module Pagy::UrlHelpers

def pagy_deprecated_params(pagy, params) # remove in 6.0

remove in 6.0
Transitional code to handle params deprecations. It will be removed in version 6.0 
def pagy_deprecated_params(pagy, params)    # remove in 6.0
  if pagy.params.is_a?(Proc)                # new code
    pagy.params.call(params)
  elsif respond_to?(:pagy_massage_params)   # deprecated code
    Warning.warn '[PAGY WARNING] The pagy_massage_params method has been deprecated and it will be ignored from version 6. ' \
                 'Set the :params variable to a Proc with the same code as the pagy_massage_params method.'
    pagy_massage_params(params)
  else
    params                                  # no massage params
  end
end

def pagy_url_for(pagy, page, absolute: false, html_escaped: false)

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: false, html_escaped: false)
  vars                = pagy.vars
  page_param          = vars[:page_param].to_s
  items_param         = vars[:items_param].to_s
  params              = pagy.params.is_a?(Hash) ? pagy.params.transform_keys(&:to_s) : {}
  params              = request.GET.merge(params)
  params[page_param]  = page
  params[items_param] = vars[:items] if vars[:items_extra]
  query_string        = "?#{Rack::Utils.build_nested_query(pagy_deprecated_params(pagy, params))}"  # remove in 6.0
  # params              = pagy.params.call(params) if pagy.params.is_a?(Proc)                       # add in 6.0
  # query_string        = "?#{Rack::Utils.build_nested_query(params)}"                              # add in 6.0
  query_string        = query_string.gsub('&', '&') if html_escaped  # the only unescaped entity
  "#{request.base_url if absolute}#{request.path}#{query_string}#{vars[:fragment]}"
end