FEATURE: much faster asset precompilation with a redis backed cache

lib/tasks/assets.rake

@@ -8,6 +8,28 @@ task 'assets:precompile:before' do
   # in the past we applied a patch that removed asset postfixes, but it is terrible practice
   # leaving very complicated build issues
   # https://github.com/rails/sprockets-rails/issues/49
+
+  # let's make precompile faster using redis magic
+  require 'sprockets'
+  require 'digest/sha1'
+
+  module ::Sprockets
+    class UglifierCompressor
+      def evaluate(context, locals, &block)
+
+        digest = Digest::SHA1.hexdigest(data)
+        key = "SPROCKETS_#{digest}"
+
+        unless compiled = $redis.get(key)
+          compiled = Uglifier.new(:comments => :none).compile(data)
+          $redis.setex(key, 1.week, compiled)
+        end
+        $redis.expire(key, 1.week)
+        compiled
+      end
+    end
+  end
+
 end
 
 task 'assets:precompile' => 'assets:precompile:before'