Active Storage: Best practice to retain/cache uploaded file when form redisplays

Question

When uploading files with Active Storage, when a file is finished uploading and the form gets redisplayed, for example when the validation for that form fails for some reason, the file is gone.

Is there a way to cache or retain it between form redisplays? Shrine has a nice Plugin for that purpose, I'm looking for something similar for Active Storage.

Answer 1

for those looking for has_many_attached solution

https://github.com/rails/rails/issues/35817#issuecomment-484158884

<% if @product.photos.attached? %>
  <% @product.photos.each do |ph| %>
    <%= f.hidden_field :photos, value: ph.signed_id %>
  <% end %>
<% end %>

Answer 2

Here's a solution to make ActiveStorage files persist on form redisplay: f.hidden_field :image, value: f.object.image.signed_id if f.object.image.attached? f.file_field :image