handle newsletter unsubscribe when the subject=user_id*

email_handler.py

@@ -1359,7 +1359,8 @@ def handle_spam(
         )
 
 
-def handle_unsubscribe(envelope: Envelope):
+def handle_unsubscribe(envelope: Envelope) -> str:
+    """return the SMTP status"""
     msg = email.message_from_bytes(envelope.original_content)
 
     # format: alias_id:
@@ -1368,6 +1369,10 @@ def handle_unsubscribe(envelope: Envelope):
         # subject has the format {alias.id}=
         if subject.endswith("="):
             alias_id = int(subject[:-1])
+        # {user.id}*
+        elif subject.endswith("*"):
+            user_id = int(subject[:-1])
+            return handle_unsubscribe_user(user_id, envelope.mail_from)
         # some email providers might strip off the = suffix
         else:
             alias_id = int(subject)
@@ -1415,6 +1420,34 @@ def handle_unsubscribe(envelope: Envelope):
     return "250 Unsubscribe request accepted"
 
 
+def handle_unsubscribe_user(user_id: int, mail_from: str) -> str:
+    """return the SMTP status"""
+    user = User.get(user_id)
+    if not user:
+        LOG.exception("No such user %s %s", user_id, mail_from)
+        return "550 SL E22 so such user"
+
+    if mail_from != user.email:
+        LOG.exception("Unauthorized mail_from %s %s", user, mail_from)
+        return "550 SL E23 unsubscribe error"
+
+    user.notification = False
+    db.session.commit()
+
+    send_email(
+        user.email,
+        f"You have been unsubscribed from SimpleLogin newsletter",
+        render(
+            "transactional/unsubscribe-newsletter.txt",
+            user=user,
+        ),
+        render(
+            "transactional/unsubscribe-newsletter.html",
+            user=user,
+        ),
+    )
+
+
 def handle_sender_email(envelope: Envelope):
     filename = (
         arrow.now().format("YYYY-MM-DD_HH-mm-ss") + "_" + random_string(10) + ".eml"

templates/emails/transactional/unsubscribe-newsletter.html

@@ -0,0 +1,22 @@
+{% extends "base.html" %}
+
+{% block content %}
+  {% call text() %}
+    <h1>
+      You have been unsubscribed from SimpleLogin newsletter.
+    </h1>
+  {% endcall %}
+
+  {% call text() %}
+    We would love to know why do you want to unsubscribe from our communication.
+    Please let us know by replying to this email.
+  {% endcall %}
+
+  {% call text() %}
+    Best, <br/>
+    SimpleLogin Team.
+  {% endcall %}
+
+{% endblock %}
+
+

templates/emails/transactional/unsubscribe-newsletter.txt

@@ -0,0 +1,12 @@
+You have been unsubscribed from SimpleLogin newsletter.
+
+We would love to know why do you want to unsubscribe from our communication.
+
+Please let us know by replying to this email.
+
+Best,
+SimpleLogin Team.
+
+
+
+