Add json_class support w/o JSON for most types

lib/chef/json_compat.rb

@@ -24,6 +24,8 @@ class Chef
   class JSONCompat
     JSON_MAX_NESTING = 1000
 
+    JSON_CLASS = "json_class".freeze
+
     class <<self
       # See CHEF-1292/PL-538. Increase the max nesting for JSON, which defaults
       # to 19, and isn't enough for some (for example, a Node within a Node)
@@ -38,7 +40,37 @@ def opts_add_max_nesting(opts)
 
       # Just call the JSON gem's parse method with a modified :max_nesting field
       def from_json(source, opts = {})
-        ::JSON.parse(source, opts_add_max_nesting(opts))
+        obj = ::Yajl::Parser.parse(source)
+        if opts[:create_additions].nil? || opts[:create_additions]
+          map_to_rb_obj(obj)
+        else
+          obj
+        end
+      end
+
+      def map_to_rb_obj(json_obj)
+        res = case json_obj
+        when Hash
+          mapped_hash = map_hash_to_rb_obj(json_obj)
+          if json_obj.has_key?(JSON_CLASS) && (class_to_inflate = class_for_json_class(json_obj[JSON_CLASS]))
+            class_to_inflate.json_create(mapped_hash)
+          else
+            mapped_hash
+          end
+        when Array
+          json_obj.map {|e| map_to_rb_obj(e) }
+        else
+          json_obj
+        end
+        res
+      end
+
+      def map_hash_to_rb_obj(json_hash)
+        mapped_hash = {}
+        json_hash.each do |key, value|
+          mapped_hash[key] = map_to_rb_obj(value)
+        end
+        mapped_hash
       end
 
       def to_json(obj, opts = nil)
@@ -48,6 +80,34 @@ def to_json(obj, opts = nil)
       def to_json_pretty(obj, opts = nil)
         ::JSON.pretty_generate(obj, opts_add_max_nesting(opts))
       end
+
+      def class_for_json_class(json_class)
+        case json_class
+        when "Chef::ApiClient"
+          Chef::ApiClient
+        when "Chef::CookbookVersion"
+          Chef::CookbookVersion
+        when "Chef::DataBag"
+          Chef::DataBag
+        when "Chef::DataBagItem"
+          Chef::DataBagItem
+        when "Chef::Environment"
+          Chef::Environment
+        when "Chef::Node"
+          Chef::Node
+        when "Chef::Role"
+          Chef::Role
+        when "Chef::Sandbox"
+          false
+        when "Chef::Resource"
+          false
+        when "Chef::ResourceCollection"
+          Chef::ResourceCollection
+        else
+          raise ArgumentError, "Unsupported `json_class` type '#{json_class}'"
+        end
+      end
+
     end
   end
 end