Add support for jsonapi top level member

CHANGELOG.md

@@ -11,4 +11,5 @@
   * remove root key option and split JSON adapter [@joaomdmoura]
   * adds FlattenJSON as default adapter [@joaomdmoura]
   * adds support for `pagination links` at top level of JsonApi adapter [@bacarini]
-  * adds extended format for `include` option to JSONAPI adapter [@beauby]
+  * adds extended format for `include` option to JsonApi adapter [@beauby]
+  * adds support for top level jsonapi member support [@beauby]

docs/general/configuration_options.md

@@ -9,3 +9,5 @@ The following configuration options can be set on `ActiveModel::Serializer.confi
 ## JSON API
 
 - `jsonapi_resource_type`: Whether the `type` attributes of resources should be singular or plural. Possible values: `:singular, :plural`. Default: `:plural`.
+- `jsonapi_toplevel_member`: Whether to include a [top level JSON API member](http://jsonapi.org/format/#document-jsonapi-object) in the response document. Default: `false`.
+- `jsonapi_version`: The latest version of the spec the API conforms to. Used when `jsonapi_toplevel_member` is `true`. Default: `'1.0'`.

lib/active_model/serializable_resource.rb

@@ -1,7 +1,8 @@
 require 'set'
 module ActiveModel
   class SerializableResource
-    ADAPTER_OPTION_KEYS = Set.new([:include, :fields, :adapter])
+    ADAPTER_OPTION_KEYS = Set.new([:include, :fields, :adapter,
+                                   :jsonapi_toplevel_meta])
 
     def initialize(resource, options = {})
       @resource = resource

lib/active_model/serializer/adapter/json_api.rb

@@ -16,11 +16,20 @@ def initialize(serializer, options = {})
 
         def serializable_hash(options = nil)
           options ||= {}
-          if serializer.respond_to?(:each)
-            serializable_hash_for_collection(serializer, options)
-          else
-            serializable_hash_for_single_resource(serializer, options)
+          hash =
+            if serializer.respond_to?(:each)
+              serializable_hash_for_collection(serializer, options)
+            else
+              serializable_hash_for_single_resource(serializer, options)
+            end
+
+          if ActiveModel::Serializer.config.jsonapi_toplevel_member
+            hash[:jsonapi] = {}
+            hash[:jsonapi][:version] = ActiveModel::Serializer.config.jsonapi_version
+            hash[:jsonapi][:meta] = @options[:jsonapi_toplevel_meta] if @options[:jsonapi_toplevel_meta]
           end
+
+          hash
         end
 
         def fragment_cache(cached_hash, non_cached_hash)

lib/active_model/serializer/configuration.rb

@@ -8,6 +8,8 @@ module Configuration
         base.config.array_serializer = ActiveModel::Serializer::ArraySerializer
         base.config.adapter = :flatten_json
         base.config.jsonapi_resource_type = :plural
+        base.config.jsonapi_toplevel_member = false
+        base.config.jsonapi_version = '1.0'
       end
     end
   end

test/adapter/json_api/toplevel_jsonapi_test.rb

@@ -0,0 +1,86 @@
+require 'test_helper'
+
+module ActiveModel
+  class Serializer
+    class Adapter
+      class JsonApi
+        class TopLevelJsonApiTest < Minitest::Test
+          def setup
+            @author = Author.new(id: 1, name: 'Steve K.')
+            @author.bio = nil
+            @author.roles = []
+            @blog = Blog.new(id: 23, name: 'AMS Blog')
+            @post = Post.new(id: 42, title: 'New Post', body: 'Body')
+            @anonymous_post = Post.new(id: 43, title: 'Hello!!', body: 'Hello, world!!')
+            @comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
+            @post.comments = [@comment]
+            @post.blog = @blog
+            @anonymous_post.comments = []
+            @anonymous_post.blog = nil
+            @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 = []
+          end
+
+          def with_config(option, value)
+            old_value = ActiveModel::Serializer.config[option]
+            ActiveModel::Serializer.config[option] = value
+            yield
+          ensure
+            ActiveModel::Serializer.config[option] = old_value
+          end
+
+          def test_disable_toplevel_jsonapi
+            with_adapter :json_api do
+              with_config(:jsonapi_toplevel_member, false) do
+                hash = ActiveModel::SerializableResource.new(@post).serializable_hash
+                assert_nil(hash[:jsonapi])
+              end
+            end
+          end
+
+          def test_enable_toplevel_jsonapi
+            with_adapter :json_api do
+              with_config(:jsonapi_toplevel_member, true) do
+                hash = ActiveModel::SerializableResource.new(@post).serializable_hash
+                refute_nil(hash[:jsonapi])
+              end
+            end
+          end
+
+          def test_default_toplevel_jsonapi_version
+            with_adapter :json_api do
+              with_config(:jsonapi_toplevel_member, true) do
+                hash = ActiveModel::SerializableResource.new(@post).serializable_hash
+                assert_equal('1.0', hash[:jsonapi][:version])
+              end
+            end
+          end
+
+          def test_toplevel_jsonapi_no_meta
+            with_adapter :json_api do
+              with_config(:jsonapi_toplevel_member, true) do
+                hash = ActiveModel::SerializableResource.new(@post).serializable_hash
+                assert_nil(hash[:jsonapi][:meta])
+              end
+            end
+          end
+
+          def test_toplevel_jsonapi_meta
+            with_adapter :json_api do
+              with_config(:jsonapi_toplevel_member, true) do
+                hash = ActiveModel::SerializableResource.new(@post, jsonapi_toplevel_meta: 'custom').serializable_hash
+                assert_equal('custom', hash[:jsonapi][:meta])
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end