Add List-Unsubscribe email header (#26085)

app/controllers/mail_subscriptions_controller.rb

@@ -9,6 +9,8 @@ class MailSubscriptionsController < ApplicationController
   before_action :set_user
   before_action :set_type
 
+  protect_from_forgery with: :null_session
+
   def show; end
 
   def create
@@ -20,6 +22,7 @@ class MailSubscriptionsController < ApplicationController
 
   def set_user
     @user = GlobalID::Locator.locate_signed(params[:token], for: 'unsubscribe')
+    not_found unless @user
   end
 
   def set_body_classes
@@ -35,7 +38,7 @@ class MailSubscriptionsController < ApplicationController
     when 'follow', 'reblog', 'favourite', 'mention', 'follow_request'
       "notification_emails.#{params[:type]}"
     else
-      raise ArgumentError
+      not_found
     end
   end
 end

app/mailers/notification_mailer.rb

@@ -8,6 +8,7 @@ class NotificationMailer < ApplicationMailer
   before_action :process_params
   before_action :set_status, only: [:mention, :favourite, :reblog]
   before_action :set_account, only: [:follow, :favourite, :reblog, :follow_request]
+  after_action :set_list_headers!
 
   default to: -> { email_address_with_name(@user.email, @me.username) }
 
@@ -61,6 +62,7 @@ class NotificationMailer < ApplicationMailer
     @me = params[:recipient]
     @user = @me.user
     @type = action_name
+    @unsubscribe_url = unsubscribe_url(token: @user.to_sgid(for: 'unsubscribe').to_s, type: @type)
   end
 
   def set_status
@@ -71,6 +73,12 @@ class NotificationMailer < ApplicationMailer
     @account = @notification.from_account
   end
 
+  def set_list_headers!
+    headers['List-ID'] = "<#{@type}.#{@me.username}.#{Rails.configuration.x.local_domain}>"
+    headers['List-Unsubscribe'] = "<#{@unsubscribe_url}>"
+    headers['List-Unsubscribe-Post'] = 'List-Unsubscribe=One-Click'
+  end
+
   def thread_by_conversation(conversation)
     return if conversation.nil?
 

app/views/layouts/mailer.html.haml

@@ -46,9 +46,9 @@
                                 %p= t 'about.hosted_on', domain: site_hostname
                                 %p
                                   = link_to t('application_mailer.notification_preferences'), settings_preferences_notifications_url
-                                  - if defined?(@type)
+                                  - if defined?(@unsubscribe_url)
                                     ·
-                                    = link_to t('application_mailer.unsubscribe'), unsubscribe_url(token: @user.to_sgid(for: 'unsubscribe').to_s, type: @type)
+                                    = link_to t('application_mailer.unsubscribe'), @unsubscribe_url
                               %td.column-cell.text-right
                                 = link_to root_url do
                                   = image_tag full_pack_url('media/images/mailer/logo.png'), alt: 'Mastodon', height: 24