allow to resent copy email

app/controllers/submissions_download_controller.rb

@@ -4,10 +4,20 @@ class SubmissionsDownloadController < ApplicationController
   skip_before_action :authenticate_user!
   skip_authorization_check
 
-  TTL = 20.minutes
+  TTL = 40.minutes
+  FILES_TTL = 5.minutes
 
   def index
-    submitter = Submitter.find_by!(slug: params[:submitter_slug])
+    submitter = Submitter.find_signed(params[:sig], purpose: :download_completed) if params[:sig].present?
+
+    signature_valid =
+      if submitter&.slug == params[:submitter_slug]
+        true
+      else
+        submitter = nil
+      end
+
+    submitter ||= Submitter.find_by!(slug: params[:submitter_slug])
 
     Submissions::EnsureResultGenerated.call(submitter)
 
@@ -17,18 +27,24 @@ class SubmissionsDownloadController < ApplicationController
 
     return head :not_found unless last_submitter.completed_at?
 
-    if last_submitter.completed_at < TTL.ago &&
-       (current_user.nil? || !current_user.account.submitters.exists?(id: last_submitter.id))
+    if last_submitter.completed_at < TTL.ago && !signature_valid && !current_user_submitter?(last_submitter)
       Rollbar.info("TTL: #{last_submitter.id}") if defined?(Rollbar)
 
       return head :not_found
     end
 
-    urls =
-      Submitters.select_attachments_for_download(last_submitter).map do |attachment|
-        ActiveStorage::Blob.proxy_url(attachment.blob)
-      end
+    render json: build_urls(last_submitter)
+  end
 
-    render json: urls
+  private
+
+  def current_user_submitter?(submitter)
+    current_user && current_user.account.submitters.exists?(id: submitter.id)
+  end
+
+  def build_urls(submitter)
+    Submitters.select_attachments_for_download(submitter).map do |attachment|
+      ActiveStorage::Blob.proxy_url(attachment.blob, expires_at: FILES_TTL.minutes.from_now.to_i)
+    end
   end
 end