class Sprockets::Rails::AssetUrlProcessor

Resolve assets referenced in CSS ‘url()` calls and replace them with the digested paths

def self.call(input) 

def self.call(input)
  context = input[:environment].context_class.new(input)
  data    = input[:data].gsub(REGEX) do |_match|
    path = Regexp.last_match[:path]
    "url(#{context.asset_path(path)})"
  end
  context.metadata.merge(data: data)
end