Agile Web Development with Rails, Edition 4

6.1 Iteration A1: Creating the Products Maintenance Application Table of Contents

2 Instant Gratification

We start with a simple "hello world!" demo application and in the process verify that everything is installed correctly.

Create the application

bundle exec /home/rubys/git/rails/bin/rails new demo1 --skip-bundle
      create  
      create  README
      create  Rakefile
      create  config.ru
      create  .gitignore
      create  Gemfile
      create  app
      create  app/controllers/application_controller.rb
      create  app/helpers/application_helper.rb
      create  app/mailers
      create  app/models
      create  app/views/layouts/application.html.erb
      create  config
      create  config/routes.rb
      create  config/application.rb
      create  config/environment.rb
      create  config/environments
      create  config/environments/development.rb
      create  config/environments/production.rb
      create  config/environments/test.rb
      create  config/initializers
      create  config/initializers/backtrace_silencers.rb
      create  config/initializers/inflections.rb
      create  config/initializers/mime_types.rb
      create  config/initializers/secret_token.rb
      create  config/initializers/session_store.rb
      create  config/locales
      create  config/locales/en.yml
      create  config/boot.rb
      create  config/database.yml
      create  db
      create  db/seeds.rb
      create  doc
      create  doc/README_FOR_APP
      create  lib
      create  lib/tasks
      create  lib/tasks/.gitkeep
      create  log
      create  log/server.log
      create  log/production.log
      create  log/development.log
      create  log/test.log
      create  public
      create  public/404.html
      create  public/422.html
      create  public/500.html
      create  public/favicon.ico
      create  public/index.html
      create  public/robots.txt
      create  public/images
      create  public/images/rails.png
      create  public/stylesheets
      create  public/stylesheets/.gitkeep
      create  public/javascripts
      create  public/javascripts/application.js
      create  public/javascripts/controls.js
      create  public/javascripts/dragdrop.js
      create  public/javascripts/effects.js
      create  public/javascripts/prototype.js
      create  public/javascripts/rails.js
      create  script
      create  script/rails
      create  test
      create  test/fixtures
      create  test/functional
      create  test/integration
      create  test/performance/browsing_test.rb
      create  test/test_helper.rb
      create  test/unit
      create  tmp
      create  tmp/sessions
      create  tmp/sockets
      create  tmp/cache
      create  tmp/pids
      create  vendor/plugins
      create  vendor/plugins/.gitkeep
bundle install --local
Resolving dependencies...
Using rake (10.1.1)
Using abstract (1.0.0)
Using activesupport (3.0.20) from source at /home/rubys/git/rails
Using builder (2.1.2)
Using i18n (0.5.3)
Using activemodel (3.0.20) from source at /home/rubys/git/rails
Using erubis (2.6.6)
Using rack (1.2.8)
Using rack-mount (0.6.14)
Using rack-test (0.5.7)
Using tzinfo (0.3.38)
Using actionpack (3.0.20) from source at /home/rubys/git/rails
Using mime-types (1.25.1)
Using polyglot (0.3.3)
Using treetop (1.4.15)
Using mail (2.2.20)
Using actionmailer (3.0.20) from source at /home/rubys/git/rails
Using arel (2.0.10)
Using activerecord (3.0.20) from source at /home/rubys/git/rails
Using activeresource (3.0.20) from source at /home/rubys/git/rails
Using bundler (1.5.2)
Using json (1.8.1)
Using rdoc (3.12.2)
Using thor (0.14.6)
Using railties (3.0.20) from source at /home/rubys/git/rails
Using rails (3.0.20) from source at /home/rubys/git/rails
Using sqlite3 (1.3.8)
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.

See what files were created

ls -p
app/	 config.ru  doc/     Gemfile.lock  log/     Rakefile  script/  tmp/
config/  db/	    Gemfile  lib/	   public/  README    test/    vendor/

Create a simple controller

rails generate controller Say hello goodbye
      create  app/controllers/say_controller.rb
       route  get "say/goodbye"
       route  get "say/hello"
      invoke  erb
      create    app/views/say
      create    app/views/say/hello.html.erb
      create    app/views/say/goodbye.html.erb
      invoke  test_unit
      create    test/functional/say_controller_test.rb
      invoke  helper
      create    app/helpers/say_helper.rb
      invoke    test_unit
      create      test/unit/helpers/say_helper_test.rb
edit app/controllers/say_controller.rb
class SayController < ApplicationController
  def hello
  end
 
  def goodbye
  end
 
end

Start the server.

Attempt to fetch the file - note that it is missing

get /say/hello

Say#hello

Find me in app/views/say/hello.html.erb

Replace file with a simple hello world

edit app/views/say/hello.html.erb
<h1>Hello from Rails!</h1>

This time it works!

get /say/hello

Hello from Rails!

Add a simple expression

edit app/views/say/hello.html.erb
<h1>Hello from Rails!</h1>
<p>
  It is now <%= Time.now %>
</p>
get /say/hello

Hello from Rails!

It is now 2014-02-04 15:40:33 -0500

Evaluate the expression in the controller.

edit app/controllers/say_controller.rb
class SayController < ApplicationController
  def hello
    @time = Time.now
  end
 
  def goodbye
  end
 
end

Reference the result in the view.

edit app/views/say/hello.html.erb
<h1>Hello from Rails!</h1>
<p>
  It is now <%= @time %>
</p>
get /say/hello

Hello from Rails!

It is now 2014-02-04 15:40:33 -0500

Replace the goodbye template

edit app/views/say/goodbye.html.erb
<h1>Goodbye!</h1>
<p>
  It was nice having you here.
</p>
get /say/goodbye

Goodbye!

It was nice having you here.

Add a link from the hello page to the goodbye page

edit app/views/say/hello.html.erb
<h1>Hello from Rails!</h1>
<p>
  It is now <%= @time %>
</p>
<p>
  Time to say
  <%= link_to "Goodbye", say_goodbye_path %>!
</p>
get /say/hello

Hello from Rails!

It is now 2014-02-04 15:40:33 -0500

Time to say Goodbye!

Add a link back to the hello page

edit app/views/say/goodbye.html.erb
<h1>Goodbye!</h1>
<p>
  It was nice having you here.
</p>
<p>
  Say <%= link_to "Hello", say_hello_path %> again.
</p>
get /say/goodbye

Goodbye!

It was nice having you here.

Say Hello again.

6.1 Iteration A1: Creating the Products Maintenance Application Table of Contents