Rails 3 Beginner to Builder 2011 Week 1

Beginner To Builder
Week 1
Richard Schneeman
@schneems

June, 2011
Friday, June 10, 2011

Background

• Georgia Tech
• 5 Years of Rails
• Rails dev for Gowalla

@Schneems

About the Class
• Why?
• Structure
• Class & Course Work
• Ruby through Rails
• 8 Weeks
• 1 hour

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Rails - Week 1
• Ruby
• Versus Rails
• Data Types
• Rails Architecture
• MVC (Model View Controller)
• ORM (Object Relational Mapping)
• RESTful (REpresentational STate)
@Schneems

Rails - Week 1
•Workspace
• Version Control - Keep your code safe
• RubyGems - Use other’s code
• Bundler - Manage Dependencies
• RVM - Keep your system clean
• Tests - make sure it works

@Schneems

Ruby Versus Rails
• Ruby - Is a programming Language
• Like C# or Python
• Can be used to program just about anything
• Rails - Is a Framework
• Provides common web functionality
• Focus on your app, not on low level details

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Rails is a Web Framework
• Develop, deploy, and maintain dynamic web apps
• Written using Ruby
• Extremely ﬂexible, expressive, and quick
development time

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Technologies
• Html - creates a view
• Javascript - makes it interactive
• css - makes it pretty
• Ruby - Makes it a web app

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Ruby Resources
• why’s (poignant) guide to ruby
• Free, quirky

• Programming Ruby (Pickaxe)
• Not free, encyclopedic

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Ruby Resources
• Metaprogramming Ruby
• Skips basics
• Unleash the power of Ruby

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Interactive Ruby Console
(IRB) or http://TryRuby.org/

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Ruby Strings
• Characters (letters, digits, punctuation)
surrounded by quotes

food = "chunky bacon"
puts "I'm hungry for, #{food}!"
>> "I'm hungry for, chunky bacon!"

"I'm hungry for, chunky bacon!".class
>> String

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Ruby (numbers)

123.class
>> Fixnum

(123.0).class
>> Float

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Ruby Symbols
•Symbols are lightweight strings
• start with a colon
• immutable
:a, :b or :why_the_lucky_stiff

:why_the_lucky_stiff.class
>> Symbol

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Ruby Hash
•A hash is a dictionary surrounded by curly
braces.
•Dictionaries match words with their deﬁnitions.
my_var = {:sup => "dog", :foo => "bar"}
my_var[:foo]
>> "bar"

{:sup => "dog", :foo => "bar"}.class
>> Hash

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Ruby Array
•An array is a list surrounded by square
brackets and separated by commas.

array = [ 1, 2, 3, 4 ]
array.first
>> 1

[ 1, 2, 3, 4 ].class
>> Array

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Ruby Array
•Zero Indexed
array = [ 1, 2, 3, 4 ]
array[0]
>> 1

array = [ 1, 2, 3, 4 ]
array[1]
>> 2

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Ruby Blocks
•Code surrounded by curly braces
2.times { puts "hello"}
>> "hello"
>> "hello"

•Do and end can be used instead
2.times do
puts "hello"
end
>> "hello"
>> "hello"
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Ruby Blocks
•Can take arguments
• variables surrounded by pipe (|)
2.times do |i|
puts "hello #{i}"
end
>> "hello 0"
>> "hello 1"

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Rails why or why-not?
• Speed
• developer vs computer
• Opinionated framework
• Quick moving ecosystem

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Rails Architecture
• Terminology
• DRY
• Convention over Conﬁguration
• Rails Architecture
• MVC (Model View Controller)
• ORM (Object Relational Mapping)
• RESTful (REpresentational State
Transfer)
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DRY
Don’t Repeat Yourself

Reuse, don’t re-invent the...

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Convention over
Configuration

Decrease the number of decisions needed,
gaining simplicity but without losing ﬂexibility.

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Model-View-Controller
• Isolates “Domain Logic”
• Can I See it?
• View
• Is it Business Logic?
• Controller
• Is it a Reusable Class Logic?
• Model
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Model-View-Controller
• Generated By Rails
• Grouped by Folders
• Connected “AutoMagically”
• Models
• Views
• Controllers
• Multiple Views Per Controller
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Database Backed Models
• Store and access massive amounts of
data
• Table
• columns (name, type, modiﬁer)
• rows
Table: Users

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SQL
• Structured Query Language
• A way to talk to databases
SELECT *
FROM Book
WHERE price > 100.00
ORDER BY title;

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SQL operations
• insert
• query
• update and delete
• schema creation and modiﬁcation

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Object Relational Mapping
• Maps database backend to ruby objects
• ActiveRecord (Rail’s Default ORM)
>> userVariable = User.where(:name => "Bob")
Generates:
SELECT "users".* FROM "users"
WHERE (name = 'bob')
>> userVariable.name
=> Bob

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• >> userVariable = User .where(:name => "Bob")
models/user.rb
class User < ActiveRecord::Base
end

the User class inherits from ActiveRecord::Base

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• >> userVariable = User. where(:name => "Bob")
where is the method that looks in the database
AutoMagically in the User Table (if you made one)

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RESTful
REpresentational State Transfer
• The state of the message matters
• Diﬀerent state = diﬀerent message

“You Again?” “You Again?”
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RESTful
• Servers don’t care about smiles
• They do care about how you access them
• (HTTP Methods)
• GET
• PUT
• POST
• DELETE

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RESTful
• Rails Maps Actions to HTTP Methods
• GET - index, show, new
• PUT - update
• POST - create
• DELETE - destroy

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Work Environment
• Version Control - Keep your code safe
• RubyGems - Use other’s code
• Bundler - Manage Dependencies
• RVM - Keep your system clean
• Tests - make sure it works

@Schneems

Version Control
• my_last_update_1.rb
• my_realy_last_update_2.rb
• really_the_good_code_last_ﬁnal_new.rb

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Version Control
• Make note of whats diﬀerent
• See changes over time
• revert back to known state
• work with a team

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Version Control
• Git (recommended)
• SVN
• Mecurial
• Perforce
• Many More

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Github

http://github.com

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RubyGems
• Gems
• External code “packages”
• Rubygems Manages these “packages”
gem install keytar
irb
>> require “rubygems”
=> true
>> require “keytar”
=> true
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Bundler
• Install
gem install bundler

• Gemﬁles
• specify dependencies
source :rubygems

gem 'rails', '3.0.4'
gem 'unicorn', '3.5.0'
gem 'keytar'

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Bundler
• Install
bundle install

• installs all gems listed in gemﬁle
• very useful managing across systems

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RVM
• Ruby Version Manager
• Clean Sandbox for each project
rvm use ruby-1.8.7-p302

rvm use ruby-1.9.2-p180

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RVM
• Use fresh gemset for each project
rvm gemset use gowalla

• Switch projects...switch gemsets
rvm gemset use keytar

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Testing
• Does your code 6 months ago work?
• What did it do again?
• Manual Versus Programatic
• Save Time in the long road by
progamatic Testing

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Testing
• Test framework built into Rails
• Swap in other frame works
• Use Continuous Integration (CI)
• All tests green
• When your(neverapp breaks, write a
test for it
web
again)

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IDE
• Mac: Textmate
• Windows: Notepad ++
• Eclipse & Aptana RadRails

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Recap
• Rails
• Framework
• Convention over Conﬁguration
• Ruby
• Expressive Scripting language

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Questions?

@Schneems

Rails 3 Beginner to Builder 2011 Week 1

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