CSS Cache Bust Jekyll Plugin

cachebust.rb

module Jekyll
  module CacheBust
    class CacheDigester
      require 'digest/md5'

      attr_accessor :file_name, :directory

      def initialize(file_name:, directory: nil)
        self.file_name = file_name
        self.directory = directory
      end

      def digest!
        [file_name, '?', Digest::MD5.hexdigest(file_contents)].join
      end

      private

      def directory_files_content
        target_path = File.join(directory, '**', '*')
        Dir[target_path].map{|f| File.read(f) unless File.directory?(f) }.join
      end

      def file_content
        FIle.read(file_name)
      end

      def file_contents
        is_directory? ? file_content : directory_files_content
      end

      def is_directory?
        directory.nil?
      end
    end
    
    def bust_css_cache(file_name)
      CacheDigester.new(file_name: file_name, directory: 'assets/_sass').digest!
    end
  end
end

Liquid::Template.register_filter(Jekyll::CacheBust)

Make sure to change this line for cache busting to work:

-         [file_name, '?', Digest::MD5.hexdigest(file_contents)].join
+         [file_name, '?v=', Digest::MD5.hexdigest(file_contents)].join