From d364c4f18831a763fee93a72300e85731c0085ef Mon Sep 17 00:00:00 2001
From: Benjamin Fleischer <github@benjaminfleischer.com>
Date: Mon, 29 Feb 2016 16:10:41 -0600
Subject: [PATCH] Spike Jsonapi Renderer registration

---
 .../register_jsonapi_renderer.rb              | 64 +++++++++++++++++++
 .../action_controller/json_api/linked_test.rb | 19 +++---
 2 files changed, 74 insertions(+), 9 deletions(-)
 create mode 100644 lib/active_model_serializers/register_jsonapi_renderer.rb

diff --git a/lib/active_model_serializers/register_jsonapi_renderer.rb b/lib/active_model_serializers/register_jsonapi_renderer.rb
new file mode 100644
index 00000000..d17841fb
--- /dev/null
+++ b/lib/active_model_serializers/register_jsonapi_renderer.rb
@@ -0,0 +1,64 @@
+# Based on discussion in https://github.com/rails/rails/pull/23712#issuecomment-184977238,
+# the JSON API media type will have its own format/renderer.
+#
+# > We recommend the media type be registered on its own as jsonapi
+# when a jsonapi Renderer and deserializer (Http::Parameters::DEFAULT_PARSERS) are added.
+#
+# Usage:
+#
+# ActiveSupport.on_load(:action_controller) do
+#   require 'active_model_serializers/register_jsonapi_renderer'
+# end
+#
+# And then in controllers, use `render jsonapi: model` rather than `render json: model, adapter: :json_api`.
+#
+# For example, in a controller action, we can:
+# respond_to do |format|
+#   format.jsonapi { render jsonapi: model }
+# end
+#
+# or
+#
+# render jsonapi: model
+#
+# No wrapper format needed as it does not apply (i.e. no `wrap_parameters format: [jsonapi]`)
+
+module ActiveModelSerializers::Jsonapi
+  MEDIA_TYPE = 'application/vnd.api+json'.freeze
+  HEADERS = {
+    response: { 'CONTENT_TYPE'.freeze => MEDIA_TYPE },
+    request:  { 'ACCEPT'.freeze => MEDIA_TYPE }
+  }.freeze
+  module ControllerSupport
+    def serialize_jsonapi(json, options)
+      options[:adapter] = :json_api
+      options.fetch(:serialization_context) { options[:serialization_context] = ActiveModelSerializers::SerializationContext.new(request) }
+      get_serializer(json, options)
+    end
+  end
+end
+
+# actionpack/lib/action_dispatch/http/mime_types.rb
+Mime::Type.register ActiveModelSerializers::Jsonapi::MEDIA_TYPE, :jsonapi
+
+parsers = Rails::VERSION::MAJOR >= 5 ? ActionDispatch::Http::Parameters : ActionDispatch::ParamsParser
+media_type = Mime::Type.lookup(ActiveModelSerializers::Jsonapi::MEDIA_TYPE)
+
+# Proposal: should actually deserialize the JSON API params
+# to the hash format expected by `ActiveModel::Serializers::JSON`
+# actionpack/lib/action_dispatch/http/parameters.rb
+parsers::DEFAULT_PARSERS[media_type] = lambda do |body|
+  data = JSON.parse(body)
+  data = { :_json => data } unless data.is_a?(Hash)
+  data.with_indifferent_access
+end
+
+# ref https://github.com/rails/rails/pull/21496
+ActionController::Renderers.add :jsonapi do |json, options|
+  json = serialize_jsonapi(json, options).to_json(options) unless json.is_a?(String)
+  self.content_type ||= media_type
+  headers.merge! ActiveModelSerializers::Jsonapi::HEADERS[:response]
+  self.response_body = json
+end
+
+ActionController::Base.send :include, ActiveModelSerializers::Jsonapi::ControllerSupport
diff --git a/test/action_controller/json_api/linked_test.rb b/test/action_controller/json_api/linked_test.rb
index 8d541f5b..5a1e3bc3 100644
--- a/test/action_controller/json_api/linked_test.rb
+++ b/test/action_controller/json_api/linked_test.rb
@@ -5,6 +5,7 @@ module ActionController
     class JsonApi
       class LinkedTest < ActionController::TestCase
         class LinkedTestController < ActionController::Base
+          require 'active_model_serializers/register_jsonapi_renderer'
           def setup_post
             ActionController::Base.cache_store.clear
             @role1 = Role.new(id: 1, name: 'admin')
@@ -38,49 +39,49 @@ module ActionController
 
           def render_resource_without_include
             setup_post
-            render json: @post, adapter: :json_api
+            render jsonapi: @post
           end
 
           def render_resource_with_include
             setup_post
-            render json: @post, include: [:author], adapter: :json_api
+            render jsonapi: @post, include: [:author]
           end
 
           def render_resource_with_include_of_custom_key_by_original
             setup_post
-            render json: @post, include: [:reviews], adapter: :json_api, serializer: PostWithCustomKeysSerializer
+            render jsonapi: @post, include: [:reviews], serializer: PostWithCustomKeysSerializer
           end
 
           def render_resource_with_nested_include
             setup_post
-            render json: @post, include: [comments: [:author]], adapter: :json_api
+            render jsonapi: @post, include: [comments: [:author]]
           end
 
           def render_resource_with_nested_has_many_include_wildcard
             setup_post
-            render json: @post, include: 'author.*', adapter: :json_api
+            render jsonapi: @post, include: 'author.*'
           end
 
           def render_resource_with_missing_nested_has_many_include
             setup_post
             @post.author = @author2 # author2 has no roles.
-            render json: @post, include: [author: [:roles]], adapter: :json_api
+            render jsonapi: @post, include: [author: [:roles]]
           end
 
           def render_collection_with_missing_nested_has_many_include
             setup_post
             @post.author = @author2
-            render json: [@post, @post2], include: [author: [:roles]], adapter: :json_api
+            render jsonapi: [@post, @post2], include: [author: [:roles]]
           end
 
           def render_collection_without_include
             setup_post
-            render json: [@post], adapter: :json_api
+            render jsonapi: [@post]
           end
 
           def render_collection_with_include
             setup_post
-            render json: [@post], include: 'author, comments', adapter: :json_api
+            render jsonapi: [@post], include: 'author, comments'
           end
         end