class Middleman::Extensions::AssetHost

def initialize(app, options_hash={}, &block)
  super
  app.rewrite_inline_urls id: :asset_host,
                          url_extensions: options.exts || app.config[:asset_extensions],
                          source_extensions: options.sources,
                          ignore: options.ignore,
                          rewrite_ignore: options.rewrite_ignore,
                          proc: method(:rewrite_url)
end

def rewrite_url(asset_path, dirpath, _request_path)
  uri = ::Middleman::Util.parse_uri(asset_path)
  relative_path = uri.path[0..0] != '/'
  full_asset_path = if relative_path
    dirpath.join(asset_path).to_s
  else
    asset_path
  end
  asset_prefix = if options[:host].is_a?(Proc)
    options[:host].call(full_asset_path)
  elsif options[:host].is_a?(String)
    options[:host]
  end
  File.join(asset_prefix, full_asset_path)
end