Fix rails-api#1759, Grape integration, adds serialization_context (#4)

* Fix rails-api#1759, Grape integration, adds serialization_context

- `serialization_context` is added in grape formatter so grape continues to render models without an explicit call to the `render` helper method
- Made it straightforward for subclasses to add other serializer options (such as `serialization_scope`).

* Updated Grape tests to include:
- paginated collections
- implicit Grape serializer (i.e. without explicit invocation of `render` helper method)

* Update Changelog with fixes.

CHANGELOG.md

@@ -10,6 +10,8 @@ Features:
 Fixes:
 - [#1754](https://github.com/rails-api/active_model_serializers/pull/1754) Fixes #1759, Grape integration, improves serialization_context
   missing error message on pagination. Document overriding CollectionSerializer#paginated?. (@bf4)
+- [#1754](https://github.com/rails-api/active_model_serializers/pull/1754) Fixes #1759, Grape integration, moved serialization_context
+  creation to Grape formatter, so resource serialization works without explicit calls to the `render` helper method. Added Grape collection tests. (@onomated)
 - [#1710](https://github.com/rails-api/active_model_serializers/pull/1710) Prevent association loading when `include_data` option
   is set to `false`. (@groyoh)
 - [#1747](https://github.com/rails-api/active_model_serializers/pull/1747) Improve jsonapi mime type registration for Rails 5 (@remear)

lib/grape/formatters/active_model_serializers.rb

@@ -2,14 +2,31 @@
 #
 # Serializer options can be passed as a hash from your Grape endpoint using env[:active_model_serializer_options],
 # or better yet user the render helper in Grape::Helpers::ActiveModelSerializers
+
+require 'active_model_serializers/serialization_context'
+
 module Grape
   module Formatters
     module ActiveModelSerializers
       def self.call(resource, env)
-        serializer_options = {}
-        serializer_options.merge!(env[:active_model_serializer_options]) if env[:active_model_serializer_options]
+        serializer_options = build_serializer_options(env)
         ::ActiveModelSerializers::SerializableResource.new(resource, serializer_options).to_json
       end
+
+      def self.build_serializer_options(env)
+        ams_options = env[:active_model_serializer_options] || {}
+
+        # Add serialization context
+        ams_options.fetch(:serialization_context) do
+          request = env['grape.request']
+          ams_options[:serialization_context] = ::ActiveModelSerializers::SerializationContext.new(
+            request_url: request.url[/\A[^?]+/],
+            query_parameters: request.params
+          )
+        end
+
+        ams_options
+      end
     end
   end
 end

lib/grape/helpers/active_model_serializers.rb

@@ -1,7 +1,5 @@
 # Helpers can be included in your Grape endpoint as: helpers Grape::Helpers::ActiveModelSerializers
 
-require 'active_model_serializers/serialization_context'
-
 module Grape
   module Helpers
     module ActiveModelSerializers
@@ -11,12 +9,6 @@ module ActiveModelSerializers
       #
       # Example: To include pagination meta data: render(posts, meta: { page: posts.page, total_pages: posts.total_pages })
       def render(resource, active_model_serializer_options = {})
-        active_model_serializer_options.fetch(:serialization_context) do
-          active_model_serializer_options[:serialization_context] = ::ActiveModelSerializers::SerializationContext.new(
-            original_url: request.url[/\A[^?]+/],
-            query_parameters: request.params
-          )
-        end
         env[:active_model_serializer_options] = active_model_serializer_options
         resource
       end

test/grape_test.rb

@@ -1,6 +1,9 @@
 require 'test_helper'
 require 'grape'
 require 'grape/active_model_serializers'
+require 'kaminari'
+require 'kaminari/hooks'
+::Kaminari::Hooks.init
 
 class ActiveModelSerializers::GrapeTest < ActiveSupport::TestCase
   include Rack::Test::Methods
@@ -21,6 +24,30 @@ def self.all
           ARModels::Post.all
         end
     end
+
+    def self.reset_all
+      ARModels::Post.delete_all
+      @all = nil
+    end
+
+    def self.collection_per
+      2
+    end
+
+    def self.collection
+      @collection ||=
+        begin
+          Kaminari.paginate_array(
+            [
+                  Profile.new(id: 1, name: 'Name 1', description: 'Description 1', comments: 'Comments 1'),
+                  Profile.new(id: 2, name: 'Name 2', description: 'Description 2', comments: 'Comments 2'),
+                  Profile.new(id: 3, name: 'Name 3', description: 'Description 3', comments: 'Comments 3'),
+                  Profile.new(id: 4, name: 'Name 4', description: 'Description 4', comments: 'Comments 4'),
+                  Profile.new(id: 5, name: 'Name 5', description: 'Description 5', comments: 'Comments 5')
+              ]
+          ).page(1).per(collection_per)
+        end
+    end
   end
 
   class GrapeTest < Grape::API
@@ -41,11 +68,28 @@ class GrapeTest < Grape::API
         posts = Models.all
         render posts, adapter: :json_api
       end
+
+      get '/render_collection_with_json_api' do
+        posts = Models.collection
+        render posts, adapter: :json_api
+      end
+
+      get '/render_with_implicit_formatter' do
+        Models.model1
+      end
+
+      get '/render_array_with_implicit_formatter' do
+        Models.all
+      end
+
+      get '/render_collection_with_implicit_formatter' do
+        Models.collection
+      end
     end
   end
 
   def app
-    GrapeTest.new
+    Grape::Middleware::Globals.new(GrapeTest.new)
   end
 
   def test_formatter_returns_json
@@ -77,6 +121,53 @@ def test_formatter_handles_arrays
     assert last_response.ok?
     assert_equal serializable_resource.to_json, last_response.body
   ensure
-    ARModels::Post.delete_all
+    Models.reset_all
+  end
+
+  def test_formatter_handles_collections
+    get '/grape/render_collection_with_json_api'
+    assert last_response.ok?
+
+    representation = JSON.parse(last_response.body)
+    assert representation.include?('data')
+    assert representation['data'].count == Models.collection_per
+    assert representation.include?('links')
+    assert representation['links'].count > 0
+  end
+
+  def test_implicit_formatter
+    ActiveModel::Serializer.config.adapter = :json_api
+    get '/grape/render_with_implicit_formatter'
+
+    post = Models.model1
+    serializable_resource = serializable(post, adapter: :json_api)
+
+    assert last_response.ok?
+    assert_equal serializable_resource.to_json, last_response.body
+  end
+
+  def test_implicit_formatter_handles_arrays
+    ActiveModel::Serializer.config.adapter = :json_api
+    get '/grape/render_array_with_implicit_formatter'
+
+    posts = Models.all
+    serializable_resource = serializable(posts, adapter: :json_api)
+
+    assert last_response.ok?
+    assert_equal serializable_resource.to_json, last_response.body
+  ensure
+    Models.reset_all
+  end
+
+  def test_implicit_formatter_handles_collections
+    ActiveModel::Serializer.config.adapter = :json_api
+    get '/grape/render_collection_with_implicit_formatter'
+    assert last_response.ok?
+
+    representation = JSON.parse(last_response.body)
+    assert representation.include?('data')
+    assert representation['data'].count == Models.collection_per
+    assert representation.include?('links')
+    assert representation['links'].count > 0
   end
 end