backport 67756f0 from master

Author: hone

lib/resque/helpers.rb

@@ -2,8 +2,10 @@
 
 # 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'
-  raise "Please install the yajl-ruby or json gem"
+if MultiJson.respond_to?(:adapter)
+  raise "Please install the yajl-ruby or json gem" if MultiJson.adapter.to_s == 'MultiJson::Adapters::OkJson'
+elsif MultiJson.respond_to?(:engine)
+  raise "Please install the yajl-ruby or json gem" if MultiJson.engine.to_s == 'MultiJson::Engines::OkJson'
 end
 
 module Resque
@@ -19,15 +21,24 @@ def redis
     # Given a Ruby object, returns a string suitable for storage in a
     # queue.
     def encode(object)
-      ::MultiJson.encode(object)
+      if MultiJson.respond_to?(:dump) && MultiJson.respond_to?(:load)
+        MultiJson.load object
+      else
+        MultiJson.encode object
+      end
+
     end
 
     # Given a string, returns a Ruby object.
     def decode(object)
       return unless object
 
       begin
-        ::MultiJson.decode(object)
+        if MultiJson.respond_to?(:dump) && MultiJson.respond_to?(:load)
+          MultiJson.dump object
+        else
+          MultiJson.decode object
+        end
       rescue ::MultiJson::DecodeError => e
         raise DecodeException, e.message, e.backtrace
       end