 4, body: "Cool Cat!", book_id: nil, created_at: nil, updated_at: nil>
2.0.0-p247 :002 > review.book = Book.last
  Book Load (0.2ms)  SELECT "books".* FROM "books" ORDER BY "books"."id" DESC LIMIT 1
 => #<Book id: 6, name: "Garfield", pages: 201, created_at: "2014-03-04 02:32:11", updated_at: "2014-03-08 17:59:01", summary: "Comic about something\r\n\r\nanother line">
2.0.0-p247 :003 > review
 => #<Review id: nil, name: "Joe Smith", rating: 4, body: "Cool Cat!", book_id: 6, created_at: nil, updated_at: nil>
2.0.0-p247 :004 > review.save
   (0.1ms)  begin transaction
  SQL (28.6ms)  INSERT INTO "reviews" ("body", "book_id", "created_at", "name", "rating", "updated_at") VALUES (?, ?, ?, ?, ?, ?)  [["body", "Cool Cat!"], ["book_id", 6], ["created_at", Sun, 09 Mar 2014 05:14:
58 UTC +00:00], ["name", "Joe Smith"], ["rating", 4], ["updated_at", Sun, 09 Mar 2014 05:14:58 UTC +00:00]]
   (37.8ms)  commit transaction
 => true
2.0.0-p247 :005 > book = Book.last
  Book Load (0.3ms)  SELECT "books".* FROM "books" ORDER BY "books"."id" DESC LIMIT 1
 => #<Book id: 6, name: "Garfield", pages: 201, created_at: "2014-03-04 02:32:11", updated_at: "2014-03-08 17:59:01", summary: "Comic about something\r\n\r\nanother line">
2.0.0-p247 :006 > book.reviews
NoMethodError: undefined method `reviews' for #<Book:0x00000000dd5c20>
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activemodel-3.2.17/lib/active_model/attribute_methods.rb:407:in `method_missing'
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-3.2.17/lib/active_record/attribute_methods.rb:149:in `method_missing'
        from (irb):6
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-3.2.17/lib/rails/commands/console.rb:47:in `start'
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-3.2.17/lib/rails/commands/console.rb:8:in `start'
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-3.2.17/lib/rails/commands.rb:41:in `<top (required)>'
        from script/rails:6:in `require'
        from script/rails:6:in `<main>'
2.0.0-p247 :007 >

  5. Add has_many to books

    class Book < ActiveRecord::Base
  has_many :reviews
  attr_accessible :name, :pages, :summary
end

  6. Back in rails console. Create a few more reviews

    $ bundle exec rails c
Loading development environment (Rails 3.2.17)
2.0.0-p247 :001 > book = Book.last
  Book Load (0.2ms)  SELECT "books".* FROM "books" ORDER BY "books"."id" DESC LIMIT 1
 => #<Book id: 6, name: "Garfield", pages: 201, created_at: "2014-03-04 02:32:11", updated_at: "2014-03-08 17:59:01", summary: "Comic about something\r\n\r\nanother line">
2.0.0-p247 :002 > book.reviews
  Review Load (0.2ms)  SELECT "reviews".* FROM "reviews" WHERE "reviews"."book_id" = 6
 => [#<Review id: 1, name: "Joe Smith", rating: 4, body: "Cool Cat!", book_id: 6, created_at: "2014-03-09 05:14:58", updated_at: "2014-03-09 05:14:58">]
2.0.0-p247 :003 > review = book.reviews.new
 => #<Review id: nil, name: nil, rating: nil, body: nil, book_id: 6, created_at: nil, updated_at: nil>
2.0.0-p247 :004 > review.attributes = {name: "Aaron Renner", rating: 5, body: "I like it!"}
 => {:name=>"Aaron Renner", :rating=>5, :body=>"I like it!"}
2.0.0-p247 :005 > review.save
   (0.1ms)  begin transaction
  SQL (4.4ms)  INSERT INTO "reviews" ("body", "book_id", "created_at", "name", "rating", "updated_at") VALUES (?, ?, ?, ?, ?, ?)  [["body", "I like it!"], ["book_id", 6], ["created_at", Sun, 09 Mar 2014 05:24:
38 UTC +00:00], ["name", "Aaron Renner"], ["rating", 5], ["updated_at", Sun, 09 Mar 2014 05:24:38 UTC +00:00]]
   (65.1ms)  commit transaction
 => true
2.0.0-p247 :006 > book.reviews.count
   (0.3ms)  SELECT COUNT(*) FROM "reviews" WHERE "reviews"."book_id" = 6
 => 2
2.0.0-p247 :007 > first_book = Book.first
  Book Load (0.3ms)  SELECT "books".* FROM "books" LIMIT 1
 => #<Book id: 5, name: "The Bible", pages: 2500, created_at: "2014-03-04 02:26:32", updated_at: "2014-03-04 02:26:32", summary: nil>
2.0.0-p247 :008 > first_book.reviews.create name: "Aaron Renner", rating: 5, body: "Timeless and Epic.\nThe ultimate source of truth."
   (0.1ms)  begin transaction
  SQL (0.6ms)  INSERT INTO "reviews" ("body", "book_id", "created_at", "name", "rating", "updated_at") VALUES (?, ?, ?, ?, ?, ?)  [["body", "Timeless and Epic.\nThe ultimate source of truth."], ["book_id", 5],
 ["created_at", Sun, 09 Mar 2014 05:26:41 UTC +00:00], ["name", "Aaron Renner"], ["rating", 5], ["updated_at", Sun, 09 Mar 2014 05:26:41 UTC +00:00]]
   (38.8ms)  commit transaction
 => #<Review id: 3, name: "Aaron Renner", rating: 5, body: "Timeless and Epic.\nThe ultimate source of truth.", book_id: 5, created_at: "2014-03-09 05:26:41", updated_at: "2014-03-09 05:26:41">
2.0.0-p247 :009 >

  7. Finding records through parents

    $ bundle exec rails c
Loading development environment (Rails 3.2.17)
2.0.0-p247 :001 > book_1 = Book.first
  Book Load (0.2ms)  SELECT "books".* FROM "books" LIMIT 1
 => #<Book id: 5, name: "The Bible", pages: 2500, created_at: "2014-03-04 02:26:32", updated_at: "2014-03-04 02:26:32", summary: nil>
2.0.0-p247 :002 > review = book_1.reviews.first
  Review Load (0.2ms)  SELECT "reviews".* FROM "reviews" WHERE "reviews"."book_id" = 5 LIMIT 1
 => #<Review id: 3, name: "Aaron Renner", rating: 5, body: "Timeless and Epic.\nThe ultimate source of truth.", book_id: 5, created_at: "2014-03-09 05:26:41", updated_at: "2014-03-09 05:26:41">
2.0.0-p247 :003 > book_2 = Book.last
  Book Load (0.3ms)  SELECT "books".* FROM "books" ORDER BY "books"."id" DESC LIMIT 1
 => #<Book id: 6, name: "Garfield", pages: 201, created_at: "2014-03-04 02:32:11", updated_at: "2014-03-08 17:59:01", summary: "Comic about something\r\n\r\nanother line">
2.0.0-p247 :004 > book_1.reviews.find(3)
  Review Load (3.2ms)  SELECT "reviews".* FROM "reviews" WHERE "reviews"."book_id" = 5 AND "reviews"."id" = ? LIMIT 1  [["id", 3]]
 => #<Review id: 3, name: "Aaron Renner", rating: 5, body: "Timeless and Epic.\nThe ultimate source of truth.", book_id: 5, created_at: "2014-03-09 05:26:41", updated_at: "2014-03-09 05:26:41">
2.0.0-p247 :005 > book_2.reviews.find(3)
  Review Load (0.3ms)  SELECT "reviews".* FROM "reviews" WHERE "reviews"."book_id" = 6 AND "reviews"."id" = ? LIMIT 1  [["id", 3]]
ActiveRecord::RecordNotFound: Couldn't find Review with id=3 [WHERE "reviews"."book_id" = 6]
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-3.2.17/lib/active_record/relation/finder_methods.rb:344:in `find_one'
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-3.2.17/lib/active_record/relation/finder_methods.rb:315:in `find_with_ids'
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-3.2.17/lib/active_record/relation/finder_methods.rb:107:in `find'
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-3.2.17/lib/active_record/associations/collection_association.rb:95:in `find'
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-3.2.17/lib/active_record/associations/collection_proxy.rb:46:in `find'
        from (irb):5
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-3.2.17/lib/rails/commands/console.rb:47:in `start'
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-3.2.17/lib/rails/commands/console.rb:8:in `start'
        from /home/action/.rvm/gems/ruby-2.0.0-p247/gems/railties-3.2.17/lib/rails/commands.rb:41:in `<top (required)>'
        from script/rails:6:in `require'
        from script/rails:6:in `<main>'
2.0.0-p247 :006 >

Displaying reviews

  1. app/controllers/books_controller.rb

    class BooksController < ApplicationController

  # Other actions omitted

  def show
    @book = Book.find params[:id]
    @reviews = @book.reviews
  end

  2. app/views/books/show.html.erb

    <h1><%= @book.name %></h1>

<%= link_to "Edit", edit_book_path(@book) %> |
<%= link_to "Delete", book_path(@book), method: :delete, data:{confirm: "Are you sure?"} %>
<p>Pages: <%= @book.pages %></p>

<%= simple_format @book.summary %>

<%= link_to "All Books", books_path %>

<h3>Reviews</h3>
<% @reviews.each do |review| %>
  <div>
    <%= simple_format review.body %>
    <p style="font-style: italic;"><%= review.name %> gave this book a <%= review.rating %> star rating.</p>
  </div>
<% end %>

  3. app/views/books/index.html.erb

    <h1>Books</h1>

<%= link_to "New Book", new_book_path %>

<table>
  <tr>
    <th>Name</th>
    <th>Pages</th>
    <th>Review Count</th>
  </tr>
  <% @books.each do |book| %>
  <tr>
    <td><%= link_to book.name, book_path(book) %></td>
    <td><%= book.pages %></td>
    <td><%= book.reviews.count %></td>
  </tr>
  <% end %>
</table>

Nested Routes

This will allow us to visit /books/1/reviews/3

  1. app/views/books/show.html.erb

    <h1><%= @book.name %></h1>

<%= link_to "Edit", edit_book_path(@book) %> |
<%= link_to "Delete", book_path(@book), method: :delete, data:{confirm: "Are you sure?"} %>
<p>Pages: <%= @book.pages %></p>

<%= simple_format @book.summary %>

<%= link_to "All Books", books_path %>

<h3>Reviews</h3>
<% @reviews.each do |review| %>
  <div>
    <%= simple_format review.body %>
    <%= link_to [@book, review], style:"font-style: italic; display: block;" do %>
      <%= review.name %> gave this book a <%= review.rating %> star rating.
    <% end %>
  </div>
<% end %>

  2. config/routes.rb

    Bookstore::Application.routes.draw do
  resources :books do
    resources :reviews, only: [:show]
  end
end

  3. Look at routes

    $ rake routes
book_review GET    /books/:book_id/reviews/:id(.:format) reviews#show
      books GET    /books(.:format)                      books#index
            POST   /books(.:format)                      books#create
   new_book GET    /books/new(.:format)                  books#new
  edit_book GET    /books/:id/edit(.:format)             books#edit
       book GET    /books/:id(.:format)                  books#show
            PUT    /books/:id(.:format)                  books#update
            DELETE /books/:id(.:format)                  books#destroy

  4. Create reviews controller (app/controllers/reviews_controller.rb)

    class ReviewsController < ApplicationController
  def show
    @book = Book.find params[:book_id]
    @review = @book.reviews.find params[:id]
  end
end

  5. Create view (app/views/reviews/show.html.erb)

    <h1>Review #<%= @review.id %> for <%= link_to @book.name, @book %></h1>

<p><%= @review.name %> gave this book <%= @review.rating %> stars</p>

<%= simple_format @review.body %>