A jekyll plugin for compressing HTML, JavaScript files when rendering.

compressor.rb

# 
# File compressor plugin for jekyll
# =================================
# 
# By [mytharcher](https://github.com/mytharcher)
# 2012-05-20
# 
# Updated by [nicoespeon](https://github.com/nicoespeon)
# 2013-04-12
# 
# This plugin for compressing text files, including
# HTML and JavaScript of jekyll site. NOT support CSS
# file yet.
# 
# The JavaScript compressing requires 'packr', a
# third-party lib. I'm not sure if GitHub has this
# extension. But the compressor for HTML files works OK.
# 
# For HTML files it uses Alan Moore's regexp : 
# http://stackoverflow.com/questions/5312349/minifying-final-html-output-using-regular-expressions-with-codeigniter
# It removes spaces between HTML, excepted within
# <textarea> and <pre> code, so you don't get into trouble!
# 

require 'packr'

module Jekyll

  module Compressor

    def compress_html(content)
      content.gsub(/(?>[^\S ]\s*|\s{2,})(?=(?:(?:[^<]++|<(?!\/?(?:textarea|pre)\b))*+)(?:<(?>textarea|pre)\b|\z))/ix, '')
    end

    # Really writing process
    def output_file(dest, content)
      FileUtils.mkdir_p(File.dirname(dest))
      File.open(dest, 'w') do |f|
        f.write(content)
      end
    end

    def output_html(dest, content)
      path = self.destination(dest)
      self.output_file(path, compress_html(content))
    end

    def output_js(dest, content)
      self.output_file(dest, Packr.pack(content,
        :shrink_vars => true
      ))
    end

  end



  # Overwrite old methods to insert a hook

  class Post

    include Compressor

    def write(dest)
      self.output_html(dest, self.output)
    end

  end



  class Page

    include Compressor

    def write(dest)
      self.output_html(dest, self.output)
    end

  end



  class StaticFile

    include Compressor
  	
    def write(dest)
      dest_path = self.destination(dest)

      return false if File.exist?(dest_path) and !self.modified?
      @@mtimes[path] = mtime

      case File.extname(dest_path)
        when '.html'
          self.output_html(dest_path, File.read(path))
        when '.js'
          self.output_js(dest_path, File.read(path))
        else
          FileUtils.mkdir_p(File.dirname(dest_path))
          FileUtils.cp(path, dest_path)
      end

      true
    end

  end

end

Nice plugin :)
I've improved it by adding a regexp matching html comments. Here is the modified function:

def compress_html(content)
  content.gsub(/>\s+</, '><').
    gsub(/<!--([^-]*(-[^-][^>])?(--[^>])?)*-*-->/m, '')
end

Maybe the regexp can be made cleaner. Here is a test case: http://rubular.com/r/GJFgiTGaUI

You can try html_press to compress html, css_press to compress css and uglifier to compress js

Very nice, it also solves the difficulties I've been having with conditional IE comments. I'll use that :)

https://github.com/stereobooster/jekyll-press

Good to see your nice work! I may have a try @stereobooster's new plugin in my next Jekyll site.

PS: I am just wondering why GitHub didn't notify me when you commented on Gist?

Jekyll Asset Pipeline adds a powerful asset pipeline to Jekyll. It supports conversion of CoffeeScript, Sass, Less or any other language via custom preprocessors. It can also automatically compress assets with Yahoo's YUI Compressor or Google's Closure Compiler.

Hey @mytharcher, thanks a lot for sharing this, it helps me so much.

I may found a solution to improve the regexp thanks to Alan Moore's one :

def compress_html(content)
  content.gsub(/(?>[^\S ]\s*|\s{2,})(?=(?:(?:[^<]++|<(?!\/?(?:textarea|pre)\b))*+)(?:<(?>textarea|pre)\b|\z))/ix, '')
end

Doing so, you keep spaces in your HTML within <textarea> or other <pre> code and so you don't get into trouble with that kind of things... What do you think?

Here is the source for the regexp.
You can also check my fork if you wish.

Cheers \o/

Thanks @nicoespeon! And sorry for delay.

It's very nice of your improvement. I will merge it.

@mytharcher This is great but it strips whitespace between liquid elements when the HTML is generated, for example the following code wouldn't output any space between the post title and excerpt:

{{ post.title }} {{ post.excerpt }}

I use a folder structure with Jekyll and this plugin seems to generate new subfolders. foo/index.html turns into foo/foo/index.html. I'd debug it myself, but I'm not keen on picking up Ruby right this instant :) Thanks for your work!

I wrote a Jekyll layout that compresses HTML in pure Liquid. It works on Github Pages.

Works great! Is there a way to exclude a specific section of HTML from being compressed? Part of my page layout relies on text-align: justify which needs a space in between elements.

Thanks man! Works great! :)

Thanks for the nice plugin. However I've made a small improvement because this plugin always fucked up my rss.xml. https://gist.github.com/kimar/cc2cc5fd86d6abe54042#file-compressor-rb-L45-L49

@jelmerdemaat why not use a   ?

great program....Fulfill my purpose 100%...

Good Job! Thanks so much man!!