Makes zippable extensions configurable in site config

README.md

@@ -46,6 +46,31 @@ In your destination directory (`_site` by default) you will find gzipped version
 
 `Jekyll::Gzip` only runs when the environment variable `JEKYLL_ENV` is set to `production` as dealing with gzipping files is unnecessary in development mode and just slows down the site build.
 
+### Configuration
+
+By default, `Jekyll::Gzip` will compress all files with the following extensions:
+
+- '.html'
+- '.css'
+- '.js'
+- '.txt'
+- '.ttf'
+- '.atom'
+- '.stl'
+- '.xml'
+- '.svg'
+- '.eot'
+
+You can supply your own extensions by adding a `gzip` key to your site's `_config.yml` listing the extensions that you want to compress. For example to only compress HTML, CSS and JavaScript files, add the following to `_config.yml`:
+
+```yml
+gzip:
+  extensions:
+    - '.html'
+    - '.css'
+    - '.js
+```
+
 ### Serving pre-compiled gzip files
 
 You will likely need to adjust your web server config to serve these precomputed gzip files. See below for common server configurations:

lib/jekyll/gzip.rb

@@ -1,30 +1,35 @@
 # frozen_string_literal: true
 
-require "jekyll/gzip/version"
-require "jekyll/gzip/compressor"
-require "pathname"
+require 'jekyll/gzip/version'
+require 'jekyll/gzip/config'
+require 'jekyll/gzip/compressor'
+require 'pathname'
 
 module Jekyll
   module Gzip
   end
 end
 
+Jekyll::Hooks.register :site, :after_init do |site|
+  config = site.config['gzip'] || {}
+  site.config['gzip'] = Jekyll::Gzip::DEFAULT_CONFIG.merge(config) || []
+  puts site.config['gzip']
+end
+
 Jekyll::Hooks.register :site, :post_write do |site|
-  if Jekyll.env == "production"
-    Jekyll::Gzip::Compressor.compress_site(site)
-  end
+  Jekyll::Gzip::Compressor.compress_site(site) if Jekyll.env == 'production'
 end
 
 begin
-  require "jekyll-assets"
+  require 'jekyll-assets'
 
   Jekyll::Assets::Hook.register :env, :after_write do |env|
-    if Jekyll.env == "production"
-      path = Pathname.new("#{env.jekyll.config["destination"]}#{env.prefix_url}")
-      Jekyll::Gzip::Compressor.compress_directory(path)
+    if Jekyll.env == 'production'
+      path = Pathname.new("#{env.jekyll.config['destination']}#{env.prefix_url}")
+      Jekyll::Gzip::Compressor.compress_directory(path, env.jekyll)
     end
   end
 rescue LoadError
   # The Jekyll site doesn't use Jekyll::Assets, so no need to compress those
   # files.
-end
+end

lib/jekyll/gzip/compressor.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
-require "zlib"
+require 'jekyll/gzip/config'
+require 'zlib'
 
 module Jekyll
   ##
@@ -24,7 +25,7 @@ module Compressor
         '.xml',
         '.svg',
         '.eot'
-      ]
+      ].freeze
 
       ##
       # Takes an instance of +Jekyll::Site+ and maps over the site files and
@@ -39,7 +40,7 @@ module Compressor
       # @return void
       def self.compress_site(site)
         site.each_site_file do |file|
-          compress_file(file.destination(site.dest))
+          compress_file(file.destination(site.dest), zippable_extensions(site))
         end
       end
 
@@ -54,9 +55,10 @@ def self.compress_site(site)
       #   compression.
       #
       # @return void
-      def self.compress_directory(dir)
-        files = Dir.glob(dir + "**/*{#{ZIPPABLE_EXTENSIONS.join(',')}}")
-        files.each { |file| compress_file(file) }
+      def self.compress_directory(dir, site)
+        extensions = zippable_extensions(site).join(',')
+        files = Dir.glob(dir + "**/*{#{extensions}")
+        files.each { |file| compress_file(file, extensions) }
       end
 
       ##
@@ -69,15 +71,21 @@ def self.compress_directory(dir)
       # @param file_name [String] The file name of the file we want to compress
       #
       # @return void
-      def self.compress_file(file_name)
-        return unless ZIPPABLE_EXTENSIONS.include?(File.extname(file_name))
+      def self.compress_file(file_name, extensions)
+        return unless extensions.include?(File.extname(file_name))
         zipped = "#{file_name}.gz"
         Zlib::GzipWriter.open(zipped, Zlib::BEST_COMPRESSION) do |gz|
           gz.mtime = File.mtime(file_name)
           gz.orig_name = file_name
           gz.write IO.binread(file_name)
         end
       end
+
+      private
+
+      def self.zippable_extensions(site)
+        site.config['gzip'] && site.config['gzip']['extensions'] || Jekyll::Gzip::DEFAULT_CONFIG['extensions']
+      end
     end
   end
-end
+end

lib/jekyll/gzip/config.rb

@@ -0,0 +1,18 @@
+module Jekyll
+  module Gzip
+    DEFAULT_CONFIG = {
+      'extensions' => [
+        '.html',
+        '.css',
+        '.js',
+        '.txt',
+        '.ttf',
+        '.atom',
+        '.stl',
+        '.xml',
+        '.svg',
+        '.eot'
+      ]
+    }.freeze
+  end
+end

spec/jekyll/gzip/compressor_spec.rb

@@ -5,19 +5,26 @@
 
 RSpec.describe Jekyll::Gzip::Compressor do
   let(:site) { make_site }
+  let(:extensions) { site.config['gzip'] && site.config['gzip']['extensions'] }
   before(:each) { site.process }
   after(:each) { FileUtils.rm_r(dest_dir) }
 
   describe "given a file name" do
     it "creates a gzip file" do
       file_name = dest_dir("index.html")
-      Jekyll::Gzip::Compressor.compress_file(file_name)
+      Jekyll::Gzip::Compressor.compress_file(file_name, ['.html'])
       expect(File.exist?("#{file_name}.gz")).to be true
     end
 
+    it "doesn't create a gzip file if the extension is not present" do
+      file_name = dest_dir("index.html")
+      Jekyll::Gzip::Compressor.compress_file(file_name, [])
+      expect(File.exist?("#{file_name}.gz")).to be false
+    end
+
     it "compresses the content of the file in the gzip file" do
       file_name = dest_dir("index.html")
-      Jekyll::Gzip::Compressor.compress_file(file_name)
+      Jekyll::Gzip::Compressor.compress_file(file_name, ['.html'])
       content = File.read(file_name)
       Zlib::GzipReader.open("#{file_name}.gz") {|gz|
         expect(gz.read).to eq(content)
@@ -26,7 +33,7 @@
 
     it "doesn't compress non text files" do
       file_name = dest_dir("images/test.png")
-      Jekyll::Gzip::Compressor.compress_file(file_name)
+      Jekyll::Gzip::Compressor.compress_file(file_name, ['.html'])
       expect(File.exist?("#{file_name}.gz")).to be false
     end
   end
@@ -49,7 +56,7 @@
 
   describe "given a destination directory" do
     it "compresses all the text files in the directory" do
-      Jekyll::Gzip::Compressor.compress_directory(dest_dir)
+      Jekyll::Gzip::Compressor.compress_directory(dest_dir, site)
       files = [
         dest_dir("index.html"),
         dest_dir("css/main.css"),