Namespace engine assets

[ryanb]

This changes the plugin new --mountable generator so it places javascript/stylesheet/image engine assets in their own namespaced directory so they don't conflict with those in the main app. Instead of app/assets/javascripts/application.js it places it in app/assets/javascripts/ENGINE_NAME/application.js. It also changes the application.html.erb layout file to use the new path.

[josevalim]

Hey @ryanb, thanks for the patch! Shouldn't the layout file be namespaced as well to avoid conflicts? Otherwise the one in the app will have higher preference.

[ryanb]

I believe the layout file is already namespaced. It is generated under app/views/layouts/ENGINE_NAME/application.html.erb.

On a similar note, it would be nice if there was some way to set the asset prefix at the engine config level just like we do with isolate_namespace. Then if we have <%= image_tag "foo.png" %> it would expand to /assets/ENGINE_NAME/foo.png. It looks like there's a config.assets.prefix setting in Rails itself, but it doesn't look like this is exposed to the engine railtie.

[josevalim]

@ryanb: right, my bad about the layout. and yes, image_tag should work transparently, this is how it works without sprockets but it seems it was not added to sprockets itself. :(