#277 Mountable Engines

Aug 01, 2011 | 13 minutes | Rails 3.1

Engines are receiving a major update in Rails 3.1. You can mount them at any path, embed assets, run generators and more. See how in this episode.

Click to Play Video ▶

Download:
source codeProject Files in Zip (56.6 KB)
mp4Full Size H.264 Video (19.6 MB)
m4vSmaller H.264 Video (12.7 MB)
webmFull Size VP8 Video (18.7 MB)
ogvFull Size Theora Video (23.3 MB)

Browse Source Code

Resources

          bash
        
rails -v
rails plugin new uhoh --mountable
rails g controller failures index
rails g model failure message:text
rake db:migrate
rake uhoh:install:migrations
cd test/dummy
rails s # to start up the dummy app
rails g controller simulate failure

          uhoh/failures_controller.rb
        
module Uhoh
  class FailuresController < ApplicationController
    def index
      @failures = Failure.all
    end
  end
end

          uhoh/failures/index.html.erb
        
<%= image_tag "uhoh/alert.png" %>

<h1>Failures</h1>
<ul>
  <% for failure in @failures %>
    <li><%= failure.message %></li>
  <% end %>
</ul>

<p><%= link_to "Failures", root_url %></p>
<p><%= link_to "Simulate Failure", main_app.simulate_failure_path %></p>

          config/routes.rb
        
root :to => "failures#index"

          config/initializers/exception_handler.rb
        
ActiveSupport::Notifications.subscribe "process_action.action_controller" do |name, start, finish, id, payload|
  if payload[:exception]
    name, message = *payload[:exception]
    Uhoh::Failure.create!(:message => message)
  end
end

          test/dummy/config/routes.rb
        
mount Uhoh::Engine => "/uhoh", :as => "uhoh_engine"

          test/dummy/app/controllers/simulate_controller.rb
        
def failure
  # redirect_to uhoh_engine.root_url
  raise "Simulating an exception"
end