SpreadsheetTagService.rb

class SpreadsheetTagService 
  include Roo
 
  def initialize(uploaded_file)
    @spreadsheet = open_spreadsheet(uploaded_file)
    do_stuff
  end 
 
  private 
    def do_stuff
      # assuming that all the different classes have the same interface you're planning to use
      @spreadsheet.each_with_pagename do |name,sheet|    
        Rails.logger.debug( sheet )
      end    
    end
 
    def open_spreadsheet(file)
      case File.extname(file.path)
        when ".csv" then Csv.new(file.path, nil, :ignore)
        when ".xls" then Excel.new(file.path, nil, :ignore)
        when ".xlsx" then Excelx.new(file.path, nil, :ignore)
        else raise "Unknown file type: #{file.original_filename}"
      end
    end
end