Agile Web Development with Rails, Edition 4

8.6 Playtime 8.4 Iteration C4: Functional Testing

8.5 Iteration C5 - Caching

Turn on caching in development

edit config/environments/development.rb
#<IndexError: regexp not matched>
  /home/rubys/git/gorp/lib/gorp/edit.rb:150:in `[]='
  /home/rubys/git/gorp/lib/gorp/edit.rb:150:in `msub'
  makedepot.rb:741:in `block (3 levels) in <main>'
  /home/rubys/git/gorp/lib/gorp/edit.rb:95:in `instance_exec'
  /home/rubys/git/gorp/lib/gorp/edit.rb:95:in `block in edit'
  /home/rubys/git/gorp/lib/gorp/edit.rb:93:in `sub!'
  /home/rubys/git/gorp/lib/gorp/edit.rb:93:in `edit'
  makedepot.rb:740:in `block (2 levels) in <main>'
  /home/rubys/git/gorp/lib/gorp/edit.rb:173:in `instance_exec'
  /home/rubys/git/gorp/lib/gorp/edit.rb:173:in `edit'
  makedepot.rb:738:in `block in <main>'
  /home/rubys/git/gorp/lib/gorp/output.rb:59:in `block (4 levels) in <top (required)>'
  /home/rubys/git/gorp/lib/gorp/output.rb:49:in `each'
  /home/rubys/git/gorp/lib/gorp/output.rb:49:in `block (3 levels) in <top (required)>'
  /home/rubys/.rvm/gems/ruby-2.3.0/gems/builder-3.2.2/lib/builder/xmlbase.rb:175:in `_nested_structures'
  /home/rubys/.rvm/gems/ruby-2.3.0/gems/builder-3.2.2/lib/builder/xmlbase.rb:68:in `tag!'
  /home/rubys/.rvm/gems/ruby-2.3.0/gems/builder-3.2.2/lib/builder/xmlbase.rb:93:in `method_missing'
  /home/rubys/git/gorp/lib/gorp/output.rb:22:in `block (2 levels) in <top (required)>'
  /home/rubys/.rvm/gems/ruby-2.3.0/gems/builder-3.2.2/lib/builder/xmlbase.rb:175:in `_nested_structures'
  /home/rubys/.rvm/gems/ruby-2.3.0/gems/builder-3.2.2/lib/builder/xmlbase.rb:68:in `tag!'
  /home/rubys/.rvm/gems/ruby-2.3.0/gems/builder-3.2.2/lib/builder/xmlbase.rb:93:in `method_missing'
  /home/rubys/git/gorp/lib/gorp/output.rb:11:in `block in <top (required)>'
    
Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.
 
  # In the development environment your application's code is reloaded on
  # every request. This slows down response time but is perfect for development
  # since you don't have to restart the web server when you make code changes.
  config.cache_classes = false
 
  # Do not eager load code on boot.
  config.eager_load = false
 
  # Show full error reports.
  config.consider_all_requests_local = true
 
  # Enable/disable caching. By default caching is disabled.
  if Rails.root.join('tmp/caching-dev.txt').exist?
    config.action_controller.perform_caching = true
    config.cache_store = :memory_store
    config.public_file_server.headers = {
      'Cache-Control' => 'public, max-age=172800'
    }
  else
    config.action_controller.perform_caching = false
    config.cache_store = :null_store
  end
 
  # Don't care if the mailer can't send.
  config.action_mailer.raise_delivery_errors = false
 
  # Print deprecation notices to the Rails logger.
  config.active_support.deprecation = :log
 
  # Raise an error on page load if there are pending migrations.
  config.active_record.migration_error = :page_load
 
  # Debug mode disables concatenation and preprocessing of assets.
  # This option may cause significant delays in view rendering with a large
  # number of complex assets.
  config.assets.debug = true
 
  # Asset digests allow you to set far-future HTTP expiration dates on all assets,
  # yet still be able to expire them through the digest params.
  config.assets.digest = true
 
  # Adds additional error checking when serving assets at runtime.
  # Checks for improperly declared sprockets dependencies.
  # Raises helpful error messages.
  config.assets.raise_runtime_errors = true
 
  # Raises error for missing translations
  # config.action_view.raise_on_missing_translations = true
 
  # Use an evented file watcher to asynchronously detect changes in source code,
  # routes, locales, etc. This feature depends on the listen gem.
  # config.file_watcher = ActiveSupport::EventedFileUpdateChecker
end

add a method to return the latest product

edit app/models/product.rb
  def self.latest
    Product.order(:updated_at).last
  end

cache sections

edit app/views/store/index.html.erb
<% if notice %>
<p id="notice"><%= notice %></p>
<% end %>
 
<h1>Your Pragmatic Catalog</h1>
 
<% cache ['store', Product.latest] do %>
  <% @products.each do |product| %>
    <% cache ['entry', product] do %>
      <div class="entry">
        <%= image_tag(product.image_url) %>
        <h3><%= product.title %></h3>
        <%= sanitize(product.description) %>
        <div class="price_line">
          <span class="price"><%= number_to_currency(product.price) %></span>
        </div>
      </div>
    <% end %>
  <% end %>
<% end %>

Turn caching back off

edit config/environments/development.rb
rm -f public/assets/*
rm -rf tmp/*cache/*

Restart the server.

8.6 Playtime 8.4 Iteration C4: Functional Testing