Implement MSC3819: Allowing widgets to send/receive to-device messages (#57)

* Implement MSC3819: Allowing widgets to send/receive to-device messages

* Fix typo

Author: robintown

src/ClientWidgetApi.ts

@@ -49,6 +49,11 @@ import {
     ISendEventFromWidgetResponseData,
     ISendEventToWidgetRequestData,
 } from "./interfaces/SendEventAction";
+import {
+    ISendToDeviceFromWidgetActionRequest,
+    ISendToDeviceFromWidgetResponseData,
+    ISendToDeviceToWidgetRequestData,
+} from "./interfaces/SendToDeviceAction";
 import { EventDirection, WidgetEventCapability } from "./models/WidgetEventCapability";
 import { IRoomEvent } from "./interfaces/IRoomEvent";
 import {
@@ -143,23 +148,27 @@ export class ClientWidgetApi extends EventEmitter {
     }
 
     public canSendRoomEvent(eventType: string, msgtype: string = null): boolean {
-        return this.allowedEvents.some(e =>
-            e.matchesAsRoomEvent(eventType, msgtype) && e.direction === EventDirection.Send);
+        return this.allowedEvents.some(e => e.matchesAsRoomEvent(EventDirection.Send, eventType, msgtype));
     }
 
     public canSendStateEvent(eventType: string, stateKey: string): boolean {
-        return this.allowedEvents.some(e =>
-            e.matchesAsStateEvent(eventType, stateKey) && e.direction === EventDirection.Send);
+        return this.allowedEvents.some(e => e.matchesAsStateEvent(EventDirection.Send, eventType, stateKey));
+    }
+
+    public canSendToDeviceEvent(eventType: string): boolean {
+        return this.allowedEvents.some(e => e.matchesAsToDeviceEvent(EventDirection.Send, eventType));
     }
 
     public canReceiveRoomEvent(eventType: string, msgtype: string = null): boolean {
-        return this.allowedEvents.some(e =>
-            e.matchesAsRoomEvent(eventType, msgtype) && e.direction === EventDirection.Receive);
+        return this.allowedEvents.some(e => e.matchesAsRoomEvent(EventDirection.Receive, eventType, msgtype));
     }
 
     public canReceiveStateEvent(eventType: string, stateKey: string): boolean {
-        return this.allowedEvents.some(e =>
-            e.matchesAsStateEvent(eventType, stateKey) && e.direction === EventDirection.Receive);
+        return this.allowedEvents.some(e => e.matchesAsStateEvent(EventDirection.Receive, eventType, stateKey));
+    }
+
+    public canReceiveToDeviceEvent(eventType: string): boolean {
+        return this.allowedEvents.some(e => e.matchesAsToDeviceEvent(EventDirection.Receive, eventType));
     }
 
     public stop() {
@@ -453,6 +462,32 @@ export class ClientWidgetApi extends EventEmitter {
         });
     }
 
+    private async handleSendToDevice(request: ISendToDeviceFromWidgetActionRequest): Promise<void> {
+        if (!request.data.type) {
+            await this.transport.reply<IWidgetApiErrorResponseData>(request, {
+                error: {message: "Invalid request - missing event type"},
+            });
+        } else if (!request.data.messages) {
+            await this.transport.reply<IWidgetApiErrorResponseData>(request, {
+                error: {message: "Invalid request - missing event contents"},
+            });
+        } else if (!this.canSendToDeviceEvent(request.data.type)) {
+            await this.transport.reply<IWidgetApiErrorResponseData>(request, {
+                error: {message: "Cannot send to-device events of this type"},
+            });
+        } else {
+            try {
+                await this.driver.sendToDevice(request.data.type, request.data.messages);
+                await this.transport.reply<ISendToDeviceFromWidgetResponseData>(request, {});
+            } catch (e) {
+                console.error("error sending to-device event", e);
+                await this.transport.reply<IWidgetApiErrorResponseData>(request, {
+                    error: {message: "Error sending event"},
+                });
+            }
+        }
+    }
+
     private handleMessage(ev: CustomEvent<IWidgetApiRequest>) {
         if (this.isStopped) return;
         const actionEv = new CustomEvent(`action:${ev.detail.action}`, {
@@ -468,6 +503,8 @@ export class ClientWidgetApi extends EventEmitter {
                     return this.replyVersions(<ISupportedVersionsActionRequest>ev.detail);
                 case WidgetApiFromWidgetAction.SendEvent:
                     return this.handleSendEvent(<ISendEventFromWidgetActionRequest>ev.detail);
+                case WidgetApiFromWidgetAction.SendToDevice:
+                    return this.handleSendToDevice(<ISendToDeviceFromWidgetActionRequest>ev.detail);
                 case WidgetApiFromWidgetAction.GetOpenIDCredentials:
                     return this.handleOIDC(<IGetOpenIDActionRequest>ev.detail);
                 case WidgetApiFromWidgetAction.MSC2931Navigate:
@@ -531,27 +568,43 @@ export class ClientWidgetApi extends EventEmitter {
      * Not the room ID of the event.
      * @returns {Promise<void>} Resolves when complete, rejects if there was an error sending.
      */
-    public feedEvent(rawEvent: IRoomEvent, currentViewedRoomId: string): Promise<void> {
+    public async feedEvent(rawEvent: IRoomEvent, currentViewedRoomId: string): Promise<void> {
         if (rawEvent.room_id !== currentViewedRoomId && !this.canUseRoomTimeline(rawEvent.room_id)) {
-            return Promise.resolve(); // no-op
+            return; // no-op
         }
 
         if (rawEvent.state_key !== undefined && rawEvent.state_key !== null) {
             // state event
             if (!this.canReceiveStateEvent(rawEvent.type, rawEvent.state_key)) {
-                return Promise.resolve(); // no-op
+                return; // no-op
             }
         } else {
             // message event
-            if (!this.canReceiveRoomEvent(rawEvent.type, (rawEvent.content || {})['msgtype'])) {
-                return Promise.resolve(); // no-op
+            if (!this.canReceiveRoomEvent(rawEvent.type, rawEvent.content?.["msgtype"])) {
+                return; // no-op
             }
         }
 
         // Feed the event into the widget
-        return this.transport.send<ISendEventToWidgetRequestData>(
+        await this.transport.send<ISendEventToWidgetRequestData>(
             WidgetApiToWidgetAction.SendEvent,
             rawEvent as ISendEventToWidgetRequestData, // it's compatible, but missing the index signature
-        ).then();
+        );
+    }
+
+    /**
+     * Feeds a to-device event to the widget. If the widget is not able to accept the
+     * event due to permissions, this will no-op and return calmly. If the widget failed
+     * to handle the event, this will raise an error.
+     * @param {IRoomEvent} rawEvent The event to (try to) send to the widget.
+     * @returns {Promise<void>} Resolves when complete, rejects if there was an error sending.
+     */
+    public async feedToDevice(rawEvent: IRoomEvent): Promise<void> {
+        if (this.canReceiveToDeviceEvent(rawEvent.type)) {
+            await this.transport.send<ISendToDeviceToWidgetRequestData>(
+                WidgetApiToWidgetAction.SendToDevice,
+                rawEvent as ISendToDeviceToWidgetRequestData, // it's compatible, but missing the index signature
+            );
+        }
     }
 }

src/WidgetApi.ts

@@ -53,6 +53,10 @@ import {
 } from "./interfaces/ModalWidgetActions";
 import { ISetModalButtonEnabledActionRequestData } from "./interfaces/SetModalButtonEnabledAction";
 import { ISendEventFromWidgetRequestData, ISendEventFromWidgetResponseData } from "./interfaces/SendEventAction";
+import {
+    ISendToDeviceFromWidgetRequestData,
+    ISendToDeviceFromWidgetResponseData,
+} from "./interfaces/SendToDeviceAction";
 import { EventDirection, WidgetEventCapability } from "./models/WidgetEventCapability";
 import { INavigateActionRequestData } from "./interfaces/NavigateAction";
 import { IReadEventFromWidgetRequestData, IReadEventFromWidgetResponseData } from "./interfaces/ReadEventAction";
@@ -179,6 +183,26 @@ export class WidgetApi extends EventEmitter {
         this.requestCapability(WidgetEventCapability.forStateEvent(EventDirection.Receive, eventType, stateKey).raw);
     }
 
+    /**
+     * Requests the capability to send a given to-device event. It is not
+     * guaranteed to be allowed, but will be asked for if the negotiation has
+     * not already happened.
+     * @param {string} eventType The room event type to ask for.
+     */
+    public requestCapabilityToSendToDevice(eventType: string) {
+        this.requestCapability(WidgetEventCapability.forToDeviceEvent(EventDirection.Send, eventType).raw);
+    }
+
+    /**
+     * Requests the capability to receive a given to-device event. It is not
+     * guaranteed to be allowed, but will be asked for if the negotiation has
+     * not already happened.
+     * @param {string} eventType The room event type to ask for.
+     */
+    public requestCapabilityToReceiveToDevice(eventType: string) {
+        this.requestCapability(WidgetEventCapability.forToDeviceEvent(EventDirection.Receive, eventType).raw);
+    }
+
     /**
      * Requests the capability to send a given room event. It is not guaranteed to be
      * allowed, but will be asked for if the negotiation has not already happened.
@@ -362,6 +386,16 @@ export class WidgetApi extends EventEmitter {
         );
     }
 
+    public sendToDevice(
+        eventType: string,
+        contentMap: { [userId: string]: { [deviceId: string]: unknown } },
+    ): Promise<ISendToDeviceFromWidgetResponseData> {
+        return this.transport.send<ISendToDeviceFromWidgetRequestData, ISendToDeviceFromWidgetResponseData>(
+            WidgetApiFromWidgetAction.SendToDevice,
+            {type: eventType, messages: contentMap},
+        );
+    }
+
     public readRoomEvents(
         eventType: string,
         limit?: number,

src/driver/WidgetDriver.ts

@@ -75,6 +75,21 @@ export abstract class WidgetDriver {
         return Promise.reject(new Error("Failed to override function"));
     }
 
+    /**
+     * Sends a to-device event. The widget API will have already verified that the widget
+     * is capable of sending the event.
+     * @param {string} eventType The event type to be sent.
+     * @param {Object} contentMap A map from user ID and device ID to event content.
+     * @returns {Promise<void>} Resolves when the event has been sent.
+     * @throws Rejected when the event could not be sent.
+     */
+    public sendToDevice(
+        eventType: string,
+        contentMap: { [userId: string]: { [deviceId: string]: unknown } },
+    ): Promise<void> {
+        return Promise.reject(new Error("Failed to override function"));
+    }
+
     /**
      * Reads all events of the given type, and optionally `msgtype` (if applicable/defined),
      * the user has access to. The widget API will have already verified that the widget is

src/index.ts

@@ -51,6 +51,7 @@ export * from "./interfaces/ModalWidgetActions";
 export * from "./interfaces/SetModalButtonEnabledAction";
 export * from "./interfaces/WidgetConfigAction";
 export * from "./interfaces/SendEventAction";
+export * from "./interfaces/SendToDeviceAction";
 export * from "./interfaces/ReadEventAction";
 export * from "./interfaces/IRoomEvent";
 export * from "./interfaces/NavigateAction";

src/interfaces/SendToDeviceAction.ts

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2022 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * 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.
+ */
+
+import { IWidgetApiRequest, IWidgetApiRequestData } from "./IWidgetApiRequest";
+import { WidgetApiFromWidgetAction, WidgetApiToWidgetAction } from "./WidgetApiAction";
+import { IWidgetApiResponseData } from "./IWidgetApiResponse";
+import { IRoomEvent } from "./IRoomEvent";
+
+export interface ISendToDeviceFromWidgetRequestData extends IWidgetApiRequestData {
+    type: string,
+    messages: { [userId: string]: { [deviceId: string]: unknown } },
+}
+
+export interface ISendToDeviceFromWidgetActionRequest extends IWidgetApiRequest {
+    action: WidgetApiFromWidgetAction.SendToDevice;
+    data: ISendToDeviceFromWidgetRequestData;
+}
+
+export interface ISendToDeviceFromWidgetResponseData extends IWidgetApiResponseData {
+    // nothing
+}
+
+export interface ISendToDeviceFromWidgetActionResponse extends ISendToDeviceFromWidgetActionRequest {
+    response: ISendToDeviceFromWidgetResponseData;
+}
+
+export interface ISendToDeviceToWidgetRequestData extends IWidgetApiRequestData, IRoomEvent {
+}
+
+export interface ISendToDeviceToWidgetActionRequest extends IWidgetApiRequest {
+    action: WidgetApiToWidgetAction.SendToDevice;
+    data: ISendToDeviceToWidgetRequestData;
+}
+
+export interface ISendToDeviceToWidgetResponseData extends IWidgetApiResponseData {
+    // nothing
+}
+
+export interface ISendToDeviceToWidgetActionResponse extends ISendToDeviceToWidgetActionRequest {
+    response: ISendToDeviceToWidgetResponseData;
+}

src/interfaces/WidgetApiAction.ts

@@ -25,6 +25,7 @@ export enum WidgetApiToWidgetAction {
     CloseModalWidget = "close_modal",
     ButtonClicked = "button_clicked",
     SendEvent = "send_event",
+    SendToDevice = "send_to_device",
 }
 
 export enum WidgetApiFromWidgetAction {
@@ -37,6 +38,7 @@ export enum WidgetApiFromWidgetAction {
     OpenModalWidget = "open_modal",
     SetModalButtonEnabled = "set_button_enabled",
     SendEvent = "send_event",
+    SendToDevice = "send_to_device",
 
     /**
      * @deprecated It is not recommended to rely on this existing - it can be removed without notice.