lib/rack/manifest.rb in rack-manifest-0.1.3 vs lib/rack/manifest.rb in rack-manifest-0.1.4

@@ -1,9 +1,8 @@
 require 'json'
 require 'erb'
-require 'action_view/helpers/asset_url_helper'
-require 'rack/request'
+require "digest/md5"
 require 'rack/manifest/version'
 require 'rack/manifest/rails' if defined?(Rails::Railtie)
 require 'rack/manifest/sprockets' if defined?(Sprockets) && defined?(Rails)
 
 class Rack::Manifest
@@ -21,33 +20,29 @@
     @app = app
   end
 
   def call(env)
     if env['PATH_INFO'] == '/manifest.json'
-      headers = {}
-      if env.has_key?('HTTP_IF_MODIFIED_SINCE')
-        fetched_date = env['HTTP_IF_MODIFIED_SINCE']
-        return [304, headers, []] if get_modified_time(FILE_PATH) == fetched_date
-      end
       manifest = load_yaml(FILE_PATH)
       json = JSON.generate(manifest)
+      etag = digest(json)
+      return [304, {}, []] if env['HTTP_IF_NONE_MATCH'] == etag
       [
         200,
-        headers.merge({
+        {
           'Content-Type' => 'application/json',
-          'Last-Modified' => get_modified_time(FILE_PATH),
+          'Etag' => etag,
           'Content-Length' => json.length.to_s
-        }),
+        },
         [json]
       ]
     else
       @app.call(env)
     end
   end
 
   private
-  def get_modified_time(path)
-    time = File.mtime(path)
-    time.strftime('%a, %d %b %Y %H:%M:%S GMT')
+  def digest(str)
+    Digest::MD5.hexdigest(str)
   end
 end