[ruby] Markdown to HTML converter CLI

md2html.rb

# encoding: utf-8

require "optparse"
require "redcarpet"

class HTMLWithSyntaxHighlighter < Redcarpet::Render::HTML
  ESCAPE_HTML_TABLE = {
    "'" => '&#39;',
    '&' => '&amp;',
    '"' => '&quot;',
    '<' => '&lt;',
    '>' => '&gt;',
  }

  def initialize(options = {})
    @custom_opts = {
      :prettify           => options[:prettify] || false,
      :syntax_highlighter => options.delete(:syntax_highlighter) || false,
      :class_for_code_tag => options.delete(:class_for_code_tag) || false,
    }
    super(options)
  end

  def block_code(code, language)
    class_value = highlight_class_value(language)
    if class_value
      if @custom_opts[:class_for_code_tag]
        "\n<pre><code class=\"#{escape_html(class_value)}\">#{escape_html(code)}</code></pre>\n"
      else
        "\n<pre class=\"#{escape_html(class_value)}\"><code>#{escape_html(code)}</code></pre>\n"
      end
    else
      "\n<pre><code>#{escape_html(code)}</code></pre>\n"
    end
  end

  def escape_html(html)
    html.gsub(/['&\"<>]/, ESCAPE_HTML_TABLE)
  end

  private

  def highlight_class_value(language)
    case
    when @custom_opts[:syntax_highlighter]
      "brush:#{language || "plain"}"
    when @custom_opts[:prettify]
      language ? "prettyprint lang-#{language}" : "prettyprint"
    else
      language
    end
  end
end

config = {
  :renderer_opts => {
    :hard_wrap => true,
  },
  :markdown_opts => {
    :no_intra_emphasis   => true,
    :tables              => true,
    :fenced_code_blocks  => true,
    :autolink            => true,
    :strikethrough       => true,
    :lax_spacing         => false,
    :space_after_headers => true,
  }
}

OptionParser.new do |opts|
  opts.on("--code-tag", "Add highlight classes for code tag instead of pre tag") do
    config[:renderer_opts][:class_for_code_tag] = true
  end
  opts.on("--prettify", "Add prettify classes") do
    config[:renderer_opts][:prettify] = true
  end
  opts.on("--highlighter", "Add SyntaxHighlighter classes") do
    config[:renderer_opts][:syntax_highlighter] = true
  end

  opts.banner << " [file...]"

  opts.parse!
end

# renderer = Redcarpet::Render::HTML.new(config[:renderer_opts])
renderer = HTMLWithSyntaxHighlighter.new(config[:renderer_opts])
markdown = Redcarpet::Markdown.new(renderer, config[:markdown_opts])

puts markdown.render(ARGF.read)

Bloggerで記事を書く時用のオレオレツール。要redcarpet

• GFM(GitHub Flavored Markdown)に近いオプション設定。
• SyntaxHighlighterとGoogle Code Prettify用のハイライトオプションを追加。
• ハイライト用のclass属性をpreじゃなくてcodeに設定するオプションを追加。
• ファイル指定と標準入力から読む(ARGF)