What's New in Rails 4.2

A brief overview of new features in Ruby on Rails 4.2

Presented at Austin on Rails on October 28, 2014

Transcript

1. What's New In
   Rails 4.2
   Anthony Lewis
   

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2. @AnthonyLewis
   Best known for my hit single “Candy Rain”
   

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3. @AnthonyLewis
   Also, wrote a book…
   

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4. Rails 4.2
   • Active Job
   • Action Mailer
   • Global ID
   • Adequate Record
   • Web Console
   • Other Changes
   • Installation
   • Release Notes
   

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5. Active Job
   • Framework for background processing using
   Resque, Delayed Job, Sidekiq, etc.
   • Switch between background runners without
   having to rewrite jobs
   • If no adapter is specified, jobs run immediately
   

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6. Configuration
   • Add your preferred background processing library
   to your application’s Gemfile:
   • Update Rails configuration:
   gem 'sidekiq'
   config.active_job.queue_adapter = :sidekiq
   

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7. Creating Jobs
   • Use the Rails generator to create a new job:
   $ bin/rail g job process_video
   create app/jobs/process_video_job.rb
   

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8. Job Source
   • The newly created job:
   class ProcessVideoJob < ActiveJob::Base
   queue_as :default
   def perform(*args)
   # Do something later
   end
   end
   

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9. Enqueue Job
   • Enqueue with or without a time:
   # Run next
   ProcessVideo.perform_later(@video)
   # Run tomorrow
   ProcessVideo.set(wait: 1.day)
   .perform_later(@video)
   

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10. Error Handling
    • Catch exceptions with a block:
    class ProcessVideoJob < ActiveJob::Base
    ...
    rescue_from(Exception) do |e|
    # do something with exception
    end
    end
    

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11. Action Mailer
    • ActionMailer now uses ActiveJob to send email
    • Call deliver_now to send a message inline
    # Send inline
    UserMailer.success_email(@user)
    .deliver_now
    

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12. Action Mailer
    • Call deliver_later to enqueue delivery
    • Accepts :wait, :wait_until, and :queue options
    # Enqueue and send later
    UserMailer.success_email(@user)
    .deliver_later
    

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13. Global ID
    • A unique identifier for a model instance
    • ActiveJob uses Global ID to automatically serialize
    and deserialize objects
    irb> video.to_global_id.to_s
    => "gid://appname/Video/1"
    

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14. Adequate Record
    • Optimizations to Active Record that make the find,
    find_by_*, and find_by methods up to 2x faster
    • Caches the static parts of the SQL query
    User.find(1)
    # Caches the static part:
    # SELECT * FROM users WHERE id = ?
    User.find(2)
    # Uses the cache, executes faster
    

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15. Web Console
    • Debugging tool for your Rails app
    • Automatically opens a Rails console on exceptions
    • Can also be opened with the console view helper
    <%= console %>
    

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17. Other Changes
    • Previously deprecated functionality has been
    removed
    • Check for deprecation warnings before updating
    • The respond_with / class-level respond_to methods
    have been moved to the responders gem
    • The default host for rails server is now localhost
    instead of 0.0.0.0
    • If you dev in a virtual machine this will bite you
    

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18. Other Changes
    • The default log level for production is now :debug,
    just like development and test
    • The HTML sanitizer has been replaced with a new
    version.
    • Some sanitized output might change
    • Foreign key support (finally)
    • And more…
    

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19. Release Notes
    • The work-in-progress release notes are online:
    http://edgeguides.rubyonrails.org/4_2_release_notes.html
    

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20. Installation
    # In your terminal:
    $ gem install rails --pre
    # In your Gemfile:
    gem 'rails', '~> 4.2.0.beta2'
    

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21. Questions?
    

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22. Thank You!
    

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