Working Implementation

Author: michael-misshore

critical-path-css.gemspec

@@ -6,9 +6,12 @@ Gem::Specification.new do |s|
   s.description = 'Critical Path CSS'
   s.authors     = ['Michael Misshore']
   s.email       = 'mmisshore@gmail.com'
-  s.files       = ['lib/critical-path-css.rb']
   s.homepage    = 'http://rubygems.org/gems/critical-path-css'
   s.license     = 'MIT'
 
   s.add_runtime_dependency 'phantomjs', ['~> 1.9.8.0']
+
+  s.files        = `git ls-files`.split("\n")
+  s.executables  = `git ls-files -- bin/*`.split("\n").map { |f| File.basename(f) }
+  s.require_path = 'lib'
 end

lib/critical-path-css.rb

@@ -1,13 +1,19 @@
 class CriticalPathCss
   require 'phantomjs'
 
-  def self.generate_css
-    Phantomjs.run("#{penthouse_path} http://google.com google.css > critical-css-google.css")
-  end
+  CACHE_NAMESPACE = 'critical-path-css'
+  PENTHOUSE_PATH = "#{File.dirname(__FILE__)}/penthouse/penthouse.js"
+
+  def self.generate (main_css_path, base_url, routes)
+    full_main_css_path = "#{Rails.root.to_s}/public#{main_css_path}"
 
-  private
+    routes.each do |route|
+      css = Phantomjs.run(PENTHOUSE_PATH, base_url + route, full_main_css_path)
+      Rails.cache.write(route, css, namespace: CACHE_NAMESPACE)
+    end
+  end
 
-  def penthouse_path
-    'penthouse/penthouse.js'
+  def self.fetch (route)
+    Rails.cache.read(route, namespace: CACHE_NAMESPACE) || ''
   end
 end