Basic initial support for room upgrades

Currently just creates a new, empty, room, and sends a tombstone in the old
room.

synapse/api/constants.py

@@ -61,6 +61,7 @@ class LoginType(object):
 class EventTypes(object):
     Member = "m.room.member"
     Create = "m.room.create"
+    Tombstone = "m.room.tombstone"
     JoinRules = "m.room.join_rules"
     PowerLevels = "m.room.power_levels"
     Aliases = "m.room.aliases"

synapse/handlers/room.py

@@ -36,6 +36,7 @@
 from synapse.storage.state import StateFilter
 from synapse.types import RoomAlias, RoomID, RoomStreamToken, StreamToken, UserID
 from synapse.util import stringutils
+from synapse.util.async_helpers import Linearizer
 from synapse.visibility import filter_events_for_client
 
 from ._base import BaseHandler
@@ -75,6 +76,124 @@ def __init__(self, hs):
         self.event_creation_handler = hs.get_event_creation_handler()
         self.room_member_handler = hs.get_room_member_handler()
 
+        # linearizer to stop two upgrades happening at once
+        self._upgrade_linearizer = Linearizer("room_upgrade_linearizer")
+
+    @defer.inlineCallbacks
+    def upgrade_room(self, requester, old_room_id, new_version):
+        """Replace a room with a new room with a different version
+
+        Args:
+            requester (synapse.types.Requester): the user requesting the upgrade
+            old_room_id (unicode): the id of the room to be replaced
+            new_version (unicode): the new room version to use
+
+        Returns:
+            Deferred[unicode]: the new room id
+        """
+        yield self.ratelimit(requester)
+
+        user_id = requester.user.to_string()
+
+        with (yield self._upgrade_linearizer.queue(old_room_id)):
+            # start by allocating a new room id
+            is_public = False  # XXX fixme
+            new_room_id = yield self._generate_room_id(
+                creator_id=user_id, is_public=is_public,
+            )
+
+            # we create and auth the tombstone event before properly creating the new
+            # room, to check our user has perms in the old room.
+            tombstone_event, tombstone_context = (
+                yield self.event_creation_handler.create_event(
+                    requester, {
+                        "type": EventTypes.Tombstone,
+                        "state_key": "",
+                        "room_id": old_room_id,
+                        "sender": user_id,
+                        "content": {
+                            "body": "This room has been replaced",
+                            "replacement_room": new_room_id,
+                        }
+                    },
+                    token_id=requester.access_token_id,
+                )
+            )
+            yield self.auth.check_from_context(tombstone_event, tombstone_context)
+
+            yield self.clone_exiting_room(
+                requester,
+                old_room_id=old_room_id,
+                new_room_id=new_room_id,
+                new_room_version=new_version,
+                tombstone_event_id=tombstone_event.event_id,
+            )
+
+            # now send the tombstone
+            yield self.event_creation_handler.send_nonmember_event(
+                requester, tombstone_event, tombstone_context,
+            )
+
+            # XXX send a power_levels in the old room, if possible
+
+        defer.returnValue(new_room_id)
+
+    @defer.inlineCallbacks
+    def clone_exiting_room(
+            self, requester, old_room_id, new_room_id, new_room_version,
+            tombstone_event_id,
+    ):
+        """Populate a new room based on an old room
+
+        Args:
+            requester (synapse.types.Requester): the user requesting the upgrade
+            old_room_id (unicode): the id of the room to be replaced
+            new_room_id (unicode): the id to give the new room (should already have been
+                created with _gemerate_room_id())
+            new_room_version (unicode): the new room version to use
+            tombstone_event_id (unicode|str): the ID of the tombstone event in the old
+                room.
+        Returns:
+            Deferred[None]
+        """
+        user_id = requester.user.to_string()
+
+        if not self.spam_checker.user_may_create_room(user_id):
+            raise SynapseError(403, "You are not permitted to create rooms")
+
+        # XXX check alias is free
+        # canonical_alias = None
+
+        # XXX create association in directory handler
+        # XXX preset
+
+        preset_config = RoomCreationPreset.PRIVATE_CHAT
+
+        creation_content = {
+            "room_version": new_room_version,
+            "predecessor": {
+                "room_id": old_room_id,
+                "event_id": tombstone_event_id,
+            }
+        }
+
+        initial_state = OrderedDict()
+
+        yield self._send_events_for_new_room(
+            requester,
+            new_room_id,
+            preset_config=preset_config,
+            invite_list=[],
+            initial_state=initial_state,
+            creation_content=creation_content,
+        )
+
+        # XXX name
+        # XXX topic
+        # XXX invites/joins
+        # XXX 3pid invites
+        # XXX directory_handler.send_room_alias_update_event
+
     @defer.inlineCallbacks
     def create_room(self, requester, config, ratelimit=True,
                     creator_join_profile=None):
@@ -416,6 +535,8 @@ def _generate_room_id(self, creator_id, is_public):
                     random_string,
                     self.hs.hostname,
                 ).to_string()
+                if isinstance(gen_room_id, bytes):
+                    gen_room_id = gen_room_id.decode('utf-8')
                 yield self.store.store_room(
                     room_id=gen_room_id,
                     room_creator_user_id=creator_id,

synapse/rest/__init__.py

@@ -47,6 +47,7 @@
     register,
     report_event,
     room_keys,
+    room_upgrade_rest_servlet,
     sendtodevice,
     sync,
     tags,
@@ -116,3 +117,4 @@ def register_servlets(client_resource, hs):
         sendtodevice.register_servlets(hs, client_resource)
         user_directory.register_servlets(hs, client_resource)
         groups.register_servlets(hs, client_resource)
+        room_upgrade_rest_servlet.register_servlets(hs, client_resource)

synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py

@@ -0,0 +1,78 @@
+# -*- coding: utf-8 -*-
+# Copyright 2016 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+
+from twisted.internet import defer
+
+from synapse.api.constants import KNOWN_ROOM_VERSIONS
+from synapse.api.errors import Codes, SynapseError
+from synapse.http.servlet import (
+    RestServlet,
+    assert_params_in_dict,
+    parse_json_object_from_request,
+)
+
+from ._base import client_v2_patterns
+
+logger = logging.getLogger(__name__)
+
+
+class RoomUpgradeRestServlet(RestServlet):
+    PATTERNS = client_v2_patterns(
+        # /rooms/$roomid/upgrade
+        "/rooms/(?P<room_id>[^/]*)/upgrade$",
+        v2_alpha=False,
+    )
+
+    def __init__(self, hs):
+        """
+
+        Args:
+            hs (synapse.server.HomeServer):
+        """
+        super(RoomUpgradeRestServlet, self).__init__()
+        self._hs = hs
+        self._room_creation_handler = hs.get_room_creation_handler()
+        self._auth = hs.get_auth()
+
+    @defer.inlineCallbacks
+    def on_POST(self, request, room_id):
+        requester = yield self._auth.get_user_by_req(request)
+
+        content = parse_json_object_from_request(request)
+        assert_params_in_dict(content, ("new_version", ))
+        new_version = content["new_version"]
+
+        if new_version not in KNOWN_ROOM_VERSIONS:
+            raise SynapseError(
+                400,
+                "Your homeserver does not support this room version",
+                Codes.UNSUPPORTED_ROOM_VERSION,
+            )
+
+        new_room_id = yield self._room_creation_handler.upgrade_room(
+            requester, room_id, new_version
+        )
+
+        ret = {
+            "replacement_room": new_room_id,
+        }
+
+        defer.returnValue((200, ret))
+
+
+def register_servlets(hs, http_server):
+    RoomUpgradeRestServlet(hs).register(http_server)

synapse/server.pyi

@@ -7,6 +7,9 @@ import synapse.handlers.auth
 import synapse.handlers.deactivate_account
 import synapse.handlers.device
 import synapse.handlers.e2e_keys
+import synapse.handlers.room
+import synapse.handlers.room_member
+import synapse.handlers.message
 import synapse.handlers.set_password
 import synapse.rest.media.v1.media_repository
 import synapse.server_notices.server_notices_manager
@@ -50,6 +53,9 @@ class HomeServer(object):
     def get_room_creation_handler(self) -> synapse.handlers.room.RoomCreationHandler:
         pass
 
+    def get_room_member_handler(self) -> synapse.handlers.room_member.RoomMemberHandler:
+        pass
+
     def get_event_creation_handler(self) -> synapse.handlers.message.EventCreationHandler:
         pass