before-filters.rb

# example 1

class WidgetsController < ApplicationController

  before_filter :filter_1, :only => [:action_1, :action_2]
  before_filter :filter_2, :only => [:action_2, :action_3]
  before_filter :filter_3, :only => [:action_1, :action_3]

  def action_1
    # code
  end

  def action_2
    # code
  end

  def action_3
    # code
  end

end

# example 2

class WidgetsController < ApplicationController

  def action_1
    filter_1
    filter_3
    # code
  end

  def action_2
    filter_1
    filter_2
    # code
  end

  def action_3
    filter_2
    filter_3
    # code
  end

end

# example 3

class WidgetsController < ApplicationController

  before_filters :filter_1, :filter_3
  def action_1
    # code
  end

  before_filters :filter_1, :filter_2
  def action_2
    # code
  end

  before_filters :filter_2, :filter_3
  def action_3
    # code
  end

end