image_path function does not add prefix when deployed on a sub uri

[bpaquet]

image_path('toto.png') in a scss is not prefixed by sub uri when app is deployed on a sub uri context : RAILS_RELATIVE_URL_ROOT is not used.

I have a patch to correct this problem here :
https://github.com/bpaquet/sass-rails/commit/f83a59fe2052dc7ba8c2d0bc9c8a653fad47fb08
I'm not sure it's the better way to solve this problem.

Remark : I have to set RAILS_RELATIVE_URL_ROOT when I run rake assets:precompile

[chriseppstein]

seems like this is a bug in sprockets/rails then. I use their url generator.

[thomaswitt]

I ran in exactly the same problem - This issue has been closed, but I don't see any commits in the project...?

[bpaquet]

No.
It does not work on rails 3.1 final. I don't know on which project to open issue.

[chriseppstein]

This is the right place for the bug. I'm in the middle of moving, will look into it soon.

Hunt & pecked on my iPhone... Sorry if it's brief!

On Sep 5, 2011, at 8:41 AM, bpaquetreply@reply.github.com wrote:

No.
It does not work on rails 3.1 final. I don't know on which project to open issue.

Reply to this email directly or view it on GitHub:
#17 (comment)

[nbarthelemy]

After a bit of digging around, I have found the issue. The issue is in Rails, specifically Sprockets::Helpers::RailsHelper::AssetPaths#compute_public_path. Sprockets::Helpers::RailsHelper::AssetPaths inherits from ActionView::AssetPaths and overrides a number of methods. When compute_public_path is called through the Sass::Rails::Resolver#public_path method is sass-rails, the rails sprocket helper picks up the task of resolving the asset. Sprockets::Helpers::RailsHelper::AssetPaths#compute_public_path defers to super which is ActionView::AssetPaths#compute_public_path. In this method there is a condition of has_request? on rewrite_relative_url_root as seen below:

def compute_public_path(source, dir, ext = nil, include_host = true, protocol = nil)
  ...
  source = rewrite_relative_url_root(source, relative_url_root) if has_request?
  ...
end

def relative_url_root
  config = controller.config if controller.respond_to?(:config)
  config ||= config.action_controller if config.action_controller.present?
  config ||= config
  config.relative_url_root
end

If you look at the internals of rewrite_relative_url_root it relies on a request to be present and the ability to derive it from the controller variable in order to resolve the relative url root. The issue is that when sprockets resolves these assets for sass it does not have a controller present and therefore no request.

I am going to file a ticket with Rails and take a stab at a patch in the next few days. Probably the easiest way to resolve this for now is to add an initializer that looks something like this:

    module Sass
      module Rails
        module Helpers
          protected
          def public_path(asset, kind)
            resolver = options[:custom][:resolver]
            asset_paths = resolver.context.asset_paths
            path = resolver.public_path(asset, kind.pluralize)
            if !asset_paths.send(:has_request?) && ENV['RAILS_RELATIVE_URL_ROOT']
              path = ENV['RAILS_RELATIVE_URL_ROOT'] + path
            end
            path
          end
        end
      end
    end

And put the following line at the top of your environment.rb file:

ENV['RAILS_RELATIVE_URL_ROOT'] = '/sub-app'

[nbarthelemy]

rails/rails#2977 It will soon be fixed in rails.