Fix issues with attaching QR code to email

Gemfile

@@ -62,6 +62,8 @@ gem "faraday"
 
 gem "rqrcode"
 
+gem "draper"
+
 group :development do
   gem "spring"
   gem "spring-commands-rspec"

Gemfile.lock

@@ -37,6 +37,10 @@ GEM
       globalid (>= 0.3.6)
     activemodel (5.2.3)
       activesupport (= 5.2.3)
+    activemodel-serializers-xml (1.0.2)
+      activemodel (> 5.x)
+      activesupport (> 5.x)
+      builder (~> 3.1)
     activerecord (5.2.3)
       activemodel (= 5.2.3)
       activesupport (= 5.2.3)
@@ -139,6 +143,12 @@ GEM
       devise (>= 4.6)
     diff-lcs (1.3)
     docile (1.3.2)
+    draper (3.1.0)
+      actionpack (>= 5.0)
+      activemodel (>= 5.0)
+      activemodel-serializers-xml (>= 1.0)
+      activesupport (>= 5.0)
+      request_store (>= 1.0)
     erubi (1.9.0)
     execjs (2.7.0)
     factory_bot (5.1.1)
@@ -454,6 +464,7 @@ DEPENDENCIES
   delorean
   devise
   devise-i18n
+  draper
   factory_bot_rails
   faker
   faraday

app/controllers/public/event_feedback_qrcodes_controller.rb

@@ -1,10 +1,10 @@
 class Public::EventFeedbackQrcodesController < Public::ApplicationController
   def show
-    event = current_conference.events.joins(:proposition).approved.find(params[:event_id])
+    event = current_conference.events.joins(:proposition).approved.find(params[:event_id]).decorate
 
     respond_to do |format|
       format.svg do
-        render(inline: helpers.feedback_qr_code_as_svg(event.id),
+        render(inline: event.feedback_qr_code_as_svg,
                filename: "feedback_qr_code_#{event.id}.svg")
       end
     end

app/decorators/application_decorator.rb

@@ -0,0 +1,8 @@
+class ApplicationDecorator < Draper::Decorator
+  # Define methods for all decorated objects.
+  # Helpers are accessed through `helpers` (aka `h`). For example:
+  #
+  #   def percent_amount
+  #     h.number_to_percentage object.amount, precision: 2
+  #   end
+end

app/decorators/event_decorator.rb

@@ -0,0 +1,20 @@
+class EventDecorator < Draper::Decorator
+  delegate_all
+
+  # Define presentation-specific methods here. Helpers are accessed through
+  # `helpers` (aka `h`). You can override attributes, for example:
+  #
+  #   def created_at
+  #     helpers.content_tag :span, class: 'time' do
+  #       object.created_at.strftime("%a %m/%d/%y")
+  #     end
+  #   end
+
+  def feedback_qr_code
+    RQRCode::QRCode.new(h.new_event_feedback_url(event_id: id), level: :l)
+  end
+
+  def feedback_qr_code_as_svg
+    feedback_qr_code.as_svg(shape_rendering: "crispEdges", module_size: 11, fill: "ffffff", offset: 10)
+  end
+end

app/helpers/application_helper.rb

@@ -85,12 +85,4 @@ module ApplicationHelper
     when 6       then t('ratings.excellent')
     end
   end
-
-  def feedback_qr_code(event_id)
-    RQRCode::QRCode.new(new_event_feedback_url(event_id: event_id), level: :l)
-  end
-
-  def feedback_qr_code_as_svg(event_id)
-    feedback_qr_code(event_id).as_svg(shape_rendering: "crispEdges", module_size: 11, fill: "ffffff", offset: 10)
-  end
 end

app/mailers/event_mailer.rb

@@ -1,11 +1,15 @@
 class EventMailer < ActionMailer::Base
+  helper ApplicationHelper
+
   def confirmation_request(event)
-    @event = event
+    @event = event.decorate
     I18n.locale = @event.proposer.language
+
     attachments['feedback-link-qr-code.svg'] = {
       mime_type: 'image/svg+xml',
-      content: helpers.feedback_qr_code_as_svg(@event.id)
+      content: @event.feedback_qr_code_as_svg
     }
+
     mail to: @event.proposer.email,
          from: "program@openfest.org",
          subject: I18n.t("event_mailer.acceptance_notification.subject",