From ac166f359054c2d03b0cd5dee047fe794600e7c2 Mon Sep 17 00:00:00 2001
From: Matt-Yorkley <9029026+Matt-Yorkley@users.noreply.github.com>
Date: Tue, 28 Apr 2020 14:15:16 +0200
Subject: [PATCH 1/8] Add CacheService

---
 app/services/cache_service.rb       | 23 +++++++++++++
 spec/services/cache_service_spec.rb | 50 +++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 app/services/cache_service.rb
 create mode 100644 spec/services/cache_service_spec.rb

diff --git a/app/services/cache_service.rb b/app/services/cache_service.rb
new file mode 100644
index 0000000000..4a87dcea9a
--- /dev/null
+++ b/app/services/cache_service.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class CacheService
+  def self.cache(cache_key, options = {})
+    Rails.cache.fetch cache_key.to_s, options do
+      yield
+    end
+  end
+
+  # Yields a cached query, expired by the most recently updated record for a given class.
+  # E.g: if *any* Spree::Taxon record is updated, all keys based on Spree::Taxon will auto-expire.
+  def self.cached_data_by_class(cache_key, cached_class)
+    Rails.cache.fetch "#{cache_key}-#{cached_class}-#{latest_timestamp_by_class(cached_class)}" do
+      yield
+    end
+  end
+
+  # Gets the :updated_at value of the most recently updated record for a given class, and returns
+  # it as a timestamp, eg: `1583836069`.
+  def self.latest_timestamp_by_class(cached_class)
+    cached_class.maximum(:updated_at).to_i
+  end
+end
diff --git a/spec/services/cache_service_spec.rb b/spec/services/cache_service_spec.rb
new file mode 100644
index 0000000000..22a6e2b772
--- /dev/null
+++ b/spec/services/cache_service_spec.rb
@@ -0,0 +1,50 @@
+require 'spec_helper'
+
+describe CacheService do
+  let(:rails_cache) { Rails.cache }
+
+  describe "#cache" do
+    before do
+      rails_cache.stub(:fetch)
+    end
+
+    it "provides a wrapper for basic #fetch calls to Rails.cache" do
+      CacheService.cache("test-cache-key", expires_in: 10.seconds) do
+        "TEST"
+      end
+
+      expect(rails_cache).to have_received(:fetch).with("test-cache-key", expires_in: 10.seconds)
+    end
+  end
+
+  describe "#cached_data_by_class" do
+    let(:timestamp) { Time.now.to_i }
+
+    before do
+      rails_cache.stub(:fetch)
+      CacheService.stub(:latest_timestamp_by_class) { timestamp }
+    end
+
+    it "caches data by timestamp for last record of that class" do
+      CacheService.cached_data_by_class("test-cache-key", Enterprise) do
+        "TEST"
+      end
+
+      expect(CacheService).to have_received(:latest_timestamp_by_class).with(Enterprise)
+      expect(rails_cache).to have_received(:fetch).with("test-cache-key-Enterprise-#{timestamp}")
+    end
+  end
+
+  describe "#latest_timestamp_by_class" do
+    let!(:taxon1) { create(:taxon) }
+    let!(:taxon2) { create(:taxon) }
+
+    it "gets the :updated_at value of the last record for a given class and returns a timestamp" do
+      taxon1.touch
+      expect(CacheService.latest_timestamp_by_class(Spree::Taxon)).to eq taxon1.updated_at.to_i
+
+      taxon2.touch
+      expect(CacheService.latest_timestamp_by_class(Spree::Taxon)).to eq taxon2.updated_at.to_i
+    end
+  end
+end

From 975afb3152b8976c62cda2c447696414eb13a571 Mon Sep 17 00:00:00 2001
From: Matt-Yorkley <9029026+Matt-Yorkley@users.noreply.github.com>
Date: Wed, 22 Apr 2020 12:35:39 +0200
Subject: [PATCH 2/8] Enable use of Action Caching in the API :tada:

See: https://guides.rubyonrails.org/api_app.html#adding-other-modules
---
 app/models/concerns/api_action_caching.rb | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 app/models/concerns/api_action_caching.rb

diff --git a/app/models/concerns/api_action_caching.rb b/app/models/concerns/api_action_caching.rb
new file mode 100644
index 0000000000..ef0eba604d
--- /dev/null
+++ b/app/models/concerns/api_action_caching.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+# API controllers inherit from ActionController::Metal to keep them slim and fast.
+# This concern adds the minimum requirements needed to use Action Caching in the API.
+
+module ApiActionCaching
+  extend ActiveSupport::Concern
+
+  included do
+    include ActionController::Caching
+    include ActionController::Caching::Actions
+    include AbstractController::Layouts
+
+    # This config is not passed to the controller automatically with ActionController::Metal
+    self.cache_store = Rails.configuration.cache_store
+
+    # ActionController::Caching asks for a controller's layout, but they're not used in the API
+    layout false
+  end
+end

From ea1ec1a1c67df84173a7fb8b83a218e50e141b17 Mon Sep 17 00:00:00 2001
From: Matt-Yorkley <9029026+Matt-Yorkley@users.noreply.github.com>
Date: Tue, 28 Apr 2020 14:20:44 +0200
Subject: [PATCH 3/8] Use ActionCaching in OrderCyclesController (taxons and
 properties)

---
 app/controllers/api/order_cycles_controller.rb | 4 +++-
 app/services/cache_service.rb                  | 2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/app/controllers/api/order_cycles_controller.rb b/app/controllers/api/order_cycles_controller.rb
index 0ac5223ea1..e2bca5a626 100644
--- a/app/controllers/api/order_cycles_controller.rb
+++ b/app/controllers/api/order_cycles_controller.rb
@@ -1,10 +1,12 @@
 module Api
   class OrderCyclesController < Api::BaseController
     include EnterprisesHelper
-    respond_to :json
+    include ApiActionCaching
 
     skip_authorization_check
 
+    caches_action :taxons, :properties, expires_in: CacheService::FILTERS_EXPIRY
+
     def products
       products = ProductsRenderer.new(
         distributor,
diff --git a/app/services/cache_service.rb b/app/services/cache_service.rb
index 4a87dcea9a..610b4ca6b4 100644
--- a/app/services/cache_service.rb
+++ b/app/services/cache_service.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class CacheService
+  FILTERS_EXPIRY = 30.seconds.freeze
+
   def self.cache(cache_key, options = {})
     Rails.cache.fetch cache_key.to_s, options do
       yield

From a25a75bbe892276171945e3452cf78458d52cdc3 Mon Sep 17 00:00:00 2001
From: Matt-Yorkley <9029026+Matt-Yorkley@users.noreply.github.com>
Date: Wed, 22 Apr 2020 19:40:24 +0200
Subject: [PATCH 4/8] Ensure action caching includes GET params

By default the auto-generated action cache keys looks like this:
`views/0.0.0.0:3000/api/order_cycles/1/properties`

With this change the cache keys now look like this:
`views/0.0.0.0:3000/api/order_cycles/1/properties?distributor=3`
---
 app/controllers/api/order_cycles_controller.rb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/app/controllers/api/order_cycles_controller.rb b/app/controllers/api/order_cycles_controller.rb
index e2bca5a626..f92927b0fe 100644
--- a/app/controllers/api/order_cycles_controller.rb
+++ b/app/controllers/api/order_cycles_controller.rb
@@ -5,7 +5,9 @@ module Api
 
     skip_authorization_check
 
-    caches_action :taxons, :properties, expires_in: CacheService::FILTERS_EXPIRY
+    caches_action :taxons, :properties,
+                  expires_in: CacheService::FILTERS_EXPIRY,
+                  cache_path: proc { |controller| controller.request.url }
 
     def products
       products = ProductsRenderer.new(

From 61d7adaf74a1276445e634599ed6bf06e82af4a1 Mon Sep 17 00:00:00 2001
From: Matt-Yorkley <9029026+Matt-Yorkley@users.noreply.github.com>
Date: Wed, 29 Apr 2020 20:04:37 +0200
Subject: [PATCH 5/8] Enable optional `caching` tag in test metadata

---
 spec/spec_helper.rb | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 5eb8cad557..ec5311f1eb 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -114,6 +114,15 @@ RSpec.configure do |config|
       .each { |s| s.driver.reset! }
   end
 
+  # Enable caching in any specs tagged with `caching: true`. Usage is exactly the same as the
+  # well-known `js: true` tag used to enable javascript in feature specs.
+  config.around(:each, :caching) do |example|
+    caching = ActionController::Base.perform_caching
+    ActionController::Base.perform_caching = example.metadata[:caching]
+    example.run
+    ActionController::Base.perform_caching = caching
+  end
+
   config.before(:all) { restart_phantomjs }
 
   # Geocoding

From 7e4c00ba3f97b80e9df947f08ecee92f893d8d3b Mon Sep 17 00:00:00 2001
From: Matt-Yorkley <9029026+Matt-Yorkley@users.noreply.github.com>
Date: Tue, 5 May 2020 18:44:48 +0200
Subject: [PATCH 6/8] Ensure caching works in cache tests for API controllers

---
 app/models/concerns/api_action_caching.rb | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/app/models/concerns/api_action_caching.rb b/app/models/concerns/api_action_caching.rb
index ef0eba604d..05dbc9f0d4 100644
--- a/app/models/concerns/api_action_caching.rb
+++ b/app/models/concerns/api_action_caching.rb
@@ -11,8 +11,9 @@ module ApiActionCaching
     include ActionController::Caching::Actions
     include AbstractController::Layouts
 
-    # This config is not passed to the controller automatically with ActionController::Metal
+    # These configs are not assigned to the controller automatically with ActionController::Metal
     self.cache_store = Rails.configuration.cache_store
+    self.perform_caching = ActionController::Base.perform_caching
 
     # ActionController::Caching asks for a controller's layout, but they're not used in the API
     layout false

From 4aac97c9855fc633730ac1ee16c70f32ad51ebee Mon Sep 17 00:00:00 2001
From: Matt-Yorkley <9029026+Matt-Yorkley@users.noreply.github.com>
Date: Tue, 5 May 2020 20:34:26 +0200
Subject: [PATCH 7/8] Add feature spec for action caching of taxon and
 properties endpoints

---
 .../consumer/caching/shops_caching_spec.rb    | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 spec/features/consumer/caching/shops_caching_spec.rb

diff --git a/spec/features/consumer/caching/shops_caching_spec.rb b/spec/features/consumer/caching/shops_caching_spec.rb
new file mode 100644
index 0000000000..7d70796e37
--- /dev/null
+++ b/spec/features/consumer/caching/shops_caching_spec.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+feature "Shops caching", js: true, caching: true do
+  include WebHelper
+  include UIComponentHelper
+
+  let!(:distributor) { create(:distributor_enterprise, with_payment_and_shipping: true, is_primary_producer: true) }
+  let!(:order_cycle) { create(:open_order_cycle, distributors: [distributor], coordinator: distributor) }
+
+  describe "API action caching on taxons and properties" do
+    let!(:taxon) { create(:taxon, name: "Cached Taxon") }
+    let!(:taxon2) { create(:taxon, name: "New Taxon") }
+    let!(:property) { create(:property, presentation: "Cached Property") }
+    let!(:property2) { create(:property, presentation: "New Property") }
+    let!(:product) { create(:product, taxons: [taxon], primary_taxon: taxon, properties: [property]) }
+    let(:exchange) { order_cycle.exchanges.to_enterprises(distributor).outgoing.first }
+
+    let(:test_domain) { "#{Capybara.current_session.server.host}:#{Capybara.current_session.server.port}" }
+    let(:taxons_key) { "views/#{test_domain}/api/order_cycles/#{order_cycle.id}/taxons?distributor=#{distributor.id}" }
+    let(:properties_key) { "views/#{test_domain}/api/order_cycles/#{order_cycle.id}/properties?distributor=#{distributor.id}" }
+    let(:options) { { expires_in: CacheService::FILTERS_EXPIRY } }
+
+    before do
+      exchange.variants << product.variants.first
+    end
+
+    it "caches rendered response for taxons and properties, with the provided options" do
+      visit enterprise_shop_path(distributor)
+
+      expect(page).to have_content "Cached Taxon"
+      expect(page).to have_content "Cached Property"
+
+      expect_cached taxons_key, options
+      expect_cached properties_key, options
+    end
+
+    it "keeps data cached for a short time on subsequent requests" do
+      # One minute ago...
+      Timecop.travel(Time.zone.now - 1.minute) do
+        visit enterprise_shop_path(distributor)
+
+        expect(page).to have_content taxon.name
+        expect(page).to have_content property.presentation
+
+        product.update_attribute(:taxons, [taxon2])
+        product.update_attribute(:primary_taxon, taxon2)
+        product.update_attribute(:properties, [property2])
+
+        visit enterprise_shop_path(distributor)
+
+        expect(page).to have_content taxon.name # Taxon list is unchanged
+        expect(page).to have_content property.presentation # Property list is unchanged
+      end
+
+      # A while later...
+      visit enterprise_shop_path(distributor)
+
+      expect(page).to have_content taxon2.name
+      expect(page).to have_content property2.presentation
+    end
+  end
+
+  def expect_cached(key, options = {})
+    expect(Rails.cache.exist?(key, options)).to be true
+  end
+end

From 9c24c1cd05a1e71d8c17600da2c1cc73fbf7d941 Mon Sep 17 00:00:00 2001
From: Matt-Yorkley <9029026+Matt-Yorkley@users.noreply.github.com>
Date: Wed, 6 May 2020 12:24:33 +0200
Subject: [PATCH 8/8] Ensure #caches_action works in test suite

---
 app/models/concerns/api_action_caching.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/models/concerns/api_action_caching.rb b/app/models/concerns/api_action_caching.rb
index 05dbc9f0d4..b3e030e408 100644
--- a/app/models/concerns/api_action_caching.rb
+++ b/app/models/concerns/api_action_caching.rb
@@ -13,7 +13,7 @@ module ApiActionCaching
 
     # These configs are not assigned to the controller automatically with ActionController::Metal
     self.cache_store = Rails.configuration.cache_store
-    self.perform_caching = ActionController::Base.perform_caching
+    self.perform_caching = true
 
     # ActionController::Caching asks for a controller's layout, but they're not used in the API
     layout false