PERF: Cache categories in Site model take 2.

Follow-up to aa4f0aee67.

Fixed the security problem in the previous attempt.

spec/models/site_spec.rb

@@ -58,30 +58,65 @@ describe Site do
     expect(Site.new(guardian).categories.last.notification_level).to eq(1)
   end
 
-  it "omits categories users can not write to from the category list" do
-    category = Fabricate(:category)
-    user = Fabricate(:user)
+  describe '#categories' do
+    fab!(:category) { Fabricate(:category) }
+    fab!(:user) { Fabricate(:user) }
+    fab!(:guardian) { Guardian.new(user) }
 
-    expect(Site.new(Guardian.new(user)).categories.count).to eq(2)
+    after do
+      Site.clear_cache
+    end
 
-    category.set_permissions(everyone: :create_post)
-    category.save
+    it "omits read restricted categories" do
+      expect(Site.new(guardian).categories.map(&:id)).to contain_exactly(
+        SiteSetting.uncategorized_category_id, category.id
+      )
 
-    guardian = Guardian.new(user)
+      category.update!(read_restricted: true)
 
-    expect(Site.new(guardian)
-        .categories
-        .keep_if { |c| c.name == category.name }
-        .first
-        .permission)
-      .not_to eq(CategoryGroup.permission_types[:full])
+      expect(Site.new(guardian).categories.map(&:id)).to contain_exactly(
+        SiteSetting.uncategorized_category_id
+      )
+    end
 
-    # If a parent category is not visible, the child categories should not be returned
-    category.set_permissions(staff: :full)
-    category.save
+    it "includes categories that a user's group can see" do
+      group = Fabricate(:group)
+      category.update!(read_restricted: true)
+      category.groups << group
 
-    sub_category = Fabricate(:category, parent_category_id: category.id)
-    expect(Site.new(guardian).categories).not_to include(sub_category)
+      expect(Site.new(guardian).categories.map(&:id)).to contain_exactly(
+        SiteSetting.uncategorized_category_id
+      )
+
+      group.add(user)
+
+      expect(Site.new(Guardian.new(user)).categories.map(&:id)).to contain_exactly(
+        SiteSetting.uncategorized_category_id, category.id
+      )
+    end
+
+    it "omits categories users can not write to from the category list" do
+      expect(Site.new(guardian).categories.count).to eq(2)
+
+      category.set_permissions(everyone: :create_post)
+      category.save!
+
+      guardian = Guardian.new(user)
+
+      expect(Site.new(guardian)
+          .categories
+          .keep_if { |c| c.name == category.name }
+          .first
+          .permission)
+        .not_to eq(CategoryGroup.permission_types[:full])
+
+      # If a parent category is not visible, the child categories should not be returned
+      category.set_permissions(staff: :full)
+      category.save!
+
+      sub_category = Fabricate(:category, parent_category_id: category.id)
+      expect(Site.new(guardian).categories).not_to include(sub_category)
+    end
   end
 
   it "omits groups user can not see" do

spec/serializers/site_serializer_spec.rb

@@ -10,13 +10,34 @@ describe SiteSerializer do
     category.custom_fields["enable_marketplace"] = true
     category.save_custom_fields
 
-    data = MultiJson.dump(described_class.new(Site.new(guardian), scope: guardian, root: false))
-    expect(data).not_to include("enable_marketplace")
+    serialized = described_class.new(Site.new(guardian), scope: guardian, root: false).as_json
+    c1 = serialized[:categories].find { |c| c[:id] == category.id }
+
+    expect(c1[:preloaded_custom_fields]).to eq(nil)
 
     Site.preloaded_category_custom_fields << "enable_marketplace"
 
-    data = MultiJson.dump(described_class.new(Site.new(guardian), scope: guardian, root: false))
-    expect(data).to include("enable_marketplace")
+    serialized = described_class.new(Site.new(guardian), scope: guardian, root: false).as_json
+    c1 = serialized[:categories].find { |c| c[:id] == category.id }
+
+    expect(c1[:preloaded_custom_fields]["enable_marketplace"]).to eq("t")
+  end
+
+  it "includes category tags" do
+    tag = Fabricate(:tag)
+    tag_group = Fabricate(:tag_group)
+    tag_group_2 = Fabricate(:tag_group)
+
+    category.tags << tag
+    category.tag_groups << tag_group
+    category.update!(required_tag_group: tag_group_2)
+
+    serialized = described_class.new(Site.new(guardian), scope: guardian, root: false).as_json
+    c1 = serialized[:categories].find { |c| c[:id] == category.id }
+
+    expect(c1[:allowed_tags]).to contain_exactly(tag.name)
+    expect(c1[:allowed_tag_groups]).to contain_exactly(tag_group.name)
+    expect(c1[:required_tag_group_name]).to eq(tag_group_2.name)
   end
 
   it "returns correct notification level for categories" do