Contents

module Torba
  # Parses content of CSS file and converts its image assets paths into Sprockets'
  # {https://github.com/sstephenson/sprockets#logical-paths logical paths}.
  class CssUrlToErbAssetPath
    URL_RE =
      /
        url\(     # url(
        \s*       # optional space
        (?!data)  # no data URIs
        ['"]?     # optional quote
        (?!\/)    # only relative location
        ([^'"]+?) # location
        ['"]?     # optional quote
        \s*       # optional space
        \)        # )
      /xm

    # @return [String] CSS file content where image "url(...)" paths are replaced by ERB
    #   interpolations "url(<%= asset_path(...) %>)".
    # @param content [String] content of original CSS file
    # @param file_path [String] absolute path to original CSS file
    # @yield [image_file_path]
    # @yieldparam image_file_path [String] absolute path to original image file which is mentioned
    #   within CSS file
    # @yieldreturn [String] logical path to image file within Sprockets' virtual filesystem.
    #
    # @example
    #   content = \
    #     ".react-toolbar {
    #       width: 100%;
    #       background: url('./images/toolbar.png');
    #     }"
    #
    #   new_content = CssUrlToErbAssetPath.call(content, "/var/downloads/react_unzipped/styles.css") do |url|
    #     url.sub("/var/downloads/react_unzipped/images", "react-toolbar-js"
    #   end
    #
    #   new_content #=>
    #     ".react-toolbar {
    #       width: 100%;
    #       background: url('<%= asset_path('react-toolbar-js/toolbar.png') %>');
    #     }"
    def self.call(content, file_path)
      content.gsub(URL_RE) do
        absolute_image_file_path = File.expand_path($1, File.dirname(file_path))
        sprockets_file_path = yield absolute_image_file_path
        "url('<%= asset_path('#{sprockets_file_path}') %>')"
      end
    end
  end
end

Version data entries

4 entries across 4 versions & 1 rubygems

Version	Path
torba-0.2.1	lib/torba/css_url_to_erb_asset_path.rb
torba-0.2.0	lib/torba/css_url_to_erb_asset_path.rb
torba-0.1.1	lib/torba/css_url_to_erb_asset_path.rb
torba-0.1.0	lib/torba/css_url_to_erb_asset_path.rb