Add a way to cache certain parts of a document

lib/hypertemplate/builder.rb

@@ -2,6 +2,7 @@ module Hypertemplate
   module Builder
     require "hypertemplate/builder/base"
     require "hypertemplate/builder/values"
+    require "hypertemplate/builder/cache"
     require "hypertemplate/builder/json"
     require "hypertemplate/builder/xml"
 

lib/hypertemplate/builder/base.rb

@@ -6,7 +6,14 @@ class Base
       undef_method :id if respond_to?(:id)
 
       class << self
-
+        def cache
+          @cache
+        end
+
+        def cache=(cache)
+          @cache = cache
+        end
+
         def media_types
           @media_types
         end
@@ -98,6 +105,12 @@ def ns(*args, &block)
         end
       end
 
+      def cache(key)
+        Cache.new(key, self) do |cache|
+          yield cache
+        end
+      end
+
       # writes a key and value pair to the representation
       # example:
       #

lib/hypertemplate/builder/cache.rb

@@ -0,0 +1,49 @@
+module Hypertemplate
+  module Builder
+    class Cache #< BasicObject
+      attr_accessor :builder
+
+      def initialize(key, builder, &block)
+        @key = key
+        @builder = builder
+
+        if cached?
+          raw = cache.read(cache_key)
+
+          if builder.class == Xml
+            data = Nokogiri::XML(raw)
+          else
+            data = MultiJson.decode(raw)
+          end
+        else
+          _builder = builder.class.new({})
+          yield _builder
+          data = _builder.raw
+
+          cache.write(cache_key, _builder.representation)
+        end
+
+        if current = builder.instance_variable_get('@current') # JSON
+          current.merge!(data)
+        else # XML
+          parent = builder.instance_variable_get('@parent')
+          data.root.children.each do |element|
+            element.parent = parent
+          end
+        end
+      end
+
+      def cached?
+        cache.exist?(cache_key)
+      end
+
+      def cache
+        Hypertemplate::Builder::Base.cache
+      end
+
+      def cache_key
+        @_generated_key ||= "#{@key}_#{builder.class.to_s.split('::').last}"
+      end
+    end
+  end
+end

lib/hypertemplate/builder/json.rb

@@ -75,7 +75,7 @@ def insert_value(name, prefix, *args, &block)
       end
 
       def representation
-        @raw.to_json
+        MultiJson.encode(@raw)
       end
 
     private

lib/hypertemplate/hook/rails.rb

@@ -1,6 +1,12 @@
 require 'hypertemplate' unless defined? ::Hypertemplate
 
 module Hypertemplate
+  class Railtie < Rails::Railtie
+    initializer "hypertemplate.setup_cache" do
+      Hypertemplate::Builder::Base.cache = Rails.cache
+    end
+  end
+
   module RegistryContainer
 
     def hypertemplate_registry