Allow modules to create and send events into rooms (#8479)

This PR allows Synapse modules making use of the `ModuleApi` to create and send non-membership events into a room. This can useful to have modules send messages, or change power levels in a room etc. Note that they must send event through a user that's already in the room.

The non-membership event limitation is currently arbitrary, as it's another chunk of work and not necessary at the moment.

2 files changed, 122 insertions, 1 deletions

diff --git a/tests/module_api/test_api.py b/tests/module_api/test_api.py
index 7c790bee7d..9b573ac24d 100644
--- a/tests/module_api/test_api.py
+++ b/tests/module_api/test_api.py
@@ -12,9 +12,12 @@
 # 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.
+from mock import Mock
 
+from synapse.events import EventBase
 from synapse.rest import admin
 from synapse.rest.client.v1 import login, room
+from synapse.types import create_requester
 
 from tests.unittest import HomeserverTestCase
 
@@ -29,6 +32,7 @@ class ModuleApiTestCase(HomeserverTestCase):
     def prepare(self, reactor, clock, homeserver):
         self.store = homeserver.get_datastore()
         self.module_api = homeserver.get_module_api()
+        self.event_creation_handler = homeserver.get_event_creation_handler()
 
     def test_can_register_user(self):
         """Tests that an external module can register a user"""
@@ -60,6 +64,97 @@ class ModuleApiTestCase(HomeserverTestCase):
         displayname = self.get_success(self.store.get_profile_displayname("bob"))
         self.assertEqual(displayname, "Bobberino")
 
+    def test_sending_events_into_room(self):
+        """Tests that a module can send events into a room"""
+        # Mock out create_and_send_nonmember_event to check whether events are being sent
+        self.event_creation_handler.create_and_send_nonmember_event = Mock(
+            spec=[],
+            side_effect=self.event_creation_handler.create_and_send_nonmember_event,
+        )
+
+        # Create a user and room to play with
+        user_id = self.register_user("summer", "monkey")
+        tok = self.login("summer", "monkey")
+        room_id = self.helper.create_room_as(user_id, tok=tok)
+
+        # Create and send a non-state event
+        content = {"body": "I am a puppet", "msgtype": "m.text"}
+        event_dict = {
+            "room_id": room_id,
+            "type": "m.room.message",
+            "content": content,
+            "sender": user_id,
+        }
+        event = self.get_success(
+            self.module_api.create_and_send_event_into_room(event_dict)
+        )  # type: EventBase
+        self.assertEqual(event.sender, user_id)
+        self.assertEqual(event.type, "m.room.message")
+        self.assertEqual(event.room_id, room_id)
+        self.assertFalse(hasattr(event, "state_key"))
+        self.assertDictEqual(event.content, content)
+
+        # Check that the event was sent
+        self.event_creation_handler.create_and_send_nonmember_event.assert_called_with(
+            create_requester(user_id),
+            event_dict,
+            ratelimit=False,
+            ignore_shadow_ban=True,
+        )
+
+        # Create and send a state event
+        content = {
+            "events_default": 0,
+            "users": {user_id: 100},
+            "state_default": 50,
+            "users_default": 0,
+            "events": {"test.event.type": 25},
+        }
+        event_dict = {
+            "room_id": room_id,
+            "type": "m.room.power_levels",
+            "content": content,
+            "sender": user_id,
+            "state_key": "",
+        }
+        event = self.get_success(
+            self.module_api.create_and_send_event_into_room(event_dict)
+        )  # type: EventBase
+        self.assertEqual(event.sender, user_id)
+        self.assertEqual(event.type, "m.room.power_levels")
+        self.assertEqual(event.room_id, room_id)
+        self.assertEqual(event.state_key, "")
+        self.assertDictEqual(event.content, content)
+
+        # Check that the event was sent
+        self.event_creation_handler.create_and_send_nonmember_event.assert_called_with(
+            create_requester(user_id),
+            {
+                "type": "m.room.power_levels",
+                "content": content,
+                "room_id": room_id,
+                "sender": user_id,
+                "state_key": "",
+            },
+            ratelimit=False,
+            ignore_shadow_ban=True,
+        )
+
+        # Check that we can't send membership events
+        content = {
+            "membership": "leave",
+        }
+        event_dict = {
+            "room_id": room_id,
+            "type": "m.room.member",
+            "content": content,
+            "sender": user_id,
+            "state_key": user_id,
+        }
+        self.get_failure(
+            self.module_api.create_and_send_event_into_room(event_dict), Exception
+        )
+
     def test_public_rooms(self):
         """Tests that a room can be added and removed from the public rooms list,
         as well as have its public rooms directory state queried.
diff --git a/tests/rest/client/test_third_party_rules.py b/tests/rest/client/test_third_party_rules.py
index c12518c931..d03e121664 100644
--- a/tests/rest/client/test_third_party_rules.py
+++ b/tests/rest/client/test_third_party_rules.py
@@ -13,10 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import threading
+from typing import Dict
 
 from mock import Mock
 
 from synapse.events import EventBase
+from synapse.module_api import ModuleApi
 from synapse.rest import admin
 from synapse.rest.client.v1 import login, room
 from synapse.types import Requester, StateMap
@@ -27,10 +29,11 @@ thread_local = threading.local()
 
 
 class ThirdPartyRulesTestModule:
-    def __init__(self, config, module_api):
+    def __init__(self, config: Dict, module_api: ModuleApi):
         # keep a record of the "current" rules module, so that the test can patch
         # it if desired.
         thread_local.rules_module = self
+        self.module_api = module_api
 
     async def on_create_room(
         self, requester: Requester, config: dict, is_requester_admin: bool
@@ -142,3 +145,26 @@ class ThirdPartyRulesTestCase(unittest.HomeserverTestCase):
         self.assertEqual(channel.result["code"], b"200", channel.result)
         ev = channel.json_body
         self.assertEqual(ev["content"]["x"], "y")
+
+    def test_send_event(self):
+        """Tests that the module can send an event into a room via the module api"""
+        content = {
+            "msgtype": "m.text",
+            "body": "Hello!",
+        }
+        event_dict = {
+            "room_id": self.room_id,
+            "type": "m.room.message",
+            "content": content,
+            "sender": self.user_id,
+        }
+        event = self.get_success(
+            current_rules_module().module_api.create_and_send_event_into_room(
+                event_dict
+            )
+        )  # type: EventBase
+
+        self.assertEquals(event.sender, self.user_id)
+        self.assertEquals(event.room_id, self.room_id)
+        self.assertEquals(event.type, "m.room.message")
+        self.assertEquals(event.content, content)