ActionController extension to fix Persian numerals

action_controller_parameters_extension.rb

module ActionControllerParametersExtension
  extend ActiveSupport::Concern

  # A recursive method to traverse the params hash. It replaces
  # persian numerals with their equivalent english numerals.
  # It's not the best way to do it, but it works for now.
  def fix_numerals(element=self)
    case element
    when Hash
      Hash[ element.map{ |k,v| [k, fix_numerals(v)] } ]
    when Array
      element.map{ |v| fix_numerals(v) }
    else
      element.tr("۱۲۳۴۵۶۷۸۹۰", "1234567890")
    end
  end

end

# Includes the extension
ActionController::Parameters.send(:include, ActionControllerParametersExtension)

NOTE:
This method doesn't return an instance of ActionController::Parameters, so it always has to be called at the end of the chain.