The Flog score of your Rails ERB templates.

contemplative.rb

require 'action_view'
require 'ostruct'
require 'erb'
require 'flog'
require 'ruby_parser'
require 'sexp_processor'

ERBHandler = ActionView::Template::Handlers::ERB.new

def new_template(body, details={format: :html})
  ActionView::Template.new(body, "irrelevant", details.fetch(:handler) {ERBHandler}, details)
end

def sort_by_combined_score(totals)
  totals.sort do |a, b|
    b[1].values.inject(&:+) <=> a[1].values.inject(&:+)
  end
end

if $0 == __FILE__
  src_dir = ARGV[0]
  raise ArgumentError, "Supply a path containing ERB templates" unless src_dir

  puts "Contemplating ERB templates from: #{src_dir}"

  erb_files = Dir.glob(File.join(src_dir, "**/*.erb"))

  totals = erb_files.inject({}) do |totals, file|
    erb_source = File.read(file)
    ruby_source = ERBHandler.call(new_template(erb_source))
    sexp_parsed = RubyParser.new.parse(ruby_source)

    flog = Flog.new
    flog.process(sexp_parsed)

    totals[file] = flog.totals
    totals
  end

  sort_by_combined_score(totals).each do |filename, totals|
    puts "#{filename} : #{totals}"
  end

end

Run it like this:
ruby contemplative.rb /path/to/your/rails/app/

Get output like this (templates sorted by Flog score):

foo/app/views/walruses/edit.html.erb : {"main#none"=>54.5979853108153, "some#method"=>7.593418202627854}
foo/app/views/walruses/new.html.erb : {"main#none"=>26.214690537940754}
foo/app/views/walruses/about.html.erb : {"main#none"=>3.830143600441112}

Keep in mind that templates can have multiple extension.

The order of these preprocessors is important. For example, if you called your JavaScript file app/assets/javascripts/projects.js.erb.coffee then it would be processed with the CoffeeScript interpreter first, which wouldn’t understand ERB and therefore you would run into problems.

Thanks for this. With the latest version of flog you need to call flog.calculate_total_scores before calling flog.totals. See here: http://docs.seattlerb.org/flog/Flog.html#method-i-calculate_total_scores

I've add the line in the fork here: https://gist.github.com/benjaminwood/9744892

Anybody know how to get the ruby source from a haml file? I've spent a bit of time on this already but couldn't figure it out. It'd be cool to run this against ERB and then again after converting to HAML and refactoring.