Should rails force asset caching in development?

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

def call env
res =
path = env[“REQUEST_PATH”]
if path =~ /assets/
if res[0] == 200
res[1][“Expires”] = ( + 1.year).utc.rfc2822
res[1][“Cache-Control”] = ‘public’
return res

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.