jekyll plugin to eval trusted code

eval_code.rb

require 'jekyll'
require 'open3'

module Jekyll
  class EvalCode < Jekyll::Generator
    def generate(site)
      @site = site
      site.pages.each { |page| eval_code(page) if page.html? }
      site.posts.docs.each { |page| eval_code(page) }
    end

    private

    def eval_code(page)
      page.content = page.content.gsub(/^(```+)\{(ruby|javascript|js)\}$(.*?)^\1$/m) do
        quote, lang, src = $1, $2, $3
        case lang
        when 'ruby'
          output, status = Open3.capture2e('ruby', stdin_data: src)
        when 'javascript', 'js'
          output, status = Open3.capture2e('node', stdin_data: src)
        end
        if status.success?
          "#{quote}#{lang}#{src}#{quote}\n`````\n#{output.chomp}\n`````\n"
        end
      end
    end
  end
end

example.md

def print_hi(name)
  puts "Hi, #{name}"
end
print_hi('Tom')
#=> prints 'Hi, Tom' to STDOUT.

puts "hello, world"

console.log('hello')

console.log('hello')

usage.md

使い方

• _plugins/eval_code.rb に eval_code.rb をおく
• example.md のような感じで code block をかく