Send/receive error details with widgets

Author: AndrewFerr

src/embedded.ts

@@ -17,6 +17,7 @@ limitations under the License.
 import {
     WidgetApi,
     WidgetApiToWidgetAction,
+    WidgetApiResponseError,
     MatrixCapabilities,
     IWidgetApiRequest,
     IWidgetApiAcknowledgeResponseData,
@@ -45,6 +46,7 @@ import {
 } from "./client.ts";
 import { SyncApi, SyncState } from "./sync.ts";
 import { SlidingSyncSdk } from "./sliding-sync-sdk.ts";
+import { MatrixError } from "./http-api/errors.ts";
 import { User } from "./models/user.ts";
 import { Room } from "./models/room.ts";
 import { ToDeviceBatch, ToDevicePayload } from "./models/ToDeviceMessage.ts";
@@ -147,6 +149,26 @@ export class RoomWidgetClient extends MatrixClient {
     ) {
         super(opts);
 
+        const transportSend = this.widgetApi.transport.send.bind(this.widgetApi.transport);
+        // eslint-disable-next-line @typescript-eslint/explicit-function-return-type
+        this.widgetApi.transport.send = async (action, data) => {
+            try {
+                return await transportSend(action, data);
+            } catch (error) {
+                processAndThrow(error);
+            }
+        };
+
+        const transportSendComplete = this.widgetApi.transport.sendComplete.bind(this.widgetApi.transport);
+        // eslint-disable-next-line @typescript-eslint/explicit-function-return-type
+        this.widgetApi.transport.sendComplete = async (action, data) => {
+            try {
+                return await transportSendComplete(action, data);
+            } catch (error) {
+                processAndThrow(error);
+            }
+        };
+
         this.widgetApiReady = new Promise<void>((resolve) => this.widgetApi.once("ready", resolve));
 
         // Request capabilities for the functionality this client needs to support
@@ -523,3 +545,9 @@ export class RoomWidgetClient extends MatrixClient {
         }
     }
 }
+
+function processAndThrow(error: unknown): never {
+    throw error instanceof WidgetApiResponseError && error.data.matrix_api_error
+        ? MatrixError.fromWidgetApiErrorData(error.data.matrix_api_error)
+        : error;
+}

src/http-api/errors.ts

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { IMatrixApiError as IWidgetMatrixError } from "matrix-widget-api";
+
 import { IUsageLimit } from "../@types/partials.ts";
 import { MatrixEvent } from "../models/event.ts";
 
@@ -131,6 +133,42 @@ export class MatrixError extends HTTPError {
         }
         return null;
     }
+
+    /**
+     * @returns this error expressed as a {@link IWidgetMatrixError}
+     * for use by Widget API error responses.
+     */
+    public asWidgetApiErrorData(): IWidgetMatrixError {
+        const headers: Record<string, string> = {};
+        if (this.httpHeaders) {
+            for (const [name, value] of this.httpHeaders) {
+                headers[name] = value;
+            }
+        }
+        return {
+            http_status: this.httpStatus ?? 400,
+            http_headers: headers,
+            url: this.url ?? "",
+            response: {
+                errcode: this.errcode ?? "M_UNKNOWN",
+                error: this.name,
+                ...this.data,
+            },
+        };
+    }
+
+    public static fromWidgetApiErrorData(data: IWidgetMatrixError): MatrixError {
+        return new MatrixError(
+            {
+                errcode: data.response.errcode,
+                error: data.response.error,
+            },
+            data.http_status,
+            data.url,
+            undefined,
+            new Headers(data.http_headers),
+        );
+    }
 }
 
 /**