Handle multiple emails in reply-to header (#2365)

email_handler.py

@@ -590,15 +590,25 @@ def handle_forward(envelope, msg: Message, rcpt_to: str) -> List[Tuple[bool, str
         contact.alias
     )  # In case the Session was closed in the get_or_create we re-fetch the alias
 
-    reply_to_contact = None
+    reply_to_contact = []
     if msg[headers.REPLY_TO]:
-        reply_to = get_header_unicode(msg[headers.REPLY_TO])
-        LOG.d("Create or get contact for reply_to_header:%s", reply_to)
-        # ignore when reply-to = alias
-        if reply_to == alias.email:
-            LOG.i("Reply-to same as alias %s", alias)
-        else:
-            reply_to_contact = get_or_create_reply_to_contact(reply_to, alias, msg)
+        reply_to_header_contents = get_header_unicode(msg[headers.REPLY_TO])
+        if reply_to_header_contents:
+            LOG.d(
+                "Create or get contact for reply_to_header:%s", reply_to_header_contents
+            )
+            for reply_to in [
+                reply_to.strip()
+                for reply_to in reply_to_header_contents.split(",")
+                if reply_to.strip()
+            ]:
+                reply_to_name, reply_to_email = parse_full_address(reply_to)
+                if reply_to_email == alias.email:
+                    LOG.i("Reply-to same as alias %s", alias)
+                else:
+                    reply_to_contact.append(
+                        get_or_create_reply_to_contact(reply_to_email, alias, msg)
+                    )
 
     if alias.user.delete_on is not None:
         LOG.d(f"user {user} is pending to be deleted. Do not forward")
@@ -701,7 +711,7 @@ def forward_email_to_mailbox(
     envelope,
     mailbox,
     user,
-    reply_to_contact: Optional[Contact],
+    reply_to_contacts: list[Contact],
 ) -> (bool, str):
     LOG.d("Forward %s -> %s -> %s", contact, alias, mailbox)
 
@@ -884,11 +894,13 @@ def forward_email_to_mailbox(
     add_or_replace_header(msg, "From", new_from_header)
     LOG.d("From header, new:%s, old:%s", new_from_header, old_from_header)
 
-    if reply_to_contact:
-        reply_to_header = msg[headers.REPLY_TO]
-        new_reply_to_header = reply_to_contact.new_addr()
+    if len(reply_to_contacts) > 0:
+        original_reply_to = get_header_unicode(msg[headers.REPLY_TO])
+        new_reply_to_header = ", ".join(
+            [reply_to_contact.new_addr() for reply_to_contact in reply_to_contacts][:5]
+        )
         add_or_replace_header(msg, "Reply-To", new_reply_to_header)
-        LOG.d("Reply-To header, new:%s, old:%s", new_reply_to_header, reply_to_header)
+        LOG.d("Reply-To header, new:%s, old:%s", new_reply_to_header, original_reply_to)
 
     # replace CC & To emails by reverse-alias for all emails that are not alias
     try:

tests/example_emls/multi_reply_to.eml

@@ -0,0 +1,21 @@
+X-SimpleLogin-Client-IP: 54.39.200.130
+Received-SPF: Softfail (mailfrom) identity=mailfrom; client-ip=34.59.200.130;
+ helo=relay.somewhere.net; envelope-from=everwaste@gmail.com;
+ receiver=<UNKNOWN>
+Received: from relay.somewhere.net (relay.somewhere.net [34.59.200.130])
+        (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
+        (No client certificate requested)
+        by mx1.sldev.ovh (Postfix) with ESMTPS id 6D8C13F069
+        for <wehrman_mannequin@sldev.ovh>; Thu, 17 Mar 2022 16:50:20 +0000 (UTC)
+Date: Thu, 17 Mar 2022 16:50:18 +0000
+To: {{ alias_email }}
+From: somewhere@rainbow.com
+Reply-To: 666-Mail Test <a1@mailcstest.com>, 777-Mail Test <a2@mailcstest.com>,
+  888-Mail Test <a3@mailcstest.com>, - 5 at mailcstest.com" <a4@simplelogin.co>
+Subject: test Thu, 17 Mar 2022 16:50:18 +0000
+Message-Id: <20220317165018.000191@somewhere-5488dd4b6b-7crp6>
+X-Mailer: swaks v20201014.0 jetmore.org/john/code/swaks/
+X-Rspamd-Queue-Id: 6D8C13F069
+X-Rspamd-Server: staging1
+
+This is a test mailing

tests/handler/test_reply_to.py

@@ -0,0 +1,33 @@
+from aiosmtpd.smtp import Envelope
+
+import email_handler
+from app.email import status, headers
+from app.email_utils import get_header_unicode, parse_full_address
+
+from app.mail_sender import mail_sender
+from app.models import Alias, Contact
+from tests.utils import create_new_user, load_eml_file
+
+
+@mail_sender.store_emails_test_decorator
+def test_multi_reply_to():
+    user = create_new_user()
+    alias = Alias.create_new_random(user)
+    envelope = Envelope()
+    envelope.mail_from = "env.somewhere"
+    envelope.rcpt_tos = [alias.email]
+    msg = load_eml_file("multi_reply_to.eml", {"alias_email": alias.email})
+    alias_id = alias.id
+    result = email_handler.MailHandler()._handle(envelope, msg)
+    assert result == status.E200
+    sent_emails = mail_sender.get_stored_emails()
+    assert 1 == len(sent_emails)
+    msg = sent_emails[0].msg
+    reply_to = get_header_unicode(msg[headers.REPLY_TO])
+    entries = reply_to.split(",")
+    assert 4 == len(entries)
+    for entry in entries:
+        dummy, email = parse_full_address(entry)
+        contact = Contact.get_by(reply_email=email)
+        assert contact is not None
+        assert contact.alias_id == alias_id