gistfile1.rb

  # GET /user/1/time_spent
  def time_spent
    @time_spent = @user.time_spent
    
    respond_to do |format|
      format.xml  { render :xml => @time_spent.to_xml }
      format.json { render :json => @time_spent.to_json }
      format.png { send_data(Spark.plot( @time_spent, :has_min => true, :has_max => true, 'has_last' => 'true', 'height' => '30', :step => 10 ), :type => 'image/png',
                    :filename => "#{@user.login}_time_spent.png",
                    :disposition => 'inline') }
    end
  end