Switching from Jekyll to Middleman

The main strengths of Middleman are, in my opinion:

• Support for erb templates. Middleman allows one to use embedded ruby rather than Liquid for “dynamic” content. On top of a more familiar syntax, which makes the construction of dynamic content simpler and more flexible (to me, at least), this feature allows to reuse a template I developed for a Rails application.
• Generation of individual pages from data using the proxy directive. Although I have not yet used this feature, the same trick in (older versions of) Jekyll requires the use of plugins. One of such plugins is Jekyll datapage generator
• Support for the asset pipeline and cache buster This has been further improved in Middleman 4.
• Simpler deployment. A Middleman extension supports deployment via rsync or ftp. To achieve the same trick with Jekyll I had to define a Rakefile, which is available here: Jekyll Rakefile.
• The build command does not regenerate files which have not been changed. This comes at the cost of a slower compilation, but it can make deployment a lot more efficient, if you care to look at the creation dates of files.
• Simpler support for helpers. Middleman support helpers written in Ruby. This makes their development easier for me. The same trick in Jekyll requires to register a new Liquid filter and ends up in more code and more difficulties in managing multiple arguments.
• Support for multiple blogs. This is a feature Jekyll also has. The main difference is that Middleman’s blog extension has commands to generate articles and allows one to keep posts’ assets together with the posts.
• Access to sitemap and resources. The access to the sitemap and to resources (e.g., page content, page metadata) is well documented.

Various other features of Middleman are similar to those Jekyll provides: support for data, support for YAML front-matter, partials, nested layouts.

Some of the issues I have found with Middleman are:

• An incompatibility between the Sass release of Foundation 5.4.7 and the compass library required by Middleman. This is, in fact, more a problem with Foundation than with Middleman. The effect on websites based on Foundation is that changes to the default configuration are ignored. I have not yet found a good workaround and I’ll just wait for Foundation to release a version which supports more recent releases of Compass (most likely: Foundation version 5.5).
• Some compatibility issues between the versions of the gems used by Rails and Middleman for asset bundling. I am not a good user of bundle exec and I ended up using chruby two manage two independent sets of Ruby installations (gem_home would have been another valid alternative). ¹
• Performances: Jekyll is (or at least seems to be) way faster. ¹

These are the main steps to migrate an existing Jekyll website to Middleman.

This section has been superseded:

• Middleman 4 now supports :assets_hosts (Asset Hosts).
• Jekyll now has a base_url variable, which can be set from the command line, simplifying the generation of absolute URLs.

One critical point (both with Jekyll and Middleman) used to be, the management of URLs, especially if the website is deployed on a sub-URI (e.g., http://www.example.com/a/b/c/). The problem is the way in which URLs are interpreted. More in details:

• Using relative URLs (x/y/z) in templates and pages is no good, because pages might be deployed at different levels of depth on the website, making relative references wrong
• Using absolute URLs (/x/y/z) won’t work, unless you specify the full path (e.g., //domain/x/y/x/). This however, breaks the possibility of previewing on the local web server and makes re-deployment on a different URL more difficult.
• Similar to the previous point, using fully qualified names (http://domain/x/y/z) breaks the possibility of previewing on the local web server and of moving your website to a different location, if needed.

To solve this problem, when I started using Jekyll, I defined a Rakefile to simplify the management of common Jekyll operations, including deployment. The Rakefile sets a variable site.url in _config.yml. The variable can thus be pre-pended to all URLs used on a website, to make them absolute.

Middleman supports a simpler solution. More in details, the :http_prefix variable can be used to pre-pend a portion of a path to all URLs defined with the standard helpers: link_to and image_tag, stylesheet_include_tag, javascript_include_tag.

Thus, for instance, if the website lives on “http://www.example.com/a/b/c/”, it is sufficient to set :http_prefix in config.rb:

configure :build do
  set :http_prefix, "/a/b/c/"
end

and Middleman will take care of replacing, e.g., <% link_to “p.html” %>= with <a href"a/b/c/p.html">=. (Notice that setting :http_prefix to a full URL, like, e.g., =http:/…=, will cause an error.)

The problem remains, however, with links defined using the native markup tags. For instance, Middleman will not replace the URL of links written in Textile (or Markdown).

The problem can be solved by defining a helper to generate absolute URLs. Add to your config.rb the following code:

helpers do
  def aurl url
    File.join(http_prefix, url)
  end
end

configure :development do
  set :http_prefix, "/"
end

configure :build do 
  set :http_prefix, "/a/b/c/"
end

and use the aurl helper every time you want to insert a link or a path using the markup of the templating language. For instance:

"Some link on my website":<%= aurl("some_page.html") %>

More in details, the following rules apply:

• If you are using one of the tags of the markup languages, always use aurl
• If you are using image_tag you are fine
• If you are using link_to you are fine