rails 3 beginner to builder 2011 week 6

June, 2011

Beginner to BuilderWeek 6

Wednesday, July 20, 2011

@Schneems

Rails - Week 6• Email in Rails

• Background Tasks

• modules

• Observers & Callbacks

• Internationalization & Localization

• I18n & L10n


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Email in Rails• What is Email?

• Why Use Email?

• How does Rails use email?


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What is Email• Communications medium defined by RFC standards

✦ RFC = Request for Comments

✦ Comprised of Header & Body

✦ Header (to, from, reply-to, content-type, subject, cc, etc.)

✦ Body (message and attachments)


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Email- Content Types• Defines How the Mail User Agent (MUA) Interprets Body

✦ Text/HTML

✦ Text/Plain

✦ Multipart/Related (Example: Inline Pictures)

✦ Multipart/Alternative

✦ Send Text/HTML with Text/Plain as backup

✦ Add Attachments


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Why use Email with Rails?

• Status Updates ( Twitter, Facebook, Etc. )

• Direct to Consumer Marketing source

• Added functionality (lost passwords, etc.)

• Send documents

• Everyone has it, and

• Everyone can use it


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How Does RoR Send Email?•Low Volume

• use Gmail

•High Volume

• use a re-mailer

• Build your own

Mail Server

Your Computer

d

Operating System

MTA

PostfixSMTP

(Sends Emails)

CourierIMAP/POP

Their Computer


• ActionMailer

• Mail Gem

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rails generate mailer Notifier

How Does RoR Send

/app/mailers/notifier.rb


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Email With Rails

Notifier.signup_notification(“[email protected]”).deliver


mailto:[email protected]


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Email With Rails

• Default Mailer Settings

• In-Line Attachments

• mail( ) method





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Email With Rails


✦Using Gmail✦ Use Port 587✦ Gmail will throttle large

number of email requests✦ Close to real life conditions✦ Relatively Easy✦ Don’t use with automated

testing

config/environments/development.rb




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Email re-cap✦ Receiving Email much harder

✦ Also less common✦ Test your Mailer using an Interceptor✦ use a re-mailer in production✦ real life application: http://whyspam.me

✦ No longer running


http://whyspam.me

http://whyspam.me

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Background Tasks• What is a background task?

• Why use one?

• Where do i put my task in rails?

• How do i keep my task alive?


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Background Task• What is a background task?

• Any server process not initiated by http request

• Commonly run for long periods of time

• Do not block or stop your application

• Clean up server, or application

• Generate reports

• Much more


• rake tasks

• organize code in “lib/tasks”

• run with:

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rake <command> RAILS_ENV=<environment>

Background Task


• Example

• cleanup.rake

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namespace :cleanup do desc "clean out Tickets over 30 days old" task :old_tickets => :environment do tickets = Ticket.find(:all, :conditions => ["created_at < ?", 30.days.ago ], :limit => 5000) tickets.each do |ticket| ticket.delete end endend

Background Task

rake cleanup:old_tickets


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Background Task• What if i don’t want to execute from

command line?

• run task with a automation program

• Cron

• Monit

• God


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Cron• Very reliable unix time scheduler

• Built into the OS

• Executes command line calls

• Smallest interval is 1 minute

• Requires full paths


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Monit• Not installed on OS by default

• Monitors and Executes (cron only executes)

• Extra functionality - Sysadmin emails etc...


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God • Written in ruby

• Very configurable

• can be memory intensive in some applications

sudo gem install god


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Background • More Options

• Workling/Starling

• Backgroundrb

• ResQue


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Modules (ruby)• Add “Mixins” to your code

• Keep code seperate with different namespaces

• put them in your rails project under /lib


• Example Mixin:

• include adds instance methods

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class Dog

include AntiCheating

end

Modules (ruby)

module AntiCheating

def drug_test

...

end

end

puppy = Dog.new

puppy.drug_test

>> Passed


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Modules (ruby)• Example Mixin 2:

class Dog


end

module AntiCheating

def self.cleanup(level)

...

end

end

dirtyDog = Dog.new

dirtyDog.cleanup

>> No Method Error


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module AntiCheating


...

end

end

AntiCheating.cleanup

>> Very Clean


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• extend adds all module methodsclass Dog

extend AntiCheating

end

module AntiCheating


...

end

end

dirtyDog = Dog.new

dirtyDog.cleanup(2)

>> “Kinda Clean”


• Extra Credit:

• class << self

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class Dog

class << self

def sniff

...

end

end

end

Modules (ruby)

==

class Dog

def self.sniff

...

end

end


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Modules (ruby)• Extra Credit:

• class << self

class Dog

class << self


end

end

module AntiCheating


...

end

end

dirtyDog = Dog.new

dirtyDog.cleanup(10)

>> “Really Clean”


• Example Namespace

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module FastDogs

class Dog

...

end

end

Modules (ruby)

module SlowDogs

class Dog

...

end

end

lassie = FastDogs::Dog.new droopy = SlowDogs::Dog.new


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Callbacks and Observers• Callbacks

• Non-polling event based method

• hooks into lifecycle of Active Record object

• Observers

• Implement trigger behavior for class outside of the original class


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• Polling

• “Are We there Yet”

• Callback

• “I’ll tell you when we’re there”

Callbacks


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Callbacks in Railssave(-) valid(1) before_validation(2) before_validation_on_create(-) validate(-) validate_on_create(3) after_validation(4) after_validation_on_create(5) before_save(6) before_create(-) create(7) after_create(8) after_save

• Lifecycle Hooks =>


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class Topic < ActiveRecord::Base

before_destroy :delete_parents

def delete_parents

self.class.delete_all "parent_id = #{id}"

end

end

end

Callbacks in Rails• Example

• before_destroy


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Observers• Add callback functionality without polluting the

model

• Will run after every new user instance is created

• Keeps your code clean(er)


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Source: @mattt

i18n & L10n


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Source: @mattt

Source: @mattt

language configuration


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fr.yml

ja.yml

Multiple Language Files


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It Worked!


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What about L10n


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Questions?

http://guides.rubyonrails.orghttp://stackoverflow.com

http://peepcode.com


http://stackoverflow.com




rails 3 beginner to builder 2011 week 6

Education