What’s new in Rails 2.1?
Keith Pitty
Sydney Rails Meetup
11 June 2008

over 1,400 contributors

more than 1,600 patches

Major features
• Time zones
• Dirty tracking
• Gem dependencies
• Named scope
• UTC-based migrations
• Better caching

New!
Time zones
courtesy of Geoff Busing

$ rake -T time
(in /Users/keithpitty/work/rails2.1demo)
rake time:zones:all # Displays names of all time zones recognized by the...
rake time:zones:local # Displays names of time zones recognized by the Rai...
rake time:zones:us # Displays names of US time zones recognized by the ...

$ rake time:zones:local
* UTC +10:00 *
Brisbane
Canberra
Guam
Hobart
Melbourne
Port Moresby
Sydney
Vladivostok

# config/environment.rb
config.time_zone = 'Sydney'

Times now stored in UTC in the db
but displayed using the default time zone

Warning!
If upgrading, times will need to be converted to UTC

Example
Add time zone support to users

Add time_zone to User model

Add time_zone_select to signup view

<h1>Sign up as a new user</h1>
<% @user.password = @user.password_confirmation = nil %>
<%= error_messages_for :user %>
<% form_for :user, :url => users_path do |f| -%>
<p><label for=\"login\">Login</label><br/>
<%= f.text_field :login %></p>
<p><label for=\"email\">Email</label><br/>
<%= f.text_field :email %></p>
<p><label for=\"password\">Password</label><br/>
<%= f.password_field :password %></p>
<p><label for=\"password_confirmation\">Confirm Password</
label><br/>
<%= f.password_field :password_confirmation %></p>
<p><label for=\"time_zone\">Time zone</label><br/>
<%= f.time_zone_select :time_zone, TimeZone.all %>
<p><%= submit_tag 'Sign up' %></p>
<% end -%>

Use before_filter to set time zone
in ApplicationController

class ApplicationController < ActionController::Base
helper :all
protect_from_forgery
include AuthenticatedSystem
before_filter :set_user_time_zone
private
def set_user_time_zone
Time.zone = current_user.time_zone if logged_in?
end
end

New!
Dirty tracking

$ ./script/console
Loading development environment (Rails 2.1.0)
>> Beer.find :first
=> #<Beer id: 1, name: \"Coopers Sparkling Ale\", created_at: \"2008-06-05 11:31:55\",
updated_at: \"2008-06-05 11:31:55\">
>> b.changed?
=> false
>> b.name = \"Coopers Pale Ale\"
=> \"Coopers Pale Ale\"
>> b.changed?
=> true
>> b.changed
=> [\"name\"]
>> b.name_changed?
=> true
>> b.name_was
=> \"Coopers Sparkling Ale\"
>> b.changes
=> {\"name\"=>[\"Coopers Sparkling Ale\", \"Coopers Pale Ale\"]}
>> b.save
=> true
>> b.changed?
=> false

Partial updates by default in new Rails 2.1 apps

SQL (0.000138) BEGIN
Beer Update (0.000304) UPDATE `beers` SET `updated_at` =
'2008-06-05 11:38:01', `name` = 'Coopers Pale Ale' WHERE
`id` = 1
SQL (0.005019) COMMIT

Warning!
Updates via other than attr= writer

>> b.name_will_change!
=> \"Coopers Pale Ale\"
>> b.name.upcase!
=> \"COOPERS PALE ALE\"
>> b.name_change
=> [\"Coopers Pale Ale\", \"COOPERS PALE ALE\"]

New!
Gem Dependencies

$ rake -T gem
(in /Users/keithpitty/work/rails2.1demo)
rake gems # List the gems that this rails application ...
rake gems:build # Build any native extensions for unpacked gems
rake gems:install # Installs all required gems for this applic...
rake gems:unpack # Unpacks the specified gem into vendor/gems.
rake gems:unpack:dependencies # Unpacks the specified gems and its depende...
rake rails:freeze:gems # Lock this application to the current gems ...

# environment.rb
# Bootstrap the Rails environment, frameworks, and default configuration
require File.join(File.dirname(__FILE__), 'boot')
Rails::Initializer.run do |config|
config.time_zone = 'Sydney'
config.action_controller.session = {
:session_key => '_rails2.1demo_session',
:secret =>
'f4a5c1596f8fff01033b7417629c47fb6344748864b8f3a25fc6884b1ea41d214642f8eba01aa274ef9d128
1fc6cdc23bc33ea57ac66878a7b1164b96d875343'
}
config.gem \"hpricot\", :version => '0.6', :source => \"http://code.whytheluckystiff.net\"
config.gem \"aws-s3\", :lib => \"aws/s3\"
end

$ rake gems
(in /Users/keithpitty/work/rails2.1demo)
[I] hpricot = 0.6
[ ] aws-s3
I = Installed
F = Frozen

$ rake gems:install

$ rake gems:unpack

$ rake gems:unpack GEM=hpricot

$ rake gems:unpack:dependencies

$ rake gems:build

# test.rb
config.gem \"mocha\"

$ rake gems RAILS_ENV='test'
(in /Users/keithpitty/work/rails2.1demo)
[I] hpricot = 0.6
[ ] aws-s3
[ ] mocha
I = Installed
F = Frozen

New!
Named scope
courtesy of Nick Kallen

class Beer < ActiveRecord::Base
named_scope :available, :conditions => {:available => true}
named_scope :unavailable, :conditions => {:available => false}
named_scope :heavy, :conditions => {:full_strength => true}
named_scope :light, :conditions => {:full_strength => false}
named_scope :cats_piss, :conditions => {:rating => 0..3}
named_scope :drinkable, :conditions => ['rating > 3']
named_scope :minimum_rating,
lambda { |min_rating| { :conditions =>
['rating >= ?', min_rating] } }
named_scope :rated,
lambda { |rating| { :conditions =>
['rating = ?', rating] } }
named_scope :awesome,
lambda { |*args| { :conditions =>
['rating >= ?', (args.first || 9)] } }
end

>> Beer.count
=> 15
>> Beer.available.count
=> 9
>> Beer.heavy.available.count
=> 8
>> Beer.heavy.available.drinkable.count
=> 6
>> Beer.heavy.available.minimum_rating(7).count
=> 5
>> Beer.heavy.available.awesome.count
=> 3
>> Beer.heavy.available.awesome(10).count
=> 1

>> Beer.heavy.available.awesome(10)
=> [#<Beer id: 888319404, name: \"Coopers Sparkling Ale\",
brewer: \"Coopers\", rating: 10, available: true,
full_strength: true, created_at: \"2008-06-08 07:13:17\",
updated_at: \"2008-06-08 07:13:17\">]

>> Beer.rated(0)
=> [#<Beer id: 177722761, name: \"Fosters Lager\",
brewer: \"Fosters\", rating: 0, available: false,
full_strength: true, created_at: \"2008-06-08
07:13:17\", updated_at: \"2008-06-08 07:13:17\">]

Also: named scope extensions, anonymous scopes

New!
UTC-based migrations

Migration prefix no longer simply sequential

Migration prefix now uses UTC timestamp

mysql> select * from schema_migrations;
+----------------+
| version |
+----------------+
| 20080604194357 |
| 20080604195453 |
| 20080605112923 |
+----------------+
3 rows in set (0.00 sec)

Especially helpful for teams (avoids most conflicts)

Also helpful when working on branches

Migrations are applied intelligently

Also: change_table method introduced to migrations

New!
Better caching

Specify preferred caching engine in environment.rb

# Following options supplied in Rails 2.1:
ActionController::Base.cache_store = memory_store
ActionController::Base.cache_store = file_store, \"path/to/cache/directory\"
ActionController::Base.cache_store = drb_store, \"druby://localhost:9192\"
ActionController::Base.cache_store = mem_cache_store, \"localhost\"

Or subclass ActiveSupport::Cache::Store
and implement read, write, delete and delete_matched methods

New!
A few other tidbits

rake rails:freeze:edge RELEASE=1.2.0

script/plugin install
supports
-e for svn export
and plugins hosted in Git repositories

script/dbconsole

>> \" A string full of white spaces \".squish
=> \"A string full of white spaces\"

Resources
• http://weblog.rubyonrails.com/2008/6/1/rails-2-1-time-zones-
dirty-caching-gem-dependencies-caching-etc
• Ryan Bates’ Railscasts
• Ryan Daigle’s feature introductions
• Ruby on Rails 2.1: What’s New? by Carlos Brando

Thanks for listening
http://keithpitty.com