✨(aliases) import existing aliases from dimail

import existing aliases from dimail, making sure usernames don't clash with
existing mailboxes. Convenient when people fall out of sync
with dimail or for domains partially operated outside people.

src/backend/mailbox_manager/utils/dimail.py

@@ -375,12 +375,16 @@ class DimailAPIClient:
             return self.raise_exception_for_unexpected_response(response)
 
         dimail_mailboxes = response.json()
-        people_mailboxes = models.Mailbox.objects.filter(domain=domain)
+        known_mailboxes = models.Mailbox.objects.filter(domain=domain)
+        known_aliases = [
+            known_alias.local_part 
+            for known_alias in models.Alias.objects.filter(domain=domain)
+        ]
         imported_mailboxes = []
         for dimail_mailbox in dimail_mailboxes:
-            if not dimail_mailbox["email"] in [
-                str(people_mailbox) for people_mailbox in people_mailboxes
-            ]:
+            if dimail_mailbox["email"] not in [
+                str(known_mailboxes) for known_mailboxes in known_mailboxes 
+            ] and dimail_mailbox['email'].split('@')[0] not in known_aliases:
                 try:
                     # sometimes dimail api returns email from another domain,
                     # so we decide to exclude this kind of email
@@ -776,3 +780,58 @@ class DimailAPIClient:
             return response
 
         return self.raise_exception_for_unexpected_response(response)
+
+    def import_aliases(self, domain):
+        """Import aliases from dimail. Useful if people fall out of sync with dimail."""
+
+        try:
+            response = session.get(
+                f"{self.API_URL}/domains/{domain.name}/aliases/",
+                headers=self.get_headers(),
+                verify=True,
+                timeout=self.API_TIMEOUT,
+            )
+        except requests.exceptions.ConnectionError as error:
+            logger.error(
+                "Connection error while trying to reach %s.",
+                self.API_URL,
+                exc_info=error,
+            )
+            raise error
+
+        if response.status_code != status.HTTP_200_OK:
+            return self.raise_exception_for_unexpected_response(response)
+
+        incoming_aliases = response.json()
+        known_aliases = [
+            (known_alias.local_part, known_alias.destination)
+            for known_alias in models.Alias.objects.filter(domain=domain)
+        ]
+        known_mailboxes = [
+            known_mailbox.local_part
+            for known_mailbox in models.Mailbox.objects.filter(domain=domain)
+        ]
+        imported_aliases = []
+        for incoming_alias in incoming_aliases:
+            if (
+                incoming_alias["username"],
+                incoming_alias["destination"],
+            ) not in known_aliases and incoming_alias[
+                "username"
+            ] not in known_mailboxes:
+                try:
+                    new_alias = models.Alias.objects.create(
+                        local_part=incoming_alias["username"],
+                        destination=incoming_alias["destination"],
+                        domain=domain,
+                    )
+                except (HeaderParseError, NonASCIILocalPartDefect) as err:
+                    logger.warning(
+                        "Import of alias %s to %s failed with error %s",
+                        incoming_alias["username"],
+                        incoming_alias["destination"],
+                        err,
+                    )
+                else:
+                    imported_aliases.append(str(new_alias))
+        return imported_aliases