Indenting generated markup in Jekyll/Ruby

Question

Well this is probably kind of a silly question but I\'m wondering if there\'s any way to have the generated markup in Jekyll to preserve the indentation of the Liquid-tag. World

Answer 1

Using a Liquid Filter

I managed to make this work using a liquid filter. There are a few caveats:

• Your input must be clean. I had some curly quotes and non-printable chars that looked like whitespace in a few files (copypasta from Word or some such) and was seeing "Invalid byte sequence in UTF-8" as a Jekyll error.

• It could break some things. I was using icons from twitter bootstrap. It replaced the empty tag with and bootstrap did not like that. Additionally, it screws up the octopress {% codeblock %}s in my content. I didn't really look into why.

• While this will clean the output of a liquid variable such as {{ content }} it does not actually solve the problem in the original post, which is to indent the html in context of the surrounding html. This will provide well formatted html, but as a fragment that will not be indented relative to tags above the fragment. If you want to format everything in context, use the Rake task instead of the filter.

-

require 'rubygems'
require 'json'
require 'nokogiri'
require 'nokogiri-pretty'

module Jekyll
  module PrettyPrintFilter
    def pretty_print(input)
      #seeing some ASCII-8 come in
      input = input.encode("UTF-8")

      #Parsing with nokogiri first cleans up some things the XSLT can't handle
      content = Nokogiri::HTML::DocumentFragment.parse input
      parsed_content = content.to_html

      #Unfortunately nokogiri-pretty can't use DocumentFragments...
      html = Nokogiri::HTML parsed_content
      pretty = html.human

      #...so now we need to remove the stuff it added to make valid HTML
      output = PrettyPrintFilter.strip_extra_html(pretty)
      output
    end

    def PrettyPrintFilter.strip_extra_html(html)
      #type declaration
      html = html.sub('','')

      #second  tag
      first = true
      html = html.gsub('') do |match|
        if first == true
          first = false
          next
        else
          ''
        end
      end

      #first  tag
      html = html.sub('','')

      #second  tag
      first = true
      html = html.gsub('') do |match|
        if first == true
          first = false
          next
        else
          ''
        end
      end

      #first  tag
      html = html.sub('','')

      #second  tag
      first = true
      html = html.gsub('') do |match|
        if first == true
          first = false
          next
        else
          ''
        end
      end

      #first  tag
      html = html.sub('','')

      html
    end
  end
end

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

Using a Rake task

I use a task in my rakefile to pretty print the output after the jekyll site has been generated.

require 'nokogiri'
require 'nokogiri-pretty'

desc "Pretty print HTML output from Jekyll"
task :pretty_print do
  #change public to _site or wherever your output goes
  html_files = File.join("**", "public", "**", "*.html")

  Dir.glob html_files do |html_file|
    puts "Cleaning #{html_file}"

    file = File.open(html_file)
    contents = file.read

    begin
      #we're gonna parse it as XML so we can apply an XSLT
      html = Nokogiri::XML(contents)

      #the human() method is from nokogiri-pretty. Just an XSL transform on the XML.
      pretty_html = html.human
    rescue Exception => msg
      puts "Failed to pretty print #{html_file}: #{msg}"
    end

    #Yep, we're overwriting the file. Potentially destructive.
    file = File.new(html_file,"w")
    file.write(pretty_html)

    file.close
  end
end