#272 Markdown with Redcarpet

Jun 27, 2011 | 6 minutes | Views, Plugins

Redcarpet is an easy-to-use gem which interprets Markdown. Here I show how to customize it and add syntax highlighting through Pygments and Albino.

Click to Play Video ▶

Download:
source codeProject Files in Zip (204 KB)
mp4Full Size H.264 Video (12.4 MB)
m4vSmaller H.264 Video (7.75 MB)
webmFull Size VP8 Video (8.32 MB)
ogvFull Size Theora Video (19.8 MB)

Browse Source Code

NOTE: This episode is out of date with the release of Redcarpet 2. Please see Episode 207: Syntax Highlighting (revised) for a better way to do what is shown here.

Resources

          bash
        
sudo easy_install pygments

          Gemfile
        
gem 'redcarpet'
gem 'albino'
gem 'nokogiri'

          application_helper.rb
        
def markdown(text)
  options = [:hard_wrap, :filter_html, :autolink, :no_intraemphasis, :fenced_code, :gh_blockcode]
  syntax_highlighter(Redcarpet.new(text, *options).to_html).html_safe
end

def syntax_highlighter(html)
  doc = Nokogiri::HTML(html)
  doc.search("//pre[@lang]").each do |pre|
    pre.replace Albino.colorize(pre.text.rstrip, pre[:lang])
  end
  doc.to_s
end

          articles/show.html.erb
        
<%= markdown(@article.content) %>