Autocreate autojoin rooms

changelog.d/3975.feature

@@ -0,0 +1 @@
+First user should autocreate autojoin rooms

synapse/config/registration.py

@@ -44,6 +44,7 @@ def read_config(self, config):
         )
 
         self.auto_join_rooms = config.get("auto_join_rooms", [])
+        self.autocreate_auto_join_rooms = config.get("autocreate_auto_join_rooms", True)
 
     def default_config(self, **kwargs):
         registration_shared_secret = random_string_with_symbols(50)
@@ -98,6 +99,9 @@ def default_config(self, **kwargs):
         # to these rooms
         #auto_join_rooms:
         #    - "#example:example.com"
+
+        # Have first user on server autocreate autojoin rooms
+        autocreate_auto_join_rooms: true
         """ % locals()
 
     def add_arguments(self, parser):

synapse/handlers/register.py

@@ -513,6 +513,34 @@ def get_or_register_3pid_guest(self, medium, address, inviter_user_id):
 
     @defer.inlineCallbacks
     def _join_user_to_room(self, requester, room_identifier):
+
+        # try to create the room if we're the first user on the server
+        if self.hs.config.autocreate_auto_join_rooms:
+            count = yield self.store.count_all_users()
+            if count == 1 and RoomAlias.is_valid(room_identifier):
+                room_creation_handler = self.hs.get_room_creation_handler()
+                info = yield room_creation_handler.create_room(
+                    requester,
+                    config={
+                        "preset": "public_chat",
+                    },
+                    ratelimit=False,
+                )
+                room_id = info["room_id"]
+
+                directory_handler = self.hs.get_handlers().directory_handler
+                room_alias = RoomAlias.from_string(room_identifier)
+                yield directory_handler.create_association(
+                    user_id=requester.user.to_string(),
+                    room_alias=room_alias,
+                    room_id=room_id,
+                    servers=[self.hs.hostname],
+                )
+
+                yield directory_handler.send_room_alias_update_event(
+                    requester, requester.user.to_string(), room_id
+                )
+
         room_id = None
         room_member_handler = self.hs.get_room_member_handler()
         if RoomID.is_valid(room_identifier):

synapse/storage/directory.py

@@ -90,7 +90,7 @@ def get_aliases_for_room(self, room_id):
 class DirectoryStore(DirectoryWorkerStore):
     @defer.inlineCallbacks
     def create_room_alias_association(self, room_alias, room_id, servers, creator=None):
-        """ Creates an associatin between  a room alias and room_id/servers
+        """ Creates an association between a room alias and room_id/servers
 
         Args:
             room_alias (RoomAlias)