You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tag_controller.rb
    path of file: ./repos/moebooru/app/controllers
    
    the code of the file until where you have to start completion: class TagController < ApplicationController
  layout "default"
  before_action :mod_only, only: [ :mass_edit, :edit_preview ]
    
  def summary
    if params[:version]
      # HTTP caching is unreliable for XHR.  If a version is supplied, and the version
      # hasn't changed since then, return an empty response.
      version = Tag.get_summary_version
      if params[:version].to_i == version
        render json: { version: version, unchanged: true }
        return
      end