Using Rails

Rails is...


The Ruby and Rails communities have a collection of tools to manage their environments. While not strictly necessary to set up a working Rails development environment, let's start things properly.

Creating a Rails Application

> rails new rails-test-project --database=postgresql
create create README.rdoc create Rakefile create create .gitignore create Gemfile create app create app/assets/images/rails.png

...and so on. Once complete, we see that the rails new command created all of this:

We need to add a database user for our new Rails application to our Postgres database:

> psql -d postgres
psql (9.3.2) Type "help" for help.
postgres=# create role rails_test_project login createdb;
postgres=# \q

We now have a working skeleton of a Rails application, which we can test:

> rails server
Booting WEBrick => Rails 3.2.14 application starting in development on => Call with -d to detach => Ctrl-C to shutdown server [2014-02-18 04:11:24] INFO WEBrick 1.3.1 [2014-02-18 04:11:24] INFO ruby 1.9.3 (2013-02-22) [x86_64-darwin12.3.0] [2014-02-18 04:11:24] INFO WEBrick::HTTPServer#start: pid=3376 port=3000

The Design of Rails

A few core principles underlie the design of Rails:

Action Controller and Action View

Rails provides additional tools for creating views and controllers corresponding to user actions. For example, if we wanted to enable users to either eat bacon or eat lutefisk, we could create an "Eat" controller with corresponding bacon and lutefisk methods

> rails generate controller Eat bacon lutefisk
create app/controllers/eat_controller.rb route get "eat/lutefisk" route get "eat/bacon" invoke erb create app/views/eat create app/views/eat/bacon.html.erb create app/views/eat/lutefisk.html.erb invoke test_unit create test/functional/eat_controller_test.rb invoke helper create app/helpers/eat_helper.rb invoke test_unit create test/unit/helpers/eat_helper_test.rb invoke assets invoke coffee create app/assets/javascripts/ invoke scss create app/assets/stylesheets/eat.css.scss


class EatController < ApplicationController def bacon end def lutefisk end end


class ApplicationController < ActionController::Base protect_from_forgery end

For a good explanation of protect_from_forgery, read

Active Record

schema.rb gets automagically generated by...

Making Database Changes

Rails Plugins

Common Libraries

There exists an endless selection of libraries, but some are worth calling out in particular: