Question

I have a Rails 3.1 application.

I am deploying it via passenger to a SubURI, not to URI root. For instance, the app root is actually accessed as http://somewhere.com/application .

I have a stylesheet.css.erb in my app using the asset pipeline, that sets a background-image with

<%= asset_path 'something.gif' %>

However, when I run rake assets:precompile, it precompiles this to /assets/something.gif, not /application/assets/something.gif — because when I’m running the rake task from the command line, it doesn’t yet know about the path prefix (“/application”) that’s going to be operative when running under Passenger at a SubURI.

What’s the right way to handle this? Is there a way to tell the assets:precompile task to use a particular path prefix, because we know when precompiling that we’re actually going to deploy to a path prefix?

• note: The path’s generated by the actual live app, for instance stylesheet_link_tag 'application' in the layout, do generate properly with the path prefix. So the asset pipeline does respect the path prefix when it’s operative. The problem is clearly that when I run assets:precompile, it’s got no way of knowing what the ultimate prefix is going to be, the way I’m running it. How do I tell it?)

Answer 1

This has come up before:
Seems to be a limitation in Sprockets that is now merged into master:
https://github.com/rails/rails/pull/2977

I guess you need to set the RAILS_RELATIVE_URL_ROOT

Sources:

• Broken precompiled assets in Rails 3.1 when deploying to a sub-URI
• Rails 3.1 SASS asset helpers not not including RAILS_RELATIVE_URL_ROOT / relative_url_root