Inability to compile nondigest and digest assets breaks compatibility with bad gems

[gwcoffey]

For instance, the jquery_mobile-rails gem does not use image-url in its CSS. This is a bug really, but it "worked fine" in Rails 3. I assume they will fix the gem eventually. But in the meantime, in Rails 4, it is broken and as far as I can tell there's no way to work around it. The simple short term fix is to compile both digest and nondigest assets for this gem, but I don't see any way to do that. I can apparently only turn digest off or on globally for the application.

A rake assets:precompile:nondigest task or something similar would provide a workaround. But it seems to be gone now.

Is there a good way to deal with this, or do I just have to drop the gem and manage jquery mobile manually outside the asset pipeline, which is a pain?

[pelargir]

+1

Removing generation of non-digest files also makes is impossible to have static 404 error pages that use the same images, JS, and CSS as the remainder of the site (without making duplicate non-digest copies of those files in /public). But then I end up with two copies of the same file in my app.

It's really unfortunate that this feature would be yanked without an explanation of how to deal with these situations.

[rafaelfranca]

From the README: Only compiles digest filenames. Static non-digest assets should simply live in public/.

[pelargir]

I saw that. So please explain how I'm supposed to reference my precompiled application.css file from my static 404 error page? Am I supposed to copy the precompiled file into /public and remove the fingerprint from the filename? So then, if I change the file in the future, I have to precompile, copy, and rename all over again? That's silly.

[guilleiguaran]

You can use a rake task like this for your case:

task non_digested: :environment do
  assets = Dir.glob(File.join(Rails.root, 'public/assets/**/*'))
  regex = /(-{1}[a-z0-9]{32}*\.{1}){1}/
  assets.each do |file|
    next if File.directory?(file) || file !~ regex

    source = file.split('/')
    source.push(source.pop.gsub(regex, '.'))

    non_digested = File.join(source)
    FileUtils.cp(file, non_digested)
  end
end

[ryana]

FWIW, I disagree with the resolution of this issue. I'm all for software being opinionated, but I shouldn't have to create a rake task like this in order to compile assets without the digest. It is my application after all ;) The bigger issue from my perspective is that this breaks applications on Heroku that are doing things like serving JS widgets that can't have digests in the name.

[ryana]

https://gist.github.com/ryana/6049833

A monkeypatch for current version of Sprockets cc: @pelargir

[tikaro]

I also disagree with the resolution of this issue:
"So please explain how I'm supposed to reference my precompiled application.css file from my static 404 error page?" is more or less the use case I have - a centralized Rails single-sign-on utility provides precompiled CSS via absolute URLS to other client applications.

[rafaelfranca]

If you need to generate assets without digest so you have to do this on your own.

[tikaro]

After talking this over, my big-chair developer decided to handle this by having Rails return a 301 redirect FROM the old, non-digested CSS location, TO whatever the latest digested CSS location is. That way, the client sites get to use a non-changing location and the rails app doesn't have to bake everything twice.

[rafaelfranca]

This was exactly because we remove the undigest version. The Rails app had to bake the compilation twice.

[guilleiguaran]

@tikaro like https://github.com/sikachu/sprockets-redirect (it's for Rails 3.x but should be easy to port to Rails 4)

[ryana]

@tikaro clever, but you'll want to 302 instead of 301. 301s are permanent and some browsers will cache them.

[tikaro]

@ryana good point, re: 302 and 301; I think I over-described what we've done, and may have gotten it wrong. Cloudfront is involved, too. Perhaps I can coax him in here so he can describe what he did.