Configuration for ETags and custom cache store

Closes codenoble#6

README.md

@@ -30,6 +30,26 @@ Features
 - **ETags** for easy HTTP caching
 - **Simlpe, Readable DSL**
 
+Configuration
+-------------
+### ETags
+```ruby
+CacheCrispies.configure do |conf|
+  conf.etags = true
+end
+```
+_`etags` is set to `false` by default._
+
+### Custom Cache Store
+```ruby
+CacheCrispies.configure do |conf|
+  conf.cache_store = ActiveSupport::Cache::DalliStore.new('localhost')
+end
+```
+`cache_store` must be set to something that quacks like a [ActiveSupport::Cache::Store](https://api.rubyonrails.org/classes/ActiveSupport/Cache/Store.html).
+
+_`cache_store` is set to `Rails.cache` by default, or `ActiveSupport::Cache::NullStore.new` if `Rails.cache` is `nil`._
+
 Usage
 -----
 ### A simple serializer

lib/cache_crispies.rb

@@ -15,12 +15,25 @@ module CacheCrispies
   require 'cache_crispies/version'
 
   # Use autoload for better Rails development
-  autoload :Attribute,    'cache_crispies/attribute'
-  autoload :Base,         'cache_crispies/base'
-  autoload :Collection,   'cache_crispies/collection'
-  autoload :Condition,    'cache_crispies/condition'
-  autoload :HashBuilder,  'cache_crispies/hash_builder'
-  autoload :Memoizer,     'cache_crispies/memoizer'
-  autoload :Controller,   'cache_crispies/controller'
-  autoload :Plan,         'cache_crispies/plan'
+  autoload :Attribute,      'cache_crispies/attribute'
+  autoload :Base,           'cache_crispies/base'
+  autoload :Collection,     'cache_crispies/collection'
+  autoload :Condition,      'cache_crispies/condition'
+  autoload :Configuration,  'cache_crispies/configuration'
+  autoload :HashBuilder,    'cache_crispies/hash_builder'
+  autoload :Memoizer,       'cache_crispies/memoizer'
+  autoload :Controller,     'cache_crispies/controller'
+  autoload :Plan,           'cache_crispies/plan'
+
+  def self.configure
+    yield config
+  end
+
+  def self.config
+    @config ||= Configuration.new
+  end
+
+  def self.cache
+    config.cache_store
+  end
 end

lib/cache_crispies/collection.rb

@@ -48,7 +48,7 @@ def cached_json
         hash[plan.cache_key] = model
       end
 
-      Rails.cache.fetch_multi(models_by_cache_key.keys) do |cache_key|
+      CacheCrispies.cache.fetch_multi(models_by_cache_key.keys) do |cache_key|
         model = models_by_cache_key[cache_key]
 
         serializer.new(model, options).as_json

lib/cache_crispies/configuration.rb

@@ -0,0 +1,26 @@
+require 'rails'
+
+module CacheCrispies
+  class Configuration
+    SETTINGS = [
+      :cache_store,
+      :etags
+    ].freeze
+
+    SETTINGS.each do |setting|
+      attr_accessor setting
+    end
+
+    def initialize
+      reset!
+    end
+
+    alias etags? etags
+
+    # Resets all values to their defaults. Useful for testing.
+    def reset!
+      @cache_store = Rails.cache || ActiveSupport::Cache::NullStore.new
+      @etags = false
+    end
+  end
+end

lib/cache_crispies/controller.rb

@@ -28,12 +28,13 @@ module Controller
     def cache_render(serializer, cacheable, options = {})
       plan = CacheCrispies::Plan.new(serializer, cacheable, options)
 
-      # TODO: It would probably be good to add configuration to etiher
-      # enable or disable this
-      response.weak_etag = plan.etag
+      if CacheCrispies.config.etags?
+        response.weak_etag = plan.etag
+      end
 
       serializer_json =
         if plan.collection?
+          # TODO: try to cache the whole collection here
           cacheable.map do |one_cacheable|
             plan.cache { serializer.new(one_cacheable, options).as_json }
           end

lib/cache_crispies/plan.rb

@@ -70,7 +70,7 @@ def cache_key
     # @return whatever the provided block returns
     def cache
       if cache?
-        Rails.cache.fetch(cache_key) { yield }
+        CacheCrispies.cache.fetch(cache_key) { yield }
       else
         yield
       end

spec/base_spec.rb → spec/cache_crispies/base_spec.rb

@@ -107,7 +107,7 @@ def id
   describe '.cache_key_base' do
     let(:nested_serializer_digest) { 'nutrition-serializer-digest' }
     let(:serializer_file_path) {
-      File.expand_path('fixtures/test_serializer.rb', __dir__)
+      File.expand_path('../fixtures/test_serializer.rb', __dir__)
     }
     let(:serializer_file_digest) {
       Digest::MD5.file(serializer_file_path).to_s

spec/collection_spec.rb → spec/cache_crispies/collection_spec.rb

@@ -35,7 +35,7 @@ def models.cache_key() end
 
         it "doesn't cache the results" do
           expect(CacheCrispies::Plan).to_not receive(:new)
-          expect(Rails).to_not receive :cache
+          expect(CacheCrispies).to_not receive :cache
           expect(subject.as_json).to eq [ {name: name1}, {name: name2} ]
         end
       end
@@ -45,7 +45,7 @@ def models.cache_key() end
 
         it "doesn't cache the results" do
           expect(CacheCrispies::Plan).to_not receive(:new)
-          expect(Rails).to_not receive :cache
+          expect(CacheCrispies).to_not receive :cache
           expect(subject.as_json).to eq [ {name: name1}, {name: name2} ]
         end
       end
@@ -55,13 +55,13 @@ def models.cache_key() end
       it 'caches the results' do
         expect(CacheCrispies::Plan).to receive(:new).with(
           serializer, model1, options
-        ).and_return double(cache_key: 'cereal-key-1')
+        ).and_return double('plan-dbl-1', cache_key: 'cereal-key-1')
 
         expect(CacheCrispies::Plan).to receive(:new).with(
           serializer, model2, options
-        ).and_return double(cache_key: 'cereal-key-2')
+        ).and_return double('plan-dbl-2', cache_key: 'cereal-key-2')
 
-        expect(Rails).to receive_message_chain(:cache, :fetch_multi).with(
+        expect(CacheCrispies).to receive_message_chain(:cache, :fetch_multi).with(
           %w[cereal-key-1 cereal-key-2]
         ).and_yield('cereal-key-1').and_return(name: name1)
           .and_yield('cereal-key-2').and_return(name: name2)
@@ -70,4 +70,4 @@ def models.cache_key() end
       end
     end
   end
-end
+end

spec/cache_crispies/configuration_spec.rb

@@ -0,0 +1,42 @@
+require 'spec_helper'
+
+describe CacheCrispies::Configuration do
+  describe '#cache_store' do
+    context 'when Rails.cache is defined' do
+      let(:cache_double) { double }
+      before { expect(Rails).to receive(:cache).and_return cache_double }
+
+      it 'is Rails.cache by default' do
+        expect(subject.cache_store).to be cache_double
+      end
+    end
+
+    context 'when Rails.cache is nil' do
+      before { expect(Rails).to receive(:cache).and_return nil }
+
+      it 'is NullStore by default' do
+        expect(subject.cache_store).to be_kind_of ActiveSupport::Cache::NullStore
+      end
+    end
+
+    it 'can be changed' do
+      cache_store = ActiveSupport::Cache::NullStore.new
+
+      expect {
+        subject.cache_store = cache_store
+      }.to change { subject.cache_store }.to cache_store
+    end
+  end
+
+  describe '#etags' do
+    it 'is false by default' do
+      expect(subject.etags).to be false
+    end
+
+    it 'can be changed' do
+      expect {
+        subject.etags = true
+      }.to change { subject.etags }.to true
+    end
+  end
+end

spec/cache_crispies/controller_spec.rb

@@ -0,0 +1,91 @@
+require 'spec_helper'
+require 'active_model'
+require 'action_controller'
+
+describe CacheCrispies::Controller do
+  class Cereal
+    include ActiveModel::Model
+    attr_accessor :name
+  end
+
+  class CerealController < ActionController::Base
+    include CacheCrispies::Controller
+  end
+
+  class CerealSerializerForController < CacheCrispies::Base
+    serialize :name
+
+    def self.key
+      'cereal'
+    end
+  end
+
+  let(:cereal_names) { ['Count Chocula', 'Eyeholes'] }
+  let(:collection) { cereal_names.map { |name| Cereal.new(name: name) } }
+
+  subject { CerealController.new }
+
+  describe '#cache_render' do
+    let(:etags) { false }
+    let(:single_json) { { cereal: { name: cereal_names.first } }.to_json }
+    let(:collection_json) {
+      { cereals: cereal_names.map { |name| { name: name } } }.to_json
+    }
+
+    before do
+      expect(
+        CacheCrispies
+      ).to receive_message_chain(:config, :etags?).and_return etags
+    end
+
+    context 'with etags disabled' do
+      it 'does not set etags' do
+        expect(subject).to receive(:render).with json: collection_json
+        expect(subject.response).to_not receive(:weak_etag=)
+
+        subject.cache_render CerealSerializerForController, collection
+      end
+    end
+
+    context 'with etags enabled' do
+      let(:etags) { true }
+
+      it 'sets etags' do
+        expect(subject).to receive(:render).with json: collection_json
+        expect_any_instance_of(
+          CacheCrispies::Plan
+        ).to receive(:etag).and_return 'test-etag'
+        expect(subject).to receive_message_chain(:response, :weak_etag=).with 'test-etag'
+
+        subject.cache_render CerealSerializerForController, collection
+      end
+    end
+
+    it 'renders a json collection' do
+      expect(subject).to receive(:render).with json: collection_json
+
+      subject.cache_render CerealSerializerForController, collection
+    end
+
+    it 'renders a single json object' do
+      expect(subject).to receive(:render).with json: single_json
+
+      subject.cache_render CerealSerializerForController, collection.first
+    end
+
+    context 'with a status: option' do
+      it 'passes the status option to the Rails render call' do
+        expect(subject).to receive(:render).with(
+          json: single_json,
+          status: 418
+        )
+
+        subject.cache_render(
+          CerealSerializerForController,
+          collection.first,
+          status: 418
+        )
+      end
+    end
+  end
+end

spec/plan_spec.rb → spec/cache_crispies/plan_spec.rb

@@ -17,7 +17,7 @@ def self.cache_key_addons(options)
 
   let(:serializer) { CerealSerializerForPlan }
   let(:serializer_file_path) {
-    File.expand_path('fixtures/test_serializer.rb', __dir__)
+    File.expand_path('../fixtures/test_serializer.rb', __dir__)
   }
   let(:model_cache_key) { 'model-cache-key' }
   let(:model) { OpenStruct.new(name: 'Sugar Smacks', cache_key: model_cache_key) }
@@ -133,7 +133,7 @@ def self.cache_key_addons(options)
   describe '#cache' do
     context 'when the plan is not cacheable' do
       it "doesn't cache the results" do
-        expect(Rails).to_not receive(:cache)
+        expect(CacheCrispies).to_not receive(:cache)
         subject.cache {}
       end
     end
@@ -142,7 +142,7 @@ def self.cache_key_addons(options)
       it "doesn't cache the results" do
         expect(subject).to receive(:cache?).and_return true
         expect(subject).to receive(:cache_key).and_return 'bar'
-        expect(Rails).to receive_message_chain(:cache, :fetch).with('bar')
+        expect(CacheCrispies).to receive_message_chain(:cache, :fetch).with('bar')
         subject.cache {}
       end
     end

spec/cache_crispies_spec.rb

@@ -0,0 +1,27 @@
+require 'spec_helper'
+
+describe CacheCrispies do
+  after { described_class.config.reset! }
+
+  describe '.configure and .config' do
+    it 'allows setting values' do
+      expect {
+        described_class.configure do |conf|
+          conf.etags = true
+        end
+      }.to change { described_class.config.etags }.from(false).to true
+    end
+  end
+
+  describe '.cache' do
+    it 'delegates to config.cache_store' do
+      cache_store = ActiveSupport::Cache::NullStore.new
+
+      expect {
+        described_class.configure do |conf|
+          conf.cache_store = cache_store
+        end
+      }.to change { described_class.cache }.to cache_store
+    end
+  end
+end