resque/resque-loner

# This is an old helpers module pulled in from Resque 1.25.1
# which will be deprecated in future Resque versions. Bringing in
# this module allows us to get rid of the deprecation message
# (Resque::Helpers will be gone with no replacement in Resque 2.0.0.)
require 'multi_json'

# OkJson won't work because it doesn't serialize symbols
# in the same way yajl and json do.
if MultiJson.engine.to_s == 'MultiJson::Engines::OkJson'
  fail 'Please install the yajl-ruby or json gem'
end

module Resque
  module Plugins
    module Loner
      # Methods used by various classes in Resque.
      module LegacyHelpers
        class DecodeException < StandardError; end

        # Direct access to the Redis instance.
        def redis
          Resque.redis
        end

        # Given a Ruby object, returns a string suitable for storage in a
        # queue.
        def encode(object)
          ::MultiJson.encode(object)
        end

        # Given a string, returns a Ruby object.
        def decode(object)
          return unless object

          begin
            ::MultiJson.decode(object)
          rescue ::MultiJson::DecodeError => e
            raise DecodeException, e.message, e.backtrace
          end
        end

        # Given a word with dashes, returns a camel cased version of it.
        #
        # classify('job-name') # => 'JobName'
        def classify(dashed_word)
          dashed_word.split('-').each { |part| part[0] = part[0].chr.upcase }.join
        end

        # Tries to find a constant with the name specified in the argument string:
        #
        # constantize("Module") # => Module
        # constantize("Test::Unit") # => Test::Unit
        #
        # The name is assumed to be the one of a top-level constant, no matter
        # whether it starts with "::" or not. No lexical context is taken into
        # account:
        #
        # C = 'outside'
        # module M
        #   C = 'inside'
        #   C # => 'inside'
        #   constantize("C") # => 'outside', same as ::C
        # end
        #
        # NameError is raised when the constant is unknown.
        def constantize(camel_cased_word)
          camel_cased_word = camel_cased_word.to_s

          if camel_cased_word.include?('-')
            camel_cased_word = classify(camel_cased_word)
          end

          names = camel_cased_word.split('::')
          names.shift if names.empty? || names.first.empty?

          constant = Object
          names.each do |name|
            args = Module.method(:const_get).arity != 1 ? [false] : []

            if constant.const_defined?(name, *args)
              constant = constant.const_get(name)
            else
              constant = constant.const_missing(name)
            end
          end
          constant
        end
      end
    end
  end
end