Provide download link for generated reports

app/controllers/admin/reports_controller.rb

@@ -2,6 +2,7 @@
 
 module Admin
   class ReportsController < Spree::Admin::BaseController
+    include ActiveStorage::SetCurrent
     include ReportsActions
     helper ReportsHelper
 
@@ -59,16 +60,16 @@ module Admin
       if OpenFoodNetwork::FeatureToggle.enabled?(:background_reports, spree_current_user)
         filename = report_filename
         filename = "#{filename}html" if report_format.blank?
-        blob = ReportBlob.create_for_upload_later!(filename)
+        @blob = ReportBlob.create_for_upload_later!(filename)
         ReportJob.perform_later(
-          report_class, spree_current_user, params, format, blob
+          report_class, spree_current_user, params, format, @blob
         )
         Timeout.timeout(max_wait_time) do
-          sleep 1 until blob.content_stored?
+          sleep 1 until @blob.content_stored?
         end
 
         # This result has been rendered by Rails in safe mode already.
-        blob.result.html_safe # rubocop:disable Rails/OutputSafety
+        @blob.result.html_safe # rubocop:disable Rails/OutputSafety
       else
         @report.render_as(format)
       end
@@ -76,7 +77,13 @@ module Admin
 
     def render_timeout_error
       assign_view_data
-      @error = ".report_taking_longer"
+      if @blob
+        @error = ".report_taking_longer_html"
+        @error_url = @blob.url
+      else
+        @error = ".report_taking_longer"
+        @error_url = ""
+      end
       render "show"
     end
 

app/views/admin/reports/show.html.haml

@@ -21,5 +21,5 @@
   - if request.post? && !@error
     %button.btn-print.icon-print{ onclick: "window.print()"}= t(:report_print)
 
-= t(@error) if @error
+= t(@error, link: link_to(t(".report_link_label"), @error_url)) if @error
 = @table

config/locales/en.yml

@@ -1445,6 +1445,11 @@ en:
           Sorry, this report took too long to process.
           It may contain a lot of data or we are busy with other reports.
           You can try again later.
+        report_taking_longer_html: >
+          This report is taking longer to process.
+          It may contain a lot of data or we are busy with other reports.
+          Once it's finished, you can download it: %{link}
+        report_link_label: Download report (when available)
       revenues_by_hub:
         name: Revenues By Hub
         description: Revenues by hub

spec/system/admin/reports_spec.rb

@@ -45,7 +45,7 @@ describe '
       expect(page).to have_content "EMAIL FIRST NAME"
     end
 
-    it "displays a friendly timeout message" do
+    it "displays a friendly timeout message and offers download" do
       ActiveJob::Base.queue_adapter.perform_enqueued_jobs = false
       login_as_admin_and_visit admin_report_path(
         report_type: :customers, report_subtype: :mailing_list
@@ -55,7 +55,16 @@ describe '
 
       click_button "Go"
 
-      expect(page).to have_content "this report took too long"
+      expect(page).to have_content "report is taking longer"
+
+      perform_enqueued_jobs(only: ReportJob)
+
+      click_link "Download report"
+
+      expect(downloaded_filename).to match /customers_[0-9]+\.html/
+
+      content = File.read(downloaded_filename)
+      expect(content).to match "<th>\nFirst Name\n</th>"
     end
   end