Support undigested assets in Rails 4.2

precompile.rake

task 'assets:precompile' => 'environment' do
  # See https://github.com/rails/sprockets-rails/issues/49
  #
  # Sprockets no longer creates undigested assets, so we have to
  # emulate the old behavior to keep vendored JS libraries happy
  #
  # For the record,
  # Digested: 4-star-de4f1f10cb13e222111c8afe0b516131.jpg
  # Undigested: 4-star.jpg

  digest = /(-{1}[a-z0-9]{64}*\.{1}){1}/
  assets = Dir.glob File.join Rails.root, 'public/assets/**/*'
  assets.each do |file|
    next if File.directory?(file) || file !~ digest
    next if File.extname(file) == '.json' # Avoid duplicate manifest

    source = file.split '/'
    source.push source.pop.gsub digest, '.'

    FileUtils.cp file, File.join(source)
  end
end