Additional configuration options for auto-join rooms (#7763)

3 files changed, 273 insertions, 67 deletions

diff --git a/synapse/config/registration.py b/synapse/config/registration.py
index fecced2d57..6badf4e75d 100644
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -18,8 +18,9 @@ from distutils.util import strtobool
 
 import pkg_resources
 
+from synapse.api.constants import RoomCreationPreset
 from synapse.config._base import Config, ConfigError
-from synapse.types import RoomAlias
+from synapse.types import RoomAlias, UserID
 from synapse.util.stringutils import random_string_with_symbols
 
 
@@ -127,7 +128,50 @@ class RegistrationConfig(Config):
         for room_alias in self.auto_join_rooms:
             if not RoomAlias.is_valid(room_alias):
                 raise ConfigError("Invalid auto_join_rooms entry %s" % (room_alias,))
+
+        # Options for creating auto-join rooms if they do not exist yet.
         self.autocreate_auto_join_rooms = config.get("autocreate_auto_join_rooms", True)
+        self.autocreate_auto_join_rooms_federated = config.get(
+            "autocreate_auto_join_rooms_federated", True
+        )
+        self.autocreate_auto_join_room_preset = (
+            config.get("autocreate_auto_join_room_preset")
+            or RoomCreationPreset.PUBLIC_CHAT
+        )
+        self.auto_join_room_requires_invite = self.autocreate_auto_join_room_preset in {
+            RoomCreationPreset.PRIVATE_CHAT,
+            RoomCreationPreset.TRUSTED_PRIVATE_CHAT,
+        }
+
+        # Pull the creater/inviter from the configuration, this gets used to
+        # send invites for invite-only rooms.
+        mxid_localpart = config.get("auto_join_mxid_localpart")
+        self.auto_join_user_id = None
+        if mxid_localpart:
+            # Convert the localpart to a full mxid.
+            self.auto_join_user_id = UserID(
+                mxid_localpart, self.server_name
+            ).to_string()
+
+        if self.autocreate_auto_join_rooms:
+            # Ensure the preset is a known value.
+            if self.autocreate_auto_join_room_preset not in {
+                RoomCreationPreset.PUBLIC_CHAT,
+                RoomCreationPreset.PRIVATE_CHAT,
+                RoomCreationPreset.TRUSTED_PRIVATE_CHAT,
+            }:
+                raise ConfigError("Invalid value for autocreate_auto_join_room_preset")
+            # If the preset requires invitations to be sent, ensure there's a
+            # configured user to send them from.
+            if self.auto_join_room_requires_invite:
+                if not mxid_localpart:
+                    raise ConfigError(
+                        "The configuration option `auto_join_mxid_localpart` is required if "
+                        "`autocreate_auto_join_room_preset` is set to private_chat or trusted_private_chat, such that "
+                        "Synapse knows who to send invitations from. Please "
+                        "configure `auto_join_mxid_localpart`."
+                    )
+
         self.auto_join_rooms_for_guests = config.get("auto_join_rooms_for_guests", True)
 
         self.enable_set_displayname = config.get("enable_set_displayname", True)
@@ -357,7 +401,11 @@ class RegistrationConfig(Config):
         #enable_3pid_changes: false
 
         # Users who register on this homeserver will automatically be joined
-        # to these rooms
+        # to these rooms.
+        #
+        # By default, any room aliases included in this list will be created
+        # as a publicly joinable room when the first user registers for the
+        # homeserver. This behaviour can be customised with the settings below.
         #
         #auto_join_rooms:
         #  - "#example:example.com"
@@ -365,10 +413,62 @@ class RegistrationConfig(Config):
         # Where auto_join_rooms are specified, setting this flag ensures that the
         # the rooms exist by creating them when the first user on the
         # homeserver registers.
+        #
+        # By default the auto-created rooms are publicly joinable from any federated
+        # server. Use the autocreate_auto_join_rooms_federated and
+        # autocreate_auto_join_room_preset settings below to customise this behaviour.
+        #
         # Setting to false means that if the rooms are not manually created,
         # users cannot be auto-joined since they do not exist.
         #
-        #autocreate_auto_join_rooms: true
+        # Defaults to true. Uncomment the following line to disable automatically
+        # creating auto-join rooms.
+        #
+        #autocreate_auto_join_rooms: false
+
+        # Whether the auto_join_rooms that are auto-created are available via
+        # federation. Only has an effect if autocreate_auto_join_rooms is true.
+        #
+        # Note that whether a room is federated cannot be modified after
+        # creation.
+        #
+        # Defaults to true: the room will be joinable from other servers.
+        # Uncomment the following to prevent users from other homeservers from
+        # joining these rooms.
+        #
+        #autocreate_auto_join_rooms_federated: false
+
+        # The room preset to use when auto-creating one of auto_join_rooms. Only has an
+        # effect if autocreate_auto_join_rooms is true.
+        #
+        # This can be one of "public_chat", "private_chat", or "trusted_private_chat".
+        # If a value of "private_chat" or "trusted_private_chat" is used then
+        # auto_join_mxid_localpart must also be configured.
+        #
+        # Defaults to "public_chat", meaning that the room is joinable by anyone, including
+        # federated servers if autocreate_auto_join_rooms_federated is true (the default).
+        # Uncomment the following to require an invitation to join these rooms.
+        #
+        #autocreate_auto_join_room_preset: private_chat
+
+        # The local part of the user id which is used to create auto_join_rooms if
+        # autocreate_auto_join_rooms is true. If this is not provided then the
+        # initial user account that registers will be used to create the rooms.
+        #
+        # The user id is also used to invite new users to any auto-join rooms which
+        # are set to invite-only.
+        #
+        # It *must* be configured if autocreate_auto_join_room_preset is set to
+        # "private_chat" or "trusted_private_chat".
+        #
+        # Note that this must be specified in order for new users to be correctly
+        # invited to any auto-join rooms which have been set to invite-only (either
+        # at the time of creation or subsequently).
+        #
+        # Note that, if the room already exists, this user must be joined and
+        # have the appropriate permissions to invite new members.
+        #
+        #auto_join_mxid_localpart: system
 
         # When auto_join_rooms is specified, setting this flag to false prevents
         # guest accounts from being automatically joined to the rooms.
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 51979ea43e..78c3772ac1 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -17,7 +17,7 @@
 import logging
 
 from synapse import types
-from synapse.api.constants import MAX_USERID_LENGTH, LoginType
+from synapse.api.constants import MAX_USERID_LENGTH, EventTypes, JoinRules, LoginType
 from synapse.api.errors import AuthError, Codes, ConsentNotGivenError, SynapseError
 from synapse.config.server import is_threepid_reserved
 from synapse.http.servlet import assert_params_in_dict
@@ -26,7 +26,8 @@ from synapse.replication.http.register import (
     ReplicationPostRegisterActionsServlet,
     ReplicationRegisterServlet,
 )
-from synapse.types import RoomAlias, RoomID, UserID, create_requester
+from synapse.storage.state import StateFilter
+from synapse.types import RoomAlias, UserID, create_requester
 from synapse.util.async_helpers import Linearizer
 
 from ._base import BaseHandler
@@ -270,51 +271,157 @@ class RegistrationHandler(BaseHandler):
 
         return user_id
 
-    async def _auto_join_rooms(self, user_id):
-        """Automatically joins users to auto join rooms - creating the room in the first place
-        if the user is the first to be created.
+    async def _create_and_join_rooms(self, user_id: str):
+        """
+        Create the auto-join rooms and join or invite the user to them.
+
+        This should only be called when the first "real" user registers.
 
         Args:
-            user_id(str): The user to join
+            user_id: The user to join
         """
-        # auto-join the user to any rooms we're supposed to dump them into
-        fake_requester = create_requester(user_id)
+        # Getting the handlers during init gives a dependency loop.
+        room_creation_handler = self.hs.get_room_creation_handler()
+        room_member_handler = self.hs.get_room_member_handler()
 
-        # try to create the room if we're the first real user on the server. Note
-        # that an auto-generated support or bot user is not a real user and will never be
-        # the user to create the room
-        should_auto_create_rooms = False
-        is_real_user = await self.store.is_real_user(user_id)
-        if self.hs.config.autocreate_auto_join_rooms and is_real_user:
-            count = await self.store.count_real_users()
-            should_auto_create_rooms = count == 1
-        for r in self.hs.config.auto_join_rooms:
+        # Generate a stub for how the rooms will be configured.
+        stub_config = {
+            "preset": self.hs.config.registration.autocreate_auto_join_room_preset,
+        }
+
+        # If the configuration providers a user ID to create rooms with, use
+        # that instead of the first user registered.
+        requires_join = False
+        if self.hs.config.registration.auto_join_user_id:
+            fake_requester = create_requester(
+                self.hs.config.registration.auto_join_user_id
+            )
+
+            # If the room requires an invite, add the user to the list of invites.
+            if self.hs.config.registration.auto_join_room_requires_invite:
+                stub_config["invite"] = [user_id]
+
+            # If the room is being created by a different user, the first user
+            # registered needs to join it. Note that in the case of an invitation
+            # being necessary this will occur after the invite was sent.
+            requires_join = True
+        else:
+            fake_requester = create_requester(user_id)
+
+        # Choose whether to federate the new room.
+        if not self.hs.config.registration.autocreate_auto_join_rooms_federated:
+            stub_config["creation_content"] = {"m.federate": False}
+
+        for r in self.hs.config.registration.auto_join_rooms:
             logger.info("Auto-joining %s to %s", user_id, r)
+
             try:
-                if should_auto_create_rooms:
-                    room_alias = RoomAlias.from_string(r)
-                    if self.hs.hostname != room_alias.domain:
-                        logger.warning(
-                            "Cannot create room alias %s, "
-                            "it does not match server domain",
-                            r,
-                        )
-                    else:
-                        # create room expects the localpart of the room alias
-                        room_alias_localpart = room_alias.localpart
-
-                        # getting the RoomCreationHandler during init gives a dependency
-                        # loop
-                        await self.hs.get_room_creation_handler().create_room(
-                            fake_requester,
-                            config={
-                                "preset": "public_chat",
-                                "room_alias_name": room_alias_localpart,
-                            },
+                room_alias = RoomAlias.from_string(r)
+
+                if self.hs.hostname != room_alias.domain:
+                    logger.warning(
+                        "Cannot create room alias %s, "
+                        "it does not match server domain",
+                        r,
+                    )
+                else:
+                    # A shallow copy is OK here since the only key that is
+                    # modified is room_alias_name.
+                    config = stub_config.copy()
+                    # create room expects the localpart of the room alias
+                    config["room_alias_name"] = room_alias.localpart
+
+                    info, _ = await room_creation_handler.create_room(
+                        fake_requester, config=config, ratelimit=False,
+                    )
+
+                    # If the room does not require an invite, but another user
+                    # created it, then ensure the first user joins it.
+                    if requires_join:
+                        await room_member_handler.update_membership(
+                            requester=create_requester(user_id),
+                            target=UserID.from_string(user_id),
+                            room_id=info["room_id"],
+                            # Since it was just created, there are no remote hosts.
+                            remote_room_hosts=[],
+                            action="join",
                             ratelimit=False,
                         )
+
+            except ConsentNotGivenError as e:
+                # Technically not necessary to pull out this error though
+                # moving away from bare excepts is a good thing to do.
+                logger.error("Failed to join new user to %r: %r", r, e)
+            except Exception as e:
+                logger.error("Failed to join new user to %r: %r", r, e)
+
+    async def _join_rooms(self, user_id: str):
+        """
+        Join or invite the user to the auto-join rooms.
+
+        Args:
+            user_id: The user to join
+        """
+        room_member_handler = self.hs.get_room_member_handler()
+
+        for r in self.hs.config.registration.auto_join_rooms:
+            logger.info("Auto-joining %s to %s", user_id, r)
+
+            try:
+                room_alias = RoomAlias.from_string(r)
+
+                if RoomAlias.is_valid(r):
+                    (
+                        room_id,
+                        remote_room_hosts,
+                    ) = await room_member_handler.lookup_room_alias(room_alias)
+                    room_id = room_id.to_string()
                 else:
-                    await self._join_user_to_room(fake_requester, r)
+                    raise SynapseError(
+                        400, "%s was not legal room ID or room alias" % (r,)
+                    )
+
+                # Calculate whether the room requires an invite or can be
+                # joined directly. Note that unless a join rule of public exists,
+                # it is treated as requiring an invite.
+                requires_invite = True
+
+                state = await self.store.get_filtered_current_state_ids(
+                    room_id, StateFilter.from_types([(EventTypes.JoinRules, "")])
+                )
+
+                event_id = state.get((EventTypes.JoinRules, ""))
+                if event_id:
+                    join_rules_event = await self.store.get_event(
+                        event_id, allow_none=True
+                    )
+                    if join_rules_event:
+                        join_rule = join_rules_event.content.get("join_rule", None)
+                        requires_invite = join_rule and join_rule != JoinRules.PUBLIC
+
+                # Send the invite, if necessary.
+                if requires_invite:
+                    await room_member_handler.update_membership(
+                        requester=create_requester(
+                            self.hs.config.registration.auto_join_user_id
+                        ),
+                        target=UserID.from_string(user_id),
+                        room_id=room_id,
+                        remote_room_hosts=remote_room_hosts,
+                        action="invite",
+                        ratelimit=False,
+                    )
+
+                # Send the join.
+                await room_member_handler.update_membership(
+                    requester=create_requester(user_id),
+                    target=UserID.from_string(user_id),
+                    room_id=room_id,
+                    remote_room_hosts=remote_room_hosts,
+                    action="join",
+                    ratelimit=False,
+                )
+
             except ConsentNotGivenError as e:
                 # Technically not necessary to pull out this error though
                 # moving away from bare excepts is a good thing to do.
@@ -322,6 +429,29 @@ class RegistrationHandler(BaseHandler):
             except Exception as e:
                 logger.error("Failed to join new user to %r: %r", r, e)
 
+    async def _auto_join_rooms(self, user_id: str):
+        """Automatically joins users to auto join rooms - creating the room in the first place
+        if the user is the first to be created.
+
+        Args:
+            user_id: The user to join
+        """
+        # auto-join the user to any rooms we're supposed to dump them into
+
+        # try to create the room if we're the first real user on the server. Note
+        # that an auto-generated support or bot user is not a real user and will never be
+        # the user to create the room
+        should_auto_create_rooms = False
+        is_real_user = await self.store.is_real_user(user_id)
+        if self.hs.config.registration.autocreate_auto_join_rooms and is_real_user:
+            count = await self.store.count_real_users()
+            should_auto_create_rooms = count == 1
+
+        if should_auto_create_rooms:
+            await self._create_and_join_rooms(user_id)
+        else:
+            await self._join_rooms(user_id)
+
     async def post_consent_actions(self, user_id):
         """A series of registration actions that can only be carried out once consent
         has been granted
@@ -392,30 +522,6 @@ class RegistrationHandler(BaseHandler):
         self._next_generated_user_id += 1
         return str(id)
 
-    async def _join_user_to_room(self, requester, room_identifier):
-        room_member_handler = self.hs.get_room_member_handler()
-        if RoomID.is_valid(room_identifier):
-            room_id = room_identifier
-        elif RoomAlias.is_valid(room_identifier):
-            room_alias = RoomAlias.from_string(room_identifier)
-            room_id, remote_room_hosts = await room_member_handler.lookup_room_alias(
-                room_alias
-            )
-            room_id = room_id.to_string()
-        else:
-            raise SynapseError(
-                400, "%s was not legal room ID or room alias" % (room_identifier,)
-            )
-
-        await room_member_handler.update_membership(
-            requester=requester,
-            target=requester.user,
-            room_id=room_id,
-            remote_room_hosts=remote_room_hosts,
-            action="join",
-            ratelimit=False,
-        )
-
     def check_registration_ratelimit(self, address):
         """A simple helper method to check whether the registration rate limit has been hit
         for a given IP address
diff --git a/synapse/rest/admin/rooms.py b/synapse/rest/admin/rooms.py
index 8173baef8f..e07c32118d 100644
--- a/synapse/rest/admin/rooms.py
+++ b/synapse/rest/admin/rooms.py
@@ -15,7 +15,7 @@
 import logging
 from typing import List, Optional
 
-from synapse.api.constants import EventTypes, JoinRules, Membership
+from synapse.api.constants import EventTypes, JoinRules, Membership, RoomCreationPreset
 from synapse.api.errors import Codes, NotFoundError, SynapseError
 from synapse.http.servlet import (
     RestServlet,
@@ -77,7 +77,7 @@ class ShutdownRoomRestServlet(RestServlet):
         info, stream_id = await self._room_creation_handler.create_room(
             room_creator_requester,
             config={
-                "preset": "public_chat",
+                "preset": RoomCreationPreset.PUBLIC_CHAT,
                 "name": room_name,
                 "power_level_content_override": {"users_default": -10},
             },