10.4 Playtime 10.2 Iteration E2: Handling Errors
Add empty cart button, remove flash for line item create, add totals to view.
Add button to the view.
edit app/views/carts/show.html.erb
<h2>Your Pragmatic Cart</h2>
<ul>
<% for item in @cart.line_items %>
<li><%= item.quantity %> × <%= item.product.title %></li>
<% end %>
</ul>
<%= button_to 'Empty cart', @cart, :method => :delete,
:confirm => 'Are you sure?' %>
Clear session and add flash notice when cart is destroyed.
edit app/controllers/carts_controller.rb
def destroy
@cart = Cart.find(params[:id])
@cart.destroy
session[:cart_id] = nil
respond_to do |format|
format.html { redirect_to(store_url,
:notice => 'Your cart is currently empty') }
format.xml { head :ok }
end
end
Try it out.
get /carts/1
Pragmatic Bookshelf
post /carts/1
get http://localhost:3000/
Pragmatic Bookshelf
Your cart is currently empty
Professional programmers develop a knack of unerringly zeroing in on the root cause of a bug. They can do that because they've written a lot of buggy code and then gained experience fixing it. This book captures all this experience -- use it, and you'll find you write fewer bugs, and the ones you do write will become easier to hunt down.
Ruby is the fastest growing and most exciting dynamic language out there. If you need to get working programs delivered fast, you should add Ruby to your toolbox.
Web Design for Developers will show you how to make your web-based application look professionally designed. We'll help you learn how to pick the right colors and fonts, avoid costly interface and accessibility mistakes -- your application will really come alive. We'll also walk you through some common Photoshop and CSS techniques and work through a web site redesign, taking a new design from concept all the way to implementation.
pub depot_h
Remove scaffolding generated flash notice for line item create.
edit app/controllers/line_items_controller.rb
def create
@cart = find_or_create_cart
product = Product.find(params[:product_id])
@line_item = @cart.add_product(product.id)
respond_to do |format|
if @line_item.save
format.html { redirect_to(@line_item.cart) }
format.xml { render :xml => @line_item,
:status => :created, :location => @line_item }
else
format.html { render :action => "new" }
format.xml { render :xml => @line_item.errors,
:status => :unprocessable_entity }
end
end
end
Update the view to add totals.
edit app/views/carts/show.html.erb
<div class="cart_title">Your Cart</div>
<table>
<% for item in @cart.line_items %>
<tr>
<td><%= item.quantity %>×</td>
<td><%= item.product.title %></td>
<td class="item_price"><%= number_to_currency(item.total_price) %></td>
</tr>
<% end %>
<tr class="total_line">
<td colspan="2">Total</td>
<td class="total_cell"><%= number_to_currency(@cart.total_price) %></td>
</tr>
</table>
<%= button_to 'Empty cart', @cart, :method => :delete,
:confirm => 'Are you sure?' %>
Add a method to compute the total price of a single line item.
edit app/models/line_item.rb
def total_price
product.price * quantity
end
Add a method to compute the total price of the items in the cart.
edit app/models/cart.rb
def total_price
line_items.to_a.sum { |item| item.total_price }
end
Add some style.
edit public/stylesheets/depot.css
/* Styles for the cart in the main page */
#store .cart_title {
font: 120% bold;
}
#store .item_price, #store .total_line {
text-align: right;
}
#store .total_line .total_cell {
font-weight: bold;
border-top: 1px solid #595;
}
Add a product to the cart, and see the total.
get /
Pragmatic Bookshelf
Professional programmers develop a knack of unerringly zeroing in on the root cause of a bug. They can do that because they've written a lot of buggy code and then gained experience fixing it. This book captures all this experience -- use it, and you'll find you write fewer bugs, and the ones you do write will become easier to hunt down.
Ruby is the fastest growing and most exciting dynamic language out there. If you need to get working programs delivered fast, you should add Ruby to your toolbox.
Web Design for Developers will show you how to make your web-based application look professionally designed. We'll help you learn how to pick the right colors and fonts, avoid costly interface and accessibility mistakes -- your application will really come alive. We'll also walk you through some common Photoshop and CSS techniques and work through a web site redesign, taking a new design from concept all the way to implementation.
post /line_items?product_id=2
get http://localhost:3000/carts/2
Pragmatic Bookshelf
Add a few more products, and watch the totals climb!
post /line_items?product_id=2
get http://localhost:3000/carts/2
Pragmatic Bookshelf
post /line_items?product_id=3
get http://localhost:3000/carts/2
Pragmatic Bookshelf