A function to filter the params sent to a REST API endpoint

params_filter.rb

class Hash
  # Public: Filters a hash to check only for those elements desired
  #
  # Examples
  #
  #   hash      = { uno: "uno", dos: "dos", tres: "tres" }
  #   whitelist = [ :uno, :dos ]
  #   hash.filter whitelist
  #   # => { uno: "uno", dos: "dos" }
  #
  # Returns a Hash
  def filter ary
    select { |k| ary.include? k }
  end
end