Add params to set_id block (#16)

* Add params to set_id block arguments

Pull request #331 added a block to the ObjectSerializer.set_id class
method, which allows passing a block to the set_id method. Currently
this block takes only one argument `record`:

```
set_id do |record|
  "#{record.name.downcase}-#{record.id}"
end
```

This PR adds another argument `params` to the block:

```
set id do |record, params|
  params[:admin] ?  record.id : "#{record.name.downcase}-#{record.id}"
end
```

This customization can be useful in situation where we serve different
clients that may need different IDs. One nice side effect is also that
the `set_id` method has the same method signature as the `attribute`
method.

* Update the README

README.md

@@ -381,13 +381,19 @@ related to a current authenticated user. The `options[:params]` value covers the
 cases by allowing you to pass in a hash of additional parameters necessary for
 your use case.
 
-Leveraging the new params is easy, when you define a custom attribute or relationship with a
+Leveraging the new params is easy, when you define a custom id, attribute or
-block you opt-in to using params by adding it as a block parameter.
+relationship with a block you opt-in to using params by adding it as a block
+parameter.
 
 ```ruby
 class MovieSerializer
   include FastJsonapi::ObjectSerializer
 
+  set_id do |movie, params|
+    # in here, params is a hash containing the `:admin` key
+    params[:admin] ? movie.owner_id : "movie-#{movie.id}"
+  end
+
   attributes :name, :year
   attribute :can_view_early do |movie, params|
     # in here, params is a hash containing the `:current_user` key
@@ -539,7 +545,7 @@ Option | Purpose | Example
 ------------ | ------------- | -------------
 set_type | Type name of Object | ```set_type :movie ```
 key | Key of Object | ```belongs_to :owner, key: :user ```
-set_id | ID of Object | ```set_id :owner_id ``` or ```set_id { \|record\| "#{record.name.downcase}-#{record.id}" }```
+set_id | ID of Object | ```set_id :owner_id ``` or ```set_id { \|record, params\| params[:admin] ? record.id : "#{record.name.downcase}-#{record.id}" }```
 cache_options | Hash to enable caching and set cache length | ```cache_options enabled: true, cache_length: 12.hours, race_condition_ttl: 10.seconds```
 id_method_name | Set custom method name to get ID of an object (If block is provided for the relationship, `id_method_name` is invoked on the return value of the block instead of the resource object) | ```has_many :locations, id_method_name: :place_ids ```
 object_method_name | Set custom method name to get related objects | ```has_many :locations, object_method_name: :places ```

lib/fast_jsonapi/serialization_core.rb

@@ -69,7 +69,7 @@ module FastJsonapi
       def record_hash(record, fieldset, includes_list, 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 = id_hash(id_from_record(record, params), record_type, true)
             temp_hash[:attributes] = attributes_hash(record, fieldset, params) if attributes_to_serialize.present?
             temp_hash[:relationships] = {}
             temp_hash[:relationships] = relationships_hash(record, cachable_relationships_to_serialize, fieldset, includes_list, params) if cachable_relationships_to_serialize.present?
@@ -80,7 +80,7 @@ module FastJsonapi
           record_hash[:meta] = meta_hash(record, params) if meta_to_serialize.present?
           record_hash
         else
-          record_hash = id_hash(id_from_record(record), record_type, true)
+          record_hash = id_hash(id_from_record(record, params), record_type, true)
           record_hash[:attributes] = attributes_hash(record, fieldset, params) if attributes_to_serialize.present?
           record_hash[:relationships] = relationships_hash(record, nil, fieldset, includes_list, params) if relationships_to_serialize.present?
           record_hash[:links] = links_hash(record, params) if data_links.present?
@@ -89,8 +89,8 @@ module FastJsonapi
         end
       end
 
-      def id_from_record(record)
+      def id_from_record(record, params)
-        return record_id.call(record) if record_id.is_a?(Proc)
+        return record_id.call(record, params) if record_id.is_a?(Proc)
         return record.send(record_id) if record_id
         raise MandatoryField, 'id is a mandatory field in the jsonapi spec' unless record.respond_to?(:id)
         record.id
@@ -146,7 +146,7 @@ module FastJsonapi
                 included_records.concat(serializer_records) unless serializer_records.empty?
               end
 
-              code = "#{record_type}_#{serializer.id_from_record(inc_obj)}"
+              code = "#{record_type}_#{serializer.id_from_record(inc_obj, params)}"
               next if known_included_objects.key?(code)
 
               known_included_objects[code] = inc_obj

spec/lib/object_serializer_class_methods_spec.rb

@@ -193,7 +193,10 @@ describe FastJsonapi::ObjectSerializer do
   end
 
   describe '#set_id' do
-    subject(:serializable_hash) { MovieSerializer.new(resource).serializable_hash }
+    let(:params) { {} }
+    subject(:serializable_hash) do
+      MovieSerializer.new(resource, { params: params }).serializable_hash
+    end
 
     context 'method name' do
       before do
@@ -223,8 +226,12 @@ describe FastJsonapi::ObjectSerializer do
     end
 
     context 'with block' do
+      let(:params) { { prefix: 'movie' } }
+
       before do
-        MovieSerializer.set_id { |record| "movie-#{record.owner_id}" }
+        MovieSerializer.set_id do |record, params|
+          "#{params[:prefix]}-#{record.owner_id}"
+        end
       end
 
       after do