Merge pull request #89 from twinturbo/caching

Serializers Cache JSON & Hashes

lib/active_model/array_serializer.rb

@@ -19,26 +19,18 @@ module ActiveModel
 
     class_attribute :root
 
-    def initialize(object, options={})
-      @object, @options = object, options
+    class_attribute :cache
+    class_attribute :perform_caching
+
+    class << self
+      # set peform caching like root
+      def cached(value = true)
+        self.perform_caching = value
+      end
     end
 
-    def serializable_array
-      @object.map do |item|
-        if @options.has_key? :each_serializer
-          serializer = @options[:each_serializer]
-        elsif item.respond_to?(:active_model_serializer)
-          serializer = item.active_model_serializer
-        end
-
-        serializable = serializer ? serializer.new(item, @options) : DefaultSerializer.new(item)
-
-        if serializable.respond_to?(:serializable_hash)
-          serializable.serializable_hash
-        else
-          serializable.as_json
-        end
-      end
+    def initialize(object, options={})
+      @object, @options = object, options
     end
 
     def meta_key
@@ -61,6 +53,52 @@ module ActiveModel
         serializable_array
       end
     end
-  end
 
+    def to_json(*args)
+      if perform_caching?
+        cache.fetch expand_cache_key([self.class.to_s.underscore, cache_key, 'to-json']) do
+          super
+        end
+      else
+        super
+      end
+    end
+
+    def serializable_array
+      if perform_caching?
+        cache.fetch expand_cache_key([self.class.to_s.underscore, cache_key, 'serializable-array']) do
+          _serializable_array
+        end
+      else
+        _serializable_array
+      end
+    end
+
+    private
+    def _serializable_array
+      @object.map do |item|
+        if @options.has_key? :each_serializer
+          serializer = @options[:each_serializer]
+        elsif item.respond_to?(:active_model_serializer)
+          serializer = item.active_model_serializer
+        end
+
+        serializable = serializer ? serializer.new(item, @options) : DefaultSerializer.new(item)
+
+        if serializable.respond_to?(:serializable_hash)
+          serializable.serializable_hash
+        else
+          serializable.as_json
+        end
+      end
+    end
+
+    def expand_cache_key(*args)
+      ActiveSupport::Cache.expand_cache_key(args)
+    end
+
+    def perform_caching?
+      perform_caching && cache && respond_to?(:cache_key)
+    end
+  end
 end

lib/active_model/serializer.rb

@@ -69,7 +69,15 @@ module ActiveModel
     class_attribute :use_default_render_json
     self.use_default_render_json = false
 
+    class_attribute :cache
+    class_attribute :perform_caching
+
     class << self
+      # set peform caching like root
+      def cached(value = true)
+        self.perform_caching = value
+      end
+
       # Define attributes to be used in the serialization.
       def attributes(*attrs)
 
@@ -266,6 +274,16 @@ module ActiveModel
       hash[meta_key] = @options[:meta] if @options.has_key?(:meta)
     end
 
+    def to_json(*args)
+      if perform_caching?
+        cache.fetch expand_cache_key([self.class.to_s.underscore, cache_key, 'to-json']) do
+          super
+        end
+      else
+        super
+      end
+    end
+
     # Returns a json representation of the serializable
     # object including the root.
     def as_json(options={})
@@ -284,10 +302,13 @@ module ActiveModel
     # Returns a hash representation of the serializable
     # object without the root.
     def serializable_hash
-      return nil if @object.nil?
-      @node = attributes
-      include_associations! if _embed
-      @node
+      if perform_caching?
+        cache.fetch expand_cache_key([self.class.to_s.underscore, cache_key, 'serializable-hash']) do
+          _serializable_hash
+        end
+      else
+        _serializable_hash
+      end
     end
 
     def include_associations!
@@ -400,6 +421,21 @@ module ActiveModel
 
     alias :read_attribute_for_serialization :send
 
+    def _serializable_hash
+      return nil if @object.nil?
+      @node = attributes
+      include_associations! if _embed
+      @node
+    end
+
+    def perform_caching?
+      perform_caching && cache && respond_to?(:cache_key)
+    end
+
+    def expand_cache_key(*args)
+      ActiveSupport::Cache.expand_cache_key(args)
+    end
+
     # Use ActiveSupport::Notifications to send events to external systems.
     # The event name is: name.class_name.serializer
     def instrument(name, payload = {}, &block)
@@ -407,7 +443,7 @@ module ActiveModel
       ActiveSupport::Notifications.instrument(event_name, payload, &block)
     end
   end
-  
+
   # DefaultSerializer
   #
   # Provides a constant interface for all items, particularly

lib/active_model_serializers.rb

@@ -23,6 +23,14 @@ if defined?(Rails)
           include app.routes.url_helpers
         end
       end
+
+      initializer "caching.active_model_serializer" do |app|
+        ActiveModel::Serializer.perform_caching = app.config.action_controller.perform_caching
+        ActiveModel::ArraySerializer.perform_caching = app.config.action_controller.perform_caching
+
+        ActiveModel::Serializer.cache = Rails.cache
+        ActiveModel::ArraySerializer.cache = Rails.cache
+      end
     end
   end
 end

test/caching_test.rb

@@ -0,0 +1,96 @@
+require "test_helper"
+
+class CachingTest < ActiveModel::TestCase
+  class NullStore
+    def fetch(key)
+      return store[key] if store[key]
+
+      store[key] = yield
+    end
+
+    def clear
+      store.clear
+    end
+
+    def store
+      @store ||= {}
+    end
+
+    def read(key)
+      store[key]
+    end
+  end
+
+  class Programmer
+    def name
+      'Adam'
+    end
+
+    def skills
+      %w(ruby)
+    end
+
+    def read_attribute_for_serialization(name)
+      send name
+    end
+  end
+
+  def test_serializers_have_a_cache_store
+    ActiveModel::Serializer.cache = NullStore.new
+
+    assert_kind_of NullStore, ActiveModel::Serializer.cache
+  end
+
+  def test_serializers_can_enable_caching
+    serializer = Class.new(ActiveModel::Serializer) do
+      cached true
+    end
+
+    assert serializer.perform_caching
+  end
+
+  def test_serializers_use_cache
+    serializer = Class.new(ActiveModel::Serializer) do
+      cached true
+      attributes :name, :skills
+
+      def self.to_s
+        'serializer'
+      end
+
+      def cache_key
+        object.name
+      end
+    end
+
+    serializer.cache = NullStore.new
+    instance = serializer.new Programmer.new
+
+    instance.to_json
+
+    assert_equal(instance.serializable_hash, serializer.cache.read('serializer/Adam/serializable-hash'))
+    assert_equal(instance.to_json, serializer.cache.read('serializer/Adam/to-json'))
+  end
+
+  def test_array_serializer_uses_cache
+    serializer = Class.new(ActiveModel::ArraySerializer) do
+      cached true
+
+      def self.to_s
+        'array_serializer'
+      end
+
+      def cache_key
+        'cache-key'
+      end
+    end
+
+    serializer.cache = NullStore.new
+    instance = serializer.new [Programmer.new]
+
+    instance.to_json
+
+    assert_equal instance.serializable_array, serializer.cache.read('array_serializer/cache-key/serializable-array')
+    assert_equal instance.to_json, serializer.cache.read('array_serializer/cache-key/to-json')
+  end
+end