Add key option to serializer associations

README.md

@@ -264,6 +264,12 @@ You may also use the `:serializer` option to specify a custom serializer class,
   has_many :comments, serializer: CommentPreviewSerializer
 ```
 
+And you can change the JSON key that the serializer should use for a particular association:
+
+```ruby
+  has_many :comments, key: :reviews
+```
+
 The `url` declaration describes which named routes to use while generating URLs
 for your JSON. Not every adapter will require URLs.
 

lib/active_model/serializer.rb

@@ -220,8 +220,9 @@ module ActiveModel
           association_options[:association_options][:virtual_value] = association_value
         end
 
+        association_key = association_options[:association_options][:key] || name
         if block_given?
-          block.call(name, serializer, association_options[:association_options])
+          block.call(association_key, serializer, association_options[:association_options])
         end
       end
     end

lib/active_model/serializer/adapter/json.rb

@@ -15,23 +15,23 @@ module ActiveModel
               serializer.attributes(options)
             end
 
-            serializer.each_association do |name, association, opts|
+            serializer.each_association do |key, association, opts|
               if association.respond_to?(:each)
                 array_serializer = association
-                @hash[name] = array_serializer.map do |item|
+                @hash[key] = array_serializer.map do |item|
                   cache_check(item) do
                     item.attributes(opts)
                   end
                 end
               else
                 if association && association.object
-                  @hash[name] = cache_check(association) do
+                  @hash[key] = cache_check(association) do
                     association.attributes(options)
                   end
                 elsif opts[:virtual_value]
-                  @hash[name] = opts[:virtual_value]
+                  @hash[key] = opts[:virtual_value]
                 else
-                  @hash[name] = nil
+                  @hash[key] = nil
                 end
               end
             end

lib/active_model/serializer/adapter/json_api.rb

@@ -75,8 +75,8 @@ module ActiveModel
           end
 
           serializers.each do |serializer|
-            serializer.each_association do |name, association, opts|
-              add_included(name, association, resource_path) if association
+            serializer.each_association do |key, association, opts|
+              add_included(key, association, resource_path) if association
             end if include_nested_assoc? resource_path
           end
         end
@@ -131,22 +131,22 @@ module ActiveModel
         def add_resource_relationships(attrs, serializer, options = {})
           options[:add_included] = options.fetch(:add_included, true)
 
-          serializer.each_association do |name, association, opts|
+          serializer.each_association do |key, association, opts|
             attrs[:relationships] ||= {}
 
             if association.respond_to?(:each)
-              add_relationships(attrs, name, association)
+              add_relationships(attrs, key, association)
             else
               if opts[:virtual_value]
-                add_relationship(attrs, name, nil, opts[:virtual_value])
+                add_relationship(attrs, key, nil, opts[:virtual_value])
               else
-                add_relationship(attrs, name, association)
+                add_relationship(attrs, key, association)
               end
             end
 
             if options[:add_included]
               Array(association).each do |association|
-                add_included(name, association)
+                add_included(key, association)
               end
             end
           end

test/adapter/json_api/json_api_test.rb

@@ -0,0 +1,38 @@
+require 'test_helper'
+
+module ActiveModel
+  class Serializer
+    class Adapter
+      class JsonApiTest < Minitest::Test
+        def setup
+          ActionController::Base.cache_store.clear
+          @author = Author.new(id: 1, name: 'Steve K.')
+          @post = Post.new(id: 1, title: 'New Post', body: 'Body')
+          @first_comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
+          @second_comment = Comment.new(id: 2, body: 'ZOMG ANOTHER COMMENT')
+          @post.comments = [@first_comment, @second_comment]
+          @first_comment.post = @post
+          @second_comment.post = @post
+          @post.author = @author
+          @blog = Blog.new(id: 1, name: "My Blog!!")
+          @post.blog = @blog
+
+        end
+
+        def test_custom_keys
+          serializer = PostWithCustomKeysSerializer.new(@post)
+          adapter = ActiveModel::Serializer::Adapter::JsonApi.new(serializer)
+
+          assert_equal({
+            reviews: { data: [
+                        {type: "comments", id: "1"},
+                        {type: "comments", id: "2"}
+                    ]},
+            writer: { data: {type: "authors", id: "1"} },
+            site: { data: {type: "blogs", id: "1" } }
+            }, adapter.serializable_hash[:data][:relationships])
+        end
+      end
+    end
+  end
+end

test/adapter/json_test.rb

@@ -7,7 +7,7 @@ module ActiveModel
         def setup
           ActionController::Base.cache_store.clear
           @author = Author.new(id: 1, name: 'Steve K.')
-          @post = Post.new(title: 'New Post', body: 'Body')
+          @post = Post.new(id: 1, title: 'New Post', body: 'Body')
           @first_comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
           @second_comment = Comment.new(id: 2, body: 'ZOMG ANOTHER COMMENT')
           @post.comments = [@first_comment, @second_comment]
@@ -27,6 +27,20 @@ module ActiveModel
                          {id: 2, body: 'ZOMG ANOTHER COMMENT'}
                        ], @adapter.serializable_hash[:post][:comments])
         end
+
+        def test_custom_keys
+          serializer = PostWithCustomKeysSerializer.new(@post)
+          adapter = ActiveModel::Serializer::Adapter::Json.new(serializer)
+
+          assert_equal({
+            id: 1,
+            reviews: [{id: 1, body: "ZOMG A COMMENT"},
+                      {id: 2, body: "ZOMG ANOTHER COMMENT"}
+                    ],
+            writer: {id: 1, name: "Steve K."},
+            site: {id: 1, name: "My Blog!!"}
+            }, adapter.serializable_hash[:post_with_custom_keys])
+        end
       end
     end
   end

test/fixtures/poro.rb

@@ -228,6 +228,14 @@ PostWithTagsSerializer = Class.new(ActiveModel::Serializer) do
   has_many :tags
 end
 
+PostWithCustomKeysSerializer = Class.new(ActiveModel::Serializer) do
+  attributes :id
+
+  has_many :comments, key: :reviews
+  belongs_to :author, key: :writer
+  has_one :blog, key: :site
+end
+
 VirtualValueSerializer = Class.new(ActiveModel::Serializer) do
   attributes :id
 

test/serializers/associations_test.rb

@@ -51,33 +51,33 @@ module ActiveModel
             bio: { type: :has_one, association_options: {} } },
           @author_serializer.class._associations
         )
-        @author_serializer.each_association do |name, serializer, options|
-          if name == :posts
+        @author_serializer.each_association do |key, serializer, options|
+          if key == :posts
             assert_equal({embed: :ids}, options)
             assert_kind_of(ActiveModel::Serializer.config.array_serializer, serializer)
-          elsif name == :bio
+          elsif key == :bio
             assert_equal({}, options)
             assert_nil serializer
-          elsif name == :roles
+          elsif key == :roles
             assert_equal({embed: :ids}, options)
             assert_kind_of(ActiveModel::Serializer.config.array_serializer, serializer)
           else
-            flunk "Unknown association: #{name}"
+            flunk "Unknown association: #{key}"
           end
         end
       end
 
       def test_has_many_with_no_serializer
-        PostWithTagsSerializer.new(@post).each_association do |name, serializer, options|
-          assert_equal name, :tags
+        PostWithTagsSerializer.new(@post).each_association do |key, serializer, options|
+          assert_equal key, :tags
           assert_equal serializer, nil
           assert_equal [{ attributes: { name: "#hashtagged" }}].to_json, options[:virtual_value].to_json
         end
       end
 
       def test_serializer_options_are_passed_into_associations_serializers
-        @post_serializer.each_association do |name, association|
-          if name == :comments
+        @post_serializer.each_association do |key, association|
+          if key == :comments
             assert association.first.custom_options[:custom_options]
           end
         end
@@ -89,15 +89,15 @@ module ActiveModel
             author: { type: :belongs_to, association_options: {} } },
           @comment_serializer.class._associations
         )
-        @comment_serializer.each_association do |name, serializer, options|
-          if name == :post
+        @comment_serializer.each_association do |key, serializer, options|
+          if key == :post
             assert_equal({}, options)
             assert_kind_of(PostSerializer, serializer)
-          elsif name == :author
+          elsif key == :author
             assert_equal({}, options)
             assert_nil serializer
           else
-            flunk "Unknown association: #{name}"
+            flunk "Unknown association: #{key}"
           end
         end
       end
@@ -105,8 +105,8 @@ module ActiveModel
       def test_belongs_to_with_custom_method
         blog_is_present = false
 
-        @post_serializer.each_association do |name, serializer, options|
-          blog_is_present = true if name == :blog
+        @post_serializer.each_association do |key, serializer, options|
+          blog_is_present = true if key == :blog
         end
 
         assert blog_is_present
@@ -132,6 +132,19 @@ module ActiveModel
         )
         assert_equal(inherited_klass._associations, expected_associations)
       end
+
+      def test_associations_custom_keys
+        serializer = PostWithCustomKeysSerializer.new(@post)
+
+        expected_association_keys = []
+        serializer.each_association do |key, serializer, options|
+          expected_association_keys << key
+        end
+
+        assert expected_association_keys.include? :reviews
+        assert expected_association_keys.include? :writer
+        assert expected_association_keys.include? :site
+      end
     end
   end
 end