Quick and dirty dot file for ActiveRecord models

dot.rake

# Quick and dirty dot file for ActiveRecord models

namespace :dot do
  task :load_models => :environment do
    Dir.glob("#{RAILS_ROOT}/app/models/**/*rb").each{|p| require p}
  end
  
  desc 'Generates a dot file of the models'
  task :models => :load_models do
    models = Object.subclasses_of ActiveRecord::Base
    open("#{RAILS_ROOT}/models.dot",'w') do |io|
      io << "digraph Models{"
      io << "node;"
      models.each do |model|
        name = model.to_s.gsub('::','')
        io << "#{format_model name,model}\n"
        model.reflect_on_all_associations.each do |a|
          if a.macro.to_s[/has_/]
            io << "#{name} -> #{a.class_name.gsub('::','')}\n"
          end
        end
      end
      io << "}"
    end
  end
  
  def format_model(name, cls)
    if cls.table_exists?
      n = 0..cls.columns.length
      col_cells = cls.columns.zip(n.to_a).map{|c,i| "<TR><TD align='left'>#{c.name}</TD><TD align='left'>#{c.type}</TD></TR>"}.join(' ')
      %!#{name} [shape=plaintext label=<<TABLE bgcolor="white" border="1" cellborder="1" cellspacing="0"><TR><TD bgcolor="#cccccc" COLSPAN="2">#{name}</TD></TR>#{col_cells}</TABLE>>]!
    else
      "#{name} [style=\"dashed\"]"
    end
  end
end