Use the has_many field for Active Storage attachments

Active Storage is implemented as an association we can take advantage of that and make the users' experience so much better!

Create the resource

For that you should create an attachment_resource.rb and configure it like so.

bin/rails generate avo:resource active_record_attachment

WARNING

Please don't use the name AttachmentResource because the generated controller will override Avo's internal controller that handles the attachments.

class ActiveRecordAttachmentResource < Avo::BaseResource
  self.title = :filename
  self.model_class = "ActiveStorage::Attachment"

  field :id, as: :id
  field :filename, as: :text
  field :service_url, as: :external_image, name: "Image"
  field :created_at, as: :date_time
end

has_many

Next, add it to your resource that has_many_attached:

class Project < ApplicationRecord
  has_many_attached :files
end

class ProjectResource < Avo::BaseResource
  # Please make sure you use the _attachments suffix.
  # So the :files key from the model file becomes :files_attachments on the resource file.
  field :files_attachments, as: :has_many
end

We suggest making this resource read-only using Pundit policies so you don't accidentaly update Active Storage keys and settings.

has_many

We can use the same resource on a different has_one association.

class Post < ApplicationRecord
  has_one_attached :cover_photo
end

class PostResource < Avo::BaseResource
  # Please make sure you use the _attachment suffix.
  # So the :cover_photo key from the model file becomes :cover_photo_attachment on the resource file.
  field :cover_photo_attachment, as: :has_one
end