Spree - Products per page to be made dynamic

Spree - Products per page to be made dynamic: How to set the product per page to be dynamic? Thanks in Advance

#Products_controller 

module Spree
class ProductsController < Spree::StoreController
before_filter :load_product, :only => :show
before_filter :load_taxon, :only => :index

rescue_from ActiveRecord::RecordNotFound, :with => :render_404
helper 'spree/taxons'

respond_to :html

def index
  @searcher = build_searcher(params)
  @taxonomies = Spree::Taxonomy.includes(root: :children)
  @products = Product.page(params[:page]).per(3)
end

def show
  return unless @product

  @variants = @product.variants_including_master.active(current_currency).includes([:option_values, :images])
  @product_properties = @product.product_properties.includes(:property)
  @taxon = Spree::Taxon.find(params[:taxon_id]) if params[:taxon_id]
end

private
  def accurate_title
    @product ? @product.name : super
  end

  def load_product
    if try_spree_current_user.try(:has_spree_role?, "admin")
      @products = Product.with_deleted
    else
      @products = Product.active(current_currency)
    end
    @product = @products.friendly.find(params[:id])
  end

  def load_taxon
    @taxon = Spree::Taxon.find(params[:taxon]) if params[:taxon].present?
  end
 end
end

Spree - Products per page to be made dynamic

How to set the product per page to be dynamic?

Thanks in Advance