Active Storage needs a checksum for each file and AWS S3 provides this
checksum as "ETag". They are both MD5 but AWS stores it as hexdigest and
Active Storage as base64digest. We need to convert it from on to the
other to get a valid checksum for Active Storage.
Where the migration task has already run (only staging servers), delete all
Active Storage data first and then run the task again:
bundle exec rake db:migrate:down VERSION=20220316055458
bundle exec rake db:migrate
bundle exec rake from_paperclip_to_active_storage:copy_content_config
bundle exec rake from_paperclip_to_active_storage:migrate
yes, this is a hack, but can't make it work as a normal behavior. For testing purpose, we use `spec/support/fixtures/stripejs-mock.js` and it seems not working with our `app/webpacker/controllers/stripe_controller.js`
Common migrations look for all models with *_file_name attributes but I
found that unreliable in our code base. It finds too many model classes
and doesn't allow us to be more selective in the migration. So I used
our own migration declaration to migrate exactly those attachments
specified.
Active Storage always touches associated records when attachments are
changed. But for the Terms of Service it's important to keep the
updated_at date because that's how we find out how new it is and if a
customer accepted those terms already.
And while we migrate files, the content of the files will stay the same
and we don't want customers to be asked to accept the same terms again.
We do this for all models in the code base. There's one special case,
the ConentConfiguration which is not a model and we can't use the same
approach there. We will have to deal with that separately later.
I chose `has_one_migrating` as method name for two reasons:
1. It reflects Active Storage's method `has_one_attached`.
2. And it has the same length as Paperclip's `has_attached_file`.
Therefore the commits don't need any whitespace changes.
When we change it to `has_one_attached`, we will also remove the
Paperclip options which then don't need whitespace changes either.
While we migrate from Paperclip to Active Storage, we need to use both
at the same time to avoid any downtime or lost images.
Once the migration is complete, we want to use the same name for
attachment as before. Using Paperclip and Active Storage at the same
time creates a name conflict on a couple of methods.
I'm using alias_method as a temporary solution to access Active Storage
methods. We will remove that after the migration. I declare Paperclip
afterwards so that we have those methods declarations for backwards
compatibility now.
