Include 'linked' member for json-api collections

The options passed to the render are partitioned into adapter options
and serializer options. 'include' and 'root' are sent to the adapter,
not sure what options would go directly to serializer, but leaving this
in until I understand that better.

.gitignore

@@ -16,4 +16,4 @@ test/tmp
 test/version_tmp
 tmp
 *.swp
-.ruby-version
+.ruby-version

README.md

@@ -1,8 +1,8 @@
-# ActiveModel::Serializers 
- 
+# ActiveModel::Serializers
+
 [![Build Status](https://travis-ci.org/rails-api/active_model_serializers.svg)](https://travis-ci.org/rails-api/active_model_serializers)
 
-ActiveModel::Serializers brings convention over configuration to your JSON generation. 
+ActiveModel::Serializers brings convention over configuration to your JSON generation.
 
 AMS does this through two components: **serializers** and **adapters**. Serializers describe which attributes and relationships should be serialized. Adapters describe how attributes and relationships should be serialized.
 
@@ -32,7 +32,7 @@ serializers:
 ```ruby
 class PostSerializer < ActiveModel::Serializer
   attributes :title, :body
- 
+
   has_many :comments
 
   url :post
@@ -61,7 +61,7 @@ ActiveModel::Serializer.config.adapter = ActiveModel::Serializer::Adapter::HalAd
 ```
 
 or
- 
+
 ```ruby
 ActiveModel::Serializer.config.adapter = :hal
 ```
@@ -85,18 +85,27 @@ end
 In this case, Rails will look for a serializer named `PostSerializer`, and if
 it exists, use it to serialize the `Post`.
 
-## Installation 
-
-Add this line to your application's Gemfile: 
+### Built in Adapters
+
+The `:json_api` adapter will include the associated resources in the `"linked"`
+member when the resource names are included in the `include` option.
 
-``` 
-gem 'active_model_serializers' 
+```ruby
+  render @posts, include: 'authors,comments'
 ```
-
-And then execute: 
 
-``` 
-$ bundle 
+## Installation
+
+Add this line to your application's Gemfile:
+
+```
+gem 'active_model_serializers'
+```
+
+And then execute:
+
+```
+$ bundle
 ```
 
 ## Creating a Serializer
@@ -141,29 +150,27 @@ class CommentSerializer < ActiveModel::Serializer
 end
 ```
 
-The attribute names are a **whitelist** of attributes to be serialized. 
- 
+The attribute names are a **whitelist** of attributes to be serialized.
+
 The `has_many` and `belongs_to` declarations describe relationships between
-resources. By default, when you serialize a `Post`, you will
-get its `Comment`s as well.
+resources. By default, when you serialize a `Post`, you will get its `Comment`s
+as well.
 
 The `url` declaration describes which named routes to use while generating URLs
 for your JSON. Not every adapter will require URLs.
 
 ## Getting Help
 
-If you find a bug, please report an
-[Issue](https://github.com/rails-api/active_model_serializers/issues/new).
+If you find a bug, please report an [Issue](https://github.com/rails-api/active_model_serializers/issues/new).
 
-If you have a question, please [post to Stack
-Overflow](http://stackoverflow.com/questions/tagged/active-model-serializers).
+If you have a question, please [post to Stack Overflow](http://stackoverflow.com/questions/tagged/active-model-serializers).
 
 Thanks!
- 
-## Contributing 
- 
-1. Fork it ( https://github.com/rails-api/active_model_serializers/fork ) 
-2. Create your feature branch (`git checkout -b my-new-feature`) 
-3. Commit your changes (`git commit -am 'Add some feature'`) 
-4. Push to the branch (`git push origin my-new-feature`) 
-5. Create a new Pull Request 
+
+## Contributing
+
+1. Fork it ( https://github.com/rails-api/active_model_serializers/fork )
+2. Create your feature branch (`git checkout -b my-new-feature`)
+3. Commit your changes (`git commit -am 'Add some feature'`)
+4. Push to the branch (`git push origin my-new-feature`)
+5. Create a new Pull Request

lib/action_controller/serialization.rb

@@ -6,15 +6,18 @@ module Serialization
 
     include ActionController::Renderers
 
+    ADAPTER_OPTION_KEYS = [:include, :root]
+
     [:_render_option_json, :_render_with_renderer_json].each do |renderer_method|
       define_method renderer_method do |resource, options|
         serializer = ActiveModel::Serializer.serializer_for(resource)
 
         if serializer
+          adapter_opts, serializer_opts =
+            options.partition { |k, _| ADAPTER_OPTION_KEYS.include? k }
           # omg hax
-          object = serializer.new(resource, options)
-          adapter = ActiveModel::Serializer.adapter.new(object)
-
+          object = serializer.new(resource, Hash[serializer_opts])
+          adapter = ActiveModel::Serializer.adapter.new(object, Hash[adapter_opts])
           super(adapter, options)
         else
           super(resource, options)
@@ -23,4 +26,3 @@ module Serialization
     end
   end
 end
-

lib/active_model/serializer/adapter.rb

@@ -10,6 +10,7 @@ class Adapter
 
       def initialize(serializer, options = {})
         @serializer = serializer
+        @options = options
       end
 
       def serializable_hash(options = {})

lib/active_model/serializer/adapter/json_api.rb

@@ -5,16 +5,19 @@ class JsonApi < Adapter
         def initialize(serializer, options = {})
           super
           serializer.root = true
+          @hash = {}
+          @top = @options.fetch(:top) { @hash }
         end
 
         def serializable_hash(options = {})
-          @root = (options[:root] || serializer.json_key.to_s.pluralize).to_sym
-          @hash = {}
+          @root = (@options[:root] || serializer.json_key.to_s.pluralize).to_sym
 
           if serializer.respond_to?(:each)
-            @hash[@root] = serializer.map{|s| self.class.new(s).serializable_hash[@root] }
+            @hash[@root] = serializer.map do |s|
+              self.class.new(s, @options.merge(top: @top)).serializable_hash[@root]
+            end
           else
-            @hash[@root] = attributes_for_serializer(serializer, {})
+            @hash[@root] = attributes_for_serializer(serializer, @options)
 
             serializer.each_association do |name, association, opts|
               @hash[@root][:links] ||= {}
@@ -44,10 +47,10 @@ def add_links(name, serializers, options)
             @hash[@root][:links][name][:ids] += serializers.map{|serializer| serializer.id.to_s }
           end
 
-          unless options[:embed] == :ids || serializers.count == 0
-            @hash[:linked] ||= {}
-            @hash[:linked][name] ||= []
-            @hash[:linked][name] += serializers.map { |item| attributes_for_serializer(item, options) }
+          unless serializers.none? || @options[:embed] == :ids
+            serializers.each do |serializer|
+              add_linked(name, serializer)
+            end
           end
         end
 
@@ -62,24 +65,42 @@ def add_link(name, serializer, options)
               @hash[@root][:links][name][:id] = serializer.id.to_s
             end
 
-            unless options[:embed] == :ids
-              plural_name = name.to_s.pluralize.to_sym
-              @hash[:linked] ||= {}
-              @hash[:linked][plural_name] ||= []
-              @hash[:linked][plural_name].push attributes_for_serializer(serializer, options)
+            unless @options[:embed] == :ids
+              add_linked(name, serializer)
             end
           else
             @hash[@root][:links][name] = nil
           end
         end
 
+        def add_linked(resource, serializer, parent = nil)
+          resource_path = [parent, resource].compact.join('.')
+          if include_assoc? resource_path
+            plural_name = resource.to_s.pluralize.to_sym
+            attrs = attributes_for_serializer(serializer, @options)
+            @top[:linked] ||= {}
+            @top[:linked][plural_name] ||= []
+            @top[:linked][plural_name].push attrs unless @top[:linked][plural_name].include? attrs
+          end
+
+          unless serializer.respond_to?(:each)
+            serializer.each_association do |name, association, opts|
+              add_linked(name, association, resource) if association
+            end
+          end
+        end
+
         private
 
         def attributes_for_serializer(serializer, options)
           attributes = serializer.attributes(options)
           attributes[:id] = attributes[:id].to_s if attributes[:id]
           attributes
         end
+
+        def include_assoc? assoc
+          @options[:include] && @options[:include].split(',').include?(assoc.to_s)
+        end
       end
     end
   end

test/action_controller/json_api_linked_test.rb

@@ -0,0 +1,104 @@
+require 'test_helper'
+
+module ActionController
+  module Serialization
+    class JsonApiLinkedTest < ActionController::TestCase
+      class MyController < ActionController::Base
+        def setup_post
+          @author = Author.new(id: 1, name: 'Steve K.')
+          @author.posts = []
+          @author2 = Author.new(id: 2, name: 'Anonymous')
+          @author2.posts = []
+          @post = Post.new(id: 1, title: 'New Post', body: 'Body')
+          @first_comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
+          @second_comment = Comment.new(id: 2, body: 'ZOMG ANOTHER COMMENT')
+          @post.comments = [@first_comment, @second_comment]
+          @post.author = @author
+          @first_comment.post = @post
+          @first_comment.author = @author2
+          @second_comment.post = @post
+          @second_comment.author = nil
+        end
+
+        def with_json_api_adapter
+          old_adapter = ActiveModel::Serializer.config.adapter
+          ActiveModel::Serializer.config.adapter = :json_api
+          yield
+        ensure
+          ActiveModel::Serializer.config.adapter = old_adapter
+        end
+
+        def render_resource_without_include
+          with_json_api_adapter do
+            setup_post
+            render json: @post
+          end
+        end
+
+        def render_resource_with_include
+          with_json_api_adapter do
+            setup_post
+            render json: @post, include: 'author'
+          end
+        end
+
+        def render_resource_with_nested_include
+          with_json_api_adapter do
+            setup_post
+            render json: @post, include: 'comments.author'
+          end
+        end
+
+        def render_collection_without_include
+          with_json_api_adapter do
+            setup_post
+            render json: [@post]
+          end
+        end
+
+        def render_collection_with_include
+          with_json_api_adapter do
+            setup_post
+            render json: [@post], include: 'author,comments'
+          end
+        end
+      end
+
+      tests MyController
+
+      def test_render_resource_without_include
+        get :render_resource_without_include
+        response = JSON.parse(@response.body)
+        refute response.key? 'linked'
+      end
+
+      def test_render_resource_with_include
+        get :render_resource_with_include
+        response = JSON.parse(@response.body)
+        assert response.key? 'linked'
+        assert_equal 1, response['linked']['authors'].size
+        assert_equal 'Steve K.', response['linked']['authors'].first['name']
+      end
+
+      def test_render_resource_with_nested_include
+        get :render_resource_with_nested_include
+        response = JSON.parse(@response.body)
+        assert response.key? 'linked'
+        assert_equal 1, response['linked']['authors'].size
+        assert_equal 'Anonymous', response['linked']['authors'].first['name']
+      end
+
+      def test_render_collection_without_include
+        get :render_collection_without_include
+        response = JSON.parse(@response.body)
+        refute response.key? 'linked'
+      end
+
+      def test_render_collection_with_include
+        get :render_collection_with_include
+        response = JSON.parse(@response.body)
+        assert response.key? 'linked'
+      end
+    end
+  end
+end

test/adapter/json/belongs_to_test.rb

@@ -11,8 +11,9 @@ def setup
             @comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
             @post.comments = [@comment]
             @anonymous_post.comments = []
-            @comment.post = @post
             @post.author = @author
+            @comment.post = @post
+            @comment.author = nil
             @anonymous_post.author = nil
 
             @serializer = CommentSerializer.new(@comment)

test/adapter/json_api/belongs_to_test.rb

@@ -13,11 +13,13 @@ def setup
             @post.comments = [@comment]
             @anonymous_post.comments = []
             @comment.post = @post
+            @comment.author = nil
             @post.author = @author
             @anonymous_post.author = nil
             @blog = Blog.new(id: 1, name: "My Blog!!")
             @blog.writer = @author
             @blog.articles = [@post, @anonymous_post]
+            @author.posts = []
 
             @serializer = CommentSerializer.new(@comment)
             @adapter = ActiveModel::Serializer::Adapter::JsonApi.new(@serializer)
@@ -28,6 +30,7 @@ def test_includes_post_id
           end
 
           def test_includes_linked_post
+            @adapter = ActiveModel::Serializer::Adapter::JsonApi.new(@serializer, include: 'post')
             assert_equal([{id: "42", title: 'New Post', body: 'Body'}], @adapter.serializable_hash[:linked][:posts])
           end