Namespace separator setting for json-api and tests (#1874)

Adds jsonapi_namespace_separator configuration

Also:

* Enable getting type from record class without serializer

Needs Followup:

- https://github.com/rails-api/active_model_serializers/pull/1874#discussion_r74607042 
- https://github.com/rails-api/active_model_serializers/pull/1874#discussion_r74607734

CHANGELOG.md

@@ -6,6 +6,9 @@ Breaking changes:
 
 Features:
 
+- [#1791](https://github.com/rails-api/active_model_serializers/pull/1791) (@bf4, @youroff, @NullVoxPopuli)
+  - Added `jsonapi_namespace_separator` config option.
+
 Fixes:
 
 - [#1833](https://github.com/rails-api/active_model_serializers/pull/1833) Remove relationship links if they are null (@groyoh)

docs/general/configuration_options.md

@@ -72,6 +72,19 @@ Possible values:
 - `:singular`
 - `:plural` (default)
 
+##### jsonapi_namespace_separator
+
+Sets separator string for namespaced models to render `type` attribute.
+
+
+| Separator | Example: Admin::User |
+|----|----|
+| `'-'` (default) | 'admin-users'
+| `'--'` (recommended) | 'admin--users'
+
+See [Recommendation for dasherizing (kebab-case-ing) namespaced object, such as `Admin::User`](https://github.com/json-api/json-api/issues/850)
+for more discussion.
+
 ##### jsonapi_include_toplevel_object
 
 Include a [top level jsonapi member](http://jsonapi.org/format/#document-jsonapi-object)

lib/active_model/serializer/configuration.rb

@@ -21,13 +21,14 @@ module ActiveModel
 
         config.default_includes = '*'
         config.adapter = :attributes
+        config.key_transform = nil
         config.jsonapi_resource_type = :plural
+        config.jsonapi_namespace_separator = '-'.freeze
         config.jsonapi_version = '1.0'
         config.jsonapi_toplevel_meta = {}
         # Make JSON API top-level jsonapi member opt-in
         # ref: http://jsonapi.org/format/#document-top-level
         config.jsonapi_include_toplevel_object = false
-        config.key_transform = nil
 
         config.schema_path = 'test/support/schemas'
       end

lib/active_model_serializers/adapter/json_api/resource_identifier.rb

@@ -2,11 +2,30 @@ module ActiveModelSerializers
   module Adapter
     class JsonApi
       class ResourceIdentifier
+        def self.type_for(class_name, serializer_type = nil, transform_options = {})
+          if serializer_type
+            raw_type = serializer_type
+          else
+            inflection =
+              if ActiveModelSerializers.config.jsonapi_resource_type == :singular
+                :singularize
+              else
+                :pluralize
+              end
+
+            raw_type = class_name.underscore
+            raw_type = ActiveSupport::Inflector.public_send(inflection, raw_type)
+            raw_type
+              .gsub!('/'.freeze, ActiveModelSerializers.config.jsonapi_namespace_separator)
+            raw_type
+          end
+          JsonApi.send(:transform_key_casing!, raw_type, transform_options)
+        end
+
         # {http://jsonapi.org/format/#document-resource-identifier-objects Resource Identifier Objects}
         def initialize(serializer, options)
           @id   = id_for(serializer)
-          @type = JsonApi.send(:transform_key_casing!, type_for(serializer),
-            options)
+          @type = type_for(serializer, options)
         end
 
         def as_json
@@ -19,13 +38,8 @@ module ActiveModelSerializers
 
         private
 
-        def type_for(serializer)
-          return serializer._type if serializer._type
-          if ActiveModelSerializers.config.jsonapi_resource_type == :singular
-            serializer.object.class.model_name.singular
-          else
-            serializer.object.class.model_name.plural
-          end
+        def type_for(serializer, transform_options)
+          self.class.type_for(serializer.object.class.name, serializer._type, transform_options)
         end
 
         def id_for(serializer)

test/adapter/json_api/linked_test.rb

@@ -223,6 +223,25 @@ module ActiveModelSerializers
           assert_equal expected, relationships
         end
 
+        def test_underscore_model_namespace_with_namespace_separator_for_linked_resource_type
+          spammy_post = Post.new(id: 123)
+          spammy_post.related = [Spam::UnrelatedLink.new(id: 456)]
+          serializer = SpammyPostSerializer.new(spammy_post)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          relationships = with_namespace_separator '--' do
+            adapter.serializable_hash[:data][:relationships]
+          end
+          expected = {
+            related: {
+              data: [{
+                type: 'spam--unrelated-links',
+                id: '456'
+              }]
+            }
+          }
+          assert_equal expected, relationships
+        end
+
         def test_multiple_references_to_same_resource
           serializer = ActiveModel::Serializer::CollectionSerializer.new([@first_comment, @second_comment])
           adapter = ActiveModelSerializers::Adapter::JsonApi.new(

test/adapter/json_api/resource_identifier_test.rb

@@ -39,6 +39,26 @@ module ActiveModelSerializers
           test_type_inflection(AuthorSerializer, 'authors', :plural)
         end
 
+        def test_type_with_namespace
+          Object.const_set(:Admin, Module.new)
+          model = Class.new(::Model)
+          Admin.const_set(:PowerUser, model)
+          serializer = Class.new(ActiveModel::Serializer)
+          Admin.const_set(:PowerUserSerializer, serializer)
+          with_namespace_separator '--' do
+            admin_user = Admin::PowerUser.new
+            serializer = Admin::PowerUserSerializer.new(admin_user)
+            expected = {
+              id: admin_user.id,
+              type: 'admin--power-users'
+            }
+
+            identifier = ResourceIdentifier.new(serializer, {})
+            actual = identifier.as_json
+            assert_equal(expected, actual)
+          end
+        end
+
         def test_id_defined_on_object
           test_id(AuthorSerializer, @model.id.to_s)
         end

test/support/serialization_testing.rb

@@ -9,6 +9,14 @@ module SerializationTesting
     ActiveModelSerializers::SerializableResource.new(obj).to_json
   end
 
+  def with_namespace_separator(seperator)
+    original_seperator = ActiveModelSerializers.config.jsonapi_namespace_separator
+    ActiveModelSerializers.config.jsonapi_namespace_separator = seperator
+    yield
+  ensure
+    ActiveModelSerializers.config.jsonapi_namespace_separator = original_seperator
+  end
+
   # Aliased as :with_configured_adapter to clarify that
   # this method tests the configured adapter.
   # When not testing configuration, it may be preferable