I've been trying to implement active storage in an existing app, and I've been running into an issue.
Using a url_for generated URL, the given url is a rails blob URL which then redirects to S3. This is fine, however in production our main S3 bucket is a CNAME'd bucket accessed via a caching proxy for performance reasons, and for prettier URLs on our domain. With paperclip you could set a property so that it would redirect requests to a set domain, as opposed to directly to the S3 bucket, but I've been pulling my hair out trying to work out how to do this with Active Storage.
Simply put, instead of rails blob URLs from url_for redirecting to cdn.example.com.s3.amazonaws.com I want them to redirect to cdn.example.com, as you could with Paperclip.