Ruby on Rails - Sharing Session for Singapore PHP User Group

Ruby on Rails

Chew Choon Keat <sharedcopy.com>9th April 2008 @ Singapore Management University

Sharing Session for Singapore PHP User Group

Background

• Chew Choon Keat @ blog.choonkeat.com

• Various startups & IT shops doing webapps

• Somehow almost always relates to mobile stuff, e.g. SMS, MMS, WAP,...

• J2EE shop

• 2004: Hello Rails

• RssFwd.com project

• SharedCopy.com

Ruby on Rails• Ruby Web Framework based on MVC

“optimized for programmer happiness and sustainable productivity”

Ruby on Railsamazon.com

BBCCapGemini

BPNCiscoC|Net

EA (Electronic Arts)IBM

JP MorganNASAOakleyOracleSiemens

ThoughtWorksYahoo!

http://blog.obiefernandez.com/content/2008/03/big-name-compan.html



Ruby Web Framework based on MVC

• A Programming Language

• Does it matter?

• What language do you use when talking to your [____________] ?

• Ever read a EULA before?

• Domain Specific Language

• Big words. Somebody else need it.

• Jargons e.g. “Google it!”

• Writing programs down to the language?

• Build the language up?

• Article belongs_to :author

• Author has_many :articles


• You could

• echo “HTTP/1.0 200 OK\r\nContent-Type: text/html\r\nContent-Length: 100\r\n\r\n<html>...”

• Or use a framework

• render “index.html”

• Common vs Exceptions


http://flickr.com/photos/kervinchong/6074454/

http://flickr.com/photos/qousqous/4682900/





• Model

• View

• Controller


http://flickr.com/photos/kodama/8050629/

http://flickr.com/photos/brutalworks/136746095/





• Structure that helps you to build GUI apps


http://flickr.com/photos/lincolnian/120277776/

http://flickr.com/photos/pulpolux/1579275746/

http://flickr.com/photos/justusthane/1252907196/







http://localhost:3000/articles

app/models/article.rbM

app/views/articles/index.html.erbV

app/controllers/articles_controller.rbC

Result






app/controllers/articles_controller.rbCGet “Articles” to fetch data from DB

Result






app/controllers/articles_controller.rbCPass @articles data to render

Result






app/controllers/articles_controller.rbC

Result

Rendered HTML goes back to browser



Formshttp://localhost:3000/articles/new

http://localhost:3000/articles/new


Formsapp/views/articles/new.html.erb http://localhost:3000/articles/new



Forms

Submitted values is accessible via “params”

Forms

Submitted values is accessible via “params”

app/controllers/articles_controller.rb

• Options

• All the options, all the time

• You may like to go... Left? Right?

• Left? Right?

• Right?

Configuration

http://flickr.com/photos/zzathras777/1477996488/



• Accept that not all roads are equal

• Common case; 80/20 Rule

• Culture that values conventions

• Development process highway

• Understand somebody else’s project

• Maintenance - when does it start?

Convention

Version Control

• Do you version control your source code?

Version Control


Who?

Version Control


What?

Who?

Version Control


What?

Who?

When?

Version Control


What?

Who?

When?

Where?

Version Control


Why?What?

Who?

When?

Where?

Version Control

• Do you version control database schema?

Version Control


idemail

User

Version Control


idemail

Useridfirst_namelast_nameemailcreated_at

User

ALTER TABLE user .... ;

Version Control


idemail


Useridnameemailcreated_atupdated_at

User

ALTER TABLE user .... ;ALTER TABLE user .... ;

Version Control


idemail


Useridnameemailcreated_atupdated_at

Useridfullnameemailcreated_atupdated_at

User

ALTER TABLE user .... ;ALTER TABLE user .... ;ALTER TABLE user .... ;

Version Control


001_create_user002_add_names_columns

003_combine_name_columns004_rename_fullname

rake db:migrate:down

rake db:migrate

Version Control

• Do you version control deployments?

Version Control


http://flickr.com/photos/ztephen/239387292/

myfacester.com v1laptop

mysqldump < schema.sql



Version Control


myfacester.com v2laptop


backup.tar?

mysqldump < alter_table.sql



Version Control


laptop


myfacester.com v2.1

/tmp/monday.tar.gz?

backup.tar?

mysqldump < alter_table2.1.sql



Version Control


laptopmyfacester.com v2.1

/tmp/monday.tar.gz?

backup.tar?

mysqldump < alter_table2.1.sql

What if there’s a problem?

Version Control


laptopmyfacester.com

svn.myfacester.com

source version control, remember?

Version Control



cap deploy

svn.myfacester.com

http://flickr.com/photos/bods/485081783/



Version Control



svn.myfacester.com

rake db:migrateschema version control, remember?

Version Control



svn.myfacester.com

Version Control



cap deploy

svn.myfacester.com




Version Control



svn.myfacester.com

rake db:migrate

Version Control



svn.myfacester.com

Version Control



cap deploy

svn.myfacester.com




Version Control



svn.myfacester.com

rake db:migrate

Version Control



svn.myfacester.com

rake db:migrate:down

cap rollback




• “Make it work, make it right, make it fast”

• scaffolding - get it working

• Learn as you go.

• add_column vs SQL

• form_for vs HTML

• ./script/server vs Capistrano

Learning the Framework

• Object Oriented

• Message Passing

• Dynamically typed

• Duck typing

• Open classes

http://www.ruby-lang.org/

http://www.ruby-lang.org

http://www.ruby-lang.org

Ruby System

http://flickr.com/photos/31637055@N00/449968042/

Programmer Craftsman



Ruby System

ruby





Ruby System

ruby



rubygems



Ruby Systemrubyforge.org (gem_server)

ruby



rubygems




rails

rfacebook

mongrelruby

rakeactionmaileractionpackactiverecordactiveresourceactivesupport



rubygems




rails

rfacebook

mongrelruby


Ruby app (*.rb)#!/bin/rubyrequire “mongrel”


Programmer CraftsmanRuby app (*.rb)#!/bin/rubyrequire “rubygems”require “mongrel”

rubygems




rubygems

rails

rfacebook

mongrelruby


Ruby app (*.rb)#!/bin/rubyrequire “rubygems”require “mongrel”




Happy User





Object Oriented

Object Oriented

Closures

Closures

Closures

Closures

http://martinfowler.com/bliki/Closure.html

Closures



Common Usage

Mixins

Mixins

Mixins

Mixins

Meta-Programming

• Write less dumb code

• What does your software already know?

Meta-Programming

• Write less dumb code

• What does your software already know?

Builder

Builder

Exercise

• Project contains image-processing code

• One day, you learn about “orientation”

• How do you update your app?

Edit > Find & Replace

img = Image.load(“photo.jpg”)img = my_new_load(“photo.jpg”)

Aliasing Methods

• Affords the confidence to march forward

• without falling down subsequently

• Less needy to overly protect design with more layers upfront

Personal Benefits

Links

• http://www.ruby-lang.org/en/

• http://rubyonrails.org/

• http://rubini.us/

• http://sharedcopy.com/

http://www.ruby-lang.org/en/

http://www.ruby-lang.org/en/

http://rubyonrails.org

http://rubyonrails.org

http://rubini.us

http://rubini.us

http://sharedcopy.com

http://sharedcopy.com

The End

Ruby on Rails - Sharing Session for Singapore PHP User Group

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