Add knocking support (#81)

Implement knocking as defined by https://github.com/matrix-org/matrix-doc/pull/2403

This is the base knocking stuff, taken from https://github.com/matrix-org/synapse/pull/6739
and does not include any public room directory changes.

While knocking hasn't merged yet on mainline due to waiting on getting Complement
into Synapse's CI, the code has been well-tested.

1 files changed, 13 insertions, 4 deletions

diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py

index 96843338ae..2fcba6abfc 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -1,7 +1,8 @@
 # -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 # Copyright 2017-2018 New Vector Ltd
-# Copyright 2019 The Matrix.org Foundation C.I.C.
+# Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+# Copyrignt 2020 Sorunome
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -40,6 +41,7 @@ from synapse.api.errors import (
 )
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersions
 from synapse.api.urls import ConsentURIBuilder
+from synapse.config.api import DEFAULT_ROOM_STATE_TYPES
 from synapse.events import EventBase
 from synapse.events.builder import EventBuilder
 from synapse.events.snapshot import EventContext
@@ -492,7 +494,7 @@ class EventCreationHandler:
             membership = builder.content.get("membership", None)
             target = UserID.from_string(builder.state_key)
 
-            if membership in {Membership.JOIN, Membership.INVITE}:
+            if membership in {Membership.JOIN, Membership.INVITE, Membership.KNOCK}:
                 # If event doesn't include a display name, add one.
                 profile = self.profile_handler
                 content = builder.content
@@ -918,8 +920,8 @@ class EventCreationHandler:
             room_version = await self.store.get_room_version_id(event.room_id)
 
         if event.internal_metadata.is_out_of_band_membership():
-            # the only sort of out-of-band-membership events we expect to see here
-            # are invite rejections we have generated ourselves.
+            # the only sort of out-of-band-membership events we expect to see here are
+            # invite rejections and rescinded knocks that we have generated ourselves.
             assert event.type == EventTypes.Member
             assert event.content["membership"] == Membership.LEAVE
         else:
@@ -1125,6 +1127,13 @@ class EventCreationHandler:
                     # TODO: Make sure the signatures actually are correct.
                     event.signatures.update(returned_invite.signatures)
 
+            if event.content["membership"] == Membership.KNOCK:
+                event.unsigned[
+                    "knock_room_state"
+                ] = await self.store.get_stripped_room_state_from_event_context(
+                    context, DEFAULT_ROOM_STATE_TYPES,
+                )
+
         if event.type == EventTypes.Redaction:
             original_event = await self.store.get_event(
                 event.redacts,