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)

Hi !

Thank you very much for this plugin which helped me a lot.
I also wanted to add "bust cache" for images and other resources in my application, so I attempted to modify the plugin so that it could be used on any type of resource.

Here is the modification of the directory_files_content function :

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

And the modification of the bust_cache function :

def bust_cache(file_name, directory)
   if directory != '.'
     CacheDigester.new(file_name: file_name, directory: directory).digest!
   else
     CacheDigester.new(file_name: file_name, directory: File.join(File.dirname('../'))).digest!
   end
end

And so the function is to be used like this now: {{ 'android-icon-36x36.png' | bust_cache: 'assets/favicon' }}

I had to add a condition when it's scss folder, and when the resource is at the root of the project.
I've never coded in rubby, there may be errors, don't hesitate to tell me, but on my side it seems to work.

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