module Pagy::UrlHelpers

def pagy_massage_params(params)

Sub-method called only by #pagy_url_for: here for easy customization of params by overriding 
def pagy_massage_params(params)
  params
end

def pagy_url_for(pagy, page, absolute: nil)

For non-rack environments you can use the standalone extra
It supports all Rack-based frameworks (Sinatra, Padrino, Rails, ...).
Return the URL for the page, relying on the params method and Rack by default. 
def pagy_url_for(pagy, page, absolute: nil)
  vars                            = pagy.vars
  params                          = request.GET.merge(vars[:params].transform_keys(&:to_s))
  params[vars[:page_param].to_s]  = page
  params[vars[:items_param].to_s] = vars[:items] if vars[:items_extra]
  query_string = "?#{Rack::Utils.build_nested_query(pagy_massage_params(params))}"
  "#{request.base_url if absolute}#{request.path}#{query_string}#{vars[:fragment]}"
end