Intro to Rails and MVC

An Introduction to Rails

Ruby on Rails history
Ruby on Rails was extracted from 37signals’ Basecamp by David Heinemeier Hansson (DHH)
July 2004: first released as open source
Feb 2005: first external commit rights
Oct 2007: ships with Mac OS X v10.5 "Leopard”

Rails Philosophy
Opinionated
Convention over configuration
DRY (Don't Repeat Yourself)
less code means it's easier to maintain & modify
Test Driven Development (TDD)
Minimal code - maximal effect

Scaffold
Model
app/models/person.rb
db/migrate/20090611073227_create_people.rb
4 views
app/views/people/index.html.erb
app/views/people/show.html.erb
app/views/people/new.html.erb
app/views/people/edit.html.erb
Controller
app/controllers/people_controller.rb
route map.resources :people

MVC

MVC
Model: ActiveRecord
Represents what is in the database
View: ActionView, erb
Model rendered as HTML
Controller: ActionController
Receives HTTP actions (GET, POST, PUT, DELETE)
Decides what to do, typically rendering a view

ActiveRecord
p = new Person
p = new Person(:first => "May", :last => "Fong")
p.save
p.save!
Person.create(:first => "May", :last => "Fong")
Person.create!(:first => "May", :last => "Fong")