Building a Rails Application. Part 2

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Louisa Lamb
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1 Building a Rails Application Part 2

3 app/views/layouts/store.rhtml <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" " <html> <head> <title>pragprog Books Online Store</title> <%= stylesheet_link_tag "depot", :media => "all" %> </head> <body id="store"> <div id="banner"> <%= image_tag("logo.png") %> "Pragmatic Bookshelf" %> </div> <div id="columns"> <div id="side"> <a href=" /> <a href=" /> <a href=" /> <a href=" /> </div> <div id="main"> <%= yield :layout %> </div> </div> </body> </html>

4 public/stylesheets also update depot.css

6 Formatting currency <h1>your pragmatic catalogue</h1> <% for product -%> <div class="entry"> <%= image_tag(product.image_url) %> <h3><%= h(product.title) %></h3> <%= product.description %> <span class="price"><%= number_to_currency(product.price) %></span> </div> <% %>

8 Add to Cart <h1>your pragmatic catalogue</h1> <% for product -%> <div class="entry"> <%= image_tag(product.image_url) %> <h3><%= h(product.title) %></h3> <%= product.description %> <span class="price"> <%= number_to_currency(product.price) %></span> <%= button_to "Add to Cart", :action => :add_to_cart, :id => product %> </div> <% %>

10 generate session_migration add_sessions migrate to current version open config/environment.rb

11 then restart the application # Force all environments to use the same logger level # (by default production uses :info, the others :debug) # config.log_level = :debug # Use the database for sessions instead of the file system # (create the session table with 'rake db:sessions:create') config.action_controller.session_store = :active_record_store # Use SQL instead of Active Record's schema dumper when creating the test database. # This is necessary if your schema can't be completely dumped by the schema dumper, # like if you have constraints or database-specific column types # config.active_record.schema_format = :sql

12 unique cookie name In: Controllers/application.rb class ApplicationController < ActionController::Base # Pick a unique cookie name to distinguish our session data from others' session :session_key => '_depot_session_id'

13 Finding the cart class StoreController < ApplicationController def = Product.find_products_for_sale private def find_cart session[:cart] = Cart.new

14 Making the Cart Create a Class Cart in Models don t use the generator as this one isn t linked to the database.

15 models/cart.rb class Cart attr_reader :items def = [] def << product

16 store_controller.rb def = find_cart product =

18 views/store/add_to_cart.rhtml <h1>your Pragmatic Cart</h1> <ul> <% for item %> <li><%= h(item.title) %></li> <% %> </ul>

20 class CartItem attr_reader :product, :quantity def = = 1 def += 1 def title product.title def * quantity

21 update class Cart def add_product(product) current_item { item item.product == product} if current_item current_item.increment_quantity << CartItem.new(product)

22 update view/add_to_cart.rhtml <h1>your Pragmatic Cart</h1> <ul> <% for cart_item %> <li><%= cart_item.quantity %> <%= h(cart_item.title) %></li> <% %> </ul>

23 Run Rake Task db:sessions:clear

26 Handling the error 1. Log the error in an internal log file 2. Output a short message to the User 3. Redisplay the catalogue page

27 update store_controller.rb def add_to_cart begin product = Product.find(params[:id]) rescue ActiveRecord::RecordNotFound logger.error("attempt to access invalid product #{params[:id]}") flash[:notice] = "Invalid product" redirect_to :action => :index =

28 Logs/development.log Processing StoreController#add_to_cart (for 0:0:0:0:0:0:0:1%0 at :58:12) [GET] Session ID: 9585c976ca2b44b53bfc0e11f177379c Parameters: {"action"=>"add_to_cart", "id"=>"wibble", "controller"=>"store"} [4;36;1mProduct Columns ( )[0m [0;1mSHOW FIELDS FROM products[0m [4;35;1mProduct Load ( )[0m [0mSELECT * FROM products WHERE (products.`id` = 0) [0m Attempt to access invalid product wibble Redirected to Completed in (34 reqs/sec) DB: (41%) 302 Found [ Processing StoreController#index (for 0:0:0:0:0:0:0:1%0 at :58:13) [GET] Session ID: 9585c976ca2b44b53bfc0e11f177379c Parameters: {"action"=>"index", "controller"=>"store"} [4;36;1mProduct Load ( )[0m [0;1mSELECT * FROM products ORDER BY title[0m Rering within layouts/store Rering store/index [4;35;1mProduct Columns ( )[0m [0mSHOW FIELDS FROM products[0m Completed in (31 reqs/sec) Rering: (65%) DB: (28%) 200 OK [

29 modify the main div of store.rhtml <div id="main"> <% if flash[:notice]-%> <div id="notice"><%= flash[:notice] %></div> <% -%> <%= yield :layout %> </div>

31 emptying the cart modify add_to_cart.rhtml <h1>your Pragmatic Cart</h1> <ul> <% for cart_item %> <li><%= cart_item.quantity %> <%= h(cart_item.title) %></li> <% %> </ul> <%= button_to "Empty Cart", :action => :empty_cart %>

32 add into store_controller.rb def empty_cart session[:cart] = nil flash[:notice] = "Your cart is currently empty" redirect_to :action => :index

34 Refactor! def add_to_cart begin product = Product.find(params[:id]) rescue ActiveRecord::RecordNotFound logger.error("attempt to access invalid product #{params[:id]}") redirect_to_index("invalid Product") = def empty_cart session[:cart] = nil redirect_to_index("your cart is currently empty") private def redirect_to_index(msg) flash[:notice] = msg redirect_to :action => :index

35 tidy up cart Replace add_to_cart.rhtml (in Views/store) with the version on the course lectures Web page add into class Cart: def { item item.price }

Building a Rails Application

Building a Rails Application Let s get started! Use MySQL to create a depot_development database Create a new Ruby on Rails project called depot Make sure root password is included in Configuration/database.yml