ElementR: Add CryptoApi.requestVerificationDM (#3643)

* Add `CryptoApi.requestVerificationDM`

* Fix RoomMessageRequest url

* Review changes

* Merge fixes

* Add BOB test data

* `requestVerificationDM` test works against old crypto (encrypted verification request)

* Update test data

src/rust-crypto/rust-crypto.ts

@@ -61,6 +61,7 @@ import { CryptoEvent } from "../crypto";
 import { TypedEventEmitter } from "../models/typed-event-emitter";
 import { RustBackupCryptoEventMap, RustBackupCryptoEvents, RustBackupManager } from "./backup";
 import { TypedReEmitter } from "../ReEmitter";
+import { randomString } from "../randomstring";
 
 const ALL_VERIFICATION_METHODS = ["m.sas.v1", "m.qr_code.scan.v1", "m.qr_code.show.v1", "m.reciprocate.v1"];
 
@@ -714,6 +715,62 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
         }
     }
 
+    /**
+     * Implementation of {@link CryptoApi#requestVerificationDM}
+     */
+    public async requestVerificationDM(userId: string, roomId: string): Promise<VerificationRequest> {
+        const userIdentity: RustSdkCryptoJs.UserIdentity | undefined = await this.olmMachine.getIdentity(
+            new RustSdkCryptoJs.UserId(userId),
+        );
+
+        if (!userIdentity) throw new Error(`unknown userId ${userId}`);
+
+        // Transform the verification methods into rust objects
+        const methods = this._supportedVerificationMethods.map((method) =>
+            verificationMethodIdentifierToMethod(method),
+        );
+        // Get the request content to send to the DM room
+        const verificationEventContent: string = await userIdentity.verificationRequestContent(methods);
+
+        // Send the request content to send to the DM room
+        const eventId = await this.sendVerificationRequestContent(roomId, verificationEventContent);
+
+        // Get a verification request
+        const request: RustSdkCryptoJs.VerificationRequest = await userIdentity.requestVerification(
+            new RustSdkCryptoJs.RoomId(roomId),
+            new RustSdkCryptoJs.EventId(eventId),
+            methods,
+        );
+        return new RustVerificationRequest(request, this.outgoingRequestProcessor, this._supportedVerificationMethods);
+    }
+
+    /**
+     * Send the verification content to a room
+     * See https://spec.matrix.org/v1.7/client-server-api/#put_matrixclientv3roomsroomidsendeventtypetxnid
+     *
+     * Prefer to use {@link OutgoingRequestProcessor.makeOutgoingRequest} when dealing with {@link RustSdkCryptoJs.RoomMessageRequest}
+     *
+     * @param roomId - the targeted room
+     * @param verificationEventContent - the request body.
+     *
+     * @returns the event id
+     */
+    private async sendVerificationRequestContent(roomId: string, verificationEventContent: string): Promise<string> {
+        const txId = randomString(32);
+        // Send the verification request content to the DM room
+        const { event_id: eventId } = await this.http.authedRequest<{ event_id: string }>(
+            Method.Put,
+            `/_matrix/client/v3/rooms/${encodeURIComponent(roomId)}/send/m.room.message/${encodeURIComponent(txId)}`,
+            undefined,
+            verificationEventContent,
+            {
+                prefix: "",
+            },
+        );
+
+        return eventId;
+    }
+
     /**
      * The verification methods we offer to the other side during an interactive verification.
      */