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Notes for Rails Meetup - Jan 2013

Rerun/Reload app

• hot-key
• hook on save
• watch
• Rack::Reloader
• guard/autotest/shotgun/etc

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Rails.application.config.database_configuration
Rails.application.load_generators
Rails.application.load_seed
Rails.application.paths['db/migrate'].to_a
Rails.application.railties.all
Rails::Engine.find(ENGINE_PATH)
Rails.env
Rails.env.development?
Rails::Generators::SessionMigrationGenerator.start [ ENV['MIGRATION'] || 'add_sessions_table' ]
Rails.root

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Nice gems

• racksh - console for Rack apps, like rails c or merb -i

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def empty?(s)
  return s.size == 0
end


class B
  def ==(s)
    "not boolean"
  end
end

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-[ ] one

-[ ] two

-[ ] three

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require 'open3'

Open3.popen2e("wget", "http://dumps.wikimedia.org/ruwiki/latest/ruwiki-latest-templatelinks.sql.gz", "-O wiki.sql.gz") do |i, oe, wait_thr|
  oe.each do |line|
    puts line[/\d+%/]
  end
end

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I often use VCR gem. And I always configure it to use rspec metadata to turn it on with just :vcr symbol.

When I know that some module will always hit the external service, I turn VCR on at the very top describe.

describe "Something", :vcr do
  it "should make coffee" do
  end

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Once I've got a task to make a lot of files stored on S3 private. In my project I used carrierwave and fog.
All files were public by default.

In order not to make many requests to AWS, I've decided to change bucket policy instead of ACL of each file.

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Processor: Intel Core i3

time ./m_ffmpeg.sh dinner.m4v
./m_ffmpeg.sh dinner.m4v 48,54s user 5,34s system 142% cpu 37,897 total

time ./m_thumbnailer.sh dinner.m4v ./m_thumbnailer.sh dinner.m4v 66,21s user 5,61s system 156% cpu 45,918 total

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require 'active_support/testing/time_helpers'

RSpec.configure do |config|
  config.include ActiveSupport::Testing::TimeHelpers

  config.after do
    travel_back
    Timecop.return
  end