Feature/adapter

README.md

@@ -57,7 +57,13 @@ by AMS. If you want to use a different adapter, such as a HalAdapter, you can
 change this in an initializer:
 
 ```ruby
-ActiveModel::Serializer.default_adapter = ActiveModel::Serializer::Adapter::HalAdapter
+ActiveModel::Serializer.config.adapter = ActiveModel::Serializer::Adapter::HalAdapter
+```
+
+or
+
+```ruby
+ActiveModel::Serializer.config.adapter = :hal
 ```
 
 You won't need to implement an adapter unless you wish to use a new format or

lib/action_controller/serialization.rb

@@ -12,7 +12,7 @@ def _render_option_json(resource, options)
       if serializer
         # omg hax
         object = serializer.new(resource)
-        adapter = ActiveModel::Serializer::Adapter::NullAdapter.new(object)
+        adapter = ActiveModel::Serializer.adapter.new(object)
 
         super(adapter, options)
       else

lib/active_model/serializer.rb

@@ -3,6 +3,7 @@ class Serializer
     extend ActiveSupport::Autoload
     autoload :Configuration
     autoload :ArraySerializer
+    autoload :Adapter
     include Configuration
 
     class << self
@@ -73,6 +74,24 @@ def self.serializer_for(resource)
       end
     end
 
+    def self.adapter
+      adapter_class = case config.adapter
+                      when Symbol
+                        class_name = "ActiveModel::Serializer::Adapter::#{config.adapter.to_s.classify}Adapter"
+                        if Object.const_defined?(class_name)
+                          Object.const_get(class_name)
+                        end
+                      when Class
+                        config.adapter
+                      end
+      unless adapter_class
+        valid_adapters = Adapter.constants.map { |klass| ":#{klass.to_s.sub('Adapter', '').downcase}" }
+        raise ArgumentError, "Unknown adapter: #{config.adapter}. Valid adapters are: #{valid_adapters}"
+      end
+
+      adapter_class
+    end
+
     attr_accessor :object
 
     def initialize(object)
@@ -84,5 +103,9 @@ def attributes
         hash[name] = send(name)
       end
     end
+
+    def associations
+      self.class._associations.dup
+    end
   end
 end

lib/active_model/serializer/adapter.rb

@@ -0,0 +1,23 @@
+module ActiveModel
+  class Serializer
+    class Adapter
+      extend ActiveSupport::Autoload
+      autoload :SimpleAdapter
+      autoload :NullAdapter
+
+      attr_reader :serializer
+
+      def initialize(serializer)
+        @serializer = serializer
+      end
+
+      def serializable_hash(options = {})
+        raise NotImplementedError, 'This is abstract method. Should be implemented at concrete adapter.'
+      end
+
+      def to_json(options={})
+        serializable_hash(options).to_json
+      end
+    end
+  end
+end

lib/active_model/serializer/adapter/null_adapter.rb

@@ -1,15 +1,9 @@
 module ActiveModel
   class Serializer
     class Adapter
-      class NullAdapter
-        def initialize(adapter)
-          @attributes = adapter.attributes 
-        end
-
-        def to_json(options={})
-          @attributes.each_with_object({}) do |(attr, value), h|
-            h[attr] = value
-          end.to_json # FIXME: why does passing options here cause {}?
+      class NullAdapter < Adapter
+        def serializable_hash(options = {})
+          {}
         end
       end
     end

lib/active_model/serializer/adapter/simple_adapter.rb

@@ -0,0 +1,13 @@
+module ActiveModel
+  class Serializer
+    class Adapter
+      class SimpleAdapter < Adapter
+        def serializable_hash(options = {})
+          serializer.attributes.each_with_object({}) do |(attr, value), h|
+            h[attr] = value
+          end
+        end
+      end
+    end
+  end
+end

lib/active_model/serializer/configuration.rb

@@ -6,6 +6,7 @@ module Configuration
 
       included do |base|
         base.config.array_serializer = ActiveModel::Serializer::ArraySerializer
+        base.config.adapter = :simple
       end
     end
   end

lib/active_model_serializers.rb

@@ -1,7 +1,7 @@
 require "active_model"
 require "active_model/serializer/version"
 require "active_model/serializer"
-require "active_model/serializer/adapter/null_adapter"
+require "active_model/serializer/adapter/simple_adapter"
 
 begin
   require 'action_controller'

test/adapter/null_adapter_test.rb

@@ -0,0 +1,25 @@
+require 'test_helper'
+
+module ActiveModel
+  class Serializer
+    class Adapter
+      class NullAdapterTest < Minitest::Test
+        def setup
+          profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
+          serializer = ProfileSerializer.new(profile)
+
+          @adapter = NullAdapter.new(serializer)
+        end
+
+        def test_serializable_hash
+          assert_equal({}, @adapter.serializable_hash)
+        end
+
+        def test_it_returns_empty_json
+          assert_equal('{}', @adapter.to_json)
+        end
+      end
+    end
+  end
+end
+

test/adapters/null_adapter_test.rb → test/adapter/simple_adapter_test.rb

@@ -3,15 +3,19 @@
 module ActiveModel
   class Serializer
     class Adapter
-      class NullAdapterTest < Minitest::Test
+      class SimpleAdapterTest < Minitest::Test
         def setup
           @profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
           @profile_serializer = ProfileSerializer.new(@profile)
 
-          @adapter = NullAdapter.new(@profile_serializer)
+          @adapter = SimpleAdapter.new(@profile_serializer)
         end
 
-        def test_null_adapter
+        def test_serializable_hash
+          assert_equal({name: 'Name 1', description: 'Description 1'}, @adapter.serializable_hash)
+        end
+
+        def test_simple_adapter
           assert_equal('{"name":"Name 1","description":"Description 1"}',
                        @adapter.to_json)
 

test/adapter_test.rb

@@ -0,0 +1,23 @@
+require 'test_helper'
+
+module ActiveModel
+  class Serializer
+    class AdapterTest < Minitest::Test
+      def setup
+        profile = Profile.new
+        @serializer = ProfileSerializer.new(profile)
+        @adapter = ActiveModel::Serializer::Adapter.new(@serializer)
+      end
+
+      def test_serializable_hash_is_abstract_method
+        assert_raises(NotImplementedError) do
+          @adapter.serializable_hash(only: [:name])
+        end
+      end
+
+      def test_serializer
+        assert_equal @serializer, @adapter.serializer
+      end
+    end
+  end
+end

test/serializers/adapter_for_test.rb

@@ -0,0 +1,50 @@
+module ActiveModel
+  class Serializer
+    class AdapterForTest < Minitest::Test
+      def setup
+        @previous_adapter = ActiveModel::Serializer.config.adapter
+      end
+
+      def teardown
+        ActiveModel::Serializer.config.adapter = @previous_adapter
+      end
+
+      def test_returns_default_adapter
+        adapter = ActiveModel::Serializer.adapter
+        assert_equal ActiveModel::Serializer::Adapter::SimpleAdapter, adapter
+      end
+
+      def test_overwrite_adapter_with_symbol
+        ActiveModel::Serializer.config.adapter = :null
+
+        adapter = ActiveModel::Serializer.adapter
+        assert_equal ActiveModel::Serializer::Adapter::NullAdapter, adapter
+      ensure
+
+      end
+
+      def test_overwrite_adapter_with_class
+        ActiveModel::Serializer.config.adapter = ActiveModel::Serializer::Adapter::NullAdapter
+
+        adapter = ActiveModel::Serializer.adapter
+        assert_equal ActiveModel::Serializer::Adapter::NullAdapter, adapter
+      end
+
+      def test_raises_exception_if_invalid_symbol_given
+        ActiveModel::Serializer.config.adapter = :unknown
+
+        assert_raises ArgumentError do
+          ActiveModel::Serializer.adapter
+        end
+      end
+
+      def test_raises_exception_if_it_does_not_know_hot_to_infer_adapter
+        ActiveModel::Serializer.config.adapter = 42
+
+        assert_raises ArgumentError do
+          ActiveModel::Serializer.adapter
+        end
+      end
+    end
+  end
+end

test/serializers/associations_test.rb

@@ -60,6 +60,25 @@ def test_has_one
 
         assert_equal({post: {type: :belongs_to, options: {}}}, @comment_serializer.class._associations)
       end
+
+      def test_associations
+        @comment_serializer_class.class_eval do
+          belongs_to :post
+          has_many :comments
+        end
+
+        expected_associations = {
+          post: {
+            type: :belongs_to,
+            options: {}
+          },
+          comments: {
+            type: :has_many,
+            options: {}
+          },
+        }
+        assert_equal(expected_associations, @comment_serializer.associations)
+      end
     end
   end
 end

test/serializers/configuration_test.rb

@@ -6,6 +6,10 @@ class ConfigurationTest < Minitest::Test
       def test_array_serializer
         assert_equal ActiveModel::Serializer::ArraySerializer, ActiveModel::Serializer.config.array_serializer
       end
+
+      def test_adapter
+        assert_equal :simple, ActiveModel::Serializer.config.adapter
+      end
     end
   end
 end