Implement support for collection serializers.

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ### 1.5.0 (Next)
 
+* [#61](https://github.com/ruby-grape/grape-active_model_serializers/pull/61): Adds support for collection serializers - [@drn](https://github.com/drn).
+* [#60](https://github.com/ruby-grape/grape-active_model_serializers/pull/60): Namespace serializer inference - [@drn](https://github.com/drn).
+* [#59](https://github.com/ruby-grape/grape-active_model_serializers/pull/59): Refactor option and serializer resolution - [@drn](https://github.com/drn).
+* [#57](https://github.com/ruby-grape/grape-active_model_serializers/pull/57): Solve line length linter issues - [@drn](https://github.com/drn).
 * [#54](https://github.com/ruby-grape/grape-active_model_serializers/pull/54): Adding support for ASM v0.10. Drops support for ASM v0.9 - [@drn](https://github.com/drn).
 
 ### 1.4.0 (July 14, 2016)
@@ -11,8 +15,8 @@
 
 ### v1.3.2 (February 27, 2015)
 
-* [#39](https://github.com/ruby-grape/grape-active_model_serializers/pull/39): Look for namespace and other options to configure serializers - [@jwkoelewijn](https://github.com/jwkoelewijn).
 * [#40](https://github.com/ruby-grape/grape-active_model_serializers/pull/40): Use env to pass AMS meta around - [@dblock](https://github.com/dblock).
+* [#39](https://github.com/ruby-grape/grape-active_model_serializers/pull/39): Look for namespace and other options to configure serializers - [@jwkoelewijn](https://github.com/jwkoelewijn).
 
 ### v1.3.1 (November 20, 2014)
 

lib/grape-active_model_serializers/serializer_resolver.rb

@@ -7,9 +7,7 @@ module Grape
       end
 
       def serializer
-        @serializer ||= (
-          serializer_class.new(resource, options) if serializer_class
-        )
+        serializer_class.new(resource, serializer_options) if serializer_class
       end
 
       private
@@ -17,13 +15,32 @@ module Grape
       attr_accessor :resource, :options
 
       def serializer_class
-        serializer_class = resource_defined_class
-        serializer_class ||= collection_class
-        serializer_class ||= options[:serializer]
+        return @serializer_class if defined?(@serializer_class)
+        @serializer_class = resource_defined_class
+        @serializer_class ||= collection_class
+        @serializer_class ||= options[:serializer]
+        @serializer_class ||= namespace_inferred_class
+        @serializer_class ||= version_inferred_class
+        @serializer_class ||= resource_serializer_class
+      end
+
+      def serializer_options
+        if collection_serializer? && !options.key?(:serializer)
+          options.merge(each_serializer_option)
+        else
+          options
+        end
+      end
+
+      def collection_serializer?
+        serializer_class == ActiveModel::Serializer.config.collection_serializer
+      end
+
+      def each_serializer_option
+        serializer_class = options[:each_serializer]
         serializer_class ||= namespace_inferred_class
         serializer_class ||= version_inferred_class
-        serializer_class ||= resource_serializer_class
-        serializer_class
+        serializer_class ? { serializer: serializer_class } : {}
       end
 
       def resource_defined_class
@@ -36,12 +53,13 @@ module Grape
       end
 
       def namespace_inferred_class
-        return nil unless options[:for]
+        return nil unless options.key?(:for)
         namespace = options[:for].to_s.deconstantize
         "#{namespace}::#{resource_serializer_klass}".safe_constantize
       end
 
       def version_inferred_class
+        return nil unless options.key?(:version)
         "#{version}::#{resource_serializer_klass}".safe_constantize
       end
 
@@ -57,14 +75,22 @@ module Grape
       end
 
       def resource_klass
-        resource.class.name.demodulize
+        resource_class.name.demodulize
       end
 
       def resource_namespace
-        klass = resource.class.name.deconstantize
+        klass = resource_class.name.deconstantize
         klass.empty? ? nil : klass
       end
 
+      def resource_class
+        if resource.respond_to?(:to_ary)
+          resource.try(:klass) || resource.compact.first.class
+        else
+          resource.class
+        end
+      end
+
       def resource_serializer_class
         ActiveModel::Serializer.serializer_for(resource)
       end

spec/grape/active_model_serializers/serializer_resolver_spec.rb

@@ -1,11 +1,12 @@
+require 'pry'
 require 'spec_helper'
 
 # asserts serializer resolution order:
 #   1. resource_defined_class     # V1::UserSerializer
-#   2. collection_class           # CollectionSerializer
-#   3. options[:serializer]       # V2::UserSerializer
-#   4. namespace_inferred_class   # V3::UserSerializer
-#   5. version_inferred_class     # V4::UserSerializer
+#   2. collection_class           # CollectionSerializer, V2::UserSerializer
+#   3. options[:serializer]       # V3::UserSerializer
+#   4. namespace_inferred_class   # V4::UserSerializer
+#   5. version_inferred_class     # V5::UserSerializer
 #   6. resource_serializer_class  # UserSerializer
 #   7. missing resource           # nil
 
@@ -15,15 +16,15 @@ describe Grape::ActiveModelSerializers::SerializerResolver do
   let(:options) {
     {
       serializer: options_serializer_class, # options defined
-      for:        V3::UsersApi,             # namespace inference
-      version:    'v4'                      # version inference
+      for:        V4::UsersApi,             # namespace inference
+      version:    'v5'                      # version inference
     }
   }
   # resource defined
   let(:resource_defined?) { true }
   let(:defined_serializer_class) { V1::UserSerializer }
   # options defined
-  let(:options_serializer_class) { V2::UserSerializer }
+  let(:options_serializer_class) { V3::UserSerializer }
 
   let(:serializer) { resolver.serializer }
 
@@ -51,12 +52,55 @@ describe Grape::ActiveModelSerializers::SerializerResolver do
       it 'returns serializer' do
         expect(serializer).to be_kind_of(serializer_class)
       end
+
+      context 'each serializer' do
+        let(:options) {
+          super().except(:serializer).merge(
+            each_serializer: V2::UserSerializer
+          )
+        }
+        let(:each_serializer) { serializer.send(:options)[:serializer] }
+
+        context 'each_serializer option' do
+          it 'returns expected serializer' do
+            expect(each_serializer).to eq(V2::UserSerializer)
+          end
+        end
+
+        context 'no each_serializer option' do
+          let(:options) { super().except(:each_serializer) }
+
+          context 'namespace inferred' do
+            it 'returns expected serializer' do
+              expect(each_serializer).to eq(V4::UserSerializer)
+            end
+          end
+
+          context 'not namespace inferred' do
+            let(:options) { super().except(:for) }
+
+            context 'version inferred' do
+              it 'returns expected serializer' do
+                expect(each_serializer).to eq(V5::UserSerializer)
+              end
+            end
+
+            context 'not version inferred' do
+              let(:options) { super().except(:version) }
+
+              it 'returns nil' do
+                expect(each_serializer).to eq(nil)
+              end
+            end
+          end
+        end
+      end
     end
 
     context 'not resource collection' do
       context 'specified by options' do
         it 'returns specified serializer' do
-          expect(serializer).to be_kind_of(V2::UserSerializer)
+          expect(serializer).to be_kind_of(V3::UserSerializer)
         end
       end
 
@@ -65,7 +109,7 @@ describe Grape::ActiveModelSerializers::SerializerResolver do
 
         context 'namespace inferred' do
           it 'returns inferred serializer' do
-            expect(serializer).to be_kind_of(V3::UserSerializer)
+            expect(serializer).to be_kind_of(V4::UserSerializer)
           end
         end
 
@@ -74,7 +118,7 @@ describe Grape::ActiveModelSerializers::SerializerResolver do
 
           context 'version inferred' do
             it 'returns inferred serializer' do
-              expect(serializer).to be_kind_of(V4::UserSerializer)
+              expect(serializer).to be_kind_of(V5::UserSerializer)
             end
           end
 

spec/support/api/v4/users_api.rb

@@ -1,4 +1,4 @@
-module V3
+module V4
   class UsersApi < Grape::API
     resource :users do
       desc 'all users'

spec/support/serializers/v5/user_serializer.rb

@@ -0,0 +1,5 @@
+module V5
+  class UserSerializer < ActiveModel::Serializer
+    attributes :first_name, :last_name, :email
+  end
+end