Convert Textile to Markdown contents in Redmin

redmine_textile2md.rb

def textile_to_markdown(textile)
  d = []
  pre = false
  table_header = false
  text_line = false

  textile.each_line do |s|
     s.chomp!

    if pre
      if s =~ /<\/pre>/
        d << "~~~"
        pre = false
      else
        d << s
      end
      next
    end

    s.gsub!(/(^|\s)\*([^\s\*].*?)\*(\s|$)/, " **\\2** ")
    s.gsub!(/(^|\s)@([^\s].*?)@(\s|$)/, " `\\2` ")
    s.gsub!(/(^|\s)-([^\s].*?)-(\s|$)/, " ~~\\2~~ ")
    s.gsub!(/"(.*?)":([^ ]+)( ?)/, "[\\1](\\2)\\3")

    d << ""  if text_line
    text_line = false

    case s
    when /^<pre><code class="(\w+)">/
      d << "~~~" + $1
      pre = true
    when /^<pre>/
      d << "~~~"
      pre = true
    when /^\*\*\* (.*)$/
      d << "      * " + $1
    when /^\*\* (.*)$/
      d << "   * " + $1
    when /^\* (.*)$/
      d << "* " + $1
    when /^\#\#\# (.*)$/
      d << "      1. " + $1
    when /^\#\# (.*)$/
      d << "   1. " + $1
    when /^\# (.*)$/
      d << "1. " + $1
    when /^h(\d)\. (.*)$/
      d << "#" * $1.to_i + " " + $2
    when /^!(.*?)!/
      d << "![](#{$1})"
    when /^\|_\./
      d << s.gsub("|_.", "| ")
      table_header = true
    when /^\|/
      d << s.gsub(/\=\..+?\|/, ":---:|").gsub(/\s+.+?\s+\|/, "---|") if table_header
      table_header = false
      d << s.gsub("|=.", "| ")
    when /^\s*$/
      d << s
    else
      d << s
      text_line = true
    end
  end

  d.join("\n") + "\n"
end


def update_content(model, attrbute)
  total = model.count
  # step = total / 10
  puts "  #{model}.#{attrbute} : #{total}"
  model.all.each_with_index do |rec, ix|
    n = ix + 1
    id = rec[:id]
    puts "  #{model}.#{id} : #{n}/#{total}"
    rec[attrbute] = textile_to_markdown(rec[attrbute])  if rec[attrbute]
    rec.save! :validate => false
  end
end

update_content(WikiContent, :text)
update_content(Project, :description)
update_content(Issue, :description)
update_content(Journal, :notes)
# update_content(News, :description)
# update_content(Document, :description)
# update_content(Message, :content)

このコードを以下のように runner で実行するとTextileがMarkdownに変換されます。

$ rails runner -e production tools/textile2md.rb