Setting the url_options hash in the controller

When grabbing the url of an ActiveStorage record through any of these methods: ActiveStorage::Blob#url,ActiveStorage::Variant#url,ActiveStorage::Preview#url you may find yourself running into this error:

Cannot generate URL for <FILENAME> using Disk service, 
please set ActiveStorage::Current.url_options.

This can be resolved in the controller by utilizing a concern that ActiveStorage provides for us; ActiveStorage::SetCurrent.

It would look like this in your controller:

class MyController < ApplicationController
  include ActiveStorage::SetCurrent
  
  # The rest of your controller...
end

And now whenever you go to call #url on your ActiveStorage record, it will know where to generate the url from!

Including ActiveStorage::SetCurrent sets the ActiveStorage::Current.url_options hash to match the current request.