Allow rejecting invites

This is done by using the same /leave flow as you would use if you had
already accepted the invite and wanted to leave.

2 files changed, 229 insertions, 82 deletions

diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 946ff97c7d..ae9d227586 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -565,7 +565,7 @@ class FederationHandler(BaseHandler):
 
     @log_function
     @defer.inlineCallbacks
-    def do_invite_join(self, target_hosts, room_id, joinee, content, snapshot):
+    def do_invite_join(self, target_hosts, room_id, joinee, content):
         """ Attempts to join the `joinee` to the room `room_id` via the
         server `target_host`.
 
@@ -581,50 +581,19 @@ class FederationHandler(BaseHandler):
 
         yield self.store.clean_room_for_join(room_id)
 
-        origin, pdu = yield self.replication_layer.make_join(
+        origin, event = yield self._make_and_verify_event(
             target_hosts,
             room_id,
             joinee,
+            "join",
             content
         )
 
-        logger.debug("Got response to make_join: %s", pdu)
-
-        event = pdu
-
-        # We should assert some things.
-        # FIXME: Do this in a nicer way
-        assert(event.type == EventTypes.Member)
-        assert(event.user_id == joinee)
-        assert(event.state_key == joinee)
-        assert(event.room_id == room_id)
-
-        event.internal_metadata.outlier = False
-
         self.room_queues[room_id] = []
-
-        builder = self.event_builder_factory.new(
-            unfreeze(event.get_pdu_json())
-        )
-
         handled_events = set()
 
         try:
-            builder.event_id = self.event_builder_factory.create_event_id()
-            builder.origin = self.hs.hostname
-            builder.content = content
-
-            if not hasattr(event, "signatures"):
-                builder.signatures = {}
-
-            add_hashes_and_signatures(
-                builder,
-                self.hs.hostname,
-                self.hs.config.signing_key[0],
-            )
-
-            new_event = builder.build()
-
+            new_event = self._sign_event(event)
             # Try the host we successfully got a response to /make_join/
             # request first.
             try:
@@ -632,11 +601,7 @@ class FederationHandler(BaseHandler):
                 target_hosts.insert(0, origin)
             except ValueError:
                 pass
-
-            ret = yield self.replication_layer.send_join(
-                target_hosts,
-                new_event
-            )
+            ret = yield self.replication_layer.send_join(target_hosts, new_event)
 
             origin = ret["origin"]
             state = ret["state"]
@@ -700,7 +665,7 @@ class FederationHandler(BaseHandler):
     @log_function
     def on_make_join_request(self, room_id, user_id, query):
         """ We've received a /make_join/ request, so we create a partial
-        join event for the room and return that. We don *not* persist or
+        join event for the room and return that. We do *not* persist or
         process it until the other server has signed it and sent it back.
         """
         event_content = {"membership": Membership.JOIN}
@@ -860,6 +825,168 @@ class FederationHandler(BaseHandler):
         defer.returnValue(event)
 
     @defer.inlineCallbacks
+    def do_remotely_reject_invite(self, target_hosts, room_id, user_id):
+        origin, event = yield self._make_and_verify_event(
+            target_hosts,
+            room_id,
+            user_id,
+            "leave",
+            {}
+        )
+        signed_event = self._sign_event(event)
+
+        # Try the host we successfully got a response to /make_join/
+        # request first.
+        try:
+            target_hosts.remove(origin)
+            target_hosts.insert(0, origin)
+        except ValueError:
+            pass
+
+        yield self.replication_layer.send_leave(
+            target_hosts,
+            signed_event
+        )
+        defer.returnValue(None)
+
+    @defer.inlineCallbacks
+    def _make_and_verify_event(self, target_hosts, room_id, user_id, membership, content):
+        origin, pdu = yield self.replication_layer.make_membership_event(
+            target_hosts,
+            room_id,
+            user_id,
+            membership,
+            content
+        )
+
+        logger.debug("Got response to make_%s: %s", membership, pdu)
+
+        event = pdu
+
+        # We should assert some things.
+        # FIXME: Do this in a nicer way
+        assert(event.type == EventTypes.Member)
+        assert(event.user_id == user_id)
+        assert(event.state_key == user_id)
+        assert(event.room_id == room_id)
+        defer.returnValue((origin, event))
+
+    def _sign_event(self, event):
+        event.internal_metadata.outlier = False
+
+        builder = self.event_builder_factory.new(
+            unfreeze(event.get_pdu_json())
+        )
+
+        builder.event_id = self.event_builder_factory.create_event_id()
+        builder.origin = self.hs.hostname
+
+        if not hasattr(event, "signatures"):
+            builder.signatures = {}
+
+        add_hashes_and_signatures(
+            builder,
+            self.hs.hostname,
+            self.hs.config.signing_key[0],
+        )
+
+        return builder.build()
+
+    @defer.inlineCallbacks
+    @log_function
+    def on_make_leave_request(self, room_id, user_id):
+        """ We've received a /make_leave/ request, so we create a partial
+        join event for the room and return that. We do *not* persist or
+        process it until the other server has signed it and sent it back.
+        """
+        builder = self.event_builder_factory.new({
+            "type": EventTypes.Member,
+            "content": {"membership": Membership.LEAVE},
+            "room_id": room_id,
+            "sender": user_id,
+            "state_key": user_id,
+        })
+
+        event, context = yield self._create_new_client_event(
+            builder=builder,
+        )
+
+        self.auth.check(event, auth_events=context.current_state)
+
+        defer.returnValue(event)
+
+    @defer.inlineCallbacks
+    @log_function
+    def on_send_leave_request(self, origin, pdu):
+        """ We have received a leave event for a room. Fully process it."""
+        event = pdu
+
+        logger.debug(
+            "on_send_leave_request: Got event: %s, signatures: %s",
+            event.event_id,
+            event.signatures,
+        )
+
+        event.internal_metadata.outlier = False
+
+        context, event_stream_id, max_stream_id = yield self._handle_new_event(
+            origin, event
+        )
+
+        logger.debug(
+            "on_send_leave_request: After _handle_new_event: %s, sigs: %s",
+            event.event_id,
+            event.signatures,
+        )
+
+        extra_users = []
+        if event.type == EventTypes.Member:
+            target_user_id = event.state_key
+            target_user = UserID.from_string(target_user_id)
+            extra_users.append(target_user)
+
+        with PreserveLoggingContext():
+            d = self.notifier.on_new_room_event(
+                event, event_stream_id, max_stream_id, extra_users=extra_users
+            )
+
+        def log_failure(f):
+            logger.warn(
+                "Failed to notify about %s: %s",
+                event.event_id, f.value
+            )
+
+        d.addErrback(log_failure)
+
+        new_pdu = event
+
+        destinations = set()
+
+        for k, s in context.current_state.items():
+            try:
+                if k[0] == EventTypes.Member:
+                    if s.content["membership"] == Membership.LEAVE:
+                        destinations.add(
+                            UserID.from_string(s.state_key).domain
+                        )
+            except:
+                logger.warn(
+                    "Failed to get destination from event %s", s.event_id
+                )
+
+        destinations.discard(origin)
+
+        logger.debug(
+            "on_send_leave_request: Sending event: %s, signatures: %s",
+            event.event_id,
+            event.signatures,
+        )
+
+        self.replication_layer.send_pdu(new_pdu, destinations)
+
+        defer.returnValue(None)
+
+    @defer.inlineCallbacks
     def get_state_for_pdu(self, origin, room_id, event_id, do_auth=True):
         yield run_on_reactor()
 
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 3f0cde56f0..60f9fa58b0 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -389,7 +389,22 @@ class RoomMemberHandler(BaseHandler):
         if event.membership == Membership.JOIN:
             yield self._do_join(event, context, do_auth=do_auth)
         else:
-            # This is not a JOIN, so we can handle it normally.
+            if event.membership == Membership.LEAVE:
+                is_host_in_room = yield self.is_host_in_room(room_id, context)
+                if not is_host_in_room:
+                    # Rejecting an invite, rather than leaving a joined room
+                    handler = self.hs.get_handlers().federation_handler
+                    inviter = yield self.get_inviter(event)
+                    if not inviter:
+                        # return the same error as join_room_alias does
+                        raise SynapseError(404, "No known servers")
+                    yield handler.do_remotely_reject_invite(
+                        [inviter.domain],
+                        room_id,
+                        event.user_id
+                    )
+                    defer.returnValue({"room_id": room_id})
+                    return
 
             # FIXME: This isn't idempotency.
             if prev_state and prev_state.membership == event.membership:
@@ -413,7 +428,7 @@ class RoomMemberHandler(BaseHandler):
         defer.returnValue({"room_id": room_id})
 
     @defer.inlineCallbacks
-    def join_room_alias(self, joinee, room_alias, do_auth=True, content={}):
+    def join_room_alias(self, joinee, room_alias, content={}):
         directory_handler = self.hs.get_handlers().directory_handler
         mapping = yield directory_handler.get_association(room_alias)
 
@@ -447,8 +462,6 @@ class RoomMemberHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def _do_join(self, event, context, room_hosts=None, do_auth=True):
-        joinee = UserID.from_string(event.state_key)
-        # room_id = RoomID.from_string(event.room_id, self.hs)
         room_id = event.room_id
 
         # XXX: We don't do an auth check if we are doing an invite
@@ -456,48 +469,18 @@ class RoomMemberHandler(BaseHandler):
         # that we are allowed to join when we decide whether or not we
         # need to do the invite/join dance.
 
-        is_host_in_room = yield self.auth.check_host_in_room(
-            event.room_id,
-            self.hs.hostname
-        )
-        if not is_host_in_room:
-            # is *anyone* in the room?
-            room_member_keys = [
-                v for (k, v) in context.current_state.keys() if (
-                    k == "m.room.member"
-                )
-            ]
-            if len(room_member_keys) == 0:
-                # has the room been created so we can join it?
-                create_event = context.current_state.get(("m.room.create", ""))
-                if create_event:
-                    is_host_in_room = True
-
+        is_host_in_room = yield self.is_host_in_room(room_id, context)
         if is_host_in_room:
             should_do_dance = False
         elif room_hosts:  # TODO: Shouldn't this be remote_room_host?
             should_do_dance = True
         else:
-            # TODO(markjh): get prev_state from snapshot
-            prev_state = yield self.store.get_room_member(
-                joinee.to_string(), room_id
-            )
-
-            if prev_state and prev_state.membership == Membership.INVITE:
-                inviter = UserID.from_string(prev_state.user_id)
-
-                should_do_dance = not self.hs.is_mine(inviter)
-                room_hosts = [inviter.domain]
-            elif "third_party_invite" in event.content:
-                if "sender" in event.content["third_party_invite"]:
-                    inviter = UserID.from_string(
-                        event.content["third_party_invite"]["sender"]
-                    )
-                    should_do_dance = not self.hs.is_mine(inviter)
-                    room_hosts = [inviter.domain]
-            else:
+            inviter = yield self.get_inviter(event)
+            if not inviter:
                 # return the same error as join_room_alias does
                 raise SynapseError(404, "No known servers")
+            should_do_dance = not self.hs.is_mine(inviter)
+            room_hosts = [inviter.domain]
 
         if should_do_dance:
             handler = self.hs.get_handlers().federation_handler
@@ -505,8 +488,7 @@ class RoomMemberHandler(BaseHandler):
                 room_hosts,
                 room_id,
                 event.user_id,
-                event.content,  # FIXME To get a non-frozen dict
-                context
+                event.content  # FIXME To get a non-frozen dict
             )
         else:
             logger.debug("Doing normal join")
@@ -524,6 +506,44 @@ class RoomMemberHandler(BaseHandler):
         )
 
     @defer.inlineCallbacks
+    def get_inviter(self, event):
+        # TODO(markjh): get prev_state from snapshot
+        prev_state = yield self.store.get_room_member(
+            event.user_id, event.room_id
+        )
+
+        if prev_state and prev_state.membership == Membership.INVITE:
+            defer.returnValue(UserID.from_string(prev_state.user_id))
+            return
+        elif "third_party_invite" in event.content:
+            if "sender" in event.content["third_party_invite"]:
+                inviter = UserID.from_string(
+                    event.content["third_party_invite"]["sender"]
+                )
+                defer.returnValue(inviter)
+        defer.returnValue(None)
+
+    @defer.inlineCallbacks
+    def is_host_in_room(self, room_id, context):
+        is_host_in_room = yield self.auth.check_host_in_room(
+            room_id,
+            self.hs.hostname
+        )
+        if not is_host_in_room:
+            # is *anyone* in the room?
+            room_member_keys = [
+                v for (k, v) in context.current_state.keys() if (
+                    k == "m.room.member"
+                )
+            ]
+            if len(room_member_keys) == 0:
+                # has the room been created so we can join it?
+                create_event = context.current_state.get(("m.room.create", ""))
+                if create_event:
+                    is_host_in_room = True
+        defer.returnValue(is_host_in_room)
+
+    @defer.inlineCallbacks
     def get_joined_rooms_for_user(self, user):
         """Returns a list of roomids that the user has any of the given
         membership states in."""