feat(widget): Rtc transports discovery for widgets

apps/web/package.json

@@ -82,7 +82,7 @@
         "maplibre-gl": "^5.0.0",
         "matrix-encrypt-attachment": "^1.0.3",
         "matrix-js-sdk": "github:matrix-org/matrix-js-sdk#develop",
-        "matrix-widget-api": "^1.16.1",
+        "matrix-widget-api": "^1.18.0",
         "memoize-one": "^6.0.0",
         "mime": "^4.0.4",
         "opus-recorder": "^8.0.3",

apps/web/src/stores/widgets/ElementWidgetDriver.ts

@@ -26,6 +26,7 @@ import {
     type IWidgetApiErrorResponseDataDetails,
     type ISearchUserDirectoryResult,
     type IGetMediaConfigResult,
+    type IRtcTransportsResult,
 } from "matrix-widget-api";
 import {
     ClientEvent,
@@ -39,7 +40,6 @@ import {
     type StateEvents,
     type TimelineEvents,
     type Room,
-    type SendDelayedEventRequestOpts,
     type MatrixClient,
 } from "matrix-js-sdk/src/matrix";
 import { logger } from "matrix-js-sdk/src/logger";
@@ -123,6 +123,7 @@ export class ElementWidgetDriver extends WidgetDriver {
             // This is a trusted Element Call widget that we control
             this.allowedCapabilities.add(MatrixCapabilities.AlwaysOnScreen);
             this.allowedCapabilities.add(MatrixCapabilities.MSC3846TurnServers);
+            this.allowedCapabilities.add(MatrixCapabilities.MSC4515RtcTransports);
             this.allowedCapabilities.add(`org.matrix.msc2762.timeline:${inRoomId}`);
             this.allowedCapabilities.add(MatrixCapabilities.MSC4157SendDelayedEvent);
             this.allowedCapabilities.add(MatrixCapabilities.MSC4157UpdateDelayedEvent);
@@ -405,27 +406,12 @@ export class ElementWidgetDriver extends WidgetDriver {
         return stickyEvents;
     }
 
-    private getSendDelayedEventOpts(delay: number | null, parentDelayId: string | null): SendDelayedEventRequestOpts {
-        if (delay !== null) {
-            return {
-                delay,
-                ...(parentDelayId !== null && { parent_delay_id: parentDelayId }),
-            };
-        } else if (parentDelayId !== null) {
-            return {
-                parent_delay_id: parentDelayId,
-            };
-        }
-        throw new Error("Must provide at least one of delay or parentDelayId");
-    }
-
     /**
      * @experimental Part of MSC4140 & MSC4157
      * @see {@link WidgetDriver#sendDelayedEvent}
      */
     public async sendDelayedEvent<K extends keyof StateEvents>(
-        delay: number | null,
-        parentDelayId: string | null,
+        delay: number,
         eventType: K,
         content: StateEvents[K],
         stateKey: string | null,
@@ -435,23 +421,21 @@ export class ElementWidgetDriver extends WidgetDriver {
      * @experimental Part of MSC4140 & MSC4157
      */
     public async sendDelayedEvent<K extends keyof TimelineEvents>(
-        delay: number | null,
-        parentDelayId: string | null,
+        delay: number,
         eventType: K,
         content: TimelineEvents[K],
         stateKey: null,
         targetRoomId: string | null,
     ): Promise<ISendDelayedEventDetails>;
     public async sendDelayedEvent(
-        delay: number | null,
-        parentDelayId: string | null,
+        delay: number,
         eventType: string,
         content: IContent,
         stateKey: string | null = null,
         targetRoomId: string | null = null,
     ): Promise<ISendDelayedEventDetails> {
         const { client, roomId } = this.getSendEventTarget(targetRoomId);
-        const delayOpts = this.getSendDelayedEventOpts(delay, parentDelayId);
+        const delayOpts = { delay };
 
         let r: SendDelayedEventResponse | null;
         if (stateKey !== null) {
@@ -485,20 +469,17 @@ export class ElementWidgetDriver extends WidgetDriver {
      * @see {@link WidgetDriver#sendStickyEvent}
      */
     public async sendDelayedStickyEvent(
-        delay: number | null,
-        parentDelayId: string | null,
+        delay: number,
         stickyDurationMs: number,
         eventType: string,
         content: unknown,
         targetRoomId?: string | null,
     ): Promise<ISendDelayedEventDetails> {
         const { client, roomId } = this.getSendEventTarget(targetRoomId);
-        const delayOpts = this.getSendDelayedEventOpts(delay, parentDelayId);
-
         const r = await client._unstable_sendStickyDelayedEvent(
             roomId,
             stickyDurationMs,
-            delayOpts,
+            { delay },
             null,
             eventType as keyof TimelineEvents,
             content as TimelineEvents[keyof TimelineEvents] & { msc4354_sticky_key: string },
@@ -765,6 +746,16 @@ export class ElementWidgetDriver extends WidgetDriver {
         }
     }
 
+    public async getRtcTransports(): Promise<IRtcTransportsResult> {
+        const client = MatrixClientPeg.safeGet();
+        // Delegate to the authenticated CS endpoint (MSC4143). Any error (e.g. the
+        // homeserver not supporting it) propagates and is turned into a widget error
+        // response by ClientWidgetApi. The js-sdk Transport and widget-api IRtcTransport
+        // types are structurally identical.
+        const transports = await client._unstable_getRTCTransports();
+        return { rtc_transports: transports };
+    }
+
     public async readEventRelations(
         eventId: string,
         roomId?: string,

apps/web/test/unit-tests/stores/widgets/ElementWidgetDriver-test.ts

@@ -14,6 +14,7 @@ import {
     type ITurnServer as IClientTurnServer,
     Direction,
     EventType,
+    MatrixError,
     MatrixEvent,
     MsgType,
     RelationType,
@@ -89,6 +90,7 @@ describe("ElementWidgetDriver", () => {
         const requestedCapabilities = new Set([
             "m.always_on_screen",
             "town.robin.msc3846.turn_servers",
+            "org.matrix.msc4515.rtc_transports",
             "org.matrix.msc2762.timeline:!1:example.org",
             "org.matrix.msc2762.send.event:org.matrix.msc4075.call.notify",
             "org.matrix.msc2762.send.event:org.matrix.msc4075.rtc.notification",
@@ -420,6 +422,31 @@ describe("ElementWidgetDriver", () => {
         });
     });
 
+    describe("getRtcTransports", () => {
+        let driver: WidgetDriver;
+
+        beforeEach(() => {
+            driver = mkDefaultDriver();
+        });
+
+        it("gets the RTC transports from the homeserver", async () => {
+            const transports = [{ type: "livekit", livekit_service_url: "https://livekit-jwt.example.com" }];
+            client._unstable_getRTCTransports.mockResolvedValue(transports);
+
+            await expect(driver.getRtcTransports()).resolves.toEqual({ rtc_transports: transports });
+
+            expect(client._unstable_getRTCTransports).toHaveBeenCalledWith();
+        });
+
+        it("propagates errors from the homeserver", async () => {
+            const error = new MatrixError({ errcode: "M_NOT_FOUND", error: "Not found" }, 404);
+
+            client._unstable_getRTCTransports.mockRejectedValue(error);
+
+            await expect(driver.getRtcTransports()).rejects.toBe(error);
+        });
+    });
+
     describe("readEventRelations", () => {
         let driver: WidgetDriver;
 
@@ -540,18 +567,12 @@ describe("ElementWidgetDriver", () => {
             driver = mkDefaultDriver();
         });
 
-        it("cannot send delayed events with missing arguments", async () => {
-            await expect(driver.sendDelayedEvent(null, null, EventType.RoomMessage, {})).rejects.toThrow(
-                "Must provide at least one of",
-            );
-        });
-
         it("sends delayed message events", async () => {
             client._unstable_sendDelayedEvent.mockResolvedValue({
                 delay_id: "id",
             });
 
-            await expect(driver.sendDelayedEvent(2000, null, EventType.RoomMessage, {})).resolves.toEqual({
+            await expect(driver.sendDelayedEvent(2000, EventType.RoomMessage, {})).resolves.toEqual({
                 roomId,
                 delayId: "id",
             });
@@ -565,31 +586,12 @@ describe("ElementWidgetDriver", () => {
             );
         });
 
-        it("sends child action delayed message events", async () => {
-            client._unstable_sendDelayedEvent.mockResolvedValue({
-                delay_id: "id-child",
-            });
-
-            await expect(driver.sendDelayedEvent(null, "id-parent", EventType.RoomMessage, {})).resolves.toEqual({
-                roomId,
-                delayId: "id-child",
-            });
-
-            expect(client._unstable_sendDelayedEvent).toHaveBeenCalledWith(
-                roomId,
-                { parent_delay_id: "id-parent" },
-                null,
-                EventType.RoomMessage,
-                {},
-            );
-        });
-
         it("sends delayed state events", async () => {
             client._unstable_sendDelayedStateEvent.mockResolvedValue({
                 delay_id: "id",
             });
 
-            await expect(driver.sendDelayedEvent(2000, null, EventType.RoomTopic, {}, "")).resolves.toEqual({
+            await expect(driver.sendDelayedEvent(2000, EventType.RoomTopic, {}, "")).resolves.toEqual({
                 roomId,
                 delayId: "id",
             });
@@ -602,25 +604,6 @@ describe("ElementWidgetDriver", () => {
                 "",
             );
         });
-
-        it("sends child action delayed state events", async () => {
-            client._unstable_sendDelayedStateEvent.mockResolvedValue({
-                delay_id: "id-child",
-            });
-
-            await expect(driver.sendDelayedEvent(null, "id-parent", EventType.RoomTopic, {}, "")).resolves.toEqual({
-                roomId,
-                delayId: "id-child",
-            });
-
-            expect(client._unstable_sendDelayedStateEvent).toHaveBeenCalledWith(
-                roomId,
-                { parent_delay_id: "id-parent" },
-                EventType.RoomTopic,
-                {},
-                "",
-            );
-        });
     });
 
     describe("updateDelayedEvent", () => {
@@ -743,7 +726,7 @@ describe("ElementWidgetDriver", () => {
                 delay_id: "id",
             });
 
-            await expect(driver.sendDelayedStickyEvent(1000, null, 2000, EventType.RoomMessage, {})).resolves.toEqual({
+            await expect(driver.sendDelayedStickyEvent(1000, 2000, EventType.RoomMessage, {})).resolves.toEqual({
                 roomId,
                 delayId: "id",
             });
@@ -757,27 +740,6 @@ describe("ElementWidgetDriver", () => {
                 {},
             );
         });
-        it("sends child action delayed sticky message events", async () => {
-            client._unstable_sendStickyDelayedEvent.mockResolvedValue({
-                delay_id: "id-child",
-            });
-
-            await expect(
-                driver.sendDelayedStickyEvent(null, "id-parent", 2000, EventType.RoomMessage, {}),
-            ).resolves.toEqual({
-                roomId,
-                delayId: "id-child",
-            });
-
-            expect(client._unstable_sendStickyDelayedEvent).toHaveBeenCalledWith(
-                roomId,
-                2000,
-                { parent_delay_id: "id-parent" },
-                null,
-                EventType.RoomMessage,
-                {},
-            );
-        });
     });
 
     describe("If the feature_dynamic_room_predecessors feature is not enabled", () => {

pnpm-workspace.yaml

@@ -136,7 +136,7 @@ overrides:
     "@types/react": "catalog:"
     "@types/react-dom": "catalog:"
     caniuse-lite: 1.0.30001806
-    matrix-widget-api: "^1.17.0"
+    matrix-widget-api: "^1.18.0"
     "@types/node": 25.9.3
     config-file-ts: 0.2.8-rc1
     node-abi: 4.33.0