Provide key case translation

CHANGELOG.md

@@ -3,6 +3,7 @@
 Breaking changes:
 
 Features:
+- [#1574](https://github.com/rails-api/active_model_serializers/pull/1574) Provide key translation. (@remear)
 - [#1494](https://github.com/rails-api/active_model_serializers/pull/1494) Make serializers serializalbe
   (using the Attributes adapter by default). (@bf4)
 - [#1550](https://github.com/rails-api/active_model_serializers/pull/1550) Add

docs/general/configuration_options.md

@@ -2,26 +2,95 @@
 
 # Configuration Options
 
-The following configuration options can be set on `ActiveModelSerializers.config`,
+The following configuration options can be set on
-preferably inside an initializer.
+`ActiveModelSerializers.config`, preferably inside an initializer.
 
 ## General
 
-- `adapter`: The [adapter](adapters.md) to use. Possible values: `:attributes, :json, :json_api`. Default: `:attributes`.
+##### adapter
-- `serializer_lookup_enabled`: When `false`, serializers must be explicitly specified. Default: `true`
+
+The [adapter](adapters.md) to use.
+
+Possible values:
+
+- `:attributes` (default)
+- `:json`
+- `:json_api`
+
+##### serializer_lookup_enabled
+
+Enable automatic serializer lookup.
+
+Possible values:
+
+- `true` (default)
+- `false`
+
+When `false`, serializers must be explicitly specified.
+
+##### key_transform
+
+The [key transform](key_transform.md) to use.
+
+Possible values:
+
+- `:camel` - ExampleKey
+- `:camel_lower` - exampleKey
+- `:dashed` - example-key
+- `:unaltered` - the original, unaltered key
+- `nil` - use the adapter default
+
+Each adapter has a default key transform configured:
+
+- `Json` - `:unaltered`
+- `JsonApi` - `:dashed`
+
+`config.key_transform` is a global override of the adapter default. Adapters
+still prefer the render option `:key_transform` over this setting.
+
 
 ## JSON API
 
-- `jsonapi_resource_type`: Whether the `type` attributes of resources should be singular or plural. Possible values: `:singular, :plural`. Default: `:plural`.
+
-- `jsonapi_include_toplevel_object`: Whether to include a [top level JSON API member](http://jsonapi.org/format/#document-jsonapi-object)
+##### jsonapi_resource_type
-   in the response document.
+
-   Default: `false`.
+Sets whether the [type](http://jsonapi.org/format/#document-resource-identifier-objects)
-- Used when `jsonapi_include_toplevel_object` is `true`:
+of the resource should be `singularized` or `pluralized` when it is not
-  - `jsonapi_version`: The latest version of the spec the API conforms to.
+[explicitly specified by the serializer](https://github.com/rails-api/active_model_serializers/blob/master/docs/general/serializers.md#type)
-    Default: `'1.0'`.
+
-  - `jsonapi_toplevel_meta`: Optional metadata. Not included if empty.
+Possible values:
-    Default: `{}`.
+
+- `:singular`
+- `:plural` (default)
+
+##### jsonapi_include_toplevel_object
+
+Include a [top level jsonapi member](http://jsonapi.org/format/#document-jsonapi-object)
+in the response document.
+
+Possible values:
+
+- `true`
+- `false` (default)
+
+##### jsonapi_version
+
+The latest version of the spec to which the API conforms.
+
+Default: `'1.0'`.
+
+*Used when `jsonapi_include_toplevel_object` is `true`*
+
+##### jsonapi_toplevel_meta
+
+Optional top-level metadata. Not included if empty.
+
+Default: `{}`.
+
+*Used when `jsonapi_include_toplevel_object` is `true`*
+
 
 ## Hooks
 
-To run a hook when ActiveModelSerializers is loaded, use `ActiveSupport.on_load(:action_controller) do end`
+To run a hook when ActiveModelSerializers is loaded, use
+`ActiveSupport.on_load(:action_controller) do end`

docs/general/key_transform.md

@@ -0,0 +1,34 @@
+[Back to Guides](../README.md)
+
+# Key Transforms
+
+Key transforms modify the keys in serialized responses.
+
+Provided key transforms:
+
+- `:camel` - ExampleKey
+- `:camel_lower` - exampleKey
+- `:dashed` - example-key
+- `:unaltered` - the original, unaltered key
+- `nil` - use the adapter default
+
+Key translation precedence is as follows:
+
+##### SerializableResource 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 key transform configured:
+
+- `Json` - `:unaltered`
+- `JsonApi` - `:dashed`

docs/general/rendering.md

@@ -79,6 +79,12 @@ PR please :)
 
 PR please :)
 
+#### key_transform
+
+```render json: posts, each_serializer: PostSerializer, key_transform: :camel_lower```
+
+See [Key Transforms](key_transforms.md) for more informaiton.
+
 #### meta
 
 A `meta` member can be used to include non-standard meta-information. `meta` can

lib/action_controller/serialization.rb

@@ -56,7 +56,9 @@ module ActionController
 
     [:_render_option_json, :_render_with_renderer_json].each do |renderer_method|
       define_method renderer_method do |resource, options|
-        options.fetch(:serialization_context) { options[:serialization_context] = ActiveModelSerializers::SerializationContext.new(request) }
+        options.fetch(:serialization_context) do
+          options[:serialization_context] = ActiveModelSerializers::SerializationContext.new(request, options)
+        end
         serializable_resource = get_serializer(resource, options)
         super(serializable_resource, options)
       end

lib/active_model/serializer/configuration.rb

@@ -26,6 +26,7 @@ module ActiveModel
         # 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/base.rb

@@ -1,3 +1,5 @@
+require 'active_model_serializers/key_transform'
+
 module ActiveModelSerializers
   module Adapter
     class Base
@@ -51,6 +53,27 @@ module ActiveModelSerializers
         json[meta_key] = meta unless meta.blank?
         json
       end
+
+      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
+
+      def transform_key_casing!(value, serialization_context)
+        return value unless serialization_context
+        transform = key_transform(serialization_context)
+        KeyTransform.send(transform, value)
+      end
     end
   end
 end

lib/active_model_serializers/adapter/json.rb

@@ -3,7 +3,8 @@ module ActiveModelSerializers
     class Json < Base
       def serializable_hash(options = nil)
         options ||= {}
-        { root => Attributes.new(serializer, instance_options).serializable_hash(options) }
+        serialized_hash = { root => Attributes.new(serializer, instance_options).serializable_hash(options) }
+        transform_key_casing!(serialized_hash, options[:serialization_context])
       end
     end
   end

lib/active_model_serializers/adapter/json_api.rb

@@ -37,15 +37,20 @@ module ActiveModelSerializers
         @fieldset = options[:fieldset] || ActiveModel::Serializer::Fieldset.new(options.delete(:fields))
       end
 
+      def default_key_transform
+        :dashed
+      end
+
       # {http://jsonapi.org/format/#crud Requests are transactional, i.e. success or failure}
       # {http://jsonapi.org/format/#document-top-level data and errors MUST NOT coexist in the same document.}
       def serializable_hash(options = nil)
         options ||= {}
-        if serializer.success?
+        document = if serializer.success?
-          success_document(options)
+                     success_document(options)
-        else
+                   else
-          failure_document
+                     failure_document
-        end
+                   end
+        transform_key_casing!(document, options[:serialization_context])
       end
 
       # {http://jsonapi.org/format/#document-top-level Primary data}

lib/active_model_serializers/key_transform.rb

@@ -0,0 +1,40 @@
+require 'active_support/core_ext/hash/keys'
+
+module ActiveModelSerializers
+  module KeyTransform
+    module_function
+
+    # Transforms keys to UpperCamelCase or PascalCase.
+    #
+    # @example:
+    #    "some_key" => "SomeKey",
+    # @see {https://github.com/rails/rails/blob/master/activesupport/lib/active_support/inflector/methods.rb#L66-L76 ActiveSupport::Inflector.camelize}
+    def camel(hash)
+      hash.deep_transform_keys! { |key| key.to_s.camelize.to_sym }
+    end
+
+    # Transforms keys to camelCase.
+    #
+    # @example:
+    #    "some_key" => "someKey",
+    # @see {https://github.com/rails/rails/blob/master/activesupport/lib/active_support/inflector/methods.rb#L66-L76 ActiveSupport::Inflector.camelize}
+    def camel_lower(hash)
+      hash.deep_transform_keys! { |key| key.to_s.camelize(:lower).to_sym }
+    end
+
+    # Transforms keys to dashed-case.
+    # This is the default case for the JsonApi adapter.
+    #
+    # @example:
+    #    "some_key" => "some-key",
+    # @see {https://github.com/rails/rails/blob/master/activesupport/lib/active_support/inflector/methods.rb#L185-L187 ActiveSupport::Inflector.dasherize}
+    def dashed(hash)
+      hash.deep_transform_keys! { |key| key.to_s.dasherize.to_sym }
+    end
+
+    # Returns the hash unaltered
+    def unaltered(hash)
+      hash
+    end
+  end
+end

lib/active_model_serializers/serialization_context.rb

@@ -4,13 +4,14 @@ module ActiveModelSerializers
       attr_writer :url_helpers, :default_url_options
     end
 
-    attr_reader :request_url, :query_parameters
+    attr_reader :request_url, :query_parameters, :key_transform
 
     def initialize(request, options = {})
       @request_url = request.original_url[/\A[^?]+/]
       @query_parameters = request.query_parameters
       @url_helpers = options.delete(:url_helpers) || self.class.url_helpers
       @default_url_options = options.delete(:default_url_options) || self.class.default_url_options
+      @key_transform = options.delete(:key_transform)
     end
 
     def self.url_helpers

test/action_controller/json_api/key_transform_test.rb

@@ -0,0 +1,180 @@
+require 'test_helper'
+
+module ActionController
+  module Serialization
+    class JsonApi
+      class KeyTransformTest < ActionController::TestCase
+        class KeyTransformTestController < ActionController::Base
+          Post = Class.new(::Model)
+          class PostSerializer < ActiveModel::Serializer
+            type 'posts'
+            attributes :title, :body, :publish_at
+            belongs_to :author
+            has_many :comments
+
+            link(:post_authors) { 'https://example.com/post_authors' }
+
+            meta do
+              {
+                rating: 5,
+                favorite_count: 10
+              }
+            end
+          end
+
+          Author = Class.new(::Model)
+          class AuthorSerializer < ActiveModel::Serializer
+            type 'authors'
+            attributes :first_name, :last_name
+          end
+
+          Comment = Class.new(::Model)
+          class CommentSerializer < ActiveModel::Serializer
+            type 'comments'
+            attributes :body
+            belongs_to :author
+          end
+
+          def setup_post
+            ActionController::Base.cache_store.clear
+            @author = Author.new(id: 1, first_name: 'Bob', last_name: 'Jones')
+            @comment1 = Comment.new(id: 7, body: 'cool', author: @author)
+            @comment2 = Comment.new(id: 12, body: 'awesome', author: @author)
+            @post = Post.new(id: 1337, title: 'Title 1', body: 'Body 1',
+                             author: @author, comments: [@comment1, @comment2],
+                             publish_at: '2020-03-16T03:55:25.291Z')
+            @comment1.post = @post
+            @comment2.post = @post
+          end
+
+          def render_resource_with_key_transform
+            setup_post
+            render json: @post, serializer: PostSerializer, adapter: :json_api,
+                   key_transform: :camel
+          end
+
+          def render_resource_with_key_transform_nil
+            setup_post
+            render json: @post, serializer: PostSerializer, adapter: :json_api,
+                   key_transform: nil
+          end
+
+          def render_resource_with_key_transform_with_global_config
+            setup_post
+            old_transform = ActiveModelSerializers.config.key_transform
+            ActiveModelSerializers.config.key_transform = :camel_lower
+            render json: @post, serializer: PostSerializer, adapter: :json_api
+            ActiveModelSerializers.config.key_transform = old_transform
+          end
+        end
+
+        tests KeyTransformTestController
+
+        def test_render_resource_with_key_transform
+          get :render_resource_with_key_transform
+          response = JSON.parse(@response.body)
+          expected = {
+            'Data' => {
+              'Id' => '1337',
+              'Type' => 'posts',
+              'Attributes' => {
+                'Title' => 'Title 1',
+                'Body' => 'Body 1',
+                'PublishAt' => '2020-03-16T03:55:25.291Z'
+              },
+              'Relationships' => {
+                'Author' => {
+                  'Data' => {
+                    'Id' => '1',
+                    'Type' => 'authors'
+                  }
+                },
+                'Comments' => {
+                  'Data' => [
+                    { 'Id' => '7', 'Type' => 'comments' },
+                    { 'Id' => '12', 'Type' => 'comments' }
+                  ]
+                }
+              },
+              'Links' => {
+                'PostAuthors' => 'https://example.com/post_authors'
+              },
+              'Meta' => { 'Rating' => 5, 'FavoriteCount' => 10 }
+            }
+          }
+          assert_equal expected, response
+        end
+
+        def test_render_resource_with_key_transform_nil
+          get :render_resource_with_key_transform_nil
+          response = JSON.parse(@response.body)
+          expected = {
+            'data' => {
+              'id' => '1337',
+              'type' => 'posts',
+              'attributes' => {
+                'title' => 'Title 1',
+                'body' => 'Body 1',
+                'publish-at' => '2020-03-16T03:55:25.291Z'
+              },
+              'relationships' => {
+                'author' => {
+                  'data' => {
+                    'id' => '1',
+                    'type' => 'authors'
+                  }
+                },
+                'comments' => {
+                  'data' => [
+                    { 'id' => '7', 'type' => 'comments' },
+                    { 'id' => '12', 'type' => 'comments' }
+                  ]
+                }
+              },
+              'links' => {
+                'post-authors' => 'https://example.com/post_authors'
+              },
+              'meta' => { 'rating' => 5, 'favorite-count' => 10 }
+            }
+          }
+          assert_equal expected, response
+        end
+
+        def test_render_resource_with_key_transform_with_global_config
+          get :render_resource_with_key_transform_with_global_config
+          response = JSON.parse(@response.body)
+          expected =  {
+            'data' => {
+              'id' => '1337',
+              'type' => 'posts',
+              'attributes' => {
+                'title' => 'Title 1',
+                'body' => 'Body 1',
+                'publishAt' => '2020-03-16T03:55:25.291Z'
+              },
+              'relationships' => {
+                'author' => {
+                  'data' => {
+                    'id' => '1',
+                    'type' => 'authors'
+                  }
+                },
+                'comments' => {
+                  'data' => [
+                    { 'id' => '7', 'type' => 'comments' },
+                    { 'id' => '12', 'type' => 'comments' }
+                  ]
+                }
+              },
+              'links' => {
+                'postAuthors' => 'https://example.com/post_authors'
+              },
+              'meta' => { 'rating' => 5, 'favoriteCount' => 10 }
+            }
+          }
+          assert_equal expected, response
+        end
+      end
+    end
+  end
+end

test/adapter/json/key_case_test.rb

@@ -0,0 +1,93 @@
+require 'test_helper'
+
+module ActiveModelSerializers
+  module Adapter
+    class Json
+      class KeyCaseTest < ActiveSupport::TestCase
+        def mock_request(key_transform = nil)
+          context = Minitest::Mock.new
+          context.expect(:request_url, URI)
+          context.expect(:query_parameters, {})
+          context.expect(:key_transform, key_transform)
+          @options = {}
+          @options[:serialization_context] = context
+        end
+
+        Post = Class.new(::Model)
+        class PostSerializer < ActiveModel::Serializer
+          attributes :id, :title, :body, :publish_at
+        end
+
+        def setup
+          ActionController::Base.cache_store.clear
+          @blog = Blog.new(id: 1, name: 'My Blog!!', special_attribute: 'neat')
+          serializer = CustomBlogSerializer.new(@blog)
+          @adapter = ActiveModelSerializers::Adapter::Json.new(serializer)
+        end
+
+        def test_key_transform_default
+          mock_request
+          assert_equal({
+            blog: { id: 1, special_attribute: 'neat', articles: nil }
+          }, @adapter.serializable_hash(@options))
+        end
+
+        def test_key_transform_global_config
+          mock_request
+          result = with_config(key_transform: :camel_lower) do
+            @adapter.serializable_hash(@options)
+          end
+          assert_equal({
+            blog: { id: 1, specialAttribute: 'neat', articles: nil }
+          }, result)
+        end
+
+        def test_key_transform_serialization_ctx_overrides_global_config
+          mock_request(:camel)
+          result = with_config(key_transform: :camel_lower) do
+            @adapter.serializable_hash(@options)
+          end
+          assert_equal({
+            Blog: { Id: 1, SpecialAttribute: 'neat', Articles: nil }
+          }, result)
+        end
+
+        def test_key_transform_undefined
+          mock_request(:blam)
+          result = nil
+          assert_raises NoMethodError do
+            result = @adapter.serializable_hash(@options)
+          end
+        end
+
+        def test_key_transform_dashed
+          mock_request(:dashed)
+          assert_equal({
+            blog: { id: 1, :"special-attribute" => 'neat', articles: nil }
+          }, @adapter.serializable_hash(@options))
+        end
+
+        def test_key_transform_unaltered
+          mock_request(:unaltered)
+          assert_equal({
+            blog: { id: 1, special_attribute: 'neat', articles: nil }
+          }, @adapter.serializable_hash(@options))
+        end
+
+        def test_key_transform_camel
+          mock_request(:camel)
+          assert_equal({
+            Blog: { Id: 1, SpecialAttribute: 'neat', Articles: nil }
+          }, @adapter.serializable_hash(@options))
+        end
+
+        def test_key_transform_camel_lower
+          mock_request(:camel_lower)
+          assert_equal({
+            blog: { id: 1, specialAttribute: 'neat', articles: nil }
+          }, @adapter.serializable_hash(@options))
+        end
+      end
+    end
+  end
+end

test/adapter/json_api/key_case_test.rb

@@ -0,0 +1,500 @@
+require 'test_helper'
+
+module ActiveModelSerializers
+  module Adapter
+    class JsonApi
+      class KeyCaseTest < ActiveSupport::TestCase
+        Post = Class.new(::Model)
+        class PostSerializer < ActiveModel::Serializer
+          type 'posts'
+          attributes :title, :body, :publish_at
+          belongs_to :author
+          has_many :comments
+
+          link(:self) { post_url(object.id) }
+          link(:post_authors) { post_authors_url(object.id) }
+          link(:subscriber_comments) { post_comments_url(object.id) }
+
+          meta do
+            {
+              rating: 5,
+              favorite_count: 10
+            }
+          end
+        end
+
+        Author = Class.new(::Model)
+        class AuthorSerializer < ActiveModel::Serializer
+          type 'authors'
+          attributes :first_name, :last_name
+        end
+
+        Comment = Class.new(::Model)
+        class CommentSerializer < ActiveModel::Serializer
+          type 'comments'
+          attributes :body
+          belongs_to :author
+        end
+
+        def mock_request(key_transform = nil)
+          context = Minitest::Mock.new
+          context.expect(:request_url, URI)
+          context.expect(:query_parameters, {})
+          context.expect(:key_transform, key_transform)
+          context.expect(:url_helpers, Rails.application.routes.url_helpers)
+          @options = {}
+          @options[:serialization_context] = context
+        end
+
+        def setup
+          Rails.application.routes.draw do
+            resources :posts do
+              resources :authors
+              resources :comments
+            end
+          end
+          @publish_at = 1.day.from_now
+          @author = Author.new(id: 1, first_name: 'Bob', last_name: 'Jones')
+          @comment1 = Comment.new(id: 7, body: 'cool', author: @author)
+          @comment2 = Comment.new(id: 12, body: 'awesome', author: @author)
+          @post = Post.new(id: 1337, title: 'Title 1', body: 'Body 1',
+                           author: @author, comments: [@comment1, @comment2],
+                           publish_at: @publish_at)
+          @comment1.post = @post
+          @comment2.post = @post
+        end
+
+        def test_success_document_key_transform_default
+          mock_request
+          serializer = PostSerializer.new(@post)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+          assert_equal({
+            data: {
+              id: '1337',
+              type: 'posts',
+              attributes: {
+                title: 'Title 1',
+                body: 'Body 1',
+                :"publish-at" => @publish_at
+              },
+              relationships: {
+                author: {
+                  data: { id: '1', type: 'authors' }
+                },
+                comments: {
+                  data: [
+                    { id: '7', type: 'comments' },
+                    { id: '12', type: 'comments' }
+                ] }
+              },
+              links: {
+                self: 'http://example.com/posts/1337',
+                :"post-authors" => 'http://example.com/posts/1337/authors',
+                :"subscriber-comments" => 'http://example.com/posts/1337/comments'
+              },
+              meta: { rating: 5, :"favorite-count" => 10 }
+            }
+          }, result)
+        end
+
+        def test_success_document_key_transform_global_config
+          mock_request
+          result = with_config(key_transform: :camel_lower) do
+            serializer = PostSerializer.new(@post)
+            adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+            adapter.serializable_hash(@options)
+          end
+          assert_equal({
+            data: {
+              id: '1337',
+              type: 'posts',
+              attributes: {
+                title: 'Title 1',
+                body: 'Body 1',
+                publishAt: @publish_at
+              },
+              relationships: {
+                author: {
+                  data: { id: '1', type: 'authors' }
+                },
+                comments: {
+                  data: [
+                    { id: '7', type: 'comments' },
+                    { id: '12', type: 'comments' }
+                ] }
+              },
+              links: {
+                self: 'http://example.com/posts/1337',
+                postAuthors: 'http://example.com/posts/1337/authors',
+                subscriberComments: 'http://example.com/posts/1337/comments'
+              },
+              meta: { rating: 5, favoriteCount: 10 }
+            }
+          }, result)
+        end
+
+        def test_success_doc_key_transform_serialization_ctx_overrides_global
+          mock_request(:camel)
+          result = with_config(key_transform: :camel_lower) do
+            serializer = PostSerializer.new(@post)
+            adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+            adapter.serializable_hash(@options)
+          end
+          assert_equal({
+            Data: {
+              Id: '1337',
+              Type: 'posts',
+              Attributes: {
+                Title: 'Title 1',
+                Body: 'Body 1',
+                PublishAt: @publish_at
+              },
+              Relationships: {
+                Author: {
+                  Data: { Id: '1', Type: 'authors' }
+                },
+                Comments: {
+                  Data: [
+                    { Id: '7', Type: 'comments' },
+                    { Id: '12', Type: 'comments' }
+                ] }
+              },
+              Links: {
+                Self: 'http://example.com/posts/1337',
+                PostAuthors: 'http://example.com/posts/1337/authors',
+                SubscriberComments: 'http://example.com/posts/1337/comments'
+              },
+              Meta: { Rating: 5, FavoriteCount: 10 }
+            }
+          }, result)
+        end
+
+        def test_success_document_key_transform_dashed
+          mock_request(:dashed)
+          serializer = PostSerializer.new(@post)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+          assert_equal({
+            data: {
+              id: '1337',
+              type: 'posts',
+              attributes: {
+                title: 'Title 1',
+                body: 'Body 1',
+                :"publish-at" => @publish_at
+              },
+              relationships: {
+                author: {
+                  data: { id: '1', type: 'authors' }
+                },
+                comments: {
+                  data: [
+                    { id: '7', type: 'comments' },
+                    { id: '12', type: 'comments' }
+                ] }
+              },
+              links: {
+                self: 'http://example.com/posts/1337',
+                :"post-authors" => 'http://example.com/posts/1337/authors',
+                :"subscriber-comments" => 'http://example.com/posts/1337/comments'
+              },
+              meta: { rating: 5, :"favorite-count" => 10 }
+            }
+          }, result)
+        end
+
+        def test_success_document_key_transform_unaltered
+          mock_request(:unaltered)
+          serializer = PostSerializer.new(@post)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+          assert_equal({
+            data: {
+              id: '1337',
+              type: 'posts',
+              attributes: {
+                title: 'Title 1',
+                body: 'Body 1',
+                publish_at: @publish_at
+              },
+              relationships: {
+                author: {
+                  data: { id: '1', type: 'authors' }
+                },
+                comments: {
+                  data: [
+                    { id: '7', type: 'comments' },
+                    { id: '12', type: 'comments' }
+                ] }
+              },
+              links: {
+                self: 'http://example.com/posts/1337',
+                post_authors: 'http://example.com/posts/1337/authors',
+                subscriber_comments: 'http://example.com/posts/1337/comments'
+              },
+              meta: { rating: 5, favorite_count: 10 }
+            }
+          }, result)
+        end
+
+        def test_success_document_key_transform_undefined
+          mock_request(:zoot)
+          serializer = PostSerializer.new(@post)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          assert_raises NoMethodError do
+            adapter.serializable_hash(@options)
+          end
+        end
+
+        def test_success_document_key_transform_camel
+          mock_request(:camel)
+          serializer = PostSerializer.new(@post)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+          assert_equal({
+            Data: {
+              Id: '1337',
+              Type: 'posts',
+              Attributes: {
+                Title: 'Title 1',
+                Body: 'Body 1',
+                PublishAt: @publish_at
+              },
+              Relationships: {
+                Author: {
+                  Data: { Id: '1', Type: 'authors' }
+                },
+                Comments: {
+                  Data: [
+                    { Id: '7', Type: 'comments' },
+                    { Id: '12', Type: 'comments' }
+                ] }
+              },
+              Links: {
+                Self: 'http://example.com/posts/1337',
+                PostAuthors: 'http://example.com/posts/1337/authors',
+                SubscriberComments: 'http://example.com/posts/1337/comments'
+              },
+              Meta: { Rating: 5, FavoriteCount: 10 }
+            }
+          }, result)
+        end
+
+        def test_success_document_key_transform_camel_lower
+          mock_request(:camel_lower)
+          serializer = PostSerializer.new(@post)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+          assert_equal({
+            data: {
+              id: '1337',
+              type: 'posts',
+              attributes: {
+                title: 'Title 1',
+                body: 'Body 1',
+                publishAt: @publish_at
+              },
+              relationships: {
+                author: {
+                  data: { id: '1', type: 'authors' }
+                },
+                comments: {
+                  data: [
+                    { id: '7', type: 'comments' },
+                    { id: '12', type: 'comments' }
+                ] }
+              },
+              links: {
+                self: 'http://example.com/posts/1337',
+                postAuthors: 'http://example.com/posts/1337/authors',
+                subscriberComments: 'http://example.com/posts/1337/comments'
+              },
+              meta: { rating: 5, favoriteCount: 10 }
+            }
+          }, result)
+        end
+
+        def test_error_document_key_transform_default
+          mock_request
+          resource = ModelWithErrors.new
+          resource.errors.add(:published_at, 'must be in the future')
+          resource.errors.add(:title, 'must be longer')
+          serializer = ActiveModel::Serializer::ErrorSerializer.new(resource)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+          expected_errors_object =
+            { :errors =>
+              [
+                {
+                  :source => { :pointer => '/data/attributes/published_at' },
+                  :detail => 'must be in the future' },
+                {
+                  :source => { :pointer => '/data/attributes/title' },
+                  :detail => 'must be longer'
+                }
+              ]
+            }
+          assert_equal expected_errors_object, result
+        end
+
+        def test_error_document_key_transform_global_config
+          mock_request
+          result = with_config(key_transform: :camel) do
+            resource = ModelWithErrors.new
+            resource.errors.add(:published_at, 'must be in the future')
+            resource.errors.add(:title, 'must be longer')
+            serializer = ActiveModel::Serializer::ErrorSerializer.new(resource)
+            adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+            adapter.serializable_hash(@options)
+          end
+          expected_errors_object =
+            { :Errors =>
+              [
+                {
+                  :Source => { :Pointer => '/data/attributes/published_at' },
+                  :Detail => 'must be in the future'
+                },
+                {
+                  :Source => { :Pointer => '/data/attributes/title' },
+                  :Detail => 'must be longer'
+                }
+              ]
+            }
+          assert_equal expected_errors_object, result
+        end
+
+        def test_error_document_key_transform_serialization_ctx_overrides_global
+          mock_request(:camel)
+          result = with_config(key_transform: :camel_lower) do
+            resource = ModelWithErrors.new
+            resource.errors.add(:published_at, 'must be in the future')
+            resource.errors.add(:title, 'must be longer')
+            serializer = ActiveModel::Serializer::ErrorSerializer.new(resource)
+            adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+            adapter.serializable_hash(@options)
+          end
+          expected_errors_object =
+            { :Errors =>
+              [
+                {
+                  :Source => { :Pointer => '/data/attributes/published_at' },
+                  :Detail => 'must be in the future'
+                },
+                {
+                  :Source => { :Pointer => '/data/attributes/title' },
+                  :Detail => 'must be longer'
+                }
+              ]
+            }
+          assert_equal expected_errors_object, result
+        end
+
+        def test_error_document_key_transform_dashed
+          mock_request(:dashed)
+
+          resource = ModelWithErrors.new
+          resource.errors.add(:published_at, 'must be in the future')
+          resource.errors.add(:title, 'must be longer')
+
+          serializer = ActiveModel::Serializer::ErrorSerializer.new(resource)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+
+          expected_errors_object =
+            { :errors =>
+              [
+                {
+                  :source => { :pointer => '/data/attributes/published_at' },
+                  :detail => 'must be in the future'
+                },
+                {
+                  :source => { :pointer => '/data/attributes/title' },
+                  :detail => 'must be longer'
+                }
+              ]
+          }
+          assert_equal expected_errors_object, result
+        end
+
+        def test_error_document_key_transform_unaltered
+          mock_request(:unaltered)
+
+          resource = ModelWithErrors.new
+          resource.errors.add(:published_at, 'must be in the future')
+          resource.errors.add(:title, 'must be longer')
+
+          serializer = ActiveModel::Serializer::ErrorSerializer.new(resource)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+
+          expected_errors_object =
+            { :errors =>
+              [
+                { :source => { :pointer => '/data/attributes/published_at' }, :detail => 'must be in the future' },
+                { :source => { :pointer => '/data/attributes/title' }, :detail => 'must be longer' }
+              ]
+          }
+          assert_equal expected_errors_object, result
+        end
+
+        def test_error_document_key_transform_undefined
+          mock_request(:krazy)
+
+          resource = ModelWithErrors.new
+          resource.errors.add(:published_at, 'must be in the future')
+          resource.errors.add(:title, 'must be longer')
+
+          serializer = ActiveModel::Serializer::ErrorSerializer.new(resource)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+
+          assert_raises NoMethodError do
+            adapter.serializable_hash(@options)
+          end
+        end
+
+        def test_error_document_key_transform_camel
+          mock_request(:camel)
+
+          resource = ModelWithErrors.new
+          resource.errors.add(:published_at, 'must be in the future')
+          resource.errors.add(:title, 'must be longer')
+
+          serializer = ActiveModel::Serializer::ErrorSerializer.new(resource)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+
+          expected_errors_object =
+            { :Errors =>
+              [
+                { :Source => { :Pointer => '/data/attributes/published_at' }, :Detail => 'must be in the future' },
+                { :Source => { :Pointer => '/data/attributes/title' }, :Detail => 'must be longer' }
+              ]
+          }
+          assert_equal expected_errors_object, result
+        end
+
+        def test_error_document_key_transform_camel_lower
+          mock_request(:camel_lower)
+
+          resource = ModelWithErrors.new
+          resource.errors.add(:published_at, 'must be in the future')
+          resource.errors.add(:title, 'must be longer')
+
+          serializer = ActiveModel::Serializer::ErrorSerializer.new(resource)
+          adapter = ActiveModelSerializers::Adapter::JsonApi.new(serializer)
+          result = adapter.serializable_hash(@options)
+
+          expected_errors_object =
+            { :errors =>
+              [
+                { :source => { :pointer => '/data/attributes/published_at' }, :detail => 'must be in the future' },
+                { :source => { :pointer => '/data/attributes/title' }, :detail => 'must be longer' }
+              ]
+          }
+          assert_equal expected_errors_object, result
+        end
+      end
+    end
+  end
+end

test/adapter/json_api/pagination_links_test.rb

@@ -25,6 +25,7 @@ module ActiveModelSerializers
           context = Minitest::Mock.new
           context.expect(:request_url, original_url)
           context.expect(:query_parameters, query_parameters)
+          context.expect(:key_transform, nil)
           @options = {}
           @options[:serialization_context] = context
         end