Adds support for top-level links to JsonApi adapter

http://jsonapi.org/format/#document-top-level

fix failing tests

support for top-level links limited to jsonapi adapter

Move docs from README to docs/ dir

move links to json-api adapter & create Links class to hold links data

Author: leandrocp

.gitignore

@@ -22,3 +22,4 @@ tmp
 .ruby-version
 .ruby-gemset
 vendor/bundle
+tags

CHANGELOG.md

@@ -65,6 +65,8 @@ Features:
     CollectionSerializer for clarity, add ActiveModelSerializers.config.collection_serializer (@bf4)
 - [#1295](https://github.com/rails-api/active_model_serializers/pull/1295) Add config `serializer_lookup_enabled` that,
   when disabled, requires serializers to explicitly specified. (@trek)
+- [#1247](https://github.com/rails-api/active_model_serializers/pull/1247) Add top-level links (@beauby)
+  * Add more tests and docs for top-level links (@leandrocp)
 
 Fixes:
 

docs/README.md

@@ -23,6 +23,7 @@ This is the documentation of ActiveModelSerializers, it's focused on the **0.10.
 - [How to add pagination links](howto/add_pagination_links.md)
 - [Using ActiveModelSerializers Outside Of Controllers](howto/outside_controller_use.md)
 - [Testing ActiveModelSerializers](howto/test.md)
+- [How to add top-level links](howto/add_top_level_links.md) (```JSON-API``` only)
 
 ## Integrations
 

docs/howto/add_top_level_links.md

@@ -0,0 +1,31 @@
+# How to add top-level links
+
+JsonApi supports a [links object](http://jsonapi.org/format/#document-links) to be specified at top-level, that you can specify in the `render`:
+
+```ruby
+  render json: @posts, links: { "self": "http://example.com/api/posts" }
+```
+
+That's the result:
+
+```json
+{
+  "data": [
+    {
+      "type": "posts",
+      "id": "1",
+      "attributes": {
+        "title": "JSON API is awesome!",
+        "body": "You should be using JSON API",
+        "created": "2015-05-22T14:56:29.000Z",
+        "updated": "2015-05-22T14:56:28.000Z"
+      }
+    }
+  ],
+  "links": {
+    "self": "http://example.com/api/posts"
+  }
+}
+```
+
+This feature is specific to JsonApi, so you have to use the use the [JsonApi Adapter](https://github.com/rails-api/active_model_serializers/blob/master/docs/general/adapters.md#jsonapi)

lib/active_model/serializer/adapter/json_api/links.rb

@@ -0,0 +1,25 @@
+module ActiveModel
+  class Serializer
+    class Adapter
+      class JsonApi < Adapter
+        class Links
+          def initialize(links = {})
+            @links = links
+          end
+
+          def serializable_hash
+            @links
+          end
+
+          def update(links = {})
+            @links.update(links)
+          end
+
+          def present?
+            !@links.empty?
+          end
+        end
+      end
+    end
+  end
+end

test/action_controller/serialization_test.rb

@@ -45,6 +45,17 @@ def render_array_using_implicit_serializer_and_meta
           render json: @profiles, meta: { total: 10 }
         end
 
+        def render_array_using_implicit_serializer_and_links
+          with_adapter ActiveModel::Serializer::Adapter::JsonApi do
+
+            @profiles = [
+              Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
+            ]
+
+            render json: @profiles, links: { self: "http://example.com/api/profiles/1" }
+          end
+        end
+
         def render_object_with_cache_enabled
           @comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
           @author  = Author.new(id: 1, name: 'Joao Moura.')
@@ -254,6 +265,29 @@ def test_render_array_using_implicit_serializer_and_meta
         assert_equal expected.to_json, @response.body
       end
 
+      def test_render_array_using_implicit_serializer_and_links
+        get :render_array_using_implicit_serializer_and_links
+
+        expected = {
+          data: [
+            {
+              id: assigns(:profiles).first.id.to_s,
+              type: "profiles",
+              attributes: {
+                name: "Name 1",
+                description: "Description 1"
+              }
+            }
+          ],
+          links: {
+            self: "http://example.com/api/profiles/1"
+          }
+        }
+
+        assert_equal 'application/json', @response.content_type
+        assert_equal expected.to_json, @response.body
+      end
+
       def test_render_with_cache_enable
         expected = {
           id: 1,

test/adapter/json_api/top_level_links_test.rb

@@ -0,0 +1,101 @@
+require 'test_helper'
+
+module ActiveModel
+  class Serializer
+    class Adapter
+      class JsonApi
+        class TopLevelLinksTest < Minitest::Test
+          URI = 'http://example.com'
+
+          def setup
+            ActionController::Base.cache_store.clear
+            @blog = Blog.new(id: 1,
+                             name: 'AMS Hints',
+                             writer: Author.new(id: 2, name: "Steve"),
+                             articles: [Post.new(id: 3, title: "AMS")])
+          end
+
+          def load_adapter(paginated_collection, options = {})
+            options = options.merge(adapter: :json_api)
+            ActiveModel::SerializableResource.new(paginated_collection, options)
+          end
+
+          def test_links_is_not_present_when_not_defined
+            adapter = load_adapter(@blog)
+
+            expected = {
+              :data => {
+                :id => "1",
+                :type => "blogs",
+                :attributes => {
+                  :name => "AMS Hints"
+                },
+                :relationships => {
+                  :writer=> {:data => {:type => "authors", :id => "2"}},
+                  :articles => {:data => [{:type => "posts", :id => "3"}]}
+               }
+            }}
+
+            assert_equal expected, adapter.serializable_hash(@options)
+          end
+
+          def test_links_is_present_when_defined
+            adapter = load_adapter(@blog, {links: links})
+
+            expected = {
+              :data => {
+                :id => "1",
+                :type => "blogs",
+                :attributes => {
+                  :name => "AMS Hints"
+                },
+                :relationships => {
+                  :writer=> {:data => {:type => "authors", :id => "2"}},
+                  :articles => {:data => [{:type => "posts", :id => "3"}]}
+               }
+              },
+               :links => {:self => "http://example.com/blogs/1"}
+            }
+
+            assert_equal expected, adapter.serializable_hash(@options)
+          end
+
+          def links
+            {
+              self: "#{URI}/blogs/1"
+            }
+          end
+
+          # def test_links_is_not_present_when_not_declared
+          #   serializer = AlternateBlogSerializer.new(@blog)
+          #   adapter = ActiveModel::Serializer::Adapter::JsonApi.new(serializer)
+          #   expected = {
+          #     data: {
+          #       id: "1",
+          #       type: "blogs",
+          #       attributes: {
+          #         title: "AMS Hints"
+          #       }
+          #     }
+          #   }
+          #   assert_equal expected, adapter.as_json
+          # end
+
+          # def test_links_is_not_present_on_flattenjson_adapter
+          #   serializer = AlternateBlogSerializer.new(@blog, :links => {:self => "/blogs/1"})
+          #   adapter = ActiveModel::Serializer::Adapter::FlattenJson.new(serializer)
+          #   expected = {:id=>1, :title=>"AMS Hints"}
+          #   assert_equal expected, adapter.as_json
+          # end
+
+          # def test_links_is_not_present_on_json_adapter
+          #   serializer = AlternateBlogSerializer.new(@blog, :links => {:self => "/blogs/1"})
+          #   adapter = ActiveModel::Serializer::Adapter::Json.new(serializer)
+          #   expected = {:blog=>{:id=>1, :title=>"AMS Hints"}}
+          #   assert_equal expected, adapter.as_json
+          # end
+        end
+      end
+    end
+  end
+end