add blobs proxy controller

app/controllers/api/active_storage_blobs_proxy_controller.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module Api
+  class ActiveStorageBlobsProxyController < ApiBaseController
+    include ActiveStorage::Streaming
+
+    skip_before_action :authenticate_user!
+    skip_authorization_check
+
+    def show
+      blob_uuid = ApplicationRecord.signed_id_verifier.verified(params[:signed_uuid])
+
+      return head :not_found unless blob_uuid
+
+      blob = ActiveStorage::Blob.find_by!(uuid: blob_uuid)
+
+      if request.headers['Range'].present?
+        send_blob_byte_range_data blob, request.headers['Range']
+      else
+        http_cache_forever public: true do
+          response.headers['Accept-Ranges'] = 'bytes'
+          response.headers['Content-Length'] = blob.byte_size.to_s
+
+          send_blob_stream blob, disposition: params[:disposition]
+        end
+      end
+    end
+  end
+end

app/controllers/submissions_download_controller.rb

@@ -15,7 +15,7 @@ class SubmissionsDownloadController < ApplicationController
 
     urls =
       Submitters.select_attachments_for_download(last_submitter).map do |attachment|
-        helpers.rails_blob_url(attachment)
+        ActiveStorage::Blob.proxy_url(attachment.blob)
       end
 
     render json: urls