Fixes

[josh-m-sharpe]

Here's a cleaned up version of the previous PR:

Some minor things:

1. eases the dependency on httparty
2. Fixes ErrorHandler to properly use Callable module.

A bit more major:
removes manifest arg and defines a method to get the current stylesheet. Basically, this was previously set up to only work with stylesheets named 'application.css' -- and it seemed, at least for me, to pass the string 'application.css' to the node server -- when in fact the file name had a hash on it - e.g. application-fab7daa9310cc448046aee95dccad8018095b572b53077b78bc4b8bc8545c5bf

I've had this branch running for a week or so now and it seems to be working well.

[wheeyls]

The way this is written you should be able to override the name of the manifest manually when you call this method. I call it like this:

= RailsCriticalCssServer::Rewrite.call(self,
  skip: current_user.present?,
  manifest: asset_url('css_manifest.css')) do

[josh-m-sharpe]

true. but then you have the manifest name twice in your template and it doesn't handle the generated hash in the filename.

[wheeyls]

The generated hash will be added to the filename, since the asset_url helper is smart enough to generate the correct digest and everything in a production environment.

This approach will also break because you may have more than one stylesheet in your HTML; for instance in one of my apps I have to split my css files up to avoid IE9 rule limit restrictions. So I have something like this:

= RailsCriticalCssServer::Rewrite.call(self,
  manifest: asset_url('css_manifest.css')) do
  = stylesheet_link_tag 'bootstrap'
  = stylesheet_link_tag 'common'
  = stylesheet_link_tag 'page_rules'

css_manifest.css in this case is a single stylesheet with all the rules, in an easy format that criticalcss can read.