How to get absolute image paths in your css files using sass/scss

When using sass-rails you get a helper called image-url which you can use instead of urlin your .scss files. Something like:

body {
  background-image: image-url(background.png);
}

which will parse into something like:

body {
  background-image: url(/assets/background.png);
}

This should be common knowledge, but it is relative, so how to get this url absolute? Simply set the asset_host config on the action_controller.

The trick:

config.action_controller.asset_host = "http://your.domain.com/"

Then your css will look something like that:

body {
  background-image: url(http://your.domain.com/assets/background.png);
}

But beware this will also trigger the asset_path helper to return absolute urls as well, but chances are very high, that if you want absolute urls in the css you also want it everywhere.