Apply key transforms to keys referenced in values

Author: remear

CHANGELOG.md

@@ -2,7 +2,11 @@
 
 Breaking changes:
 
+- [#1645](https://github.com/rails-api/active_model_serializers/pull/1645) Changed :dashed key transform to :dash. (@remear)
+- [#1574](https://github.com/rails-api/active_model_serializers/pull/1574) Default key case for the JsonApi adapter changed to dashed. (@remear)
+
 Features:
+- [#1645](https://github.com/rails-api/active_model_serializers/pull/1645) Transform keys referenced in values. (@remear)
 - [#1650](https://github.com/rails-api/active_model_serializers/pull/1650) Fix serialization scope options `scope`, `scope_name`
   take precedence over `serialization_scope` in the controller.
   Fix tests that required tearing down dynamic methods. (@bf4)

active_model_serializers.gemspec

@@ -57,4 +57,10 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'grape', ['>= 0.13', '< 1.0']
   spec.add_development_dependency 'json_schema'
   spec.add_development_dependency 'rake', ['>= 10.0', '< 12.0']
+
+  spec.post_install_message = <<-EOF
+NOTE: The default key case for the JsonApi adapter has changed to dashed.
+See https://github.com/rails-api/active_model_serializers/blob/master/docs/general/key_transform.md
+for more information on configuring this behavior.
+EOF
 end

docs/general/configuration_options.md

@@ -30,20 +30,24 @@ When `false`, serializers must be explicitly specified.
 
 ##### key_transform
 
-The [key transform](key_transform.md) to use.
+The [key transform](key_transforms.md) to use.
 
-Possible values:
 
-- `:camel` - ExampleKey
-- `:camel_lower` - exampleKey
-- `:dashed` - example-key
-- `:unaltered` - the original, unaltered key
-- `nil` - use the adapter default
+| Option | Result |
+|----|----|
+| `:camel` | ExampleKey |
+| `:camel_lower` | exampleKey |
+| `:dash` | example-key |
+| `:unaltered` | the original, unaltered key |
+| `:underscore` | example_key |
+| `nil` | use the adapter default |
 
 Each adapter has a default key transform configured:
 
-- `Json` - `:unaltered`
-- `JsonApi` - `:dashed`
+| Adapter | Default Key Transform |
+|----|----|
+| `Json` | `:unaltered` |
+| `JsonApi` | `:dash` |
 
 `config.key_transform` is a global override of the adapter default. Adapters
 still prefer the render option `:key_transform` over this setting.

docs/general/key_transform.md

@@ -0,0 +1,40 @@
+[Back to Guides](../README.md)
+
+# Key Transforms
+
+Key Transforms modify the casing of keys and keys referenced in values in
+serialized responses.
+
+Provided key transforms:
+
+| Option | Result |
+|----|----|
+| `:camel` | ExampleKey |
+| `:camel_lower` | exampleKey |
+| `:dash` | example-key |
+| `:unaltered` | the original, unaltered key |
+| `:underscore` | example_key |
+| `nil` | use the adapter default |
+
+Key translation precedence is as follows:
+
+##### Adapter option
+
+`key_transform` is provided as an option via render.
+
+```render json: posts, each_serializer: PostSerializer, key_transform: :camel_lower```
+
+##### Configuration option
+
+`key_transform` is set in `ActiveModelSerializers.config.key_transform`.
+
+```ActiveModelSerializers.config.key_transform = :camel_lower```
+
+##### Adapter default
+
+Each adapter has a default transform configured:
+
+| Adapter | Default Key Transform |
+|----|----|
+| `Json` | `:unaltered` |
+| `JsonApi` | `:dash` |

docs/general/key_transforms.md

@@ -58,25 +58,32 @@ def include_meta(json)
         json
       end
 
-      def default_key_transform
-        :unaltered
-      end
+      class << self
+        # Sets the default transform for the adapter.
+        #
+        # @return [Symbol] the default transform for the adapter
+        def default_key_transform
+          :unaltered
+        end
 
-      # Determines the transform to use in order of precedence:
-      #   serialization context, global config, adapter default.
-      #
-      # @param serialization_context [Object] the SerializationContext
-      # @return [Symbol] the transform to use
-      def key_transform(serialization_context)
-        serialization_context.key_transform ||
-        ActiveModelSerializers.config.key_transform ||
-        default_key_transform
-      end
+        # Determines the transform to use in order of precedence:
+        #   adapter option, global config, adapter default.
+        #
+        # @param options [Object]
+        # @return [Symbol] the transform to use
+        def transform(options)
+          return options[:key_transform] if options && options[:key_transform]
+          ActiveModelSerializers.config.key_transform || default_key_transform
+        end
 
-      def transform_key_casing!(value, serialization_context)
-        return value unless serialization_context
-        transform = key_transform(serialization_context)
-        KeyTransform.send(transform, value)
+        # Transforms the casing of the supplied value.
+        #
+        # @param value [Object] the value to be transformed
+        # @param options [Object] serializable resource options
+        # @return [Symbol] the default transform for the adapter
+        def transform_key_casing!(value, options)
+          KeyTransform.send(transform(options), value)
+        end
       end
     end
   end

lib/active_model_serializers/adapter/base.rb

@@ -4,7 +4,7 @@ class Json < Base
       def serializable_hash(options = nil)
         options ||= {}
         serialized_hash = { root => Attributes.new(serializer, instance_options).serializable_hash(options) }
-        transform_key_casing!(serialized_hash, options[:serialization_context])
+        self.class.transform_key_casing!(serialized_hash, options)
       end
     end
   end

lib/active_model_serializers/adapter/json.rb

@@ -37,8 +37,8 @@ def initialize(serializer, options = {})
         @fieldset = options[:fieldset] || ActiveModel::Serializer::Fieldset.new(options.delete(:fields))
       end
 
-      def default_key_transform
-        :dashed
+      def self.default_key_transform
+        :dash
       end
 
       # {http://jsonapi.org/format/#crud Requests are transactional, i.e. success or failure}
@@ -48,9 +48,9 @@ def serializable_hash(options = nil)
         document = if serializer.success?
                      success_document(options)
                    else
-                     failure_document
+                     failure_document(options)
                    end
-        transform_key_casing!(document, options[:serialization_context])
+        self.class.transform_key_casing!(document, options)
       end
 
       # {http://jsonapi.org/format/#document-top-level Primary data}
@@ -71,7 +71,7 @@ def serializable_hash(options = nil)
       def success_document(options)
         is_collection = serializer.respond_to?(:each)
         serializers = is_collection ? serializer : [serializer]
-        primary_data, included = resource_objects_for(serializers)
+        primary_data, included = resource_objects_for(serializers, options)
 
         hash = {}
         # toplevel_data
@@ -148,7 +148,7 @@ def success_document(options)
       #   }.reject! {|_,v| v.nil? }
       # prs:
       #  https://github.com/rails-api/active_model_serializers/pull/1004
-      def failure_document
+      def failure_document(options)
         hash = {}
         # PR Please :)
         # Jsonapi.add!(hash)
@@ -163,10 +163,10 @@ def failure_document
         #   ]
         if serializer.respond_to?(:each)
           hash[:errors] = serializer.flat_map do |error_serializer|
-            Error.resource_errors(error_serializer)
+            Error.resource_errors(error_serializer, options)
           end
         else
-          hash[:errors] = Error.resource_errors(serializer)
+          hash[:errors] = Error.resource_errors(serializer, options)
         end
         hash
       end
@@ -224,21 +224,21 @@ def fragment_cache(cached_hash, non_cached_hash)
       #     [x] url helpers https://github.com/rails-api/active_model_serializers/issues/1269
       #   meta
       #     [x] https://github.com/rails-api/active_model_serializers/pull/1340
-      def resource_objects_for(serializers)
+      def resource_objects_for(serializers, options)
         @primary = []
         @included = []
         @resource_identifiers = Set.new
-        serializers.each { |serializer| process_resource(serializer, true) }
-        serializers.each { |serializer| process_relationships(serializer, @include_tree) }
+        serializers.each { |serializer| process_resource(serializer, true, options) }
+        serializers.each { |serializer| process_relationships(serializer, @include_tree, options) }
 
         [@primary, @included]
       end
 
-      def process_resource(serializer, primary)
-        resource_identifier = ResourceIdentifier.new(serializer).as_json
+      def process_resource(serializer, primary, options)
+        resource_identifier = ResourceIdentifier.new(serializer, options).as_json
         return false unless @resource_identifiers.add?(resource_identifier)
 
-        resource_object = resource_object_for(serializer)
+        resource_object = resource_object_for(serializer, options)
         if primary
           @primary << resource_object
         else
@@ -248,21 +248,21 @@ def process_resource(serializer, primary)
         true
       end
 
-      def process_relationships(serializer, include_tree)
+      def process_relationships(serializer, include_tree, options)
         serializer.associations(include_tree).each do |association|
-          process_relationship(association.serializer, include_tree[association.key])
+          process_relationship(association.serializer, include_tree[association.key], options)
         end
       end
 
-      def process_relationship(serializer, include_tree)
+      def process_relationship(serializer, include_tree, options)
         if serializer.respond_to?(:each)
-          serializer.each { |s| process_relationship(s, include_tree) }
+          serializer.each { |s| process_relationship(s, include_tree, options) }
           return
         end
         return unless serializer && serializer.object
-        return unless process_resource(serializer, false)
+        return unless process_resource(serializer, false, options)
 
-        process_relationships(serializer, include_tree)
+        process_relationships(serializer, include_tree, options)
       end
 
       # {http://jsonapi.org/format/#document-resource-object-attributes Document Resource Object Attributes}
@@ -286,9 +286,9 @@ def attributes_for(serializer, fields)
       end
 
       # {http://jsonapi.org/format/#document-resource-objects Document Resource Objects}
-      def resource_object_for(serializer)
+      def resource_object_for(serializer, options)
         resource_object = cache_check(serializer) do
-          resource_object = ResourceIdentifier.new(serializer).as_json
+          resource_object = ResourceIdentifier.new(serializer, options).as_json
 
           requested_fields = fieldset && fieldset.fields_for(resource_object[:type])
           attributes = attributes_for(serializer, requested_fields)
@@ -297,7 +297,7 @@ def resource_object_for(serializer)
         end
 
         requested_associations = fieldset.fields_for(resource_object[:type]) || '*'
-        relationships = relationships_for(serializer, requested_associations)
+        relationships = relationships_for(serializer, requested_associations, options)
         resource_object[:relationships] = relationships if relationships.any?
 
         links = links_for(serializer)
@@ -425,15 +425,16 @@ def resource_object_for(serializer)
       #     id: 'required-id',
       #     meta: meta
       #   }.reject! {|_,v| v.nil? }
-      def relationships_for(serializer, requested_associations)
+      def relationships_for(serializer, requested_associations, options)
         include_tree = ActiveModel::Serializer::IncludeTree.from_include_args(requested_associations)
         serializer.associations(include_tree).each_with_object({}) do |association, hash|
           hash[association.key] = Relationship.new(
             serializer,
             association.serializer,
-            association.options,
-            association.links,
-            association.meta
+            options,
+            options: association.options,
+            links: association.links,
+            meta: association.meta
           ).as_json
         end
       end

lib/active_model_serializers/adapter/json_api.rb

@@ -182,14 +182,14 @@ def parse_relationship(assoc_name, assoc_data, options)
           prefix_key = field_key(assoc_name, options).to_s.singularize
           hash =
             if assoc_data.is_a?(Array)
-              { "#{prefix_key}_ids".to_sym => assoc_data.map { |ri| ri[:id] } }
+              { "#{prefix_key}_ids".to_sym => assoc_data.map { |ri| ri['id'] } }
             else
-              { "#{prefix_key}_id".to_sym => assoc_data && assoc_data.is_a?(Hash) ? assoc_data[:id] : nil }
+              { "#{prefix_key}_id".to_sym => assoc_data ? assoc_data['id'] : nil }
             end
 
           polymorphic = (options[:polymorphic] || []).include?(assoc_name.to_sym)
           if polymorphic
-            hash["#{prefix_key}_type".to_sym] = assoc_data.present? ? assoc_data[:type] : nil
+            hash["#{prefix_key}_type".to_sym] = assoc_data.present? ? assoc_data['type'] : nil
           end
 
           hash
@@ -198,7 +198,7 @@ def parse_relationship(assoc_name, assoc_data, options)
         # @api private
         def parse_relationships(relationships, options)
           transform_keys(relationships, options)
-            .map { |(k, v)| parse_relationship(k, v[:data], options) }
+            .map { |(k, v)| parse_relationship(k, v['data'], options) }
             .reduce({}, :merge)
         end
 

lib/active_model_serializers/adapter/json_api/deserialization.rb

@@ -10,8 +10,10 @@ module Error
         #
         # @param [ActiveModel::Serializer::ErrorSerializer] error_serializer
         # @return [Array<Symbol, Array<String>>] i.e. attribute_name, [attribute_errors]
-        def self.resource_errors(error_serializer)
+        def self.resource_errors(error_serializer, options)
           error_serializer.as_json.flat_map do |attribute_name, attribute_errors|
+            attribute_name = JsonApi.send(:transform_key_casing!, attribute_name,
+              options)
             attribute_error_objects(attribute_name, attribute_errors)
           end
         end