feat(newsletter): add List-Unsubscribe headers and RFC 8058 one-click handler

src/Controller/SubscriptionController.php

@@ -22,6 +22,12 @@ public function unsubscribeNewsletter(
         string $username,
         string $unsubscribeKey
     ): Response {
+        if ($request->isMethod('POST') && 'List-Unsubscribe=One-Click' === $request->request->get('List-Unsubscribe')) {
+            $subscriptionModel->unsubscribeNewsletter($username, $unsubscribeKey);
+
+            return new Response('', Response::HTTP_OK);
+        }
+
         $form = $this->createForm(NewsletterUnsubscribeType::class);
         $form->handleRequest($request);
 

src/Service/Mailer.php

@@ -133,7 +133,9 @@ public function sendNewsletterEmail(Newsletter $newsletter, Member $receiver, ar
             $parameters['sender'],
             $receiver,
             'newsletter',
-            $parameters
+            $parameters,
+            null,
+            $this->buildNewsletterHeaders($newsletter, $receiver, $parameters),
         );
     }
 
@@ -301,7 +303,7 @@ private function getBeWelcomeAddress(Member $sender, $email): Address
      *
      * @return bool
      */
-    private function sendTemplateEmail($sender, $receiver, string $template, array $parameters, ?string $replyTo = null): bool
+    private function sendTemplateEmail($sender, $receiver, string $template, array $parameters, ?string $replyTo = null, array $extraTextHeaders = []): bool
     {
         $currentLocale = $this->translator->getLocale();
         $success = true;
@@ -344,6 +346,10 @@ private function sendTemplateEmail($sender, $receiver, string $template, array $
             $email->replyTo(new Address($replyTo));
         }
 
+        foreach ($extraTextHeaders as $name => $value) {
+            $email->getHeaders()->addTextHeader($name, $value);
+        }
+
         try {
             $this->mailer->send($email);
         } catch (TransportExceptionInterface $e) {
@@ -363,6 +369,36 @@ private function setTranslatorLocale(Member $receiver)
         $this->translator->setLocale($language->getShortCode());
     }
 
+    private function buildNewsletterHeaders(Newsletter $newsletter, Member $receiver, array $parameters): array
+    {
+        $transactionalTypes = [
+            'RemindToLog',
+            'MailToConfirmReminder',
+            Newsletter::SUSPENSION_NOTIFICATION,
+            Newsletter::TERMS_OF_USE,
+        ];
+        if (\in_array($newsletter->getType(), $transactionalTypes, true)) {
+            return [];
+        }
+
+        $unsubscribeKey = $parameters['unsubscribe_key'] ?? null;
+        if (null === $unsubscribeKey) {
+            return [];
+        }
+
+        $unsubscribeUrl = $this->urlGenerator->generate(
+            'regular_newsletter_unsubscribe',
+            ['username' => $receiver->getUsername(), 'unsubscribeKey' => $unsubscribeKey],
+            UrlGeneratorInterface::ABSOLUTE_URL
+        );
+
+        return [
+            'Precedence'            => 'bulk',
+            'List-Unsubscribe'      => '<' . $unsubscribeUrl . '>',
+            'List-Unsubscribe-Post' => 'List-Unsubscribe=One-Click',
+        ];
+    }
+
     private function prepareParametersForNewsletter(Newsletter $newsletter, Member $receiver): array
     {
         $newsletterType = $newsletter->getType();