Move serialization logic into Serializer and CollectionSerializer

lib/active_model/serializer.rb

@@ -98,6 +98,22 @@ def self.get_serializer_for(klass)
       end
     end
 
+    # @api private
+    def self.include_directive_from_options(options)
+      if options[:include_directive]
+        options[:include_directive]
+      elsif options[:include]
+        JSONAPI::IncludeDirective.new(options[:include], allow_wildcard: true)
+      else
+        ActiveModelSerializers.default_include_directive
+      end
+    end
+
+    # @api private
+    def self.serialization_adapter_instance
+      @serialization_adapter_instance ||= ActiveModelSerializers::Adapter::Attributes
+    end
+
     attr_accessor :object, :root, :scope
 
     # `scope_name` is set as :current_user by default in the controller.
@@ -123,9 +139,7 @@ def success?
     # associations, similar to how ActiveModel::Serializers::JSON is used
     # in ActiveRecord::Base.
     #
-    # TODO: Move to here the Attributes adapter logic for
-    # +serializable_hash_for_single_resource(options)+
-    # and include <tt>ActiveModel::Serializers::JSON</tt>.
+    # TODO: Include <tt>ActiveModel::Serializers::JSON</tt>.
     # So that the below is true:
     #   @param options [nil, Hash] The same valid options passed to `serializable_hash`
     #      (:only, :except, :methods, and :include).
@@ -149,11 +163,13 @@ def success?
     #     serializer.as_json(include: :posts)
     #     # Second level and higher order associations work as well:
     #     serializer.as_json(include: { posts: { include: { comments: { only: :body } }, only: :title } })
-    def serializable_hash(adapter_opts = nil)
-      adapter_opts ||= {}
-      adapter_opts = { include: '*', adapter: :attributes }.merge!(adapter_opts)
-      adapter = ActiveModelSerializers::Adapter.create(self, adapter_opts)
-      adapter.serializable_hash(adapter_opts)
+    def serializable_hash(adapter_options = nil, options = {}, adapter_instance = self.class.serialization_adapter_instance)
+      adapter_options ||= {}
+      options[:include_directive] ||= ActiveModel::Serializer.include_directive_from_options(adapter_options)
+      cached_attributes = adapter_options[:cached_attributes] ||= {}
+      resource = cached_attributes(options[:fields], cached_attributes, adapter_instance)
+      relationships = resource_relationships(adapter_options, options, adapter_instance)
+      resource.merge(relationships)
     end
     alias to_hash serializable_hash
     alias to_h serializable_hash
@@ -185,6 +201,35 @@ def read_attribute_for_serialization(attr)
       end
     end
 
+    # @api private
+    def resource_relationships(adapter_options, options, adapter_instance)
+      relationships = {}
+      include_directive = options.fetch(:include_directive)
+      associations(include_directive).each do |association|
+        adapter_opts = adapter_options.merge(include_directive: include_directive[association.key])
+        relationships[association.key] ||= relationship_value_for(association, adapter_opts, adapter_instance)
+      end
+
+      relationships
+    end
+
+    # @api private
+    def relationship_value_for(association, adapter_options, adapter_instance)
+      return association.options[:virtual_value] if association.options[:virtual_value]
+      association_serializer = association.serializer
+      association_object = association_serializer && association_serializer.object
+      return unless association_object
+
+      relationship_value = association_serializer.serializable_hash(adapter_options, {}, adapter_instance)
+
+      if association.options[:polymorphic] && relationship_value
+        polymorphic_type = association_object.class.name.underscore
+        relationship_value = { type: polymorphic_type, polymorphic_type.to_sym => relationship_value }
+      end
+
+      relationship_value
+    end
+
     protected
 
     attr_accessor :instance_options

lib/active_model/serializer/caching.rb

@@ -318,7 +318,7 @@ def cache_key(adapter_instance)
 
         parts = []
         parts << object_cache_key
-        parts << adapter_instance.cached_name
+        parts << adapter_instance.cache_key
         parts << self.class._cache_digest unless self.class._skip_digest?
         @cache_key = parts.join('/')
       end

lib/active_model/serializer/collection_serializer.rb

@@ -11,22 +11,23 @@ def initialize(resources, options = {})
         @object                  = resources
         @options                 = options
         @root                    = options[:root]
-        serializer_context_class = options.fetch(:serializer_context_class, ActiveModel::Serializer)
-        @serializers = resources.map do |resource|
-          serializer_class = options.fetch(:serializer) { serializer_context_class.serializer_for(resource) }
-
-          if serializer_class.nil? # rubocop:disable Style/GuardClause
-            fail NoSerializerError, "No serializer found for resource: #{resource.inspect}"
-          else
-            serializer_class.new(resource, options.except(:serializer))
-          end
-        end
+        @serializers             = serializers_from_resources
       end
 
       def success?
         true
       end
 
+      # @api private
+      def serializable_hash(adapter_options, options, adapter_instance)
+        include_directive = ActiveModel::Serializer.include_directive_from_options(adapter_options)
+        adapter_options[:cached_attributes] ||= ActiveModel::Serializer.cache_read_multi(self, adapter_instance, include_directive)
+        adapter_opts = adapter_options.merge(include_directive: include_directive)
+        serializers.map do |serializer|
+          serializer.serializable_hash(adapter_opts, options, adapter_instance)
+        end
+      end
+
       # TODO: unify naming of root, json_key, and _type.  Right now, a serializer's
       # json_key comes from the root option or the object's model name, by default.
       # But, if a dev defines a custom `json_key` method with an explicit value,
@@ -59,6 +60,25 @@ def paginated?
       protected
 
       attr_reader :serializers, :options
+
+      private
+
+      def serializers_from_resources
+        serializer_context_class = options.fetch(:serializer_context_class, ActiveModel::Serializer)
+        object.map do |resource|
+          serializer_from_resource(resource, serializer_context_class, options)
+        end
+      end
+
+      def serializer_from_resource(resource, serializer_context_class, options)
+        serializer_class = options.fetch(:serializer) { serializer_context_class.serializer_for(resource) }
+
+        if serializer_class.nil? # rubocop:disable Style/GuardClause
+          fail NoSerializerError, "No serializer found for resource: #{resource.inspect}"
+        else
+          serializer_class.new(resource, options.except(:serializer))
+        end
+      end
     end
   end
 end

lib/active_model_serializers/adapter.rb

@@ -51,6 +51,10 @@ def register(name, klass = name)
         self
       end
 
+      def registered_name(adapter_class)
+        ADAPTER_MAP.key adapter_class
+      end
+
       # @param  adapter [String, Symbol, Class] name to fetch adapter by
       # @return [ActiveModelSerializers::Adapter] subclass of Adapter
       # @raise  [UnknownAdapterError]

lib/active_model_serializers/adapter/attributes.rb

@@ -1,65 +1,9 @@
 module ActiveModelSerializers
   module Adapter
     class Attributes < Base
-      def initialize(serializer, options = {})
-        super
-        @include_directive =
-          if options[:include_directive]
-            options[:include_directive]
-          elsif options[:include]
-            JSONAPI::IncludeDirective.new(options[:include], allow_wildcard: true)
-          else
-            ActiveModelSerializers.default_include_directive
-          end
-      end
-
       def serializable_hash(options = nil)
         options = serialization_options(options)
-
-        if serializer.respond_to?(:each)
-          serializable_hash_for_collection(options)
-        else
-          serializable_hash_for_single_resource(options)
-        end
-      end
-
-      private
-
-      def serializable_hash_for_collection(options)
-        instance_options[:cached_attributes] ||= ActiveModel::Serializer.cache_read_multi(serializer, self, @include_directive)
-        opts = instance_options.merge(include_directive: @include_directive)
-        serializer.map { |s| Attributes.new(s, opts).serializable_hash(options) }
-      end
-
-      def serializable_hash_for_single_resource(options)
-        cached_attributes = instance_options[:cached_attributes] || {}
-        resource = serializer.cached_attributes(options[:fields], cached_attributes, self)
-        relationships = resource_relationships(options)
-        resource.merge(relationships)
-      end
-
-      def resource_relationships(options)
-        relationships = {}
-        serializer.associations(@include_directive).each do |association|
-          relationships[association.key] ||= relationship_value_for(association, options)
-        end
-
-        relationships
-      end
-
-      def relationship_value_for(association, options)
-        return association.options[:virtual_value] if association.options[:virtual_value]
-        return unless association.serializer && association.serializer.object
-
-        opts = instance_options.merge(include_directive: @include_directive[association.key])
-        relationship_value = Attributes.new(association.serializer, opts).serializable_hash(options)
-
-        if association.options[:polymorphic] && relationship_value
-          polymorphic_type = association.serializer.object.class.name.underscore
-          relationship_value = { type: polymorphic_type, polymorphic_type.to_sym => relationship_value }
-        end
-
-        relationship_value
+        serializer.serializable_hash(instance_options, options, self)
       end
     end
   end

lib/active_model_serializers/adapter/base.rb

@@ -8,17 +8,47 @@ def self.inherited(subclass)
         ActiveModelSerializers::Adapter.register(subclass)
       end
 
+      # Sets the default transform for the adapter.
+      #
+      # @return [Symbol] the default transform for the adapter
+      def self.default_key_transform
+        :unaltered
+      end
+
+      # Determines the transform to use in order of precedence:
+      #   adapter option, global config, adapter default.
+      #
+      # @param options [Object]
+      # @return [Symbol] the transform to use
+      def self.transform(options)
+        return options[:key_transform] if options && options[:key_transform]
+        ActiveModelSerializers.config.key_transform || default_key_transform
+      end
+
+      # Transforms the casing of the supplied value.
+      #
+      # @param value [Object] the value to be transformed
+      # @param options [Object] serializable resource options
+      # @return [Symbol] the default transform for the adapter
+      def self.transform_key_casing!(value, options)
+        KeyTransform.send(transform(options), value)
+      end
+
+      def self.cache_key
+        @cache_key ||= ActiveModelSerializers::Adapter.registered_name(self)
+      end
+
+      def self.fragment_cache(cached_hash, non_cached_hash)
+        non_cached_hash.merge cached_hash
+      end
+
       attr_reader :serializer, :instance_options
 
       def initialize(serializer, options = {})
         @serializer = serializer
         @instance_options = options
       end
 
-      def cached_name
-        @cached_name ||= self.class.name.demodulize.underscore
-      end
-
       # Subclasses that implement this method must first call
       #   options = serialization_options(options)
       def serializable_hash(_options = nil)
@@ -29,8 +59,12 @@ def as_json(options = nil)
         serializable_hash(options)
       end
 
+      def cache_key
+        self.class.cache_key
+      end
+
       def fragment_cache(cached_hash, non_cached_hash)
-        non_cached_hash.merge cached_hash
+        self.class.fragment_cache(cached_hash, non_cached_hash)
       end
 
       private
@@ -44,34 +78,6 @@ def serialization_options(options)
       def root
         serializer.json_key.to_sym if serializer.json_key
       end
-
-      class << self
-        # Sets the default transform for the adapter.
-        #
-        # @return [Symbol] the default transform for the adapter
-        def default_key_transform
-          :unaltered
-        end
-
-        # Determines the transform to use in order of precedence:
-        #   adapter option, global config, adapter default.
-        #
-        # @param options [Object]
-        # @return [Symbol] the transform to use
-        def transform(options)
-          return options[:key_transform] if options && options[:key_transform]
-          ActiveModelSerializers.config.key_transform || default_key_transform
-        end
-
-        # Transforms the casing of the supplied value.
-        #
-        # @param value [Object] the value to be transformed
-        # @param options [Object] serializable resource options
-        # @return [Symbol] the default transform for the adapter
-        def transform_key_casing!(value, options)
-          KeyTransform.send(transform(options), value)
-        end
-      end
     end
   end
 end

lib/active_model_serializers/adapter/json_api.rb

@@ -31,16 +31,27 @@ class JsonApi < Base
       autoload :Error
       autoload :Deserialization
 
+      def self.default_key_transform
+        :dash
+      end
+
+      def self.fragment_cache(cached_hash, non_cached_hash, root = true)
+        core_cached       = cached_hash.first
+        core_non_cached   = non_cached_hash.first
+        no_root_cache     = cached_hash.delete_if { |key, _value| key == core_cached[0] }
+        no_root_non_cache = non_cached_hash.delete_if { |key, _value| key == core_non_cached[0] }
+        cached_resource   = (core_cached[1]) ? core_cached[1].deep_merge(core_non_cached[1]) : core_non_cached[1]
+        hash = root ? { root => cached_resource } : cached_resource
+
+        hash.deep_merge no_root_non_cache.deep_merge no_root_cache
+      end
+
       def initialize(serializer, options = {})
         super
         @include_directive = JSONAPI::IncludeDirective.new(options[:include], allow_wildcard: true)
         @fieldset = options[:fieldset] || ActiveModel::Serializer::Fieldset.new(options.delete(:fields))
       end
 
-      def self.default_key_transform
-        :dash
-      end
-
       # {http://jsonapi.org/format/#crud Requests are transactional, i.e. success or failure}
       # {http://jsonapi.org/format/#document-top-level data and errors MUST NOT coexist in the same document.}
       def serializable_hash(*)
@@ -52,6 +63,11 @@ def serializable_hash(*)
         self.class.transform_key_casing!(document, instance_options)
       end
 
+      def fragment_cache(cached_hash, non_cached_hash)
+        root = !instance_options.include?(:include)
+        self.class.fragment_cache(cached_hash, non_cached_hash, root)
+      end
+
       # {http://jsonapi.org/format/#document-top-level Primary data}
       # definition:
       #   ☐ toplevel_data (required)
@@ -174,18 +190,6 @@ def failure_document
         hash
       end
 
-      def fragment_cache(cached_hash, non_cached_hash)
-        root = false if instance_options.include?(:include)
-        core_cached       = cached_hash.first
-        core_non_cached   = non_cached_hash.first
-        no_root_cache     = cached_hash.delete_if { |key, _value| key == core_cached[0] }
-        no_root_non_cache = non_cached_hash.delete_if { |key, _value| key == core_non_cached[0] }
-        cached_resource   = (core_cached[1]) ? core_cached[1].deep_merge(core_non_cached[1]) : core_non_cached[1]
-        hash = root ? { root => cached_resource } : cached_resource
-
-        hash.deep_merge no_root_non_cache.deep_merge no_root_cache
-      end
-
       protected
 
       attr_reader :fieldset