Refactor config loader

Author: michael-misshore

lib/critical-path-css-rails.rb

@@ -28,6 +28,14 @@ def self.fetch(route)
   end
 
   def self.fetcher
-    @fetcher ||= CssFetcher.new(Configuration.new(CriticalPathCss::Rails::ConfigLoader.new.load))
+    @fetcher ||= CssFetcher.new(Configuration.new(config))
+  end
+
+  def self.config
+    @config ||= begin
+      loader = CriticalPathCss::Rails::ConfigLoader.new
+      loader.load
+      loader.config
+    end
   end
 end

lib/critical_path_css/rails/config_loader.rb

@@ -3,22 +3,15 @@ module Rails
     class ConfigLoader
       CONFIGURATION_FILENAME = 'critical_path_css.yml'.freeze
 
+      attr_reader :config
+
       def load
-        config = YAML.safe_load(ERB.new(File.read(configuration_file_path)).result, [], [], true)[::Rails.env]
-        validate_css_path config
-        if config['css_path']
-          config['css_path'] = "#{::Rails.root}/public" + (
-            config['css_path'] ||
-              ActionController::Base.helpers.stylesheet_path(
-                config['manifest_name'], host: ''
-              )
-          )
-          config['css_paths'] = []
-        else
-          config['css_path'] = ''
-          config['css_paths'] = config['css_paths'].collect { |path| "#{::Rails.root}/public#{path}" }
-        end
-        config
+        validate_css_paths
+        format_css_paths
+      end
+
+      def config
+        @config ||= YAML.safe_load(ERB.new(File.read(configuration_file_path)).result, [], [], true)[::Rails.env]
       end
 
       private
@@ -27,7 +20,21 @@ def configuration_file_path
         @configuration_file_path ||= ::Rails.root.join('config', CONFIGURATION_FILENAME)
       end
 
-      def validate_css_path(config)
+      def format_css_paths
+        if config['css_path']
+          config['css_path']  = format_path(config['css_path'])
+          config['css_paths'] = []
+        else
+          config['css_path']  = ''
+          config['css_paths'] = config['css_paths'].collect { |path| format_path(path) }
+        end
+      end
+
+      def format_path(path)
+        "#{::Rails.root}/public#{path}"
+      end
+
+      def validate_css_paths
         if config['css_path'] && config['css_paths']
           raise LoadError, 'Cannot specify both css_path and css_paths'
         elsif config['css_paths'] && config['css_paths'].length != config['routes'].length

spec/lib/critical_path_css/rails/config_loader_spec.rb

@@ -2,6 +2,7 @@
 
 RSpec.describe 'ConfigLoader' do
   let(:subject) { CriticalPathCss::Rails::ConfigLoader.new }
+
   describe '#load' do
     before do
       allow(File).to receive(:read).and_return(config_file)
@@ -24,16 +25,16 @@
         CONFIG
       }
 
-      it 'sets css_path with the path' do
-        config = subject.load
+      before do
+        subject.load
+      end
 
-        expect(config['css_path']).to eq '/app/spec/internal/public/test.css'
+      it 'sets css_path with the path' do
+        expect(subject.config['css_path']).to eq '/app/spec/internal/public/test.css'
       end
 
       it 'leaves css_paths empty' do
-        config = subject.load
-
-        expect(config['css_paths']).to eq []
+        expect(subject.config['css_paths']).to eq []
       end
     end
 
@@ -57,16 +58,16 @@
         CONFIG
       }
 
-      it 'sets css_path to empty string' do
-        config = subject.load
+      before do
+        subject.load
+      end
 
-        expect(config['css_path']).to eq ''
+      it 'sets css_path to empty string' do
+        expect(subject.config['css_path']).to eq ''
       end
 
       it 'leaves css_paths to an array of paths' do
-        config = subject.load
-
-        expect(config['css_paths']).to eq ['/app/spec/internal/public/test.css','/app/spec/internal/public/test2.css']
+        expect(subject.config['css_paths']).to eq ['/app/spec/internal/public/test.css','/app/spec/internal/public/test2.css']
       end
     end