FEATURE: fragment cache for use with serializers

app/serializers/application_serializer.rb

@@ -1,3 +1,28 @@
+require 'distributed_cache'
+
 class ApplicationSerializer < ActiveModel::Serializer
   embed :ids, include: true
+
+  class CachedFragment
+    def initialize(json)
+      @json = json
+    end
+    def as_json(*_args)
+      @json
+    end
+  end
+
+  def self.expire_cache_fragment!(name)
+    fragment_cache.delete(name)
+  end
+
+  def self.fragment_cache
+    @cache ||= DistributedCache.new("am_serializer_fragment_cache")
+  end
+
+  protected
+
+  def cache_fragment(name)
+    ApplicationSerializer.fragment_cache[name] ||= yield
+  end
 end