class ActiveStorage::Variant

for its redirection.
for a variant that points to the ActiveStorage::RepresentationsController, which in turn will use this +service_call+ method
Use url_for(variant) (or the implied form, like +link_to variant+ or +redirect_to variant+) to get the stable URL

Returns the URL of the blob variant on the service. See {ActiveStorage::Blob#url} for details.

def url(expires_in: ActiveStorage.service_urls_expire_in, disposition: :inline)
  service.url key, expires_in: expires_in, disposition: disposition, filename: filename, content_type: content_type
end