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<!DOCTYPE html>
<html>
<head>
<title>static-pages</title>
<link rel="stylesheet" href="pygments.css" type="text/css" />
<link rel="stylesheet" href="polytexnic.css" type="text/css" />
</head>
<body>
<div id="book">
<h1 class="title">Ruby on Rails Tutorial </h1>
<h1 class="subtitle"> Learn Web Development with Rails</h1>
<h2 class="author">Michael Hartl</h2>
<h2 class="contents">Contents</h2>
<div id="table_of_contents"><ol><li class="chapter"><a href="beginning.html#top"><span class="number">Chapter 1</span> From zero to deploy</a></li><li><ol><li class="section"><a href="beginning.html#sec-introduction"><span class="number">1.1</span> Introduction</a></li><li><ol><li class="subsection"><a href="beginning.html#sec-comments_for_various_readers"><span class="number">1.1.1</span> Comments for various readers</a></li><li class="subsection"><a href="beginning.html#sec-1_1_2"><span class="number">1.1.2</span> “Scaling” Rails</a></li><li class="subsection"><a href="beginning.html#sec-conventions"><span class="number">1.1.3</span> Conventions in this book</a></li></ol></li><li class="section"><a href="beginning.html#sec-up_and_running"><span class="number">1.2</span> Up and running</a></li><li><ol><li class="subsection"><a href="beginning.html#sec-development_tools"><span class="number">1.2.1</span> Development environments</a></li><li><ol><li class="subsubsection"><a href="beginning.html#sec-1_2_1_1">IDEs</a></li><li class="subsubsection"><a href="beginning.html#sec-1_2_1_2">Text editors and command lines</a></li><li class="subsubsection"><a href="beginning.html#sec-1_2_1_3">Browsers</a></li><li class="subsubsection"><a href="beginning.html#sec-1_2_1_4">A note about tools</a></li></ol></li><li class="subsection"><a href="beginning.html#sec-rubygems"><span class="number">1.2.2</span> Ruby, RubyGems, Rails, and Git</a></li><li><ol><li class="subsubsection"><a href="beginning.html#sec-rails_installer_windows">Rails Installer (Windows)</a></li><li class="subsubsection"><a href="beginning.html#sec-install_git">Install Git</a></li><li class="subsubsection"><a href="beginning.html#sec-install_ruby">Install Ruby</a></li><li class="subsubsection"><a href="beginning.html#sec-install_rubygems">Install RubyGems</a></li><li class="subsubsection"><a href="beginning.html#sec-install_rails">Install Rails</a></li></ol></li><li class="subsection"><a href="beginning.html#sec-the_first_application"><span class="number">1.2.3</span> The first application</a></li><li class="subsection"><a href="beginning.html#sec-bundler"><span class="number">1.2.4</span> Bundler</a></li><li class="subsection"><a href="beginning.html#sec-rails_server"><span class="number">1.2.5</span> <tt>rails server</tt></a></li><li class="subsection"><a href="beginning.html#sec-mvc"><span class="number">1.2.6</span> Model-view-controller (MVC)</a></li></ol></li><li class="section"><a href="beginning.html#sec-version_control"><span class="number">1.3</span> Version control with Git</a></li><li><ol><li class="subsection"><a href="beginning.html#sec-git_setup"><span class="number">1.3.1</span> Installation and setup</a></li><li><ol><li class="subsubsection"><a href="beginning.html#sec-1_3_1_1">First-time system setup</a></li><li class="subsubsection"><a href="beginning.html#sec-1_3_1_2">First-time repository setup</a></li></ol></li><li class="subsection"><a href="beginning.html#sec-adding_and_committing"><span class="number">1.3.2</span> Adding and committing</a></li><li class="subsection"><a href="beginning.html#sec-1_3_3"><span class="number">1.3.3</span> What good does Git do you?</a></li><li class="subsection"><a href="beginning.html#sec-github"><span class="number">1.3.4</span> GitHub</a></li><li class="subsection"><a href="beginning.html#sec-git_commands"><span class="number">1.3.5</span> Branch, edit, commit, merge</a></li><li><ol><li class="subsubsection"><a href="beginning.html#sec-git_branch">Branch</a></li><li class="subsubsection"><a href="beginning.html#sec-git_edit">Edit</a></li><li class="subsubsection"><a href="beginning.html#sec-git_commit">Commit</a></li><li class="subsubsection"><a href="beginning.html#sec-git_merge">Merge</a></li><li class="subsubsection"><a href="beginning.html#sec-git_push">Push</a></li></ol></li></ol></li><li class="section"><a href="beginning.html#sec-deploying"><span class="number">1.4</span> Deploying</a></li><li><ol><li class="subsection"><a href="beginning.html#sec-heroku_setup"><span class="number">1.4.1</span> Heroku setup</a></li><li class="subsection"><a href="beginning.html#sec-heroku_step_one"><span class="number">1.4.2</span> Heroku deployment, step one</a></li><li class="subsection"><a href="beginning.html#sec-1_4_3"><span class="number">1.4.3</span> Heroku deployment, step two</a></li><li class="subsection"><a href="beginning.html#sec-heroku_commands"><span class="number">1.4.4</span> Heroku commands</a></li></ol></li><li class="section"><a href="beginning.html#sec-beginning_conclusion"><span class="number">1.5</span> Conclusion</a></li></ol></li><li class="chapter"><a href="a-demo-app.html#top"><span class="number">Chapter 2</span> A demo app</a></li><li><ol><li class="section"><a href="a-demo-app.html#sec-planning_the_application"><span class="number">2.1</span> Planning the application</a></li><li><ol><li class="subsection"><a href="a-demo-app.html#sec-modeling_demo_users"><span class="number">2.1.1</span> Modeling demo users</a></li><li class="subsection"><a href="a-demo-app.html#sec-modeling_demo_microposts"><span class="number">2.1.2</span> Modeling demo microposts</a></li></ol></li><li class="section"><a href="a-demo-app.html#sec-demo_users_resource"><span class="number">2.2</span> The Users resource</a></li><li><ol><li class="subsection"><a href="a-demo-app.html#sec-a_user_tour"><span class="number">2.2.1</span> A user tour</a></li><li class="subsection"><a href="a-demo-app.html#sec-mvc_in_action"><span class="number">2.2.2</span> MVC in action</a></li><li class="subsection"><a href="a-demo-app.html#sec-weaknesses_of_this_users_resource"><span class="number">2.2.3</span> Weaknesses of this Users resource</a></li></ol></li><li class="section"><a href="a-demo-app.html#sec-microposts_resource"><span class="number">2.3</span> The Microposts resource</a></li><li><ol><li class="subsection"><a href="a-demo-app.html#sec-a_micropost_microtour"><span class="number">2.3.1</span> A micropost microtour</a></li><li class="subsection"><a href="a-demo-app.html#sec-putting_the_micro_in_microposts"><span class="number">2.3.2</span> Putting the <em>micro</em> in microposts</a></li><li class="subsection"><a href="a-demo-app.html#sec-demo_user_has_many_microposts"><span class="number">2.3.3</span> A user <tt>has_many</tt> microposts</a></li><li class="subsection"><a href="a-demo-app.html#sec-inheritance_hierarchies"><span class="number">2.3.4</span> Inheritance hierarchies</a></li><li class="subsection"><a href="a-demo-app.html#sec-deploying_the_demo_app"><span class="number">2.3.5</span> Deploying the demo app</a></li></ol></li><li class="section"><a href="a-demo-app.html#sec-2_4"><span class="number">2.4</span> Conclusion</a></li></ol></li><li class="chapter"><a href="static-pages.html#top"><span class="number">Chapter 3</span> Mostly static pages</a></li><li><ol><li class="section"><a href="static-pages.html#sec-static_pages"><span class="number">3.1</span> Static pages</a></li><li class="section"><a href="static-pages.html#sec-first_tests"><span class="number">3.2</span> Our first tests</a></li><li><ol><li class="subsection"><a href="static-pages.html#sec-TDD"><span class="number">3.2.1</span> Test-driven development</a></li><li class="subsection"><a href="static-pages.html#sec-adding_a_page"><span class="number">3.2.2</span> Adding a page</a></li><li><ol><li class="subsubsection"><a href="static-pages.html#sec-red">Red</a></li><li class="subsubsection"><a href="static-pages.html#sec-green">Green</a></li><li class="subsubsection"><a href="static-pages.html#sec-refactor">Refactor</a></li></ol></li></ol></li><li class="section"><a href="static-pages.html#sec-slightly_dynamic_pages"><span class="number">3.3</span> Slightly dynamic pages</a></li><li><ol><li class="subsection"><a href="static-pages.html#sec-testing_a_title_change"><span class="number">3.3.1</span> Testing a title change</a></li><li class="subsection"><a href="static-pages.html#sec-passing_title_tests"><span class="number">3.3.2</span> Passing title tests</a></li><li class="subsection"><a href="static-pages.html#sec-embedded_ruby"><span class="number">3.3.3</span> Embedded Ruby</a></li><li class="subsection"><a href="static-pages.html#sec-layouts"><span class="number">3.3.4</span> Eliminating duplication with layouts</a></li></ol></li><li class="section"><a href="static-pages.html#sec-static_pages_conclusion"><span class="number">3.4</span> Conclusion</a></li><li class="section"><a href="static-pages.html#sec-static_pages_exercises"><span class="number">3.5</span> Exercises</a></li><li class="section"><a href="static-pages.html#sec-advanced_setup"><span class="number">3.6</span> Advanced setup</a></li><li><ol><li class="subsection"><a href="static-pages.html#sec-eliminating_bundle_exec"><span class="number">3.6.1</span> Eliminating <tt>bundle exec</tt></a></li><li><ol><li class="subsubsection"><a href="static-pages.html#sec-rvm_bundler_integration">RVM Bundler integration</a></li><li class="subsubsection"><a href="static-pages.html#sec-binstubs">binstubs</a></li></ol></li><li class="subsection"><a href="static-pages.html#sec-guard"><span class="number">3.6.2</span> Automated tests with Guard</a></li><li class="subsection"><a href="static-pages.html#sec-spork"><span class="number">3.6.3</span> Speeding up tests with Spork</a></li><li><ol><li class="subsubsection"><a href="static-pages.html#sec-spork_and_guard">Guard with Spork</a></li></ol></li><li class="subsection"><a href="static-pages.html#sec-tests_inside_sublime_text"><span class="number">3.6.4</span> Tests inside Sublime Text</a></li></ol></li></ol></li><li class="chapter"><a href="rails-flavored-ruby.html#top"><span class="number">Chapter 4</span> Rails-flavored Ruby</a></li><li><ol><li class="section"><a href="rails-flavored-ruby.html#sec-motivation"><span class="number">4.1</span> Motivation</a></li><li class="section"><a href="rails-flavored-ruby.html#sec-strings_and_methods"><span class="number">4.2</span> Strings and methods</a></li><li><ol><li class="subsection"><a href="rails-flavored-ruby.html#sec-comments"><span class="number">4.2.1</span> Comments</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-strings"><span class="number">4.2.2</span> Strings</a></li><li><ol><li class="subsubsection"><a href="rails-flavored-ruby.html#sec-printing">Printing</a></li><li class="subsubsection"><a href="rails-flavored-ruby.html#sec-single_quoted_strings">Single-quoted strings</a></li></ol></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-objects_and_message_passing"><span class="number">4.2.3</span> Objects and message passing</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-method_definitions"><span class="number">4.2.4</span> Method definitions</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-back_to_the_title_helper"><span class="number">4.2.5</span> Back to the title helper</a></li></ol></li><li class="section"><a href="rails-flavored-ruby.html#sec-other_data_structures"><span class="number">4.3</span> Other data structures</a></li><li><ol><li class="subsection"><a href="rails-flavored-ruby.html#sec-arrays_and_ranges"><span class="number">4.3.1</span> Arrays and ranges</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-blocks"><span class="number">4.3.2</span> Blocks</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-hashes_and_symbols"><span class="number">4.3.3</span> Hashes and symbols</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-css_revisited"><span class="number">4.3.4</span> CSS revisited</a></li></ol></li><li class="section"><a href="rails-flavored-ruby.html#sec-ruby_classes"><span class="number">4.4</span> Ruby classes</a></li><li><ol><li class="subsection"><a href="rails-flavored-ruby.html#sec-constructors"><span class="number">4.4.1</span> Constructors</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-a_class_of_our_own"><span class="number">4.4.2</span> Class inheritance</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-modifying_built_in_classes"><span class="number">4.4.3</span> Modifying built-in classes</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-a_controller_class"><span class="number">4.4.4</span> A controller class</a></li><li class="subsection"><a href="rails-flavored-ruby.html#sec-a_user_class"><span class="number">4.4.5</span> A user class</a></li></ol></li><li class="section"><a href="rails-flavored-ruby.html#sec-conclusion"><span class="number">4.5</span> Conclusion</a></li><li class="section"><a href="rails-flavored-ruby.html#sec-exercises"><span class="number">4.6</span> Exercises</a></li></ol></li><li class="chapter"><a href="filling-in-the-layout.html#top"><span class="number">Chapter 5</span> Filling in the layout</a></li><li><ol><li class="section"><a href="filling-in-the-layout.html#sec-structure"><span class="number">5.1</span> Adding some structure</a></li><li><ol><li class="subsection"><a href="filling-in-the-layout.html#sec-adding_to_the_layout"><span class="number">5.1.1</span> Site navigation</a></li><li class="subsection"><a href="filling-in-the-layout.html#sec-custom_css"><span class="number">5.1.2</span> Bootstrap and custom CSS</a></li><li class="subsection"><a href="filling-in-the-layout.html#sec-partials"><span class="number">5.1.3</span> Partials</a></li></ol></li><li class="section"><a href="filling-in-the-layout.html#sec-sass_and_the_asset_pipeline"><span class="number">5.2</span> Sass and the asset pipeline</a></li><li><ol><li class="subsection"><a href="filling-in-the-layout.html#sec-the_asset_pipeline"><span class="number">5.2.1</span> The asset pipeline</a></li><li><ol><li class="subsubsection"><a href="filling-in-the-layout.html#sec-5_2_1_1">Asset directories</a></li><li class="subsubsection"><a href="filling-in-the-layout.html#sec-5_2_1_2">Manifest files</a></li><li class="subsubsection"><a href="filling-in-the-layout.html#sec-5_2_1_3">Preprocessor engines</a></li><li class="subsubsection"><a href="filling-in-the-layout.html#sec-5_2_1_4">Efficiency in production</a></li></ol></li><li class="subsection"><a href="filling-in-the-layout.html#sec-sass"><span class="number">5.2.2</span> Syntactically awesome stylesheets</a></li><li><ol><li class="subsubsection"><a href="filling-in-the-layout.html#sec-5_2_2_1">Nesting</a></li><li class="subsubsection"><a href="filling-in-the-layout.html#sec-5_2_2_2">Variables</a></li></ol></li></ol></li><li class="section"><a href="filling-in-the-layout.html#sec-layout_links"><span class="number">5.3</span> Layout links</a></li><li><ol><li class="subsection"><a href="filling-in-the-layout.html#sec-route_tests"><span class="number">5.3.1</span> Route tests</a></li><li class="subsection"><a href="filling-in-the-layout.html#sec-rails_routes"><span class="number">5.3.2</span> Rails routes</a></li><li class="subsection"><a href="filling-in-the-layout.html#sec-named_routes"><span class="number">5.3.3</span> Named routes</a></li><li class="subsection"><a href="filling-in-the-layout.html#sec-pretty_rspec"><span class="number">5.3.4</span> Pretty RSpec</a></li></ol></li><li class="section"><a href="filling-in-the-layout.html#sec-user_signup"><span class="number">5.4</span> User signup: A first step</a></li><li><ol><li class="subsection"><a href="filling-in-the-layout.html#sec-users_controller"><span class="number">5.4.1</span> Users controller</a></li><li class="subsection"><a href="filling-in-the-layout.html#sec-signup_url"><span class="number">5.4.2</span> Signup URL</a></li></ol></li><li class="section"><a href="filling-in-the-layout.html#sec-layout_conclusion"><span class="number">5.5</span> Conclusion</a></li><li class="section"><a href="filling-in-the-layout.html#sec-layout_exercises"><span class="number">5.6</span> Exercises</a></li></ol></li><li class="chapter"><a href="modeling-users.html#top"><span class="number">Chapter 6</span> Modeling users</a></li><li><ol><li class="section"><a href="modeling-users.html#sec-user_model"><span class="number">6.1</span> User model</a></li><li><ol><li class="subsection"><a href="modeling-users.html#sec-database_migrations"><span class="number">6.1.1</span> Database migrations</a></li><li class="subsection"><a href="modeling-users.html#sec-the_model_file"><span class="number">6.1.2</span> The model file</a></li><li class="subsection"><a href="modeling-users.html#sec-creating_user_objects"><span class="number">6.1.3</span> Creating user objects</a></li><li class="subsection"><a href="modeling-users.html#sec-finding_user_objects"><span class="number">6.1.4</span> Finding user objects</a></li><li class="subsection"><a href="modeling-users.html#sec-updating_user_objects"><span class="number">6.1.5</span> Updating user objects</a></li></ol></li><li class="section"><a href="modeling-users.html#sec-user_validations"><span class="number">6.2</span> User validations</a></li><li><ol><li class="subsection"><a href="modeling-users.html#sec-initial_user_tests"><span class="number">6.2.1</span> Initial user tests</a></li><li class="subsection"><a href="modeling-users.html#sec-presence_validation"><span class="number">6.2.2</span> Validating presence</a></li><li class="subsection"><a href="modeling-users.html#sec-length_validation"><span class="number">6.2.3</span> Length validation</a></li><li class="subsection"><a href="modeling-users.html#sec-format_validation"><span class="number">6.2.4</span> Format validation</a></li><li class="subsection"><a href="modeling-users.html#sec-uniqueness_validation"><span class="number">6.2.5</span> Uniqueness validation</a></li><li><ol><li class="subsubsection"><a href="modeling-users.html#sec-the_caveat">The uniqueness caveat</a></li></ol></li></ol></li><li class="section"><a href="modeling-users.html#sec-adding_a_secure_password"><span class="number">6.3</span> Adding a secure password</a></li><li><ol><li class="subsection"><a href="modeling-users.html#sec-a_hashed_password"><span class="number">6.3.1</span> A hashed password</a></li><li class="subsection"><a href="modeling-users.html#sec-password_and_confirmation"><span class="number">6.3.2</span> Password and confirmation</a></li><li class="subsection"><a href="modeling-users.html#sec-user_authentication"><span class="number">6.3.3</span> User authentication</a></li><li class="subsection"><a href="modeling-users.html#sec-has_secure_password"><span class="number">6.3.4</span> User has secure password</a></li><li class="subsection"><a href="modeling-users.html#sec-creating_a_user"><span class="number">6.3.5</span> Creating a user</a></li></ol></li><li class="section"><a href="modeling-users.html#sec-6_4"><span class="number">6.4</span> Conclusion</a></li><li class="section"><a href="modeling-users.html#sec-modeling_users_exercises"><span class="number">6.5</span> Exercises</a></li></ol></li><li class="chapter"><a href="sign-up.html#top"><span class="number">Chapter 7</span> Sign up</a></li><li><ol><li class="section"><a href="sign-up.html#sec-showing_users"><span class="number">7.1</span> Showing users</a></li><li><ol><li class="subsection"><a href="sign-up.html#sec-rails_environments"><span class="number">7.1.1</span> Debug and Rails environments</a></li><li class="subsection"><a href="sign-up.html#sec-a_users_resource"><span class="number">7.1.2</span> A Users resource</a></li><li class="subsection"><a href="sign-up.html#sec-tests_with_factories"><span class="number">7.1.3</span> Testing the user show page (with factories)</a></li><li class="subsection"><a href="sign-up.html#sec-a_gravatar_image"><span class="number">7.1.4</span> A Gravatar image and a sidebar</a></li></ol></li><li class="section"><a href="sign-up.html#sec-signup_form"><span class="number">7.2</span> Signup form</a></li><li><ol><li class="subsection"><a href="sign-up.html#sec-tests_for_user_signup"><span class="number">7.2.1</span> Tests for user signup</a></li><li class="subsection"><a href="sign-up.html#sec-using_form_for"><span class="number">7.2.2</span> Using <tt>form_for</tt></a></li><li class="subsection"><a href="sign-up.html#sec-the_form_html"><span class="number">7.2.3</span> The form HTML</a></li></ol></li><li class="section"><a href="sign-up.html#sec-signup_failure"><span class="number">7.3</span> Signup failure</a></li><li><ol><li class="subsection"><a href="sign-up.html#sec-a_working_form"><span class="number">7.3.1</span> A working form</a></li><li class="subsection"><a href="sign-up.html#sec-strong_parameters"><span class="number">7.3.2</span> Strong parameters</a></li><li class="subsection"><a href="sign-up.html#sec-signup_error_messages"><span class="number">7.3.3</span> Signup error messages</a></li></ol></li><li class="section"><a href="sign-up.html#sec-signup_success"><span class="number">7.4</span> Signup success</a></li><li><ol><li class="subsection"><a href="sign-up.html#sec-the_finished_signup_form"><span class="number">7.4.1</span> The finished signup form</a></li><li class="subsection"><a href="sign-up.html#sec-the_flash"><span class="number">7.4.2</span> The flash</a></li><li class="subsection"><a href="sign-up.html#sec-the_first_signup"><span class="number">7.4.3</span> The first signup</a></li><li class="subsection"><a href="sign-up.html#sec-deploying_to_production_with_ssl"><span class="number">7.4.4</span> Deploying to production with SSL</a></li></ol></li><li class="section"><a href="sign-up.html#sec-7_5"><span class="number">7.5</span> Conclusion</a></li><li class="section"><a href="sign-up.html#sec-signup_exercises"><span class="number">7.6</span> Exercises</a></li></ol></li><li class="chapter"><a href="sign-in-sign-out.html#top"><span class="number">Chapter 8</span> Sign in, sign out</a></li><li><ol><li class="section"><a href="sign-in-sign-out.html#sec-signin_failure"><span class="number">8.1</span> Sessions and signin failure</a></li><li><ol><li class="subsection"><a href="sign-in-sign-out.html#sec-sessions_controller"><span class="number">8.1.1</span> Sessions controller</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-signin_tests"><span class="number">8.1.2</span> Signin tests</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-signin_form"><span class="number">8.1.3</span> Signin form</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-reviewing_form_submission"><span class="number">8.1.4</span> Reviewing form submission</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-rendering_with_a_flash_message"><span class="number">8.1.5</span> Rendering with a flash message</a></li></ol></li><li class="section"><a href="sign-in-sign-out.html#sec-signin_success"><span class="number">8.2</span> Signin success</a></li><li><ol><li class="subsection"><a href="sign-in-sign-out.html#sec-remember_me"><span class="number">8.2.1</span> Remember me</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-a_working_sign_in_method"><span class="number">8.2.2</span> A working <tt>sign_in</tt> method</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-current_user"><span class="number">8.2.3</span> Current user</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-changing_the_layout_links"><span class="number">8.2.4</span> Changing the layout links</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-signin_upon_signup"><span class="number">8.2.5</span> Signin upon signup</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-signing_out"><span class="number">8.2.6</span> Signing out</a></li></ol></li><li class="section"><a href="sign-in-sign-out.html#sec-cucumber"><span class="number">8.3</span> Introduction to cucumber (optional)</a></li><li><ol><li class="subsection"><a href="sign-in-sign-out.html#sec-installation_and_setup"><span class="number">8.3.1</span> Installation and setup</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-features_and_steps"><span class="number">8.3.2</span> Features and steps</a></li><li class="subsection"><a href="sign-in-sign-out.html#sec-rspec_custom_matchers"><span class="number">8.3.3</span> Counterpoint: RSpec custom matchers</a></li></ol></li><li class="section"><a href="sign-in-sign-out.html#sec-8_4"><span class="number">8.4</span> Conclusion</a></li><li class="section"><a href="sign-in-sign-out.html#sec-sign_in_out_exercises"><span class="number">8.5</span> Exercises</a></li></ol></li><li class="chapter"><a href="updating-showing-and-deleting-users.html#top"><span class="number">Chapter 9</span> Updating, showing, and deleting users</a></li><li><ol><li class="section"><a href="updating-showing-and-deleting-users.html#sec-updating_users"><span class="number">9.1</span> Updating users</a></li><li><ol><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-edit_form"><span class="number">9.1.1</span> Edit form</a></li><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-unsuccessful_edits"><span class="number">9.1.2</span> Unsuccessful edits</a></li><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-successful_edits"><span class="number">9.1.3</span> Successful edits</a></li></ol></li><li class="section"><a href="updating-showing-and-deleting-users.html#sec-authorization"><span class="number">9.2</span> Authorization</a></li><li><ol><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-requiring_signed_in_users"><span class="number">9.2.1</span> Requiring signed-in users</a></li><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-requiring_the_right_user"><span class="number">9.2.2</span> Requiring the right user</a></li><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-friendly_forwarding"><span class="number">9.2.3</span> Friendly forwarding</a></li></ol></li><li class="section"><a href="updating-showing-and-deleting-users.html#sec-showing_all_users"><span class="number">9.3</span> Showing all users</a></li><li><ol><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-user_index"><span class="number">9.3.1</span> User index</a></li><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-sample_users"><span class="number">9.3.2</span> Sample users</a></li><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-pagination"><span class="number">9.3.3</span> Pagination</a></li><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-partial_refactoring"><span class="number">9.3.4</span> Partial refactoring</a></li></ol></li><li class="section"><a href="updating-showing-and-deleting-users.html#sec-destroying_users"><span class="number">9.4</span> Deleting users</a></li><li><ol><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-administrative_users"><span class="number">9.4.1</span> Administrative users</a></li><li><ol><li class="subsubsection"><a href="updating-showing-and-deleting-users.html#sec-revisiting_strong_parameters">Revisiting strong parameters</a></li></ol></li><li class="subsection"><a href="updating-showing-and-deleting-users.html#sec-the_destroy_action"><span class="number">9.4.2</span> The <tt>destroy</tt> action</a></li></ol></li><li class="section"><a href="updating-showing-and-deleting-users.html#sec-updating_and_deleting_users_conclusion"><span class="number">9.5</span> Conclusion</a></li><li class="section"><a href="updating-showing-and-deleting-users.html#sec-updating_deleting_exercises"><span class="number">9.6</span> Exercises</a></li></ol></li><li class="chapter"><a href="user-microposts.html#top"><span class="number">Chapter 10</span> User microposts</a></li><li><ol><li class="section"><a href="user-microposts.html#sec-a_micropost_model"><span class="number">10.1</span> A Micropost model</a></li><li><ol><li class="subsection"><a href="user-microposts.html#sec-the_basic_model"><span class="number">10.1.1</span> The basic model</a></li><li class="subsection"><a href="user-microposts.html#sec-first_micropost_validation"><span class="number">10.1.2</span> The first validation</a></li><li class="subsection"><a href="user-microposts.html#sec-user_micropost_associations"><span class="number">10.1.3</span> User/Micropost associations</a></li><li class="subsection"><a href="user-microposts.html#sec-ordering_and_dependency"><span class="number">10.1.4</span> Micropost refinements</a></li><li><ol><li class="subsubsection"><a href="user-microposts.html#sec-default_scope">Default scope</a></li><li class="subsubsection"><a href="user-microposts.html#sec-dependent_destroy">Dependent: destroy</a></li></ol></li><li class="subsection"><a href="user-microposts.html#sec-micropost_validations"><span class="number">10.1.5</span> Content validations</a></li></ol></li><li class="section"><a href="user-microposts.html#sec-showing_microposts"><span class="number">10.2</span> Showing microposts</a></li><li><ol><li class="subsection"><a href="user-microposts.html#sec-augmenting_the_user_show_page"><span class="number">10.2.1</span> Augmenting the user show page</a></li><li class="subsection"><a href="user-microposts.html#sec-sample_microposts"><span class="number">10.2.2</span> Sample microposts</a></li></ol></li><li class="section"><a href="user-microposts.html#sec-manipulating_microposts"><span class="number">10.3</span> Manipulating microposts</a></li><li><ol><li class="subsection"><a href="user-microposts.html#sec-access_control"><span class="number">10.3.1</span> Access control</a></li><li class="subsection"><a href="user-microposts.html#sec-creating_microposts"><span class="number">10.3.2</span> Creating microposts</a></li><li class="subsection"><a href="user-microposts.html#sec-a_proto_feed"><span class="number">10.3.3</span> A proto-feed</a></li><li class="subsection"><a href="user-microposts.html#sec-destroying_microposts"><span class="number">10.3.4</span> Destroying microposts</a></li></ol></li><li class="section"><a href="user-microposts.html#sec-10_4"><span class="number">10.4</span> Conclusion</a></li><li class="section"><a href="user-microposts.html#sec-micropost_exercises"><span class="number">10.5</span> Exercises</a></li></ol></li><li class="chapter"><a href="following-users.html#top"><span class="number">Chapter 11</span> Following users</a></li><li><ol><li class="section"><a href="following-users.html#sec-the_relationship_model"><span class="number">11.1</span> The Relationship model</a></li><li><ol><li class="subsection"><a href="following-users.html#sec-a_problem_with_the_data_model"><span class="number">11.1.1</span> A problem with the data model (and a solution)</a></li><li class="subsection"><a href="following-users.html#sec-relationship_user_associations"><span class="number">11.1.2</span> User/relationship associations</a></li><li class="subsection"><a href="following-users.html#sec-relationship_validations"><span class="number">11.1.3</span> Validations</a></li><li class="subsection"><a href="following-users.html#sec-following"><span class="number">11.1.4</span> Followed users</a></li><li class="subsection"><a href="following-users.html#sec-followers"><span class="number">11.1.5</span> Followers</a></li></ol></li><li class="section"><a href="following-users.html#sec-a_web_interface_for_following_and_followers"><span class="number">11.2</span> A web interface for following users</a></li><li><ol><li class="subsection"><a href="following-users.html#sec-sample_following_data"><span class="number">11.2.1</span> Sample following data</a></li><li class="subsection"><a href="following-users.html#sec-stats_and_a_follow_form"><span class="number">11.2.2</span> Stats and a follow form</a></li><li class="subsection"><a href="following-users.html#sec-following_and_followers_pages"><span class="number">11.2.3</span> Following and followers pages</a></li><li class="subsection"><a href="following-users.html#sec-a_working_follow_button_the_standard_way"><span class="number">11.2.4</span> A working follow button the standard way</a></li><li class="subsection"><a href="following-users.html#sec-a_working_follow_button_with_ajax"><span class="number">11.2.5</span> A working follow button with Ajax</a></li></ol></li><li class="section"><a href="following-users.html#sec-the_status_feed"><span class="number">11.3</span> The status feed</a></li><li><ol><li class="subsection"><a href="following-users.html#sec-motivation_and_strategy"><span class="number">11.3.1</span> Motivation and strategy</a></li><li class="subsection"><a href="following-users.html#sec-a_first_feed_implementation"><span class="number">11.3.2</span> A first feed implementation</a></li><li class="subsection"><a href="following-users.html#sec-scopes_subselects_and_a_lambda"><span class="number">11.3.3</span> Subselects</a></li><li class="subsection"><a href="following-users.html#sec-the_new_status_feed"><span class="number">11.3.4</span> The new status feed</a></li></ol></li><li class="section"><a href="following-users.html#sec-following_conclusion"><span class="number">11.4</span> Conclusion</a></li><li><ol><li class="subsection"><a href="following-users.html#sec-extensions_to_the_sample_application"><span class="number">11.4.1</span> Extensions to the sample application</a></li><li><ol><li class="subsubsection"><a href="following-users.html#sec-replies">Replies</a></li><li class="subsubsection"><a href="following-users.html#sec-messaging">Messaging</a></li><li class="subsubsection"><a href="following-users.html#sec-follower_notifications">Follower notifications</a></li><li class="subsubsection"><a href="following-users.html#sec-password_reminders">Password reminders</a></li><li class="subsubsection"><a href="following-users.html#sec-signup_confirmation">Signup confirmation</a></li><li class="subsubsection"><a href="following-users.html#sec-rss_feed">RSS feed</a></li><li class="subsubsection"><a href="following-users.html#sec-rest_api">REST API</a></li><li class="subsubsection"><a href="following-users.html#sec-search">Search</a></li></ol></li><li class="subsection"><a href="following-users.html#sec-guide_to_further_resources"><span class="number">11.4.2</span> Guide to further resources</a></li></ol></li><li class="section"><a href="following-users.html#sec-following_exercises"><span class="number">11.5</span> Exercises</a></li></ol></li></ol></div>
<div id="main_content"></div>
<p> <span class="preamble">
<span id="foreword">
<strong> Foreword</strong> <br />
</span>
</span></p>
<p>My former company (CD Baby) was one of the first to loudly switch to Ruby on Rails, and then even more loudly switch back to PHP (Google me to read about the drama). This book by Michael Hartl came so highly recommended that I had to try it, and the <em>Ruby on Rails Tutorial</em> is what I used to switch back to Rails again.</p>
<p>Though I’ve worked my way through many Rails books, this is the one that finally made me “get” it. Everything is done very much “the Rails way”—a way that felt very unnatural to me before, but now after doing this book finally feels natural. This is also the only Rails book that does test-driven development the entire time, an approach highly recommended by the experts but which has never been so clearly demonstrated before. Finally, by including Git, GitHub, and Heroku in the demo examples, the author really gives you a feel for what it’s like to do a real-world project. The tutorial’s code examples are not in isolation.</p>
<p>The linear narrative is such a great format. Personally, I powered through the <em>Rails Tutorial</em> in three long days, doing all the examples and challenges at the end of each chapter. Do it from start to finish, without jumping around, and you’ll get the ultimate benefit.</p>
<p>Enjoy!</p>
<p><a href="http://sivers.org/">Derek Sivers</a> (<a href="http://sivers.org/">sivers.org</a>) <br />
<em>Founder, CD Baby</em> <br /></p>
<p> <span class="preamble">
<strong> Acknowledgments</strong> <br />
</span></p>
<p>The <em>Ruby on Rails Tutorial</em> owes a lot to my previous Rails book, <em>RailsSpace</em>, and hence to my coauthor <a href="http://aure.com/">Aurelius Prochazka</a>. I’d like to thank Aure both for the work he did on that book and for his support of this one. I’d also like to thank Debra Williams Cauley, my editor on both <em>RailsSpace</em> and the <em>Ruby on Rails Tutorial</em>; as long as she keeps taking me to baseball games, I’ll keep writing books for her.</p>
<p>I’d like to acknowledge a long list of Rubyists who have taught and inspired me over the years: David Heinemeier Hansson, Yehuda Katz, Carl Lerche, Jeremy Kemper, Xavier Noria, Ryan Bates, Geoffrey Grosenbach, Peter Cooper, Matt Aimonetti, Gregg Pollack, Wayne E. Seguin, Amy Hoy, Dave Chelimsky, Pat Maddox, Tom Preston-Werner, Chris Wanstrath, Chad Fowler, Josh Susser, Obie Fernandez, Ian McFarland, Steven Bristol, Pratik Naik, Sarah Mei, Sarah Allen, Wolfram Arnold, Alex Chaffee, Giles Bowkett, Evan Dorn, Long Nguyen, James Lindenbaum, Adam Wiggins, Tikhon Bernstam, Ron Evans, Wyatt Greene, Miles Forrest, the good people at Pivotal Labs, the Heroku gang, the thoughtbot guys, and the GitHub crew. Finally, many, many readers—far too many to list—have contributed a huge number of bug reports and suggestions during the writing of this book, and I gratefully acknowledge their help in making it as good as it can be. <br /></p>
<p> <span class="preamble">
<span id="author">
<strong> About the author</strong> <br />
</span>
</span></p>
<p><a href="http://michaelhartl.com/">Michael Hartl</a> is the author of the <a href="http://ruby.railstutorial.org/"><em>Ruby on Rails Tutorial</em></a>, the leading introduction to web development with <a href="http://rubyonrails.org/">Ruby on Rails</a>. His prior experience includes writing and developing <em>RailsSpace</em>, an extremely obsolete Rails tutorial book, and developing Insoshi, a once-popular and now-obsolete social networking platform in Ruby on Rails. In 2011, Michael received a <a href="http://rubyheroes.com/heroes">Ruby Hero Award</a> for his contributions to the Ruby community. He is a graduate of <a href="http://college.harvard.edu/">Harvard College</a>, has a <a href="http://resolver.caltech.edu/CaltechETD:etd-05222003-161626">Ph.D. in Physics</a> from <a href="http://www.caltech.edu/">Caltech</a>, and is an alumnus of the <a href="http://ycombinator.com/">Y Combinator</a> entrepreneur program. <br /></p>
<p> <span id="license" class="preamble">
<strong> Copyright and license</strong> <br />
</span></p>
<p><em>Ruby on Rails Tutorial: Learn Web Development with Rails</em>. Copyright © 2013 by Michael Hartl. All source code in the <em>Ruby on Rails Tutorial</em> is available jointly under the <a href="http://opensource.org/licenses/MIT">MIT License</a> and the <a href="http://people.freebsd.org/~phk/">Beerware License</a>.</p>
<div class="code"><div class="highlight"><pre>The MIT License
Copyright (c) 2013 Michael Hartl
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
</pre></div>
</div>
<div class="code"><div class="highlight"><pre>/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* Michael Hartl wrote this code. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return.
* ----------------------------------------------------------------------------
*/
</pre></div>
</div>
<div id="top"></div>
<h1 class="chapter"><a id="sec-3" href="static-pages.html#top" class="heading"><span class="number">Chapter 3</span> Mostly static pages</a></h1>
<p>In this chapter, we will begin developing the sample application that will serve as our example throughout the rest of this tutorial. Although the sample app will eventually have users, microposts, and a full login and authentication framework, we will begin with a seemingly limited topic: the creation of static pages. Despite its apparent simplicity, making static pages is a highly instructive exercise, rich in implications—a perfect start for our nascent application.</p>
<p>Although Rails is designed for making database-backed dynamic websites, it also excels at making the kind of static pages we might make with raw HTML files. In fact, using Rails even for static pages yields a distinct advantage: we can easily add just a <em>small</em> amount of dynamic content. In this chapter we’ll learn how. Along the way, we’ll get our first taste of <em>automated testing</em>, which will help us be more confident that our code is correct. Moreover, having a good test suite will allow us to <em>refactor</em> our code with confidence, changing its form without changing its function.</p>
<p>There’s a lot of code in this chapter, especially in <a class="ref" href="static-pages.html#sec-first_tests">Section 3.2</a> and <a class="ref" href="static-pages.html#sec-slightly_dynamic_pages">Section 3.3</a>, and if you’re new to Ruby you shouldn’t worry about understanding the details right now. As noted in <a class="ref" href="beginning.html#sec-comments_for_various_readers">Section 1.1.1</a>, one strategy is to copy-and-paste the tests and use them to verify the application code, without worrying at this point how they work. In addition, <a class="ref" href="rails-flavored-ruby.html#top">Chapter 4</a> covers Ruby in more depth, so there is plenty of opportunity for these ideas to sink in. Finally, RSpec tests will recur throughout the tutorial, so if you get stuck now I recommend forging ahead; you’ll be amazed how, after just a few more chapters, initially inscrutable code will suddenly look simple. (You might also consider the <a href="http://www.codeschool.com/courses/testing-with-rspec">RSpec course at Code School</a>, which one reader has said answered a lot of his RSpec questions.)</p>
<p>As in <a class="ref" href="a-demo-app.html#top">Chapter 2</a>, before getting started we need to create a new Rails project, this time called <code>sample_app</code>:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> <span class="nb">cd</span> ~/rails_projects
<span class="gp">$</span> rails new sample_app --skip-test-unit
<span class="gp">$</span> <span class="nb">cd </span>sample_app
</pre></div>
</div>
<p>Here the <tt class="verb">--skip-test-unit</tt> option to the <code>rails</code> command tells Rails not to generate a <code>test</code> directory associated with the default <code>Test::Unit</code> framework. This is not because we won’t be writing tests; on the contrary, starting in <a class="ref" href="static-pages.html#sec-first_tests">Section 3.2</a> we will be using an alternate testing framework called <em>RSpec</em> to write a thorough test suite.</p>
<p>As in <a class="ref" href="a-demo-app.html#sec-planning_the_application">Section 2.1</a>, our next step is to use a text editor to update the <code>Gemfile</code> with the gems needed by our application. On the other hand, for the sample application we’ll also need two gems we didn’t need before: the gem for RSpec and the gem for the RSpec library specific to Rails. The code to include them is shown in <a class="ref" href="static-pages.html#code-gemfile_rspec">Listing 3.1</a>. (<em>Note</em>: If you would like to install <em>all</em> the gems needed for the sample application, you should use the code in <a class="ref" href="updating-showing-and-deleting-users.html#code-final_gemfile">Listing 9.47</a> at this time.)</p>
<div class="label" id="code-gemfile_rspec"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.1.</span> <span class="description">A <code>Gemfile</code> for the sample app.</span> </div>
<div class="code"><div class="highlight"><pre><span class="n">source</span> <span class="s1">'https://rubygems.org'</span>
<span class="n">ruby</span> <span class="s1">'2.0.0'</span>
<span class="c1">#ruby-gemset=railstutorial_rails_4_0</span>
<span class="n">gem</span> <span class="s1">'rails'</span><span class="p">,</span> <span class="s1">'4.0.4'</span>
<span class="n">group</span> <span class="ss">:development</span><span class="p">,</span> <span class="ss">:test</span> <span class="k">do</span>
<span class="n">gem</span> <span class="s1">'sqlite3'</span><span class="p">,</span> <span class="s1">'1.3.8'</span>
<span class="n">gem</span> <span class="s1">'rspec-rails'</span><span class="p">,</span> <span class="s1">'2.13.1'</span>
<span class="k">end</span>
<span class="n">group</span> <span class="ss">:test</span> <span class="k">do</span>
<span class="n">gem</span> <span class="s1">'selenium-webdriver'</span><span class="p">,</span> <span class="s1">'2.35.1'</span>
<span class="n">gem</span> <span class="s1">'capybara'</span><span class="p">,</span> <span class="s1">'2.1.0'</span>
<span class="k">end</span>
<span class="n">gem</span> <span class="s1">'sass-rails'</span><span class="p">,</span> <span class="s1">'4.0.1'</span>
<span class="n">gem</span> <span class="s1">'uglifier'</span><span class="p">,</span> <span class="s1">'2.1.1'</span>
<span class="n">gem</span> <span class="s1">'coffee-rails'</span><span class="p">,</span> <span class="s1">'4.0.1'</span>
<span class="n">gem</span> <span class="s1">'jquery-rails'</span><span class="p">,</span> <span class="s1">'3.0.4'</span>
<span class="n">gem</span> <span class="s1">'turbolinks'</span><span class="p">,</span> <span class="s1">'1.1.1'</span>
<span class="n">gem</span> <span class="s1">'jbuilder'</span><span class="p">,</span> <span class="s1">'1.0.2'</span>
<span class="n">group</span> <span class="ss">:doc</span> <span class="k">do</span>
<span class="n">gem</span> <span class="s1">'sdoc'</span><span class="p">,</span> <span class="s1">'0.3.20'</span><span class="p">,</span> <span class="nb">require</span><span class="p">:</span> <span class="kp">false</span>
<span class="k">end</span>
<span class="n">group</span> <span class="ss">:production</span> <span class="k">do</span>
<span class="n">gem</span> <span class="s1">'pg'</span><span class="p">,</span> <span class="s1">'0.15.1'</span>
<span class="n">gem</span> <span class="s1">'rails_12factor'</span><span class="p">,</span> <span class="s1">'0.0.2'</span>
<span class="k">end</span>
</pre></div>
</div></div>
<p>This includes <tt>rspec-rails</tt> in a development environment so that we have access to RSpec-specific generators, and it includes it in test mode in order to run the tests. We don’t have to install RSpec itself because it is a dependency of <tt>rspec-rails</tt> and will thus be installed automatically. We also include the <a href="https://github.com/jnicklas/capybara">Capybara gem</a>, which allows us to simulate a user’s interaction with the sample application using a natural English-like syntax, together with <a href="http://docs.seleniumhq.org/projects/webdriver/">Selenium</a>, one of Capybara’s dependencies.<sup class="footnote" id="fnref-3_1"><a href="#fn-3_1">1</a></sup> As in <a class="ref" href="a-demo-app.html#top">Chapter 2</a>, we also must include the PostgreSQL and static assets gems in production for deployment to Heroku:</p>
<div class="code"><div class="highlight"><pre><span class="n">group</span> <span class="ss">:production</span> <span class="k">do</span>
<span class="n">gem</span> <span class="s1">'pg'</span><span class="p">,</span> <span class="s1">'0.15.1'</span>
<span class="n">gem</span> <span class="s1">'rails_12factor'</span><span class="p">,</span> <span class="s1">'0.0.2'</span>
<span class="k">end</span>
</pre></div>
</div>
<p>Heroku recommends against using different databases in development and production, but for the sample application it won’t make any difference, and SQLite is <em>much</em> easier than PostgreSQL to install and configure. Installing and configuring PostgreSQL on your local machine is left as an exercise (<a class="ref" href="static-pages.html#sec-static_pages_exercises">Section 3.5</a>).</p>
<p>To install and include the new gems, we run <code>bundle update</code> and <code>bundle install</code>:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> bundle install --without production
<span class="gp">$</span> bundle update
<span class="gp">$</span> bundle install
</pre></div>
</div>
<p>As in <a class="ref" href="beginning.html#sec-heroku_setup">Section 1.4.1</a> and <a class="ref" href="a-demo-app.html#top">Chapter 2</a>, we suppress the installation of production gems using the option <tt class="verb">--without</tt> <tt class="verb">production</tt>. This is a “remembered option”, which means that we don’t have to include it in future invocations of Bundler. Instead, we can write simply <code>bundle install</code> and production gems will be ignored automatically.<sup class="footnote" id="fnref-3_2"><a href="#fn-3_2">2</a></sup></p>
<p>Because the sample application is shared as a public repository, it’s important to update the so-called <em>secret token</em> used by Rails to protect session variables so that it is dynamically generated rather than hard-coded (<a class="ref" href="static-pages.html#code-secret_token">Listing 3.2</a>). (The code in <a class="ref" href="static-pages.html#code-secret_token">Listing 3.2</a> is fairly advanced for so early in the tutorial, but because it’s a potentially serious security issue I feel it’s important to include it even at this early stage.) Be sure to use the augmented <code>.gitignore</code> file from <a class="ref" href="beginning.html#code-gitignore">Listing 1.7</a> so that the <code>.secret</code> key isn’t exposed in your repository.</p>
<div class="label" id="code-secret_token"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.2.</span> <span class="description">Dynamically generating a secret token. <br /> <code>config/initializers/secret_token.rb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="c1"># Be sure to restart your server when you modify this file.</span>
<span class="c1"># Your secret key is used for verifying the integrity of signed cookies.</span>
<span class="c1"># If you change this key, all old signed cookies will become invalid!</span>
<span class="c1"># Make sure the secret is at least 30 characters and all random,</span>
<span class="c1"># no regular words or you'll be exposed to dictionary attacks.</span>
<span class="c1"># You can use `rake secret` to generate a secure secret key.</span>
<span class="c1"># Make sure your secret_key_base is kept private</span>
<span class="c1"># if you're sharing your code publicly.</span>
<span class="nb">require</span> <span class="s1">'securerandom'</span>
<span class="k">def</span> <span class="nf">secure_token</span>
<span class="n">token_file</span> <span class="o">=</span> <span class="no">Rails</span><span class="o">.</span><span class="n">root</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="s1">'.secret'</span><span class="p">)</span>
<span class="k">if</span> <span class="no">File</span><span class="o">.</span><span class="n">exist?</span><span class="p">(</span><span class="n">token_file</span><span class="p">)</span>
<span class="c1"># Use the existing token.</span>
<span class="no">File</span><span class="o">.</span><span class="n">read</span><span class="p">(</span><span class="n">token_file</span><span class="p">)</span><span class="o">.</span><span class="n">chomp</span>
<span class="k">else</span>
<span class="c1"># Generate a new token and store it in token_file.</span>
<span class="n">token</span> <span class="o">=</span> <span class="no">SecureRandom</span><span class="o">.</span><span class="n">hex</span><span class="p">(</span><span class="mi">64</span><span class="p">)</span>
<span class="no">File</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">token_file</span><span class="p">,</span> <span class="n">token</span><span class="p">)</span>
<span class="n">token</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="ss">SampleApp::Application</span><span class="o">.</span><span class="n">config</span><span class="o">.</span><span class="n">secret_key_base</span> <span class="o">=</span> <span class="n">secure_token</span>
</pre></div>
</div></div>
<p>Next, we need to configure Rails to use RSpec in place of <code>Test::Unit</code>. This can be accomplished with <code>rails generate rspec:install</code>:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> rails generate rspec:install
</pre></div>
</div>
<p>If your system complains about the lack of a JavaScript runtime, visit the <a href="https://github.com/sstephenson/execjs">execjs page at GitHub</a> for a list of possibilities. I particularly recommend installing <a href="http://nodejs.org/">Node.js</a>.</p>
<p>With that, all we have left is to initialize the Git repository:<sup class="footnote" id="fnref-3_3"><a href="#fn-3_3">3</a></sup></p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> git init
<span class="gp">$</span> git add .
<span class="gp">$</span> git commit -m <span class="s2">"Initial commit"</span>
</pre></div>
</div>
<p>As with the first application, I suggest updating the <code>README</code> file (located in the root directory of the application) to be more helpful and descriptive, as shown in <a class="ref" href="static-pages.html#code-sample_app_readme">Listing 3.3</a>.</p>
<div class="label" id="code-sample_app_readme"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.3.</span> <span class="description">An improved <code>README</code> file for the sample app.</span> </div>
<div class="code"><div class="highlight"><pre># Ruby on Rails Tutorial: sample application
This is the sample application for
the [*Ruby on Rails Tutorial*](http://railstutorial.org/)
by [Michael Hartl](http://michaelhartl.com/).
</pre></div>
</div></div>
<p>Then change it to use the Markdown extension <code>.md</code> and commit the changes:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> git mv README.rdoc README.md
<span class="gp">$</span> git commit -am <span class="s2">"Improve the README"</span>
</pre></div>
</div>
<p>You may recall from <a class="ref" href="beginning.html#sec-git_commands">Section 1.3.5</a> that we used the Git command <code>git commit -a -m "Message"</code>, with flags for “all changes” (<code>-a</code>) and a message (<code>-m</code>). As shown in the second command above, Git also lets us roll the two flags into one using <code>git commit -am "Message"</code>.</p>
<p>Since we’ll be using this sample app throughout the rest of the book, it’s a good idea to <a href="https://github.com/new">make a new repository at GitHub</a> and push it up:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> git remote add origin https://github.com/<username>/sample_app.git
<span class="gp">$</span> git push -u origin master
</pre></div>
</div>
<p>As a result of my performing this step, you can find the <a href="https://github.com/railstutorial/sample_app_rails_4">Rails Tutorial sample application code on GitHub</a> (under the username <tt>railstutorial</tt> and the slightly different name <tt>sample_app_rails_4</tt>).<sup class="footnote" id="fnref-3_4"><a href="#fn-3_4">4</a></sup></p>
<p>Of course, we can optionally deploy the app to Heroku even at this early stage:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> heroku create
<span class="gp">$</span> git push heroku master
<span class="gp">$</span> heroku run rake db:migrate
</pre></div>
</div>
<p>(As noted in <a class="ref" href="beginning.html#sec-heroku_setup">Section 1.4.1</a>, some readers have reported needing to precompile static assets (such as CSS and images), which can be included by hand as follows:</p>
<div class="code"><div class="highlight"><pre><span class="gp">#</span> This should only be used <span class="k">if </span>your Heroku deploy fails without it.
<span class="gp">$</span> rake assets:precompile
<span class="gp">$</span> git add .
<span class="gp">$</span> git commit -m <span class="s2">"Add precompiled assets for Heroku"</span>
<span class="gp">$</span> git push heroku master
</pre></div>
</div>
<p>This shouldn’t be necessary, and I have been unable to reproduce the issue, but the reports are common enough that I include it here for reference.)</p>
<p>As you proceed through the rest of the book, I recommend pushing and deploying the application regularly:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> git push
<span class="gp">$</span> git push heroku
<span class="gp">$</span> heroku run rake db:migrate
</pre></div>
</div>
<p>This provides remote backups and lets you catch any production errors as soon as possible. If you run into problems at Heroku, make sure to take a look at the production logs to try to diagnose the problem:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> heroku logs
</pre></div>
</div>
<p>With all the preparation finished, we’re finally ready to get started developing the sample application.</p>
<div class="label" id="sec-static_pages"></div>
<h2><a id="sec-3_1" href="static-pages.html#sec-static_pages" class="heading"><span class="number">3.1</span> Static pages</a></h2>
<p>In this section, we’ll take a first step toward making dynamic pages by creating a set of Rails <em>actions</em> and <em>views</em> containing (for now) only static HTML.<sup class="footnote" id="fnref-3_5"><a href="#fn-3_5">5</a></sup> Rails actions come bundled together inside <em>controllers</em> (the C in MVC from <a class="ref" href="beginning.html#sec-mvc">Section 1.2.6</a>), which contain sets of actions related by a common purpose. We got a glimpse of controllers in <a class="ref" href="a-demo-app.html#top">Chapter 2</a>, and will come to a deeper understanding once we explore the <a href="http://en.wikipedia.org/wiki/Representational_State_Transfer">REST architecture</a> more fully (starting in <a class="ref" href="modeling-users.html#top">Chapter 6</a>); in essence, a controller is a container for a group of (possibly dynamic) web pages.</p>
<p>In order to get our bearings, it’s helpful to recall the Rails directory structure from <a class="ref" href="beginning.html#sec-the_first_application">Section 1.2.3</a> (<a class="ref" href="beginning.html#fig-directory_structure_rails">Figure 1.2</a>). In this section, we’ll be working mainly in the <code>app/controllers</code> and <code>app/views</code> directories. (In <a class="ref" href="static-pages.html#sec-first_tests">Section 3.2</a>, we’ll even add a new directory of our own.) I suggest opening the sample app in your text editor or IDE at this time (<a class="ref" href="static-pages.html#sidebar-opening_the_project">Box 3.1</a>).</p>
<div class="label" id="sidebar-opening_the_project"></div>
<div class="sidebar"><span class="title"><span class="header">Box 3.1.</span><span class="description">Opening the project</span></span>
<p>It’s useful to be able to open the entire Rails project in your text editor or IDE. Unfortunately, how to do this is system-dependent, but in many cases you can open the current application directory, represented in Unix by a dot “<code>.</code>”, using the command-line command for your editor of choice:</p>
<pre class="verbatim"> $ cd ~/rails_projects/sample_app
$ <editor name> .</pre>
<p>For example, to open the sample app in Sublime Text, you type</p>
<pre class="verbatim"> $ subl .</pre>
<p>For Vim, you type</p>
<pre class="verbatim"> $ vim .</pre>
<p>(where <code>vim</code> might be <code>gvim</code> or <code>mvim</code> depending on which flavor of Vim you use).</p>
</div>
<p>To get started with static pages, recall from <a class="ref" href="beginning.html#sec-git_commands">Section 1.3.5</a> that, when using Git, it’s a good practice to do our work on a separate topic branch rather than the master branch. If you’re using Git for version control, you should run the following command:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> git checkout -b static-pages
</pre></div>
</div>
<p>Rails comes with a script for making controllers called <code>generate</code>; all it needs to work its magic is the controller’s name. Since we’ll be making a controller to handle static pages, we’ll call it the StaticPages controller. We’ll also plan to make actions for a Home page, a Help page, and an About page. The <code>generate</code> script takes an optional list of actions, so we’ll include two of the initial actions directly on the command line (<a class="ref" href="static-pages.html#code-generating_pages">Listing 3.4</a>).</p>
<div class="label" id="code-generating_pages"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.4.</span> <span class="description">Generating a StaticPages controller.</span> </div>
<div class="code"><div class="highlight"><pre>$ rails generate controller StaticPages home help --no-test-framework
create app/controllers/static_pages_controller.rb
route get "static_pages/help"
route get "static_pages/home"
invoke erb
create app/views/static_pages
create app/views/static_pages/home.html.erb
create app/views/static_pages/help.html.erb
invoke helper
create app/helpers/static_pages_helper.rb
invoke assets
invoke coffee
create app/assets/javascripts/static_pages.js.coffee
invoke scss
create app/assets/stylesheets/static_pages.css.scss
</pre></div>
</div></div>
<p>Here we’ve used the option <tt class="verb">--no-test-framework</tt> to suppress the generation of the default RSpec tests, which we won’t be using. Instead, we’ll create the tests by hand starting in <a class="ref" href="static-pages.html#sec-first_tests">Section 3.2</a>. We’ve also intentionally left off the <code>about</code> action from the command line arguments in <a class="ref" href="static-pages.html#code-generating_pages">Listing 3.4</a> so that we can see how to add it using test-driven development, or TDD (<a class="ref" href="static-pages.html#sec-first_tests">Section 3.2</a>).</p>
<p>In <a class="ref" href="static-pages.html#code-generating_pages">Listing 3.4</a>, note that we have passed the controller name as so-called <a href="https://en.wikipedia.org/wiki/CamelCase">CamelCase</a>, which leads to the creation of a controller file written in <a href="https://en.wikipedia.org/wiki/Snake_case">snake case</a>, so that a controller called StaticPages yields a file called <code>static_pages_controller.rb</code>. This is merely a convention, and in fact using snake case at the command line also works: the command</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> rails generate controller static_pages ...
</pre></div>
</div>
<p>also generates a controller called <code>static_pages_controller.rb</code>. Because Ruby uses CamelCase for class names (<a class="ref" href="rails-flavored-ruby.html#sec-ruby_classes">Section 4.4</a>), my preference is to refer to controllers using their CamelCase names, but this is a matter of taste. (Since Ruby filenames typically use snake case, the Rails generator converts CamelCase to snake case using the <a href="http://api.rubyonrails.org/classes/ActiveSupport/Inflector.html#method-i-underscore"><tt>underscore</tt></a> method.)</p>
<p>By the way, if you ever make a mistake when generating code, it’s useful to know how to reverse the process. See <a class="ref" href="static-pages.html#sidebar-undoing_things">Box 3.2</a> for some techniques on how to undo things in Rails.</p>
<div class="label" id="sidebar-undoing_things"></div>
<div class="sidebar"><span class="title"><span class="header">Box 3.2.</span><span class="description">Undoing things</span></span>
<p>Even when you’re very careful, things can sometimes go wrong when developing Rails applications. Happily, Rails has some facilities to help you recover.</p>
<p>One common scenario is wanting to undo code generation—for example, if you change your mind on the name of a controller. When generating a controller, Rails creates many more files than the controller file itself (as seen in <a class="ref" href="static-pages.html#code-generating_pages">Listing 3.4</a>). Undoing the generation means removing not only the principal generated file, but all the ancillary files as well. (In fact, we also want to undo any automatic edits made to the <tt>routes.rb</tt> file.) In Rails, this can be accomplished with <tt>rails destroy</tt>. In particular, these two commands cancel each other out:</p>
<pre class="verbatim"> $ rails generate controller FooBars baz quux
$ rails destroy controller FooBars baz quux</pre>
<p>Similarly, in <a class="ref" href="modeling-users.html#top">Chapter 6</a> we’ll generate a <em>model</em> as follows:</p>
<pre class="verbatim"> $ rails generate model Foo bar:string baz:integer</pre>
<p>This can be undone using</p>
<pre class="verbatim"> $ rails destroy model Foo</pre>
<p>(In this case, it turns out we can omit the other command-line arguments. When you get to <a class="ref" href="modeling-users.html#top">Chapter 6</a>, see if you can figure out why.)</p>
<p>Another technique related to models involves undoing <em>migrations</em>, which we saw briefly in <a class="ref" href="a-demo-app.html#top">Chapter 2</a> and will see much more of starting in <a class="ref" href="modeling-users.html#top">Chapter 6</a>. Migrations change the state of the database using</p>
<pre class="verbatim"> $ rake db:migrate</pre>
<p>We can undo a single migration step using</p>
<pre class="verbatim"> $ rake db:rollback</pre>
<p>To go all the way back to the beginning, we can use</p>
<pre class="verbatim"> $ rake db:migrate VERSION=0</pre>
<p>As you might guess, substituting any other number for <tt>0</tt> migrates to that version number, where the version numbers come from listing the migrations sequentially.</p>
<p>With these techniques in hand, we are well-equipped to recover from the inevitable development <a href="http://en.wikipedia.org/wiki/SNAFU">snafus</a>.</p>
</div>
<p>The StaticPages controller generation in <a class="ref" href="static-pages.html#code-generating_pages">Listing 3.4</a> automatically updates the <em>routes</em> file, called <code>config/routes.rb</code>, which Rails uses to find the correspondence between URLs and web pages. This is our first encounter with the <code>config</code> directory, so it’s helpful to take a quick look at it (<a class="ref" href="static-pages.html#fig-config_directory_rails">Figure 3.1</a>). The <code>config</code> directory is where Rails collects files needed for the application configuration (hence the name).</p>
<div class="label" id="fig-config_directory_rails"></div>
<div class="figure"><div class="center"><span class="graphic"><img src="images/figures/config_directory_rails_4.png" alt="config_directory_rails_4" /></span></div><div class="caption"><span class="header">Figure 3.1: </span><span class="description">Contents of the sample app’s <code>config</code> directory. <a href="http://railstutorial.org/images/figures/config_directory_rails_4-full.png">(full size)</a></span></div></div>
<p>Since we generated <code>home</code> and <code>help</code> actions, the routes file already has a rule for each one, as seen in <a class="ref" href="static-pages.html#code-pages_routes">Listing 3.5</a>.</p>
<div class="label" id="code-pages_routes"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.5.</span> <span class="description">The routes for the <code>home</code> and <code>help</code> actions in the StaticPages controller. <br /> <code>config/routes.rb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="ss">SampleApp::Application</span><span class="o">.</span><span class="n">routes</span><span class="o">.</span><span class="n">draw</span> <span class="k">do</span>
<span class="n">get</span> <span class="s2">"static_pages/home"</span>
<span class="n">get</span> <span class="s2">"static_pages/help"</span>
<span class="o">.</span>
<span class="o">.</span>
<span class="o">.</span>
<span class="k">end</span>
</pre></div>
</div></div>
<p>Here the rule</p>
<div class="code"><div class="highlight"><pre><span class="n">get</span> <span class="s2">"static_pages/home"</span>
</pre></div>
</div>
<p>maps requests for the URL /static_pages/home to the <code>home</code> action in the StaticPages controller. Moreover, by using <code>get</code> we arrange for the route to respond to a <tt>GET</tt> request, which is one of the fundamental
<em>HTTP verbs</em> supported by the hypertext transfer protocol (<a class="ref" href="static-pages.html#sidebar-get_etc">Box 3.3</a>). In our case, this means that when we generate a <code>home</code> action inside the StaticPages controller we automatically get a page at the address /static_pages/home. To see the results, navigate to <a href="http://localhost:3000/static_pages/home">/static_pages/home</a> (<a class="ref" href="static-pages.html#fig-raw_home_view">Figure 3.2</a>).</p>
<div class="label" id="fig-raw_home_view"></div>
<div class="figure"><div class="center"><span class="graphic"><img src="images/figures/raw_home_view_31.png" alt="raw_home_view_31" /></span></div><div class="caption"><span class="header">Figure 3.2: </span><span class="description">The raw home view (<a href="http://localhost:3000/static_pages/home">/static_pages/home</a>). <a href="http://railstutorial.org/images/figures/raw_home_view_31-full.png">(full size)</a></span></div></div>
<div class="label" id="sidebar-get_etc"></div>
<div class="sidebar"><span class="title"><span class="header">Box 3.3.</span><span class="description"><tt>GET</tt>, et cet.</span></span>
<p>The hypertext transfer protocol (<a href="http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol#Request_methods">HTTP</a>) defines the basic operations <tt>GET</tt>, <tt>POST</tt>, <tt>PATCH</tt>, and <tt>DELETE</tt>. These refer to operations between a <em>client</em> computer (typically running a web browser such as Firefox or Safari) and a <em>server</em> (typically running a web server such as Apache or Nginx). (It’s important to understand that, when developing Rails applications on a local computer, the client and server are the same physical machine, but in general they are different.) An emphasis on HTTP verbs is typical of web frameworks (including Rails) influenced by the <em>REST architecture</em>, which we saw briefly in <a class="ref" href="a-demo-app.html#top">Chapter 2</a> and will start learning about more in <a class="ref" href="sign-up.html#top">Chapter 7</a>.</p>
<p><tt>GET</tt> is the most common HTTP operation, used for <em>reading</em> data on the web; it just means “get a page”, and every time you visit a site like google.com or wikipedia.org your browser is submitting a <tt>GET</tt> request. <tt>POST</tt> is the next most common operation; it is the request sent by your browser when you submit a form. In Rails applications, <tt>POST</tt> requests are typically used for <em>creating</em> things (although HTTP also allows <tt>POST</tt> to perform updates); for example, the <tt>POST</tt> request sent when you submit a registration form creates a new user on the remote site. The other two verbs, <tt>PATCH</tt> and <tt>DELETE</tt>, are designed for <em>updating</em> and <em>destroying</em> things on the remote server. These requests are less common than <tt>GET</tt> and <tt>POST</tt> since browsers are incapable of sending them natively, but some web frameworks (including Ruby on Rails) have clever ways of making it <em>seem</em> like browsers are issuing such requests.</p>
<p>By the way, previous versions of Rails used <tt>PUT</tt> in place of <tt>PATCH</tt>, and Rails 4.0 still supports this usage, but <tt>PATCH</tt> <a href="http://weblog.rubyonrails.org/2012/2/26/edge-rails-patch-is-the-new-primary-http-method-for-updates/">matches the intended HTTP usage better</a> and is preferred for new applications.</p>
</div>
<p>To understand where this page comes from, let’s start by taking a look at the StaticPages controller in a text editor; you should see something like <a class="ref" href="static-pages.html#code-static_pages_controller">Listing 3.6</a>. You may note that, unlike the demo Users and Microposts controllers from <a class="ref" href="a-demo-app.html#top">Chapter 2</a>, the StaticPages controller does not use the standard REST actions. This is normal for a collection of static pages—the REST architecture isn’t the best solution to every problem.</p>
<div class="label" id="code-static_pages_controller"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.6.</span> <span class="description">The StaticPages controller made by <a class="ref" href="static-pages.html#code-generating_pages">Listing 3.4</a>. <br /> <code>app/controllers/static_pages_controller.rb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="k">class</span> <span class="nc">StaticPagesController</span> <span class="o"><</span> <span class="no">ApplicationController</span>
<span class="k">def</span> <span class="nf">home</span>
<span class="k">end</span>
<span class="k">def</span> <span class="nf">help</span>
<span class="k">end</span>
<span class="k">end</span>
</pre></div>
</div></div>
<p>We see from the <code>class</code> keyword in <a class="ref" href="static-pages.html#code-static_pages_controller">Listing 3.6</a> that <code>static_pages_controller.rb</code> defines a <em>class</em>, in this case called <code>StaticPagesController</code>. Classes are simply a convenient way to organize <em>functions</em> (also called <em>methods</em>) like the <code>home</code> and <code>help</code> actions, which are defined using the <code>def</code> keyword. The angle bracket <code><</code> indicates that <code>StaticPagesController</code> <em>inherits</em> from the Rails class <code>ApplicationController</code>; as we’ll see momentarily, this means that our pages come equipped with a large amount of Rails-specific functionality. (We’ll learn more about both classes and inheritance in <a class="ref" href="rails-flavored-ruby.html#sec-ruby_classes">Section 4.4</a>.)</p>
<p>In the case of the StaticPages controller, both its methods are initially empty:</p>
<div class="code"><div class="highlight"><pre><span class="k">def</span> <span class="nf">home</span>
<span class="k">end</span>
<span class="k">def</span> <span class="nf">help</span>
<span class="k">end</span>
</pre></div>
</div>
<p>In plain Ruby, these methods would simply do nothing. In Rails, the situation is different—<code>StaticPagesController</code> is a Ruby class, but because it inherits from <code>ApplicationController</code> the behavior of its methods is specific to Rails: when visiting the URL /static_pages/home, Rails looks in the StaticPages controller and executes the code in the <code>home</code> action, and then renders the <em>view</em> (the V in MVC from <a class="ref" href="beginning.html#sec-mvc">Section 1.2.6</a>) corresponding to the action. In the present case, the <code>home</code> action is empty, so all visiting /static_pages/home does is render the view. So, what does a view look like, and how do we find it?</p>
<p>If you take another look at the output in <a class="ref" href="static-pages.html#code-generating_pages">Listing 3.4</a>, you might be able to guess the correspondence between actions and views: an action like <code>home</code> has a corresponding view called <code>home.html.erb</code>. We’ll learn in <a class="ref" href="static-pages.html#sec-slightly_dynamic_pages">Section 3.3</a> what the <code>.erb</code> part means; from the <code>.html</code> part you probably won’t be surprised that it basically looks like HTML (<a class="ref" href="static-pages.html#code-raw_home_view">Listing 3.7</a>).</p>
<div class="label" id="code-raw_home_view"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.7.</span> <span class="description">The generated view for the Home page. <br /> <code>app/views/static_pages/home.html.erb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="nt"><h1></span>StaticPages#home<span class="nt"></h1></span>
<span class="nt"><p></span>Find me in app/views/static_pages/home.html.erb<span class="nt"></p></span>
</pre></div>
</div></div>
<p>The view for the <code>help</code> action is analogous (<a class="ref" href="static-pages.html#code-raw_help_view">Listing 3.8</a>).</p>
<div class="label" id="code-raw_help_view"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.8.</span> <span class="description">The generated view for the Help page. <br /> <code>app/views/static_pages/help.html.erb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="nt"><h1></span>StaticPages#help<span class="nt"></h1></span>
<span class="nt"><p></span>Find me in app/views/static_pages/help.html.erb<span class="nt"></p></span>
</pre></div>
</div></div>
<p>Both of these views are just placeholders: they have a top-level heading (inside the <code>h1</code> tag) and a paragraph (<code>p</code> tag) with the full path to the relevant file. We’ll add some (very slightly) dynamic content starting in <a class="ref" href="static-pages.html#sec-slightly_dynamic_pages">Section 3.3</a>, but as they stand these views underscore an important point: Rails views can simply contain static HTML.</p>
<p>In the remainder of this chapter, we’ll add some custom content to the Home and Help pages, and then add in the About page we left off in <a class="ref" href="static-pages.html#sec-static_pages">Section 3.1</a>. Then we’ll add a very small amount of dynamic content by changing the title on a per-page basis.</p>
<p>Before moving on, if you’re using Git it’s a good idea to add the files for the StaticPages controller to the repository:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> git add .
<span class="gp">$</span> git commit -m <span class="s2">"Add a StaticPages controller"</span>
</pre></div>
</div>
<div class="label" id="sec-first_tests"></div>
<h2><a id="sec-3_2" href="static-pages.html#sec-first_tests" class="heading"><span class="number">3.2</span> Our first tests</a></h2>
<p>The <em>Rails Tutorial</em> takes an intuitive approach to testing that emphasizes the behavior of the application rather than its precise implementation, a variant of test-driven development (TDD) known as behavior-driven development (BDD). Our main tools will be <em>integration tests</em> (starting in this section) and <em>unit tests</em> (starting in <a class="ref" href="modeling-users.html#top">Chapter 6</a>). Integration tests, known as <em>request specs</em> in the context of RSpec, allow us to simulate the actions of a user interacting with our application using a web browser. Together with the natural-language syntax provided by Capybara, integration tests provide a powerful method to test our application’s functionality without having to manually check each page with a browser. (Another popular choice for BDD, called Cucumber, is introduced in <a class="ref" href="sign-in-sign-out.html#sec-cucumber">Section 8.3</a>.)</p>
<p>The defining quality of TDD is writing tests <em>first</em>, before the application code. Initially, this might take some getting used to, but the benefits are significant. By writing a <em>failing</em> test first and then implementing the application code to get it to pass, we increase our confidence that the test is actually covering the functionality we think it is. Moreover, the fail-implement-pass development cycle induces a <a href="http://en.wikipedia.org/wiki/Flow_(psychology)">flow state</a>, leading to enjoyable coding and high productivity. Finally, the tests act as a <em>client</em> for the application code, often leading to more elegant software designs.</p>
<p>It’s important to understand that TDD is not always the right tool for the job: there’s no reason to dogmatically insist that tests always should be written first, that they should cover every single feature, or that there should necessarily be any tests at all. For example, when you aren’t at all sure how to solve a given programming problem, it’s often useful to skip the tests and write only application code, just to get a sense of what the solution will look like. (In the language of <a href="http://en.wikipedia.org/wiki/Extreme_Programming">Extreme Programming (XP)</a>, this exploratory step is called a <em>spike</em>.) Once you see the general shape of the solution, you can then use TDD to implement a more polished version.</p>
<p>In this section, we’ll be running the tests using the <code>rspec</code> command supplied by the RSpec gem. This practice is straightforward but not ideal, and if you are a more advanced user I suggest setting up your system as described in <a class="ref" href="static-pages.html#sec-advanced_setup">Section 3.6</a>.</p>
<div class="label" id="sec-TDD"></div>
<h3><a id="sec-3_2_1" href="static-pages.html#sec-TDD" class="heading"><span class="number">3.2.1</span> Test-driven development</a></h3>
<p>In test-driven development, we first write a <em>failing</em> test, represented in many testing tools by the color red. We then implement code to get the test to pass, represented by the color green. Finally, if necessary, we refactor the code, changing its form (by eliminating duplication, for example) without changing its function. This cycle is known as “Red, Green, Refactor”.</p>
<p>We’ll begin by adding some content to the Home page using test-driven development, including a top-level heading (<code><h1></code>) with the content <code>Sample App</code>. The first step is to generate an integration test (request spec) for our static pages:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> rails generate integration_test static_pages
<span class="go"> invoke rspec</span>
<span class="go"> create spec/requests/static_pages_spec.rb</span>
</pre></div>
</div>
<p>This creates the <code>static_pages_spec.rb</code> in the <code>spec/requests</code> directory. As with most generated code, the result is not pretty, so let’s open <code>static_pages_spec.rb</code> with a text editor and replace it with the contents of <a class="ref" href="static-pages.html#code-home_page_content_spec">Listing 3.9</a>.</p>
<div class="label" id="code-home_page_content_spec"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.9.</span> <span class="description">Code to test the contents of the Home page. <br /> <code>spec/requests/static_pages_spec.rb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="nb">require</span> <span class="s1">'spec_helper'</span>
<span class="n">describe</span> <span class="s2">"Static pages"</span> <span class="k">do</span>
<span class="n">describe</span> <span class="s2">"Home page"</span> <span class="k">do</span>
<span class="n">it</span> <span class="s2">"should have the content 'Sample App'"</span> <span class="k">do</span>
<span class="n">visit</span> <span class="s1">'/static_pages/home'</span>
<span class="n">expect</span><span class="p">(</span><span class="n">page</span><span class="p">)</span><span class="o">.</span><span class="n">to</span> <span class="n">have_content</span><span class="p">(</span><span class="s1">'Sample App'</span><span class="p">)</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="k">end</span>
</pre></div>
</div></div>
<p>The code in <a class="ref" href="static-pages.html#code-home_page_content_spec">Listing 3.9</a> is pure Ruby, but even if you’ve studied Ruby before it might not look familiar. This is because RSpec uses the general malleability of Ruby to define a <em>domain-specific language</em> (DSL) built just for testing. The important point is that <em>you do not need to understand RSpec’s syntax to be able to use RSpec</em>. It may seem like magic at first, but RSpec and Capybara are designed to read more or less like English, and if you follow the examples in this tutorial you’ll pick it up fairly quickly.</p>
<p><a class="ref" href="static-pages.html#code-home_page_content_spec">Listing 3.9</a> contains a <code>describe</code> block with one <em>example</em>, i.e., a block starting with <code>it "…" do</code>:</p>
<div class="code"><div class="highlight"><pre><span class="n">describe</span> <span class="s2">"Home page"</span> <span class="k">do</span>
<span class="n">it</span> <span class="s2">"should have the content 'Sample App'"</span> <span class="k">do</span>
<span class="n">visit</span> <span class="s1">'/static_pages/home'</span>
<span class="n">expect</span><span class="p">(</span><span class="n">page</span><span class="p">)</span><span class="o">.</span><span class="n">to</span> <span class="n">have_content</span><span class="p">(</span><span class="s1">'Sample App'</span><span class="p">)</span>
<span class="k">end</span>
<span class="k">end</span>
</pre></div>
</div>
<p>The first line indicates that we are describing the Home page. This description is just a string, and it can be anything you want; RSpec doesn’t care, but you and other human readers probably do. Then the spec says that when you visit the Home page at <code>/static_pages/home</code>, the content should contain the words “Sample App”. As with the first line, what goes inside the quote marks is irrelevant to RSpec, and is intended to be descriptive to human readers. Then the line</p>
<div class="code"><div class="highlight"><pre><span class="n">visit</span> <span class="s1">'/static_pages/home'</span>
</pre></div>
</div>
<p>uses the Capybara function <code>visit</code> to simulate visiting the URL <code>/static_pages/home</code> in a browser, while the line</p>
<div class="code"><div class="highlight"><pre><span class="n">expect</span><span class="p">(</span><span class="n">page</span><span class="p">)</span><span class="o">.</span><span class="n">to</span> <span class="n">have_content</span><span class="p">(</span><span class="s1">'Sample App'</span><span class="p">)</span>
</pre></div>
</div>
<p>uses the <code>page</code> variable (also provided by Capybara) to express the expectation that the resulting page should have the right content.</p>
<p>To get the test to run properly, we have to add a line to the <code>spec_helper.rb</code> file, as shown in <a class="ref" href="static-pages.html#code-capybara_dsl">Listing 3.10</a>. (In the full third edition of the <em>Rails Tutorial</em>, I plan to eliminate this requirement by adopting the newer technique of <a href="https://www.relishapp.com/rspec/rspec-rails/docs/feature-specs/feature-spec">feature specs</a>.)</p>
<div class="label" id="code-capybara_dsl"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.10.</span> <span class="description">Adding the Capybara DSL to the RSpec helper file. <br /> <code>spec/spec_helper.rb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="c1"># This file is copied to spec/ when you run 'rails generate rspec:install'</span>
<span class="o">.</span>
<span class="o">.</span>
<span class="o">.</span>
<span class="no">RSpec</span><span class="o">.</span><span class="n">configure</span> <span class="k">do</span> <span class="o">|</span><span class="n">config</span><span class="o">|</span>
<span class="o">.</span>
<span class="o">.</span>
<span class="o">.</span>
<span class="n">config</span><span class="o">.</span><span class="n">include</span> <span class="ss">Capybara::DSL</span>
<span class="k">end</span>
</pre></div>
</div></div>
<p>To actually run the test, we have several options, including some convenient but rather advanced tools discussed in <a class="ref" href="static-pages.html#sec-advanced_setup">Section 3.6</a>. For now, we’ll use the <code>rspec</code> command at the command line (executed with <code>bundle exec</code> to ensure that RSpec runs in the environment specified by our <code>Gemfile</code>):<sup class="footnote" id="fnref-3_6"><a href="#fn-3_6">6</a></sup></p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> bundle <span class="nb">exec </span>rspec spec/requests/static_pages_spec.rb
</pre></div>
</div>
<p>This yields a failing test. The appearance of the result depends on your system; on my system, the red failing test appears as in <a class="ref" href="static-pages.html#fig-red_failing_spec">Figure 3.3</a>.<sup class="footnote" id="fnref-3_7"><a href="#fn-3_7">7</a></sup></p>
<div class="label" id="fig-red_failing_spec"></div>
<div class="figure"><div class="center"><span class="graphic"><img src="images/figures/red_failing_spec_4_0.png" alt="red_failing_spec_4_0" /></span></div><div class="caption"><span class="header">Figure 3.3: </span><span class="description">A red (failing) test. <a href="http://railstutorial.org/images/figures/red_failing_spec_4_0-full.png">(full size)</a></span></div></div>
<p>To get the test to pass, we’ll replace the default Home page test with the HTML in <a class="ref" href="static-pages.html#code-home_page_passing">Listing 3.11</a>.</p>
<div class="label" id="code-home_page_passing"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.11.</span> <span class="description">Code to get a passing test for the Home page. <br /> <code>app/views/static_pages/home.html.erb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="nt"><h1></span>Sample App<span class="nt"></h1></span>
<span class="nt"><p></span>
This is the home page for the
<span class="nt"><a</span> <span class="na">href=</span><span class="s">"http://railstutorial.org/"</span><span class="nt">></span>Ruby on Rails Tutorial<span class="nt"></a></span>
sample application.
<span class="nt"></p></span>
</pre></div>
</div></div>
<p>This arranges for a top-level heading (<code><h1></code>) with the content <code>Sample App</code>, which should get the test to pass. We also include an <em>anchor</em> tag <code>a</code>, which creates links to the given URL (called an “href”, or “hypertext reference”, in the context of an anchor tag):</p>
<div class="code"><div class="highlight"><pre><span class="nt"><a</span> <span class="na">href=</span><span class="s">"http://railstutorial.org/"</span><span class="nt">></span>Ruby on Rails Tutorial<span class="nt"></a></span>
</pre></div>
</div>
<p>Now re-run the test to see the effect:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> bundle <span class="nb">exec </span>rspec spec/requests/static_pages_spec.rb
</pre></div>
</div>
<p>On my system, the passing test appears as in <a class="ref" href="static-pages.html#fig-green_passing_spec">Figure 3.4</a>.</p>
<div class="label" id="fig-green_passing_spec"></div>
<div class="figure"><div class="center"><span class="graphic"><img src="images/figures/green_passing_spec_4_0.png" alt="green_passing_spec_4_0" /></span></div><div class="caption"><span class="header">Figure 3.4: </span><span class="description">A green (passing) test. <a href="http://railstutorial.org/images/figures/green_passing_spec_4_0-full.png">(full size)</a></span></div></div>
<p>Based on the example for the Home page, you can probably guess the analogous test and application code for the Help page. We start by testing for the relevant content, in this case the string <code>’Help’</code> (<a class="ref" href="static-pages.html#code-help_content_spec">Listing 3.12</a>).</p>
<div class="label" id="code-help_content_spec"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.12.</span> <span class="description">Adding code to test the contents of the Help page. <br /> <code>spec/requests/static_pages_spec.rb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="nb">require</span> <span class="s1">'spec_helper'</span>
<span class="n">describe</span> <span class="s2">"Static pages"</span> <span class="k">do</span>
<span class="n">describe</span> <span class="s2">"Home page"</span> <span class="k">do</span>
<span class="n">it</span> <span class="s2">"should have the content 'Sample App'"</span> <span class="k">do</span>
<span class="n">visit</span> <span class="s1">'/static_pages/home'</span>
<span class="n">expect</span><span class="p">(</span><span class="n">page</span><span class="p">)</span><span class="o">.</span><span class="n">to</span> <span class="n">have_content</span><span class="p">(</span><span class="s1">'Sample App'</span><span class="p">)</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="n">describe</span> <span class="s2">"Help page"</span> <span class="k">do</span>
<span class="n">it</span> <span class="s2">"should have the content 'Help'"</span> <span class="k">do</span>
<span class="n">visit</span> <span class="s1">'/static_pages/help'</span>
<span class="n">expect</span><span class="p">(</span><span class="n">page</span><span class="p">)</span><span class="o">.</span><span class="n">to</span> <span class="n">have_content</span><span class="p">(</span><span class="s1">'Help'</span><span class="p">)</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="k">end</span>
</pre></div>
</div></div>
<p>Then run the tests:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> bundle <span class="nb">exec </span>rspec spec/requests/static_pages_spec.rb
</pre></div>
</div>
<p>One test should fail. (Since systems will vary, and since keeping track of how many tests there are at each stage of the tutorial is a maintenance nightmare, I’ll omit the RSpec output from now on.)</p>
<p>The application code is similar to the code in <a class="ref" href="static-pages.html#code-home_page_passing">Listing 3.11</a>, as seen in <a class="ref" href="static-pages.html#code-help_page_passing">Listing 3.13</a>.</p>
<div class="label" id="code-help_page_passing"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.13.</span> <span class="description">Code to get a passing test for the Help page. <br /> <code>app/views/static_pages/help.html.erb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="nt"><h1></span>Help<span class="nt"></h1></span>
<span class="nt"><p></span>
Get help on the Ruby on Rails Tutorial at the
<span class="nt"><a</span> <span class="na">href=</span><span class="s">"http://railstutorial.org/help"</span><span class="nt">></span>Rails Tutorial help page<span class="nt"></a></span>.
To get help on this sample app, see the
<span class="nt"><a</span> <span class="na">href=</span><span class="s">"http://railstutorial.org/book"</span><span class="nt">></span>Rails Tutorial book<span class="nt"></a></span>.
<span class="nt"></p></span>
</pre></div>
</div></div>
<p>The tests should now pass:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> bundle <span class="nb">exec </span>rspec spec/requests/static_pages_spec.rb
</pre></div>
</div>
<div class="label" id="sec-adding_a_page"></div>
<h3><a id="sec-3_2_2" href="static-pages.html#sec-adding_a_page" class="heading"><span class="number">3.2.2</span> Adding a page</a></h3>
<p>Having seen test-driven development in action in a simple example, we’ll use the same technique to accomplish the slightly more complicated task of adding a new page, namely, the About page that we intentionally left off in <a class="ref" href="static-pages.html#sec-static_pages">Section 3.1</a>. By writing a test and running RSpec at each step, we’ll see how TDD can guide us through the development of our application code.</p>
<div class="label" id="sec-red"></div>
<h4><a id="sec-3_2_2_1" href="static-pages.html#sec-red" class="heading">Red</a></h4>
<p>We’ll get to the Red part of the Red-Green cycle by writing a failing test for the About page. Following the models from <a class="ref" href="static-pages.html#code-help_content_spec">Listing 3.12</a>, you can probably guess the right test (<a class="ref" href="static-pages.html#code-about_page_content_spec">Listing 3.14</a>).</p>
<div class="label" id="code-about_page_content_spec"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.14.</span> <span class="description">Adding code to test the contents of the About page. <br /> <code>spec/requests/static_pages_spec.rb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="nb">require</span> <span class="s1">'spec_helper'</span>
<span class="n">describe</span> <span class="s2">"Static pages"</span> <span class="k">do</span>
<span class="n">describe</span> <span class="s2">"Home page"</span> <span class="k">do</span>
<span class="n">it</span> <span class="s2">"should have the content 'Sample App'"</span> <span class="k">do</span>
<span class="n">visit</span> <span class="s1">'/static_pages/home'</span>
<span class="n">expect</span><span class="p">(</span><span class="n">page</span><span class="p">)</span><span class="o">.</span><span class="n">to</span> <span class="n">have_content</span><span class="p">(</span><span class="s1">'Sample App'</span><span class="p">)</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="n">describe</span> <span class="s2">"Help page"</span> <span class="k">do</span>
<span class="n">it</span> <span class="s2">"should have the content 'Help'"</span> <span class="k">do</span>
<span class="n">visit</span> <span class="s1">'/static_pages/help'</span>
<span class="n">expect</span><span class="p">(</span><span class="n">page</span><span class="p">)</span><span class="o">.</span><span class="n">to</span> <span class="n">have_content</span><span class="p">(</span><span class="s1">'Help'</span><span class="p">)</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="n">describe</span> <span class="s2">"About page"</span> <span class="k">do</span>
<span class="n">it</span> <span class="s2">"should have the content 'About Us'"</span> <span class="k">do</span>
<span class="n">visit</span> <span class="s1">'/static_pages/about'</span>
<span class="n">expect</span><span class="p">(</span><span class="n">page</span><span class="p">)</span><span class="o">.</span><span class="n">to</span> <span class="n">have_content</span><span class="p">(</span><span class="s1">'About Us'</span><span class="p">)</span>
<span class="k">end</span>
<span class="k">end</span>
<span class="k">end</span>
</pre></div>
</div></div>
<div class="label" id="sec-green"></div>
<h4><a id="sec-3_2_2_2" href="static-pages.html#sec-green" class="heading">Green</a></h4>
<p>Recall from <a class="ref" href="static-pages.html#sec-static_pages">Section 3.1</a> that we can generate a static page in Rails by creating an action and corresponding view with the page’s name. In our case, the About page will first need an action called <code>about</code> in the StaticPages controller. Having written a failing test, we can now be confident that, in getting it to pass, we will actually have created a working About page.</p>
<p>If you run the RSpec example using</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> bundle <span class="nb">exec </span>rspec spec/requests/static_pages_spec.rb
</pre></div>
</div>
<p>the output includes the following complaint:</p>
<div class="code"><div class="highlight"><pre>No route matches [GET] "/static_pages/about"
</pre></div>
</div>
<p>This is a hint that we need to add <code>/static_pages/about</code> to the routes file, which we can accomplish by following the pattern in <a class="ref" href="static-pages.html#code-pages_routes">Listing 3.5</a>, as shown in <a class="ref" href="static-pages.html#code-about_route">Listing 3.15</a>.</p>
<div class="label" id="code-about_route"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.15.</span> <span class="description">Adding the <code>about</code> route. <br /> <code>config/routes.rb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="ss">SampleApp::Application</span><span class="o">.</span><span class="n">routes</span><span class="o">.</span><span class="n">draw</span> <span class="k">do</span>
<span class="n">get</span> <span class="s2">"static_pages/home"</span>
<span class="n">get</span> <span class="s2">"static_pages/help"</span>
<span class="n">get</span> <span class="s2">"static_pages/about"</span>
<span class="o">.</span>
<span class="o">.</span>
<span class="o">.</span>
<span class="k">end</span>
</pre></div>
</div></div>
<p>Now running</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> bundle <span class="nb">exec </span>rspec spec/requests/static_pages_spec.rb
</pre></div>
</div>
<p>complains that</p>
<div class="code"><div class="highlight"><pre>The action 'about' could not be found for StaticPagesController
</pre></div>
</div>
<p>To solve this problem, we follow the model provided by <code>home</code> and <code>help</code> from <a class="ref" href="static-pages.html#code-static_pages_controller">Listing 3.6</a> by adding an <code>about</code> action in the StaticPages controller (<a class="ref" href="static-pages.html#code-adding_the_about_page">Listing 3.16</a>).</p>
<div class="label" id="code-adding_the_about_page"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.16.</span> <span class="description">The StaticPages controller with added <code>about</code> action. <br /> <code>app/controllers/static_pages_controller.rb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="k">class</span> <span class="nc">StaticPagesController</span> <span class="o"><</span> <span class="no">ApplicationController</span>
<span class="k">def</span> <span class="nf">home</span>
<span class="k">end</span>
<span class="k">def</span> <span class="nf">help</span>
<span class="k">end</span>
<span class="k">def</span> <span class="nf">about</span>
<span class="k">end</span>
<span class="k">end</span>
</pre></div>
</div></div>
<p>Now running</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> bundle <span class="nb">exec </span>rspec spec/requests/static_pages_spec.rb
</pre></div>
</div>
<p>says that we are missing a “template”, i.e., a view:</p>
<div class="code"><div class="highlight"><pre>Missing template static_pages/about
</pre></div>
</div>
<p>To solve this issue, we add the <code>about</code> view. This involves creating a new file called <code>about.html.erb</code> in the <code>app/views/static_pages</code> directory with the contents shown in <a class="ref" href="static-pages.html#code-about_view">Listing 3.17</a>.</p>
<div class="label" id="code-about_view"></div>
<div class="codelisting">
<div class="listing"><span class="header">Listing 3.17.</span> <span class="description">Code for the About page. <br /> <code>app/views/static_pages/about.html.erb</code></span> </div>
<div class="code"><div class="highlight"><pre><span class="nt"><h1></span>About Us<span class="nt"></h1></span>
<span class="nt"><p></span>
The <span class="nt"><a</span> <span class="na">href=</span><span class="s">"http://railstutorial.org/"</span><span class="nt">></span>Ruby on Rails Tutorial<span class="nt"></a></span>
is a project to make a book and screencasts to teach web development
with <span class="nt"><a</span> <span class="na">href=</span><span class="s">"http://rubyonrails.org/"</span><span class="nt">></span>Ruby on Rails<span class="nt"></a></span>. This
is the sample application for the tutorial.
<span class="nt"></p></span>
</pre></div>
</div></div>
<p>Running RSpec should now get us back to Green:</p>
<div class="code"><div class="highlight"><pre><span class="gp">$</span> bundle <span class="nb">exec </span>rspec spec/requests/static_pages_spec.rb
</pre></div>
</div>
<p>Of course, it’s never a bad idea to take a look at the page in a browser to make sure our tests aren’t completely crazy (<a class="ref" href="static-pages.html#fig-about_us">Figure 3.5</a>).</p>
<div class="label" id="fig-about_us"></div>
<div class="figure"><div class="center"><span class="graphic"><img src="images/figures/about_us_2nd_edition.png" alt="about_us_2nd_edition" /></span></div><div class="caption"><span class="header">Figure 3.5: </span><span class="description">The new About page (<a href="http://localhost:3000/static_pages/about">/static_pages/about</a>). <a href="http://railstutorial.org/images/figures/about_us_2nd_edition-full.png">(full size)</a></span></div></div>
<div class="label" id="sec-refactor"></div>
<h4><a id="sec-3_2_2_3" href="static-pages.html#sec-refactor" class="heading">Refactor</a></h4>
<p>Now that we’ve gotten to Green, we are free to refactor our code with confidence. Oftentimes code will start to “smell”, meaning that it gets ugly, bloated, or filled with repetition. The computer doesn’t care, of course, but humans do, so it is important to keep the code base clean by refactoring frequently. Having a good test suite is an invaluable tool in this regard, as it dramatically lowers the probability of introducing bugs while refactoring.</p>
<p>Our sample app is a little too small to refactor right now, but code smell seeps in at every crack, and we won’t have to wait long: we’ll already get busy refactoring in <a class="ref" href="static-pages.html#sec-layouts">Section 3.3.4</a>.</p>
<div class="label" id="sec-slightly_dynamic_pages"></div>