For a perhaps better solution for .html.md files that also supports embedding Erb in your Markdown, check out @wjbuys's answer on Stackoverflow.

This gem allows you to write static Rails views and partials using the Markdown syntax. No more editing prose in HTML!

Add the following to your Gemfile:

gem 'markdown-rails'

Now add views or partials ending in .md or .markdown.

In app/views/home/about.html.md:

# About This Site

*Markdown code goes here ...*

Keep in mind that unlike static files dropped in public, you still need a matching route, such as get ':action', :controller => :home, to route /about to home#about.

In app/views/posts/edit.html.erb:

<form>... dynamic code goes here ...</form>
<div class="help">
  <%= render :partial => "posts/edit_help" %>
</div>

In app/views/posts/_edit_help.html.md:

## How To Edit

This text is written in **Markdown**. :-)

Note: If you are including Markdown partials from a Haml view, <pre> blocks inside your Markdown may be indented when Haml is not in "ugly" (production) mode, causing leading white-space to appear in development mode. To fix this, set Haml::Template.options[:ugly] = true.

By default markdown-rails uses the RDiscount parser. You can change this by calling config.render like so:

MarkdownRails.configure do |config|
  config.render do |markdown_source|
    # Return compiled HTML here ...
  end
end

You might in particular want to use Redcarpet, which allows you to enable various aspects of GitHub Flavored Markdown through its parser options. To do so, add the redcarpet gem to your Gemfile, and add the following into a config/initializers/markdown.rb file:

MarkdownRails.configure do |config|
  markdown = Redcarpet::Markdown.new(Redcarpet::Render::HTML,
    :fenced_code_blocks => true,
    :autolink => true,
    ... etc ...)
  config.render do |markdown_source|
    markdown.render(markdown_source)
  end
end

Despite Markdown being a static language, you should not use this gem to process untrusted Markdown views (or partials). In other words, do not add Markdown views from a source if you wouldn't trust Erb views from them.

• It's not possible to embed Ruby code in the Markdown code. Unfortunately, you cannot simply chain template handlers (.md.erb) like you can with asset handlers. This is reasonable if you consider that unlike assets, templates are precompiled not into strings but into Ruby code, which is then called every time the template is served. Still, the performance of modern Markdown parsers is good enough that you could afford to reparse the Markdown on every template view, so having Markdown with Erb in it should be possible in principle.

  In the meantime, you can use HAML's :markdown filter to the same effect.

• The only truly Markdown-specific code in the source is RDiscount.new(markdown_source).to_html and the .md/.markdown file name extensions. This gem can and should be generalized into a general-purpose static template gem, so that you can easily use other static templating languages in Rails. Perhaps tilt will come in useful.