From https://once.com/writebook

lib/rails_ext/active_storage_sluggable.rb

@@ -0,0 +1,32 @@
+module ActiveStorage::Sluggable
+  extend ActiveSupport::Concern
+
+  included do
+    before_create :set_slug
+  end
+
+  def slug_url(host: ActiveStorage::Current.host)
+    Rails.application.routes.url_helpers.action_text_markdown_upload_url(slug, host: host)
+  end
+
+  private
+    def set_slug
+      self.slug = "#{slug_basename}-#{SecureRandom.alphanumeric(6)}.#{slug_extension}"
+    end
+
+    def slug_basename
+      File.basename(slug_filename, ".*").parameterize
+    end
+
+    def slug_extension
+      File.extname(slug_filename).delete(".").parameterize
+    end
+
+    def slug_filename
+      slug.presence || filename.to_s
+    end
+end
+
+ActiveSupport.on_load :active_storage_attachment do
+  ActiveStorage::Attachment.include ActiveStorage::Sluggable
+end