Ruby on Rails 2.2: What's New, Release History & Support Lifecycle

What Is New in Ruby on Rails 2.2

How does Rails 2.2 make internationalization easier?

Rails 2.2 ships with a first-class i18n framework that lets you store translations in YAML files and use the I18n.t helper throughout your app.

• All model error messages are now pulled from the i18n locale files.
• Helpers such as link_to and form_for automatically look up labels.
• Deprecated interpolation syntax (%s, %d) forces you to adopt the newer %{key} style.

In practice you add a config.i18n.default_locale = :de line to config/application.rb and place de.yml under config/locales.

What thread-safety and connection-pooling options does Rails 2.2 add?

Rails 2.2 introduces a production-ready thread-safe mode and configurable database connection pools.

# Enable thread-safe mode in production
config.threadsafe!

# Example pool configuration (config/database.yml)
development:
  adapter: mysql
  username: root
  database: sample_development
  pool: 10
  wait_timeout: 10

• Thread-safe mode reduces memory pressure by sharing a single Rails instance across threads.
• Connection pools grow up to the pool size, defaulting to 5, and wait up to wait_timeout seconds for a free slot.
• These settings are essential when deploying behind Puma, Thin, or JRuby servers that use native threads.

Which Active Record enhancements help migrations and joins in Rails 2.2?

Rails 2.2 adds transactional migrations, hash-based join conditions, and new dynamic finders.

# Transactional migration (PostgreSQL)
class AddIndexes < ActiveRecord::Migration
  def self.up
    transaction do
      add_index :users, :email
      add_index :orders, :created_at
    end
  end
end

• All steps inside a migration are wrapped in a DDL transaction; a failure rolls back the whole change.
• Join conditions can now be expressed as hashes, e.g. Product.all(:joins => :photos, :conditions => { :photos => { :copyright => false } }).
• New dynamic finders find_last_by_attribute and find_by_attribute! reduce boilerplate and raise ActiveRecord::RecordNotFound when appropriate.

How have routing and controller features changed in Rails 2.2?

Rails 2.2 refines routing with shallow nesting, method-array routes, and fine-grained resource generation.

# Shallow nesting example
map.resources :publishers, :shallow => true do |publisher|
  publisher.resources :magazines do |magazine|
    magazine.resources :photos
  end
end

# Method array for collection route
map.resources :photos, :collection => { :search => [:get, :post] }

# Restrict generated actions
map.resources :products, :except => :destroy

• Shallow routes eliminate deeply-nested URLs while preserving RESTful semantics.
• Arrays of HTTP verbs let a single route respond to both GET and POST without duplication.
• The :only and :except options cut down on generated routes, saving memory and improving request-dispatch speed.
• Controllers now support stale? and fresh_when helpers for automatic ETag/Last-Modified handling, returning 304 responses when appropriate.