Turbocharge your web development with Rails Vagmi Mudumbai presented an overview of Ruby on Rails web development. The presentation covered installing Ruby and Rails, the MVC framework, generating models and migrations, querying the database, controllers and routes, views and forms. Attendees learned the basics of building a Rails application including setting up models, controllers and views to create, read, update and delete data through a RESTful interface.

1. Turbocharge your web
development with Rails
Vagmi Mudumbai
Dharana Software Innovations Pvt Ltd
@vagmi / vagmi@dharanasoft.com

2. About me
http://vagmim.com
RailsPundit
ChennaiGeeks
facebook.com/groups/chennaigeeks

3. http://www.catb.org/~esr/hacker-emblem/

5. Agenda
• About Ruby
• Controllers
• About Rails
• Layouts
• MVC
• Views
• Models
• Forms
• Relationships
• Q &A
• Routes

6. •Created by Yakuhiro
“Matz” Matsumoto in
1995 in Japan
•Generally available to
the english speaking
world at 2000

7. •Multi paradigm language
•Supports imperative/Object Oriented/
Functional styles of programming

8. # The Greeter class
class Greeter
def initialize(name)
@name = name.capitalize
end
def salute
puts "Hello #{@name}!"
end
end
# Create a new object
g = Greeter.new("world")
# Output "Hello World!"
g.salute

9. •Many Flavors
•MRI/YARV
•JRuby
•Rubinius
•IronRuby
•Maglev
•And more

10. • Created in 2005 by
David Heinemeier
Hannson (a.k.a. DHH)
• A web framework to
helps you actually
enjoy programming

11. • Intended to be simple and consistent to use
• Convention over configuration
• Freedom from needless XML situps

12. Installing Ruby
• For windows you can get Ruby from
• http://rubyinstaller.org/

13. Installing Ruby
• For Linux and Mac OSX
• Install via RVM
• http://rvm.beginrescueend.com/
• http://amerine.net/2010/02/24/rvm-rails3-
ruby-1-9-2-setup.html

14. Installing Rails
$ gem install rails

15. Rails MVC
Router
Controller
View Model DB
HTML/CSS/JS

16. Create a Rails App
$ rails new todolist

17. Rails Project Structure
myapp/
|-- Gemfile # all the dependencies go here
|-- Rakefile # the build file??
|-- app # The entire application sits here
|-- config # Configure the app to your heart's content
|-- db # Database migrations, seed file
|-- lib # Custom rake tasks and your libraries
|-- log # The directory we all love
|-- public # Static assets like CSS, JS and images
|-- script # Contains one file "rails"
|-- test # Tests - unit, functional, integration
|-- tmp # misc stuff like sessions, pids and working files
`-- vendor # 3rd party stuff - not used as much these days

18. Rails Project Structure
myapp/
`-- app
|-- controllers # controllers
| `-- application_controller.rb
|-- helpers
| `-- application_helper.rb # view helpers
|-- mailers
|-- models
`-- views
`-- layouts
`-- application.html.erb # could be haml or any other
# templating language

19. Rails Project Structure
myapp/
`-- config
|-- application.rb # the main application config file
|-- boot.rb # setup bundler and the environment
|-- database.yml # setup database connections
|-- environments
| |-- development.rb # development specific setup
| |-- production.rb # production specific setup
| `-- test.rb # test specific setup
|-- initializers
| |-- inflections.rb # any file put inside
| |-- mime_types.rb # this directory will
| |-- secret_token.rb # be executed when the
| `-- session_store.rb # rails application boots
|-- locales
| `-- en.yml # setup internationalization
`-- routes.rb # map URLs to Controllers/Actions

20. Models

21. Create a model
$ rails g model todo title:string done:boolean completed_at:datetime
invoke active_record
create db/migrate/20110625034305_create_todos.rb
create app/models/todo.rb
invoke test_unit
create test/unit/todo_test.rb
create test/fixtures/todos.yml

22. class CreateTodos < ActiveRecord::Migration
def self.up
create_table :todos do |t|
t.string :title
t.boolean :done
t.datetime :completed_at
t.timestamps
end
end
def self.down
drop_table :todos
end
end
Migration

23. The model class
class Todo < ActiveRecord::Base
# seriously thats it
# rails does rest of the magic
end

24. Create the table
$ rake db:migrate
(in /path/to/myapp)
== CreateTodos: migrating ================
-- create_table(:todos)
-> 0.0015s
== CreateTodos: migrated (0.0016s)
===========================================

25. $ rails console
Loading development environment (Rails 3.0.7)
ruby-1.9.2-p180 :001 >
The Rails console
The REPL for Rails

26. > todo=Todo.new
# => #<Todo id: nil, title: nil, done: nil,
completed_at: nil, created_at: nil, updated_at:
nil>
> todo.title="Some title"
# => "Some title"
> todo.save
# AREL (0.5ms) INSERT INTO "todos" ("title",
"done", "completed_at", "created_at",
"updated_at") VALUES ('Some title', NULL, NULL,
'2011-06-25 04:21:47.272312', '2011-06-25
04:21:47.272312')
=> true
Create a new object

27. > todo = Todo.new(:title=>"Teach
Rails",:done=>true,:completed_at=>Time.now)
=> #<Todo id: nil, title: "Teach Rails", done:
true, completed_at: "2011-06-25 04:26:29",
created_at: nil, updated_at: nil>
> todo.save
AREL (0.8ms) INSERT INTO "todos" ("title",
"done", "completed_at", "created_at", "updated_at")
VALUES ('Teach Rails', 't', '2011-06-25
04:26:29.853087', '2011-06-25 04:26:38.869335',
'2011-06-25 04:26:38.869335')
=> true
Create a new object

28. Querying
> Todo.where(:done=>true).all
Todo Load (0.4ms) SELECT "todos".* FROM
"todos" WHERE "todos"."done" = 't'
=> [#<Todo id: 2, title: "Teach Rails",
done: true, completed_at: "2011-06-25
04:26:29", created_at: "2011-06-25
04:26:38", updated_at: "2011-06-25
04:26:38">]

29. > t = Todo.where(:done=>true).first
Todo Load (0.4ms) SELECT "todos".* FROM
"todos" WHERE "todos"."done" = 't' LIMIT 1
=> #<Todo id: 2, title: "Teach Rails", done:
true, completed_at: "2011-06-25 04:26:29",
created_at: "2011-06-25 04:26:38", updated_at:
"2011-06-25 04:26:38">
> t.done=false
=> false
> t.save
AREL (0.5ms) UPDATE "todos" SET "done" =
'f', "updated_at" = '2011-06-25
05:31:07.025845' WHERE "todos"."id" = 2
=> true
Update object

30. Deleting objects
> t.destroy
AREL (0.5ms) DELETE FROM "todos" WHERE
"todos"."id" = 2
=> #<Todo id: 2, title: "Teach Rails",
done: false, completed_at: "2011-06-25
04:26:29", created_at: "2011-06-25
04:26:38", updated_at: "2011-06-25
05:31:07">

31. Relationships
$ rails g bucket name:string
$ rails g task title:string done:boolean bucket:references
create_table :buckets do |t|
class Bucket < ActiveRecord::Base
t.string :name
has_many :tasks
t.timestamps
end
end
create_table :tasks do |t|
t.string :title
class Task < ActiveRecord::Base
t.boolean :done
belongs_to :bucket
t.references :bucket
end
t.timestamps
end

32. Creating and querying relationships
> bucket = Bucket.create(:name=>"work") # create work bucket
> bucket.tasks.create(:title=>"Fill in timesheets") # create task
under bucket
> bucket.tasks.create(:title=>"Fix bug #234") #create another task
> bucket.tasks.count # => 2
> bucket.tasks
> t=Task.first # get the task object
> t.bucket # access the bucket object from the task object

33. Still awake?

34. Controllers & Routes

35. config/routes.rb
Myapp::Application.routes.draw do
# direct root (/) to WelcomeController's
# index action
root :to => "welcome#index"
end
$ rails g controller welcome

36. Welcome Controller
# app/controllers/welcome_controller.rb
class WelcomeController < ApplicationController
def index
render :text=>"hello world"
end
end

37. Views
# app/controller/welcome_controller.rb
class WelcomeController <
ApplicationController
def index
@time = Time.now
end
end
<!-- in app/views/welcome/index.html.erb -->
<h1>The time is <%=@time.strftime('%d-%b-%Y %H:%M:
%S')%></h1>

38. ReST and Resources
Myapp::Application.routes.draw do
resources :tasks
end
$ rake routes
(in /path/to/myapp)
tasks GET /tasks(.:format) {:action=>"index", :controller=>"tasks"}
POST /tasks(.:format) {:action=>"create", :controller=>"tasks"}
new_task GET /tasks/new(.:format) {:action=>"new", :controller=>"tasks"}
edit_task GET /tasks/:id/edit(.:format) {:action=>"edit", :controller=>"tasks"}
task GET /tasks/:id(.:format) {:action=>"show", :controller=>"tasks"}
PUT /tasks/:id(.:format) {:action=>"update", :controller=>"tasks"}
DELETE /tasks/:id(.:format) {:action=>"destroy", :controller=>"tasks"}

39. ReST and Resources
class TasksController < ApplicationController
# index displays a list of tasks
# new presents a form to create a task
# create processes the form submitted by the new action
# show displays an individual task
# edit presents a form to update a task
# update processes the form submitted by the edit action
# destroy deletes a task
end

40. Nested resources
Myapp::Application.routes.draw do
resources :buckets, :shallow=>true do
resources :tasks
end
end
$ rake routes
(in /path/to/myapp)
bucket_tasks GET /buckets/:bucket_id/tasks(.:format) {:action=>"index", :controller=>"tasks"}
POST /buckets/:bucket_id/tasks(.:format) {:action=>"create", :controller=>"tasks"}
new_bucket_task GET /buckets/:bucket_id/tasks/new(.:format) {:action=>"new", :controller=>"tasks"}
edit_task GET /tasks/:id/edit(.:format) {:action=>"edit", :controller=>"tasks"}
task GET /tasks/:id(.:format) {:action=>"show", :controller=>"tasks"}
PUT /tasks/:id(.:format) {:action=>"update", :controller=>"tasks"}
DELETE /tasks/:id(.:format) {:action=>"destroy", :controller=>"tasks"}
buckets GET /buckets(.:format) {:action=>"index", :controller=>"buckets"}
POST /buckets(.:format) {:action=>"create", :controller=>"buckets"}
new_bucket GET /buckets/new(.:format) {:action=>"new", :controller=>"buckets"}
edit_bucket GET /buckets/:id/edit(.:format) {:action=>"edit", :controller=>"buckets"}
bucket GET /buckets/:id(.:format) {:action=>"show", :controller=>"buckets"}
PUT /buckets/:id(.:format) {:action=>"update", :controller=>"buckets"}
DELETE /buckets/:id(.:format) {:action=>"destroy", :controller=>"buckets"}
* If you squint hard enough, you will be able to read it.

41. BucketsController
def index
@buckets = Bucket.all
end
def show
@bucket=Bucket.find(params[:id])
end
def destroy
@bucket=Bucket.find(params[:id])
@bucket.destroy
redirect_to buckets_path
end

42. BucketsController
def new
@bucket = Bucket.new
end
def create
@bucket = Bucket.new(params[:bucket])
if(@bucket.save)
flash[:notice] = "Bucket created"
redirect_to @bucket
else
render :action=>:new
end
end

43. BucketsController
def edit
@bucket = Bucket.find(params[:id])
end
def update
@bucket=Bucket.find(params[:id])
if(@bucket.update_attributes(params[:bucket]))
flash[:notice]="Bucket updated"
redirect_to @bucket
else
render :action=>:edit
end
end

44. Tasks Controller
def new
@bucket = Bucket.find(params[:bucket_id])
@task = @bucket.tasks.build
end
def create
@bucket = Bucket.find(params[:bucket_id])
# the form should have passed bucket_id
# as one of the parameters via
# a hidden field
@task = Task.new(params[:task])
if(@task.save)
flash[:notice]="task created"
redirect_to @task
else
render :action=>:new
end
end
The other actions remain the same

45. Fantastic Forms

46. Formtastic
# add these to your
# Gemfile
gem 'formtastic'
gem 'jquery-rails'
$ rails g formtastic:install
$ rails g jquery:install
<!-- in app/views/buckets/new.html.erb -->
<%= semantic_form_for @bucket do |f| %>
<%= f.inputs %>
<%= f.buttons %>
<% end %>

47. Hands On

48. Vagmi Mudumbai
vagmi@dharanasoft.com
twitter.com/vagmi
facebook.com/vagmi
linkedin.com/in/vagmi
github.com/vagmi
plus.google.com/
106483555843485143380/
Thank you