Rack::PageCaching

Rack::PageCaching is a Rack middleware that aids in static page caching. It serves the same purpose as Rails page caching and was designed to be a drop-in replacement for it.

Rack::PageCaching provides a few differences from Rails page caching. It is implemented as a Rack middleware, which means transformations done on the response by other middlewares will be present in the generated static page. Examples of middlewares that work well with page caching include htmlcompressor and rack-pjax. Implementing it in Rack also means that it can also be used in other Rack-compatible frameworks like Sinatra.

While it was designed to be a drop-in replacement for Rails page caching, it provides additional features like including the hostname in the path of the generated static page.

Installation

Add this line to your application's Gemfile:

gem 'rack-page_caching'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rack-page_caching

Tell your app to use the Rack::PageCaching middleware. For Rails 3+ apps:

# In config/application.rb
config.middleware.use Rack::PageCaching

Or for Rackup files:

# In config.ru
use Rack::PageCaching

When you want page caching to be applied to a response modified by other middlewares, make sure you place Rack::PageCaching before those middlewares.

It has been tested on Rails 3 and 4, and on Ruby 1.9.3 and 2.x.

Usage

Rack::PageCaching accepts all the options accepted by Rails page caching:

config.middleware.use Rack::PageCaching,
  # Directory where the pages are stored. Defaults to the public folder in
  # Rails, but you'll probably want to customize this
  page_cache_directory: Rails.root.join('public', 'page_cache'),
  # Gzipped version of the files are generated with compression level
  # specified. It accepts the symbol versions of the constants in Zlib,
  # e.g. :best_speed and :best_compression. To turn off gzip, pass in false.
  gzip: :best_speed,
  # Hostnames can be included in the path of the page cache. Default is false.
  include_hostname: true

Rack::PageCaching respects config.action_controller.perform_caching and will skip cache generation if it is false.

To configure your web server to serve the generated pages directly, point it to page_cache_directory. For Nginx, it would look something like the following if you include hostnames:

if (-f $document_root/page_cache/$host/$uri/index.html) {
  rewrite (.*) /page_cache/$host/$1/index.html break;
}

if (-f $document_root/page_cache/$host/$uri.html) {
  rewrite (.*) /page_cache/$host/$1.html break;
}

Rack::PageCaching implements the same class methods Rails page caching provides, so if you were using it previously you can leave it as is:

class WeblogController < ActionController::Base
  caches_page :show, :new
end

Expiration is also supported the same way:

class WeblogController < ActionController::Base
  def update
    List.update(params[:list][:id], params[:list])
    expire_page action: 'show', id: params[:list][:id]
    redirect_to action: 'show', id: params[:list][:id]
  end
end

You can delete pages manually (e.g. in a rake task) using the following command:

Rack::PageCaching::Cache.delete 'weblog/*.html'
# if you have hostnames enabled, use '**/weblog/*.html' to delete regardless
# of which hostname the files are nested in

Acknowledgements

Tests for compatibility with Rails page caching and ActionController integration were heavily inspired by code in the Rails page caching gem.

Contributing

1. Fork it ( https://github.com/[my-github-username]/rack-page_caching/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request