Enhance/Extract auto-scoping logic

Author: Lee Richmond

lib/jsonapi_compliable.rb

@@ -15,6 +15,7 @@
 require "jsonapi_compliable/scope/filter"
 require "jsonapi_compliable/util/include_params"
 require "jsonapi_compliable/util/field_params"
+require "jsonapi_compliable/util/scoping"
 
 module JsonapiCompliable
   autoload :Base,           'jsonapi_compliable/base'

lib/jsonapi_compliable/base.rb

@@ -7,6 +7,8 @@ module Base
 
     included do
       class_attribute :_jsonapi_compliable
+      attr_reader :_jsonapi_scoped
+
       before_action :parse_fieldsets!
       after_action :reset_scope_flag
     end
@@ -45,8 +47,7 @@ def parse_fieldsets!
     end
 
     def render_ams(scope, opts = {})
-      opts[:scope] = true unless opts[:scope] == false
-      scope = jsonapi_scope(scope) if !@_jsonapi_scoped && opts.delete(:scope)
+      scope = jsonapi_scope(scope) if Util::Scoping.apply?(self, scope, opts.delete(:scope))
       options = default_ams_options
       options[:include] = forced_includes || Util::IncludeParams.scrub(self)
       options[:json] = scope

lib/jsonapi_compliable/util/scoping.rb

@@ -0,0 +1,20 @@
+module JsonapiCompliable
+  module Util
+    class Scoping
+      def self.apply?(controller, object, force)
+        return false if force == false
+        return true if !controller._jsonapi_scoped && object.is_a?(ActiveRecord::Relation)
+
+        already_scoped = !!controller._jsonapi_scoped
+        is_activerecord = object.is_a?(ActiveRecord::Base)
+        is_activerecord_array = object.is_a?(Array) && object[0].is_a?(ActiveRecord::Base)
+
+        if [already_scoped, is_activerecord, is_activerecord_array].any?
+          false
+        else
+          true
+        end
+      end
+    end
+  end
+end

spec/util/scoping_spec.rb

@@ -0,0 +1,49 @@
+require 'spec_helper'
+
+RSpec.describe JsonapiCompliable::Util::Scoping do
+  describe '.apply?' do
+    let(:force)      { true }
+    let(:controller) { double.as_null_object }
+    let(:object)     { Author.all }
+
+    subject { described_class.apply?(controller, object, force) }
+
+    before do
+      allow(controller).to receive(:_jsonapi_scoped) { nil }
+    end
+
+    it { is_expected.to be(true) }
+
+    context 'when forcing no scope' do
+      let(:force) { false }
+
+      it { is_expected.to be(false) }
+    end
+
+    context 'when controller has already scoped' do
+      before do
+        allow(controller).to receive(:_jsonapi_scoped) { true }
+      end
+
+      it { is_expected.to be(false) }
+    end
+
+    context 'when a PORO' do
+      let(:object) { Class.new }
+
+      it { is_expected.to be(true) }
+    end
+
+    context 'when object is an ActiveRecord instance' do
+      let(:object) { Author.new }
+
+      it { is_expected.to be(false) }
+    end
+
+    context 'when object is an array of ActiveRecord instances' do
+      let(:object) { [Author.new] }
+
+      it { is_expected.to be(false) }
+    end
+  end
+end