making object level links similar to attributes

Author: shishirmk

README.md

@@ -205,6 +205,31 @@ class MovieSerializer
 end
 ```
 
+### Links Per Object
+Links are defined in FastJsonapi using the `link` method. By default, link are read directly from the model property of the same name.In this example, `public_url` is expected to be a property of the object being serialized.
+
+You can configure the method to use on the object for example a link with key `self` will get set to the value returned by a method called `url` on the movie object.
+
+You can also use a block to define a url as shown in `custom_url`. You can access params in these blocks as well as shown in `personalized_url`
+
+```ruby
+class MovieSerializer
+  include FastJsonapi::ObjectSerializer
+
+  link :public_url
+
+  link :self, :url
+
+  link :custom_url do |object|
+    "http://movies.com/#{object.name}-(#{object.year})"
+  end
+
+  link :personalized_url do |object, params|
+    "http://movies.com/#{object.name}-#{params[:user].reference_code}"
+  end
+end
+```
+
 ### Compound Document
 
 Support for top-level and nested included associations through ` options[:include] `.

lib/fast_jsonapi/object_serializer.rb

@@ -38,7 +38,7 @@ def hash_for_one_record
 
       return serializable_hash unless @resource
 
-      serializable_hash[:data] = self.class.record_hash(@resource, @params, self)
+      serializable_hash[:data] = self.class.record_hash(@resource, @params)
       serializable_hash[:included] = self.class.get_included_records(@resource, @includes, @known_included_objects, @params) if @includes.present?
       serializable_hash
     end
@@ -49,7 +49,7 @@ def hash_for_collection
       data = []
       included = []
       @resource.each do |record|
-        data << self.class.record_hash(record, @params, self)
+        data << self.class.record_hash(record, @params)
         included.concat self.class.get_included_records(record, @includes, @known_included_objects, @params) if @includes.present?
       end
 
@@ -229,9 +229,11 @@ def fetch_polymorphic_option(options)
         {}
       end
 
-      def link(name, value = nil, &block)
-        self.data_links = {} unless data_links
-        self.data_links[name] = block || value
+      def link(link_name, link_method_name = nil, &block)
+        self.data_links = {} if self.data_links.nil?
+        link_method_name = link_name if link_method_name.nil?
+        key = run_key_transform(link_name)
+        self.data_links[key] = block || link_method_name
       end
 
       def validate_includes!(includes)

lib/fast_jsonapi/serialization_core.rb

@@ -62,9 +62,13 @@ def ids_hash_from_record_and_relationship(record, relationship, params = {})
         id_hash_from_record associated_object, polymorphic
       end
 
-      def links_hash(record, serializer_instance)
-        @data_links.each_with_object({}) do |(key, method), link_hash|
-          link_hash[key] = method.is_a?(Proc) ? serializer_instance.instance_exec(record, &method) : record.public_send(method)
+      def links_hash(record, params = {})
+        data_links.each_with_object({}) do |(key, method), link_hash|
+          link_hash[key] = if method.is_a?(Proc)
+            method.arity == 1 ? method.call(record) : method.call(record, params)
+          else
+            record.public_send(method)
+          end
         end
       end
 
@@ -90,17 +94,14 @@ def relationships_hash(record, relationships = nil, params = {})
         end
       end
 
-      def record_hash(record, params = {}, serializer_instance)
+      def record_hash(record, params = {})
         if cached
           record_hash = Rails.cache.fetch(record.cache_key, expires_in: cache_length, race_condition_ttl: race_condition_ttl) do
             temp_hash = id_hash(id_from_record(record), record_type, true)
             temp_hash[:attributes] = attributes_hash(record, params) if attributes_to_serialize.present?
             temp_hash[:relationships] = {}
             temp_hash[:relationships] = relationships_hash(record, cachable_relationships_to_serialize, params) if cachable_relationships_to_serialize.present?
-            if @data_links.present?
-              temp_links_hash = links_hash(record, serializer_instance)
-              temp_hash[:links] = temp_links_hash if temp_links_hash
-            end
+            temp_hash[:links] = links_hash(record, params) if data_links.present?
             temp_hash
           end
           record_hash[:relationships] = record_hash[:relationships].merge(relationships_hash(record, uncachable_relationships_to_serialize, params)) if uncachable_relationships_to_serialize.present?
@@ -109,10 +110,7 @@ def record_hash(record, params = {}, serializer_instance)
           record_hash = id_hash(id_from_record(record), record_type, true)
           record_hash[:attributes] = attributes_hash(record, params) if attributes_to_serialize.present?
           record_hash[:relationships] = relationships_hash(record, nil, params) if relationships_to_serialize.present?
-          if @data_links.present?
-            temp_links_hash = links_hash(record, serializer_instance)
-            record_hash[:links] = temp_links_hash if temp_links_hash
-          end
+          record_hash[:links] = links_hash(record, params) if data_links.present?
           record_hash
         end
       end
@@ -168,7 +166,7 @@ def get_included_records(record, includes_list, known_included_objects, params =
               next if known_included_objects.key?(code)
 
               known_included_objects[code] = inc_obj
-              included_records << serializer.record_hash(inc_obj, params, serializer.new(record))
+              included_records << serializer.record_hash(inc_obj, params)
             end
           end
         end

spec/lib/object_serializer_class_methods_spec.rb

@@ -243,7 +243,7 @@
     context 'with block calling instance method on serializer' do
       before do
         MovieSerializer.link(:self) do |movie_object|
-          movie_url(movie_object)
+          movie_object.url
         end
       end
       let(:url) { "http://movies.com/#{movie.id}" }
@@ -275,6 +275,16 @@
         expect(serializable_hash[:data][:links][:object_id]).to eq movie.id
       end
     end
+
+    context 'with method and convention' do
+      before do
+        MovieSerializer.link(:url)
+      end
+
+      it 'returns correct hash when serializable_hash is called' do
+        expect(serializable_hash[:data][:links][:url]).to eq movie.url
+      end
+    end
   end
 
   describe '#key_transform' do

spec/lib/object_serializer_spec.rb

@@ -287,7 +287,7 @@ class BlahSerializer
   context 'when serializing included, serialize any links' do
     before do
       ActorSerializer.link(:self) do |actor_object|
-        actor_url(actor_object)
+        actor_object.url
       end
     end
     subject(:serializable_hash) do

spec/shared/contexts/movie_context.rb

@@ -42,6 +42,10 @@ def advertising_campaign
       def cache_key
         "#{id}"
       end
+
+      def url
+        "http://movies.com/#{id}"
+      end
     end
 
     class Actor
@@ -68,6 +72,10 @@ def awards
       def award_ids
         [id * 9, id * 9 + 1]
       end
+
+      def url
+        "http://movies.com/actors/#{id}"
+      end
     end
 
     class AdvertisingCampaign
@@ -144,10 +152,6 @@ class MovieSerializer
       belongs_to :owner, record_type: :user
       belongs_to :movie_type
       has_one :advertising_campaign
-
-      def movie_url(movie)
-        "http://movies.com/#{movie.id}"
-      end
     end
 
     class MovieWithoutIdStructSerializer
@@ -184,10 +188,6 @@ class ActorSerializer
       belongs_to :agency
       has_many :awards
       belongs_to :agency
-
-      def actor_url(actor)
-        "http://movies.com/actors/#{actor.id}"
-      end
     end
 
     class AgencySerializer