Rails Project 2020

Ruby on Rails, often simply Rails, is an open source web application framework which runs on the Ruby programming language. It is a full-stack framework: it allows creating pages and applications that gather information from the web server, talk to or query the database, and render templates out of the box. As a result, Rails features a routing system that is independent of the web server. - from wiki

The Rails philosophy includes two major guiding principles:
DRY - "Don't Repeat Yourself" - suggests that writing the same code over and over again is a bad thing.
Convention Over Configuration - means that Rails makes assumptions about what we want to do and how we're going to do it, rather than requiring us to specify every little thing through endless configuration files. - from http://guides.rubyonrails.org/

The RubyGems software allows us to download, install, and use ruby software packages on our system. RubyGems is a package manager for Ruby projects and contains a package Ruby application or library (including Rails). It is available as Ruby packages, or gems.

Ruby 1.9 and newer ships with RubyGems built-in but we may need to upgrade for bug fixes or new features. To upgrade RubyGems or install it, visit the download page.

Note: we may want to update/upgrade our current system. As an example, for Ubuntu, we do:

$ apt-get update
$ apt-get upgrade

Now, let's work on RubyGems:

$ sudo gem install rubygems-update
Fetching: rubygems-update-2.2.2.gem (100%)
Successfully installed rubygems-update-2.2.2
Parsing documentation for rubygems-update-2.2.2
Installing ri documentation for rubygems-update-2.2.2
Done installing documentation for rubygems-update after 5 seconds
1 gem installed

$ sudo update_rubygems 
RubyGems 2.2.2 installed
Installing ri documentation for rubygems-2.2.2
...
RubyGems installed the following executables:
	/usr/bin/gem1.9.1
...

The RubyGems has been installed.

We need to make sure Ruby is already installed:

$ ruby -v
ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]

To install Rails, use the gem install command provided by RubyGems which we discussed in the previous section: the RubyGems is a package manager for Ruby:

$ gem install rails
Successfully installed rails-4.1.1
1 gem installed

Rails provides us with a number of scripts called generators that are designed to create everything that's necessary to start working on a particular task. One of these is the new application generator, which will provide us with the foundation of a fresh Rails application so that we don't have to write it ourselves.

The syntax looks like this:

$ rails new PROJECT_NAME
$ cd PROJECT_NAME

Now, we will create a Rails application called Blog in a directory called blog and install the gem dependencies that are already mentioned in Gemfile using bundle install.

$ rails new blog

We may get the following error:

$ rails new blog
...
      create  vendor/assets/stylesheets
      create  vendor/assets/stylesheets/.keep
         run  bundle install
/usr/bin/ruby1.9.1: No such file or directory -- /usr/share/rubygems-integration/1.9.1/gems/bundler-1.3.5/bin/bundle (LoadError)

Then, we should install the gem dependencies that are already mentioned in Gemfile using bundle install:

$ gem install bundler
$ bundle install

If we run the rails new blog again:

$ rm -rf blog
$ rails new blog
      create  
      create  README.rdoc
      create  Rakefile
      create  config.ru
      create  .gitignore
      create  Gemfile
      create  app
      create  app/assets/javascripts/application.js
      create  app/assets/stylesheets/application.css
      create  app/controllers/application_controller.rb
      create  app/helpers/application_helper.rb
      create  app/views/layouts/application.html.erb
      create  app/assets/images/.keep
      create  app/mailers/.keep
      create  app/models/.keep
      create  app/controllers/concerns/.keep
      create  app/models/concerns/.keep
      create  bin
      create  bin/bundle
      create  bin/rails
      create  bin/rake
      create  config
      create  config/routes.rb
      create  config/application.rb
      create  config/environment.rb
      create  config/secrets.yml
      create  config/environments
      create  config/environments/development.rb
      create  config/environments/production.rb
      create  config/environments/test.rb
      create  config/initializers
      create  config/initializers/backtrace_silencers.rb
      create  config/initializers/cookies_serializer.rb
      create  config/initializers/filter_parameter_logging.rb
      create  config/initializers/inflections.rb
      create  config/initializers/mime_types.rb
      create  config/initializers/session_store.rb
      create  config/initializers/wrap_parameters.rb
      create  config/locales
      create  config/locales/en.yml
      create  config/boot.rb
      create  config/database.yml
      create  db
      create  db/seeds.rb
      create  lib
      create  lib/tasks
      create  lib/tasks/.keep
      create  lib/assets
      create  lib/assets/.keep
      create  log
      create  log/.keep
      create  public
      create  public/404.html
      create  public/422.html
      create  public/500.html
      create  public/favicon.ico
      create  public/robots.txt
      create  test/fixtures
      create  test/fixtures/.keep
      create  test/controllers
      create  test/controllers/.keep
      create  test/mailers
      create  test/mailers/.keep
      create  test/models
      create  test/models/.keep
      create  test/helpers
      create  test/helpers/.keep
      create  test/integration
      create  test/integration/.keep
      create  test/test_helper.rb
      create  tmp/cache
      create  tmp/cache/assets
      create  vendor/assets/javascripts
      create  vendor/assets/javascripts/.keep
      create  vendor/assets/stylesheets
      create  vendor/assets/stylesheets/.keep
         run  bundle install
...
Fetching gem metadata from https://rubygems.org/..........
Fetching additional metadata from https://rubygems.org/..
Resolving dependencies...
Using rake 10.3.1
Using i18n 0.6.9
Using json 1.8.1
Using minitest 5.3.3
Using thread_safe 0.3.3
Using tzinfo 1.1.0
Using activesupport 4.1.1
Using builder 3.2.2
Using erubis 2.7.0
Using actionview 4.1.1
Using rack 1.5.2
Using rack-test 0.6.2
Using actionpack 4.1.1
Using mime-types 1.25.1
Using polyglot 0.3.4
Using treetop 1.4.15
Using mail 2.5.4
Using actionmailer 4.1.1
Using activemodel 4.1.1
Using arel 5.0.1.20140414130214
Using activerecord 4.1.1
Using bundler 1.6.2
Using coffee-script-source 1.7.0
Using execjs 2.0.2
Using coffee-script 2.2.0
Using thor 0.19.1
Using railties 4.1.1
Using coffee-rails 4.0.1
Using hike 1.2.3
Using multi_json 1.10.0
Using jbuilder 2.0.7
Using jquery-rails 3.1.0
Using tilt 1.4.1
Using sprockets 2.11.0
Using sprockets-rails 2.1.3
Using rails 4.1.1
Using rdoc 4.1.1
Using sass 3.2.19
Using sass-rails 4.0.3
Using sdoc 0.4.0
Using spring 1.1.3
Using sqlite3 1.3.9
Using turbolinks 2.2.2
Using uglifier 2.5.0
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.
         run  bundle exec spring binstub --all
* bin/rake: spring inserted
* bin/rails: spring inserted
$ 

The rails new blog command we ran above created a folder in our working directory called blog. The blog directory has a number of auto-generated files and folders that make up the structure of a Rails application (see the picture above and the table below).