diff --git a/changelog.d/18195.feature b/changelog.d/18195.feature
new file mode 100644
index 0000000000..7f7903bd71
--- /dev/null
+++ b/changelog.d/18195.feature
@@ -0,0 +1 @@
+Add plain-text handling for rich-text topics as per [MSC3765](https://github.com/matrix-org/matrix-spec-proposals/pull/3765).
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 386375d64b..d24b094d45 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -1296,7 +1296,7 @@ class RoomCreationHandler:
topic = room_config["topic"]
topic_event, topic_context = await create_event(
EventTypes.Topic,
- {"topic": topic},
+ {"topic": topic, "m.topic": {"m.text": [{"body": topic}]}},
True,
)
events_to_send.append((topic_event, topic_context))
diff --git a/synapse/handlers/stats.py b/synapse/handlers/stats.py
index 8f90c17060..aa33260809 100644
--- a/synapse/handlers/stats.py
+++ b/synapse/handlers/stats.py
@@ -36,6 +36,7 @@ from synapse.metrics import event_processing_positions
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.storage.databases.main.state_deltas import StateDelta
from synapse.types import JsonDict
+from synapse.util.events import get_plain_text_topic_from_event_content
if TYPE_CHECKING:
from synapse.server import HomeServer
@@ -299,7 +300,9 @@ class StatsHandler:
elif delta.event_type == EventTypes.Name:
room_state["name"] = event_content.get("name")
elif delta.event_type == EventTypes.Topic:
- room_state["topic"] = event_content.get("topic")
+ room_state["topic"] = get_plain_text_topic_from_event_content(
+ event_content
+ )
elif delta.event_type == EventTypes.RoomAvatar:
room_state["avatar"] = event_content.get("url")
elif delta.event_type == EventTypes.CanonicalAlias:
diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index 26fbc1a483..b043df68f5 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -78,6 +78,7 @@ from synapse.types import (
from synapse.types.handlers import SLIDING_SYNC_DEFAULT_BUMP_EVENT_TYPES
from synapse.types.state import StateFilter
from synapse.util import json_encoder
+from synapse.util.events import get_plain_text_topic_from_event_content
from synapse.util.iterutils import batch_iter, sorted_topologically
from synapse.util.stringutils import non_null_str_or_none
@@ -3102,7 +3103,10 @@ class PersistEventsStore:
def _store_room_topic_txn(self, txn: LoggingTransaction, event: EventBase) -> None:
if isinstance(event.content.get("topic"), str):
self.store_event_search_txn(
- txn, event, "content.topic", event.content["topic"]
+ txn,
+ event,
+ "content.topic",
+ get_plain_text_topic_from_event_content(event.content) or "",
)
def _store_room_name_txn(self, txn: LoggingTransaction, event: EventBase) -> None:
diff --git a/synapse/storage/databases/main/stats.py b/synapse/storage/databases/main/stats.py
index 79c49e7fd9..74830b7129 100644
--- a/synapse/storage/databases/main/stats.py
+++ b/synapse/storage/databases/main/stats.py
@@ -48,6 +48,7 @@ from synapse.storage.databases.main.events_worker import InvalidEventError
from synapse.storage.databases.main.state_deltas import StateDeltasStore
from synapse.types import JsonDict
from synapse.util.caches.descriptors import cached
+from synapse.util.events import get_plain_text_topic_from_event_content
if TYPE_CHECKING:
from synapse.server import HomeServer
@@ -611,7 +612,9 @@ class StatsStore(StateDeltasStore):
elif event.type == EventTypes.Name:
room_state["name"] = event.content.get("name")
elif event.type == EventTypes.Topic:
- room_state["topic"] = event.content.get("topic")
+ room_state["topic"] = get_plain_text_topic_from_event_content(
+ event.content
+ )
elif event.type == EventTypes.RoomAvatar:
room_state["avatar"] = event.content.get("url")
elif event.type == EventTypes.CanonicalAlias:
diff --git a/synapse/util/events.py b/synapse/util/events.py
index ad9b946578..1e8f53c4e9 100644
--- a/synapse/util/events.py
+++ b/synapse/util/events.py
@@ -13,6 +13,9 @@
#
#
+from typing import Optional
+
+from synapse.types import JsonDict
from synapse.util.stringutils import random_string
@@ -27,3 +30,31 @@ def generate_fake_event_id() -> str:
A string intended to look like an event ID, but with no actual meaning.
"""
return "$" + random_string(43)
+
+
+def get_plain_text_topic_from_event_content(content: JsonDict) -> Optional[str]:
+ """
+ Given the content of an m.room.topic event returns the plain text topic
+ representation if any exists.
+
+ Returns:
+ A string representing the plain text topic.
+ """
+ topic = content.get("topic")
+
+ m_topic = content.get("m.topic")
+ if not m_topic:
+ return topic
+
+ m_text = m_topic.get("m.text")
+ if not m_text:
+ return topic
+
+ representation = next(
+ (r for r in m_text if "mimetype" not in r or r["mimetype"] == "text/plain"),
+ None,
+ )
+ if not representation or "body" not in representation:
+ return topic
+
+ return representation["body"]
diff --git a/tests/rest/client/test_rooms.py b/tests/rest/client/test_rooms.py
index 6c93ead3b8..3ba7584c65 100644
--- a/tests/rest/client/test_rooms.py
+++ b/tests/rest/client/test_rooms.py
@@ -757,6 +757,59 @@ class RoomsCreateTestCase(RoomBase):
assert channel.resource_usage is not None
self.assertEqual(37, channel.resource_usage.db_txn_count)
+ def test_post_room_topic(self) -> None:
+ # POST with topic key, expect new room id
+ channel = self.make_request("POST", "/createRoom", b'{"topic":"shenanigans"}')
+ self.assertEqual(HTTPStatus.OK, channel.code)
+ self.assertTrue("room_id" in channel.json_body)
+ room_id = channel.json_body["room_id"]
+
+ # GET topic event, expect content from topic key
+ channel = self.make_request("GET", "/rooms/%s/state/m.room.topic" % (room_id,))
+ self.assertEqual(HTTPStatus.OK, channel.code)
+ self.assertEqual(
+ {"topic": "shenanigans", "m.topic": {"m.text": [{"body": "shenanigans"}]}},
+ channel.json_body,
+ )
+
+ def test_post_room_topic_initial_state(self) -> None:
+ # POST with m.room.topic in initial state, expect new room id
+ channel = self.make_request(
+ "POST",
+ "/createRoom",
+ b'{"initial_state":[{"type": "m.room.topic", "content": {"topic": "foobar"}}]}',
+ )
+ self.assertEqual(HTTPStatus.OK, channel.code)
+ self.assertTrue("room_id" in channel.json_body)
+ room_id = channel.json_body["room_id"]
+
+ # GET topic event, expect content from initial state
+ channel = self.make_request("GET", "/rooms/%s/state/m.room.topic" % (room_id,))
+ self.assertEqual(HTTPStatus.OK, channel.code)
+ self.assertEqual(
+ {"topic": "foobar"},
+ channel.json_body,
+ )
+
+ def test_post_room_topic_overriding_initial_state(self) -> None:
+ # POST with m.room.topic in initial state and topic key, expect new room id
+ channel = self.make_request(
+ "POST",
+ "/createRoom",
+ b'{"initial_state":[{"type": "m.room.topic", "content": {"topic": "foobar"}}], "topic":"shenanigans"}',
+ )
+ self.assertEqual(HTTPStatus.OK, channel.code)
+ self.assertTrue("room_id" in channel.json_body)
+ room_id = channel.json_body["room_id"]
+
+ # GET topic event, expect content from topic key
+ channel = self.make_request("GET", "/rooms/%s/state/m.room.topic" % (room_id,))
+ self.assertEqual(HTTPStatus.OK, channel.code)
+ self.assertEqual(
+ {"topic": "shenanigans", "m.topic": {"m.text": [{"body": "shenanigans"}]}},
+ channel.json_body,
+ )
+
def test_post_room_visibility_key(self) -> None:
# POST with visibility config key, expect new room id
channel = self.make_request("POST", "/createRoom", b'{"visibility":"private"}')
diff --git a/tests/util/test_events.py b/tests/util/test_events.py
new file mode 100644
index 0000000000..f6c73261d4
--- /dev/null
+++ b/tests/util/test_events.py
@@ -0,0 +1,97 @@
+#
+# This file is licensed under the Affero General Public License (AGPL) version 3.
+#
+# Copyright (C) 2025 New Vector, Ltd
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# See the GNU Affero General Public License for more details:
+# <https://www.gnu.org/licenses/agpl-3.0.html>.
+#
+# Originally licensed under the Apache License, Version 2.0:
+# <http://www.apache.org/licenses/LICENSE-2.0>.
+#
+# [This file includes modifications made by New Vector Limited]
+#
+#
+
+
+from synapse.util.events import get_plain_text_topic_from_event_content
+
+from tests import unittest
+
+
+class EventsTestCase(unittest.TestCase):
+ def test_get_plain_text_topic_no_topic(self) -> None:
+ # No legacy or rich topic, expect None
+ topic = get_plain_text_topic_from_event_content({})
+ self.assertEqual(None, topic)
+
+ def test_get_plain_text_topic_no_rich_topic(self) -> None:
+ # Only legacy topic, expect legacy topic
+ topic = get_plain_text_topic_from_event_content({"topic": "shenanigans"})
+ self.assertEqual("shenanigans", topic)
+
+ def test_get_plain_text_topic_rich_topic_without_representations(self) -> None:
+ # Legacy topic and rich topic without representations, expect legacy topic
+ topic = get_plain_text_topic_from_event_content(
+ {"topic": "shenanigans", "m.topic": {"m.text": []}}
+ )
+ self.assertEqual("shenanigans", topic)
+
+ def test_get_plain_text_topic_rich_topic_without_plain_text_representation(
+ self,
+ ) -> None:
+ # Legacy topic and rich topic without plain text representation, expect legacy topic
+ topic = get_plain_text_topic_from_event_content(
+ {
+ "topic": "shenanigans",
+ "m.topic": {
+ "m.text": [
+ {"mimetype": "text/html", "body": "<strong>foobar</strong>"}
+ ]
+ },
+ }
+ )
+ self.assertEqual("shenanigans", topic)
+
+ def test_get_plain_text_topic_rich_topic_with_plain_text_representation(
+ self,
+ ) -> None:
+ # Legacy topic and rich topic with plain text representation, expect plain text representation
+ topic = get_plain_text_topic_from_event_content(
+ {
+ "topic": "shenanigans",
+ "m.topic": {"m.text": [{"mimetype": "text/plain", "body": "foobar"}]},
+ }
+ )
+ self.assertEqual("foobar", topic)
+
+ def test_get_plain_text_topic_rich_topic_with_implicit_plain_text_representation(
+ self,
+ ) -> None:
+ # Legacy topic and rich topic with implicit plain text representation, expect plain text representation
+ topic = get_plain_text_topic_from_event_content(
+ {"topic": "shenanigans", "m.topic": {"m.text": [{"body": "foobar"}]}}
+ )
+ self.assertEqual("foobar", topic)
+
+ def test_get_plain_text_topic_rich_topic_with_plain_text_and_other_representation(
+ self,
+ ) -> None:
+ # Legacy topic and rich topic with plain text representation, expect plain text representation
+ topic = get_plain_text_topic_from_event_content(
+ {
+ "topic": "shenanigans",
+ "m.topic": {
+ "m.text": [
+ {"mimetype": "text/html", "body": "<strong>foobar</strong>"},
+ {"mimetype": "text/plain", "body": "foobar"},
+ ]
+ },
+ }
+ )
+ self.assertEqual("foobar", topic)