Ruby on Rails

When working in development mode (using webrick) it is painful waiting for pages to load when there are a lot of css and js assets that are loaded one by one.

This has annoyed me for years but today it dawned on me how easy the fix is.  I'm using Rails 4.1.x

in development.rb

Add the digest to assets
 
config.assets.digest = true

and then add middleware that caches assets for a year (in development.rb only, in prod we cache via apache/nginx).

config.middleware.use CacheAssets

My CacheAssets class looks like so

class CacheAssets
  def initialize app
    @app = app
  end

  def call env
    res = @app.call(env)
    path = env["REQUEST_PATH"]
    if path =~ /assets/
      if res[0] == 200
        res[1]["Expires"] = (Time.now + 1.year).utc.rfc2822
        res[1]["Cache-Control"] = 'public'
      end
      return res
    end
    res
  end
end


If I edit any CSS or JS file it will get a new digest key so there is no need to clear the cache to pick up my latest changes while developing.

In the interest of making the development environment faster by default, maybe this should be baked into Rails 5?   disclaimer, i haven't used Rails 5 yet so maybe something like this is already there.

Thoughts?
Tony