Merge pull request #1672 from tvdeyen/page-api-pagination

Page api pagination

.gitignore

@@ -21,3 +21,4 @@ spec/dummy/public/assets
 .ruby-gemset
 .ruby-version
 .env
+.rspec

Gemfile

@@ -27,5 +27,6 @@ group :development, :test do
     gem 'localeapp', '~> 3.0', require: false
     gem 'dotenv', '~> 2.2'
     gem 'github_fast_changelog', require: false
+    gem 'active_record_query_trace', require: false
   end
 end

app/controllers/alchemy/api/pages_controller.rb

@@ -13,10 +13,24 @@ def index
       else
         @pages = Page.accessible_by(current_ability, :index)
       end
+      @pages = @pages.includes(*page_includes)
       if params[:page_layout].present?
+        Alchemy::Deprecation.warn <<~WARN
+          Passing page_layout parameter to Alchemy::Api::PagesController#index is deprecated.
+          Please pass a Ransack search query instead:
+              q: {
+                page_layout_eq: '#{params[:page_layout]}'
+              }
+        WARN
         @pages = @pages.where(page_layout: params[:page_layout])
       end
-      render json: @pages, adapter: :json, root: 'pages'
+      @pages = @pages.ransack(params[:q]).result
+
+      if params[:page]
+        @pages = @pages.page(params[:page]).per(params[:per_page])
+      end
+
+      render json: @pages, adapter: :json, root: 'pages', meta: meta_data
     end
 
     # Returns all pages as nested json object for tree views
@@ -54,5 +68,51 @@ def load_page
               ) ||
               raise(ActiveRecord::RecordNotFound)
     end
+
+    def meta_data
+      {
+        total_count: total_count_value,
+        per_page: per_page_value,
+        page: page_value
+      }
+    end
+
+    def total_count_value
+      params[:page] ? @pages.total_count : @pages.size
+    end
+
+    def per_page_value
+      if params[:page]
+        (params[:per_page] || Kaminari.config.default_per_page).to_i
+      else
+        @pages.size
+      end
+    end
+
+    def page_value
+      params[:page] ? params[:page].to_i : nil
+    end
+
+    def page_includes
+      [
+        :tags,
+        {
+          elements: [
+            {
+              nested_elements: [
+                {
+                  contents: :essence
+                },
+                :tags
+              ]
+            },
+            {
+              contents: :essence
+            },
+            :tags
+          ]
+        }
+      ]
+    end
   end
 end

app/models/alchemy/content.rb

@@ -24,7 +24,7 @@ class Content < BaseRecord
     # Concerns
     include Alchemy::Content::Factory
 
-    belongs_to :essence, polymorphic: true, dependent: :destroy
+    belongs_to :essence, polymorphic: true, dependent: :destroy, inverse_of: :content
     belongs_to :element, touch: true, inverse_of: :contents
     has_one :page, through: :element
 

app/models/alchemy/element.rb

@@ -62,7 +62,7 @@ class Element < BaseRecord
 
     # Content positions are scoped by their essence_type, so positions can be the same for different contents.
     # In order to get contents in creation order we also order them by id.
-    has_many :contents, -> { order(:position, :id) }, dependent: :destroy
+    has_many :contents, -> { order(:position, :id) }, dependent: :destroy, inverse_of: :element
 
     has_many :all_nested_elements,
       -> { order(:position) },

app/serializers/alchemy/page_serializer.rb

@@ -16,9 +16,5 @@ class PageSerializer < ActiveModel::Serializer
       :status
 
     has_many :elements
-
-    def elements
-      object.elements.published
-    end
   end
 end

lib/alchemy/essence.rb

@@ -37,7 +37,7 @@ def acts_as_essence(options = {})
           stampable stamper_class_name: Alchemy.user_class_name
           validate :validate_ingredient, on: :update, if: -> { validations.any? }
 
-          has_one :content, as: :essence, class_name: "Alchemy::Content"
+          has_one :content, as: :essence, class_name: "Alchemy::Content", inverse_of: :essence
           has_one :element, through: :content, class_name: "Alchemy::Element"
           has_one :page,    through: :element, class_name: "Alchemy::Page"
 

spec/controllers/alchemy/api/pages_controller_spec.rb

@@ -8,16 +8,19 @@ module Alchemy
 
     describe '#index' do
       let!(:page) { create(:alchemy_page, :public) }
+      let(:result) { JSON.parse(response.body) }
 
-      it "returns all public pages as json objects" do
+      it 'returns JSON' do
         get :index, params: {format: :json}
 
         expect(response.status).to eq(200)
         expect(response.media_type).to eq('application/json')
+        expect(result).to have_key('pages')
+      end
 
-        result = JSON.parse(response.body)
+      it "returns all public pages" do
+        get :index, params: {format: :json}
 
-        expect(result).to have_key('pages')
         expect(result['pages'].size).to eq(2)
       end
 
@@ -27,12 +30,6 @@ module Alchemy
         it "returns only page with this page layout" do
           get :index, params: {page_layout: 'news', format: :json}
 
-          expect(response.status).to eq(200)
-          expect(response.media_type).to eq('application/json')
-
-          result = JSON.parse(response.body)
-
-          expect(result).to have_key('pages')
           expect(result['pages'].size).to eq(1)
         end
       end
@@ -41,12 +38,6 @@ module Alchemy
         it "returns all pages" do
           get :index, params: {page_layout: '', format: :json}
 
-          expect(response.status).to eq(200)
-          expect(response.media_type).to eq('application/json')
-
-          result = JSON.parse(response.body)
-
-          expect(result).to have_key('pages')
           expect(result['pages'].size).to eq(2)
         end
       end
@@ -59,13 +50,42 @@ module Alchemy
         it "returns all pages" do
           get :index, params: {format: :json}
 
-          expect(response.status).to eq(200)
-          expect(response.media_type).to eq('application/json')
+          expect(result['pages'].size).to eq(Alchemy::Page.count)
+        end
+      end
 
-          result = JSON.parse(response.body)
+      it 'includes meta data' do
+        get :index, params: { format: :json }
 
-          expect(result).to have_key('pages')
-          expect(result['pages'].size).to eq(Alchemy::Page.count)
+        expect(result['pages'].size).to eq(2)
+        expect(result['meta']['page']).to be_nil
+        expect(result['meta']['per_page']).to eq(2)
+        expect(result['meta']['total_count']).to eq(2)
+      end
+
+      context 'with page param given' do
+        let!(:page1) { create(:alchemy_page) }
+        let!(:page2) { create(:alchemy_page) }
+
+        before do
+          expect(Kaminari.config).to receive(:default_per_page).at_least(:once) { 1 }
+        end
+
+        it 'returns paginated result' do
+          get :index, params: { page: 2, format: :json }
+
+          expect(result['pages'].size).to eq(1)
+          expect(result['meta']['page']).to eq(2)
+          expect(result['meta']['per_page']).to eq(1)
+          expect(result['meta']['total_count']).to eq(2)
+        end
+      end
+
+      context 'with ransack query param given' do
+        it 'returns filtered result' do
+          get :index, params: { q: { name_eq: page.name }, format: :json }
+
+          expect(result['pages'].size).to eq(1)
         end
       end
     end

spec/dummy/config/initializers/active_record_query_trace.rb

@@ -0,0 +1,10 @@
+if Rails.env.development?
+  require 'active_record_query_trace'
+  ActiveRecordQueryTrace.enabled = true
+  ActiveRecordQueryTrace.level = :custom
+  ActiveRecordQueryTrace.backtrace_cleaner = ->(trace) do
+    trace.reject do |line|
+      line =~ /\b(active_record_query_trace|active_support|active_record|rack-mini-profiler)\b/
+    end
+  end
+end