Another domain checker

middleman-core/lib/middleman-core/util.rb

@@ -18,6 +18,7 @@ require 'middleman-core/sitemap/resource'
 require 'hashie'
 
 # For URI templating
+require 'public_suffix'
 require 'addressable/uri'
 require 'addressable/template'
 require 'active_support/inflector'
@@ -357,7 +358,7 @@ module Middleman
         begin
           uri = ::Addressable::URI.parse(asset_path)
 
-          if uri.relative? && uri.host.nil? && !asset_path.match(/^[^\/].*[a-z]+\.[a-z]+\/.*/) && (result = yield(asset_path))
+          if uri.relative? && uri.host.nil? && !::PublicSuffix.valid?(asset_path) && (result = yield(asset_path))
             "#{opening_character}#{result}"
           else
             match

middleman-core/middleman-core.gemspec

@@ -24,6 +24,7 @@ Gem::Specification.new do |s|
   s.add_dependency('tilt', ['~> 1.4.1'])
   s.add_dependency('erubis')
   s.add_dependency('fast_blank')
+  s.add_dependency('public_suffix')
 
   # Helpers
   s.add_dependency('activesupport', ['~> 4.2'])