gistfile1.txt

#!/usr/bin/env ruby
## Shows model relationships on the given RoR app.

puts ARGV

Dir.chdir( ARGV.shift || '.' )  do
require 'config/environment'

  finder = 'find app/models -type f -name \*.rb -print0 |xargs -0 -- grep ActiveRecord::Base |sort'

    dot = []
  %x[#{finder}].map do |line|

    line =~ /class (\w+)/
    model = Object.const_get $1		# get the class from string
      puts "#{model}"
    relation_shown = nil

    o = []
  model.reflect_on_all_associations. each do |assoc|
      next unless assoc.options[:through].nil?   # a :through relation will have the :has_many elsewhere.

      related = (
          assoc.options[:class_name] ||     # if :class_name is specified in the assoc
          assoc.name.to_s.classify        # else use assoc name as class_name
      )
      # This model relates to the related model, by :macro ( belongs_to, has_many ... )
      o << "    #{assoc.macro} #{related}"
      relation_shown = true

      dot << "#{model}  -> #{related}  \n" ## if assoc.macro == 'has_many'  #//[label=#{assoc.macro}]\n"
    end
      o << "    (no relations)"  if relation_shown.nil?
      puts o.sort.uniq
  end


  IO.popen('dot -Tpng -omodels.png', 'w') do |io|
    io.write <<__DOT
digraph x {
    node [ shape=box, color=gray, fontname="Sans", fontsize=10 ]
    edge [ color=gray, arrowhead=none ]
#{dot}
}
__DOT
  end

end