I’ve been migrating my personal Rails 7 project from Heroku to dedicated server. In this project I heavily rely on ActiveStorage for file uploads/images.

So this task should be really easy: Just pg_dump (or download Heroku PostgreSQL backup) of the existing database, restore it in new server and given you use the same buckets all should work right ?

Well no there are two bottlenecks to be careful about:

1. you need same secret_key_base Any asset uploads are hashed with secret_key_base. So before you delete your Heroku app be sure you save the value of SECRET_KEY_BASE environment variable (and yes it’s different than the one stored in your Rails credentials file)

2 ActionText file uploads are saved with current subdomain If you upload a File using ActionText it will store the full url in the content. That means if you had your application on https://www.myapp.com and you change domain to https://app.myapp.com your action text attachments will not show up. You need to manually change subdomain in DB table records for ActionText