こういうかんじしたくて

kouiukannji.rb

class NyanController < ApplicationController
  def index
    where = {
      :type1 => 1,
      :type2 => 1
    }

    if params[:nyan1].is_a?(String) && /^(?:1|true|TRUE|True|T|t|yes|YES|Yes|Y|y)$/ =~ params[:nyan1]
      where[:type1] = 2
    else
      where[:type2] = 2
    end

    if params[:nyan2].is_a?(String) && /^(?:1|true|TRUE|True|T|t|yes|YES|Yes|Y|y)$/ =~ params[:nyan2]
      where[:type3] = 1
    end

    records = Nyan.where(where).page(params[:page]).per(params[:per_page])

    respond_to do |format|
      format.json {render :json => records}
    end
  end
end