Experiment in pagination that defaults to the last page

paginate_in_reverse.rb

ActiveRecord::Base.class_eval do
  def self.paginate_in_reverse(options = {})
    unless options[:page]
      # we only default to the last page if no explicit page has been given
      total_entries = self.count(:conditions => options[:conditions])
      # calculate the last page
      total_pages = (total_entries / self.per_page.to_f).ceil
      # update the options hash to hold this information
      options = options.merge(:page => total_pages, :total_entries => total_entries)
    end
    
    # do the usual stuff
    self.paginate(options)
  end
end

# example usage:

User.paginate_in_reverse :page => params[:page],
  :conditions => 'name IS NOT NULL', :order => 'created_at DESC'

  # now if params[:page] is nil (there's no explicit page), this will default to
  # the last page in the collection instead of page 1