v34.0.0-rc.1

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Fixes https://github.com/element-hq/element-web/issues/27666

.eslintrc.js

@@ -49,6 +49,22 @@ module.exports = {
             },
         ],
 
+        "no-restricted-properties": [
+            "error",
+            {
+                object: "window",
+                property: "setImmediate",
+                message: "Use setTimeout instead.",
+            },
+        ],
+        "no-restricted-globals": [
+            "error",
+            {
+                name: "setImmediate",
+                message: "Use setTimeout instead.",
+            },
+        ],
+
         "import/no-restricted-paths": [
             "error",
             {

.github/workflows/sonarcloud.yml

@@ -30,7 +30,7 @@ jobs:
                   target_url: https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}
 
             - name: "🧮 Checkout code"
-              uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+              uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4
               with:
                   repository: ${{ github.event.workflow_run.head_repository.full_name }}
                   ref: ${{ github.event.workflow_run.head_branch }} # checkout commit that triggered this workflow

CHANGELOG.md

@@ -1,3 +1,17 @@
+Changes in [33.1.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v33.1.0) (2024-06-18)
+==================================================================================================
+## ✨ Features
+
+* MSC4108 support OIDC QR code login ([#4134](https://github.com/matrix-org/matrix-js-sdk/pull/4134)). Contributed by @t3chguy.
+* Add crypto methods for export and import of secrets bundle ([#4227](https://github.com/matrix-org/matrix-js-sdk/pull/4227)). Contributed by @t3chguy.
+
+## 🐛 Bug Fixes
+
+* Fix screen sharing in recent Chrome ([#4243](https://github.com/matrix-org/matrix-js-sdk/pull/4243)). Contributed by @RiotRobot.
+* Fix incorrect assumptions about required fields in /search response ([#4228](https://github.com/matrix-org/matrix-js-sdk/pull/4228)). Contributed by @t3chguy.
+* Fix the queueToDevice tests for the new fakeindexeddb ([#4225](https://github.com/matrix-org/matrix-js-sdk/pull/4225)). Contributed by @dbkr.
+
+
 Changes in [33.0.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v33.0.0) (2024-06-04)
 ==================================================================================================
 ## 🚨 BREAKING CHANGES

README.md

@@ -95,7 +95,7 @@ Object.keys(client.store.rooms).forEach((roomId) => {
 
 ## Authenticated media
 
-Servers supporting [MSC3916](https://github.com/matrix-org/matrix-spec-proposals/pull/3916) will require clients, like
+Servers supporting [MSC3916](https://github.com/matrix-org/matrix-spec-proposals/pull/3916) (Matrix 1.11) will require clients, like
 yours, to include an `Authorization` header when `/download`ing or `/thumbnail`ing media. For NodeJS environments this
 may be as easy as the following code snippet, though web browsers may need to use [Service Workers](https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API)
 to append the header when using the endpoints in `<img />` elements and similar.

babel.config.js

@@ -17,9 +17,9 @@ module.exports = {
         "@babel/preset-typescript",
     ],
     plugins: [
-        "@babel/plugin-proposal-numeric-separator",
-        "@babel/plugin-proposal-class-properties",
-        "@babel/plugin-proposal-object-rest-spread",
+        "@babel/plugin-transform-numeric-separator",
+        "@babel/plugin-transform-class-properties",
+        "@babel/plugin-transform-object-rest-spread",
         "@babel/plugin-syntax-dynamic-import",
         "@babel/plugin-transform-runtime",
     ],

package.json

@@ -1,6 +1,6 @@
 {
     "name": "matrix-js-sdk",
-    "version": "33.0.0",
+    "version": "34.0.0-rc.1",
     "description": "Matrix Client-Server SDK for Javascript",
     "engines": {
         "node": ">=18.0.0"
@@ -53,7 +53,7 @@
     ],
     "dependencies": {
         "@babel/runtime": "^7.12.5",
-        "@matrix-org/matrix-sdk-crypto-wasm": "^5.0.0",
+        "@matrix-org/matrix-sdk-crypto-wasm": "^6.0.0",
         "another-json": "^0.2.0",
         "bs58": "^5.0.0",
         "content-type": "^1.0.4",
@@ -65,7 +65,7 @@
         "p-retry": "4",
         "sdp-transform": "^2.14.1",
         "unhomoglyph": "^1.0.6",
-        "uuid": "9"
+        "uuid": "10"
     },
     "devDependencies": {
         "@action-validator/cli": "^0.6.0",
@@ -74,10 +74,10 @@
         "@babel/core": "^7.12.10",
         "@babel/eslint-parser": "^7.12.10",
         "@babel/eslint-plugin": "^7.12.10",
-        "@babel/plugin-proposal-class-properties": "^7.12.1",
-        "@babel/plugin-proposal-numeric-separator": "^7.12.7",
-        "@babel/plugin-proposal-object-rest-spread": "^7.12.1",
         "@babel/plugin-syntax-dynamic-import": "^7.8.3",
+        "@babel/plugin-transform-class-properties": "^7.12.1",
+        "@babel/plugin-transform-numeric-separator": "^7.12.7",
+        "@babel/plugin-transform-object-rest-spread": "^7.12.1",
         "@babel/plugin-transform-runtime": "^7.12.10",
         "@babel/preset-env": "^7.12.11",
         "@babel/preset-typescript": "^7.12.7",
@@ -87,7 +87,6 @@
         "@types/bs58": "^4.0.1",
         "@types/content-type": "^1.1.5",
         "@types/debug": "^4.1.7",
-        "@types/domexception": "^4.0.0",
         "@types/jest": "^29.0.0",
         "@types/node": "18",
         "@types/sdp-transform": "^2.4.5",
@@ -96,7 +95,6 @@
         "@typescript-eslint/parser": "^7.0.0",
         "babel-jest": "^29.0.0",
         "debug": "^4.3.4",
-        "domexception": "^4.0.0",
         "eslint": "8.57.0",
         "eslint-config-google": "^0.14.0",
         "eslint-config-prettier": "^9.0.0",
@@ -105,7 +103,7 @@
         "eslint-plugin-jest": "^28.0.0",
         "eslint-plugin-jsdoc": "^48.0.0",
         "eslint-plugin-matrix-org": "^1.0.0",
-        "eslint-plugin-tsdoc": "^0.2.17",
+        "eslint-plugin-tsdoc": "^0.3.0",
         "eslint-plugin-unicorn": "^53.0.0",
         "fake-indexeddb": "^5.0.2",
         "fetch-mock": "9.11.0",
@@ -119,7 +117,7 @@
         "lint-staged": "^15.0.2",
         "matrix-mock-request": "^2.5.0",
         "node-fetch": "^2.7.0",
-        "prettier": "3.2.5",
+        "prettier": "3.3.2",
         "rimraf": "^5.0.0",
         "ts-node": "^10.9.2",
         "typedoc": "^0.25.10",

spec/integ/crypto/crypto.spec.ts

@@ -630,6 +630,27 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("crypto (%s)", (backend: string,
                 expect(ev.decryptionFailureReason).toEqual(DecryptionFailureCode.HISTORICAL_MESSAGE_USER_NOT_JOINED);
             });
 
+            newBackendOnly(
+                "fails with NOT_JOINED if user is not member of room (MSC4115 unstable prefix)",
+                async () => {
+                    fetchMock.get("path:/_matrix/client/v3/room_keys/version", {
+                        status: 404,
+                        body: { errcode: "M_NOT_FOUND", error: "No current backup version." },
+                    });
+                    expectAliceKeyQuery({ device_keys: { "@alice:localhost": {} }, failures: {} });
+                    await startClientAndAwaitFirstSync();
+
+                    const ev = await sendEventAndAwaitDecryption({
+                        unsigned: {
+                            [UNSIGNED_MEMBERSHIP_FIELD.altName!]: "leave",
+                        },
+                    });
+                    expect(ev.decryptionFailureReason).toEqual(
+                        DecryptionFailureCode.HISTORICAL_MESSAGE_USER_NOT_JOINED,
+                    );
+                },
+            );
+
             newBackendOnly(
                 "fails with another error when the server reports user was a member of the room",
                 async () => {
@@ -654,6 +675,30 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("crypto (%s)", (backend: string,
                 },
             );
 
+            newBackendOnly(
+                "fails with another error when the server reports user was a member of the room (MSC4115 unstable prefix)",
+                async () => {
+                    // This tests that when the server reports that the user
+                    // was invited at the time the event was sent, then we
+                    // don't get a HISTORICAL_MESSAGE_USER_NOT_JOINED error,
+                    // and instead get some other error, since the user should
+                    // have gotten the key for the event.
+                    fetchMock.get("path:/_matrix/client/v3/room_keys/version", {
+                        status: 404,
+                        body: { errcode: "M_NOT_FOUND", error: "No current backup version." },
+                    });
+                    expectAliceKeyQuery({ device_keys: { "@alice:localhost": {} }, failures: {} });
+                    await startClientAndAwaitFirstSync();
+
+                    const ev = await sendEventAndAwaitDecryption({
+                        unsigned: {
+                            [UNSIGNED_MEMBERSHIP_FIELD.altName!]: "invite",
+                        },
+                    });
+                    expect(ev.decryptionFailureReason).toEqual(DecryptionFailureCode.HISTORICAL_MESSAGE_NO_KEY_BACKUP);
+                },
+            );
+
             newBackendOnly(
                 "fails with another error when the server reports user was a member of the room",
                 async () => {
@@ -676,6 +721,29 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("crypto (%s)", (backend: string,
                     expect(ev.decryptionFailureReason).toEqual(DecryptionFailureCode.HISTORICAL_MESSAGE_NO_KEY_BACKUP);
                 },
             );
+
+            newBackendOnly(
+                "fails with another error when the server reports user was a member of the room (MSC4115 unstable prefix)",
+                async () => {
+                    // This tests that when the server reports the user's
+                    // membership, and reports that the user was joined, then we
+                    // don't get a HISTORICAL_MESSAGE_USER_NOT_JOINED error, and
+                    // instead get some other error.
+                    fetchMock.get("path:/_matrix/client/v3/room_keys/version", {
+                        status: 404,
+                        body: { errcode: "M_NOT_FOUND", error: "No current backup version." },
+                    });
+                    expectAliceKeyQuery({ device_keys: { "@alice:localhost": {} }, failures: {} });
+                    await startClientAndAwaitFirstSync();
+
+                    const ev = await sendEventAndAwaitDecryption({
+                        unsigned: {
+                            [UNSIGNED_MEMBERSHIP_FIELD.altName!]: "join",
+                        },
+                    });
+                    expect(ev.decryptionFailureReason).toEqual(DecryptionFailureCode.HISTORICAL_MESSAGE_NO_KEY_BACKUP);
+                },
+            );
         });
 
         it("Decryption fails with Unable to decrypt for other errors", async () => {

spec/integ/crypto/megolm-backup.spec.ts

@@ -796,7 +796,7 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("megolm-keys backup (%s)", (backe
 
             const result = await aliceCrypto.checkKeyBackupAndEnable();
             expect(result).toBeTruthy();
-            jest.runAllTimers();
+            jest.advanceTimersByTime(10 * 60 * 1000);
             await failurePromise;
 
             // Fix the endpoint to do successful uploads
@@ -829,7 +829,7 @@ describe.each(Object.entries(CRYPTO_BACKENDS))("megolm-keys backup (%s)", (backe
             });
 
             // run the timers, which will make the backup loop redo the request
-            await jest.runAllTimersAsync();
+            await jest.advanceTimersByTimeAsync(10 * 60 * 1000);
             await successPromise;
             await allKeysUploadedPromise;
         });

spec/integ/matrix-client-methods.spec.ts

@@ -257,7 +257,7 @@ describe("MatrixClient", function () {
                 .when("POST", "/knock/" + encodeURIComponent(roomId))
                 .check((request) => {
                     expect(request.data).toEqual({ reason: opts.reason });
-                    expect(request.queryParams).toEqual({ server_name: opts.viaServers });
+                    expect(request.queryParams).toEqual({ server_name: opts.viaServers, via: opts.viaServers });
                 })
                 .respond(200, { room_id: roomId });
 
@@ -1293,18 +1293,109 @@ describe("MatrixClient", function () {
     });
 
     describe("getCapabilities", () => {
-        it("should cache by default", async () => {
+        it("should return cached capabilities if present", async () => {
+            const capsObject = {
+                "m.change_password": false,
+            };
+
+            httpBackend!.when("GET", "/versions").respond(200, {});
+            httpBackend!.when("GET", "/pushrules").respond(200, {});
+            httpBackend!.when("POST", "/filter").respond(200, { filter_id: "a filter id" });
             httpBackend.when("GET", "/capabilities").respond(200, {
-                capabilities: {
-                    "m.change_password": false,
-                },
+                capabilities: capsObject,
             });
-            const prom = httpBackend.flushAllExpected();
-            const capabilities1 = await client.getCapabilities();
-            const capabilities2 = await client.getCapabilities();
+
+            client.startClient();
+            await httpBackend!.flushAllExpected();
+
+            expect(await client.getCapabilities()).toEqual(capsObject);
+        });
+
+        it("should fetch capabilities if cache not present", async () => {
+            const capsObject = {
+                "m.change_password": false,
+            };
+
+            httpBackend.when("GET", "/capabilities").respond(200, {
+                capabilities: capsObject,
+            });
+
+            const capsPromise = client.getCapabilities();
+            await httpBackend!.flushAllExpected();
+
+            expect(await capsPromise).toEqual(capsObject);
+        });
+    });
+
+    describe("getCachedCapabilities", () => {
+        it("should return cached capabilities or undefined", async () => {
+            const capsObject = {
+                "m.change_password": false,
+            };
+
+            httpBackend!.when("GET", "/versions").respond(200, {});
+            httpBackend!.when("GET", "/pushrules").respond(200, {});
+            httpBackend!.when("POST", "/filter").respond(200, { filter_id: "a filter id" });
+            httpBackend.when("GET", "/capabilities").respond(200, {
+                capabilities: capsObject,
+            });
+
+            expect(client.getCachedCapabilities()).toBeUndefined();
+
+            client.startClient();
+
+            await httpBackend!.flushAllExpected();
+
+            expect(client.getCachedCapabilities()).toEqual(capsObject);
+        });
+    });
+
+    describe("fetchCapabilities", () => {
+        const capsObject = {
+            "m.change_password": false,
+        };
+
+        beforeEach(() => {
+            httpBackend.when("GET", "/capabilities").respond(200, {
+                capabilities: capsObject,
+            });
+        });
+
+        afterEach(() => {
+            jest.useRealTimers();
+        });
+
+        it("should always fetch capabilities and then cache", async () => {
+            const prom = client.fetchCapabilities();
+            await httpBackend.flushAllExpected();
+            const caps = await prom;
+
+            expect(caps).toEqual(capsObject);
+        });
+
+        it("should write-through the cache", async () => {
+            httpBackend!.when("GET", "/versions").respond(200, {});
+            httpBackend!.when("GET", "/pushrules").respond(200, {});
+            httpBackend!.when("POST", "/filter").respond(200, { filter_id: "a filter id" });
+
+            client.startClient();
+            await httpBackend!.flushAllExpected();
+
+            expect(client.getCachedCapabilities()).toEqual(capsObject);
+
+            const newCapsObject = {
+                "m.change_password": true,
+            };
+
+            httpBackend.when("GET", "/capabilities").respond(200, {
+                capabilities: newCapsObject,
+            });
+
+            const prom = client.fetchCapabilities();
+            await httpBackend.flushAllExpected();
             await prom;
 
-            expect(capabilities1).toStrictEqual(capabilities2);
+            expect(client.getCachedCapabilities()).toEqual(newCapsObject);
         });
     });
 

spec/integ/matrix-client-syncing-errors.spec.ts

@@ -105,13 +105,13 @@ describe("MatrixClient syncing errors", () => {
 
         await client!.startClient();
         expect(await syncEvents[0].promise).toBe(SyncState.Error);
-        jest.runAllTimers(); // this will skip forward to trigger the keepAlive/sync
+        jest.advanceTimersByTime(60 * 1000); // this will skip forward to trigger the keepAlive/sync
         expect(await syncEvents[1].promise).toBe(SyncState.Error);
-        jest.runAllTimers(); // this will skip forward to trigger the keepAlive/sync
+        jest.advanceTimersByTime(60 * 1000); // this will skip forward to trigger the keepAlive/sync
         expect(await syncEvents[2].promise).toBe(SyncState.Prepared);
-        jest.runAllTimers(); // this will skip forward to trigger the keepAlive/sync
+        jest.advanceTimersByTime(60 * 1000); // this will skip forward to trigger the keepAlive/sync
         expect(await syncEvents[3].promise).toBe(SyncState.Syncing);
-        jest.runAllTimers(); // this will skip forward to trigger the keepAlive/sync
+        jest.advanceTimersByTime(60 * 1000); // this will skip forward to trigger the keepAlive/sync
         expect(await syncEvents[4].promise).toBe(SyncState.Syncing);
     });
 
@@ -119,6 +119,7 @@ describe("MatrixClient syncing errors", () => {
         jest.useFakeTimers();
         fetchMock.config.overwriteRoutes = false;
         fetchMock
+            .get("end:capabilities", {})
             .getOnce("end:versions", {}) // first version check without credentials needs to succeed
             .get("end:versions", unknownTokenErrorData) // further version checks fails with 401
             .get("end:pushrules/", 401) // fails with 401 without an error. This does happen in practice e.g. with Synapse

spec/integ/rendezvous/MSC4108SignInWithQR.spec.ts

@@ -0,0 +1,356 @@
+/*
+Copyright 2024 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 { QrCodeData, QrCodeMode } from "@matrix-org/matrix-sdk-crypto-wasm";
+import { mocked } from "jest-mock";
+import fetchMock from "fetch-mock-jest";
+
+import {
+    MSC4108FailureReason,
+    MSC4108RendezvousSession,
+    MSC4108SecureChannel,
+    MSC4108SignInWithQR,
+    PayloadType,
+    RendezvousError,
+} from "../../../src/rendezvous";
+import { defer } from "../../../src/utils";
+import {
+    ClientPrefix,
+    DEVICE_CODE_SCOPE,
+    IHttpOpts,
+    IMyDevice,
+    MatrixClient,
+    MatrixError,
+    MatrixHttpApi,
+} from "../../../src";
+import { mockOpenIdConfiguration } from "../../test-utils/oidc";
+
+function makeMockClient(opts: { userId: string; deviceId: string; msc4108Enabled: boolean }): MatrixClient {
+    const baseUrl = "https://example.com";
+    const crypto = {
+        exportSecretsForQrLogin: jest.fn(),
+    };
+    const client = {
+        doesServerSupportUnstableFeature(feature: string) {
+            return Promise.resolve(opts.msc4108Enabled && feature === "org.matrix.msc4108");
+        },
+        getUserId() {
+            return opts.userId;
+        },
+        getDeviceId() {
+            return opts.deviceId;
+        },
+        baseUrl,
+        getDomain: () => "example.com",
+        getDevice: jest.fn(),
+        getCrypto: jest.fn(() => crypto),
+        getAuthIssuer: jest.fn().mockResolvedValue({ issuer: "https://issuer/" }),
+    } as unknown as MatrixClient;
+    client.http = new MatrixHttpApi<IHttpOpts & { onlyData: true }>(client, {
+        baseUrl: client.baseUrl,
+        prefix: ClientPrefix.Unstable,
+        onlyData: true,
+    });
+    return client;
+}
+
+describe("MSC4108SignInWithQR", () => {
+    beforeEach(() => {
+        fetchMock.get(
+            "https://issuer/.well-known/openid-configuration",
+            mockOpenIdConfiguration("https://issuer/", [DEVICE_CODE_SCOPE]),
+        );
+        fetchMock.get("https://issuer/jwks", {
+            status: 200,
+            headers: {
+                "Content-Type": "application/json",
+            },
+            keys: [],
+        });
+    });
+
+    afterEach(() => {
+        fetchMock.reset();
+    });
+
+    const url = "https://fallbackserver/rz/123";
+    const deviceId = "DEADB33F";
+    const verificationUri = "https://example.com/verify";
+    const verificationUriComplete = "https://example.com/verify/complete";
+
+    it("should generate qr code data as expected", async () => {
+        const session = new MSC4108RendezvousSession({
+            url,
+        });
+        const channel = new MSC4108SecureChannel(session);
+        const login = new MSC4108SignInWithQR(channel, false);
+
+        await login.generateCode();
+        const code = login.code;
+        expect(code).toHaveLength(71);
+        const text = new TextDecoder().decode(code);
+        expect(text.startsWith("MATRIX")).toBeTruthy();
+        expect(text.endsWith(url)).toBeTruthy();
+
+        // Assert that the code is stable
+        await login.generateCode();
+        expect(login.code).toEqual(code);
+    });
+
+    describe("should be able to connect as a reciprocating device", () => {
+        let client: MatrixClient;
+        let ourLogin: MSC4108SignInWithQR;
+        let opponentLogin: MSC4108SignInWithQR;
+
+        beforeEach(async () => {
+            let ourData = defer<string>();
+            let opponentData = defer<string>();
+
+            const ourMockSession = {
+                send: jest.fn(async (newData) => {
+                    ourData.resolve(newData);
+                }),
+                receive: jest.fn(() => {
+                    const prom = opponentData.promise;
+                    prom.then(() => {
+                        opponentData = defer();
+                    });
+                    return prom;
+                }),
+                url,
+                cancelled: false,
+                cancel: () => {
+                    // @ts-ignore
+                    ourMockSession.cancelled = true;
+                    ourData.resolve("");
+                },
+            } as unknown as MSC4108RendezvousSession;
+            const opponentMockSession = {
+                send: jest.fn(async (newData) => {
+                    opponentData.resolve(newData);
+                }),
+                receive: jest.fn(() => {
+                    const prom = ourData.promise;
+                    prom.then(() => {
+                        ourData = defer();
+                    });
+                    return prom;
+                }),
+                url,
+            } as unknown as MSC4108RendezvousSession;
+
+            client = makeMockClient({ userId: "@alice:example.com", deviceId: "alice", msc4108Enabled: true });
+
+            const ourChannel = new MSC4108SecureChannel(ourMockSession);
+            const qrCodeData = QrCodeData.fromBytes(
+                await ourChannel.generateCode(QrCodeMode.Reciprocate, client.getDomain()!),
+            );
+            const opponentChannel = new MSC4108SecureChannel(opponentMockSession, qrCodeData.publicKey);
+
+            ourLogin = new MSC4108SignInWithQR(ourChannel, true, client);
+            opponentLogin = new MSC4108SignInWithQR(opponentChannel, false);
+        });
+
+        it("should be able to connect with opponent and share server name & check code", async () => {
+            await Promise.all([
+                expect(ourLogin.negotiateProtocols()).resolves.toEqual({}),
+                expect(opponentLogin.negotiateProtocols()).resolves.toEqual({ serverName: client.getDomain() }),
+            ]);
+
+            expect(ourLogin.checkCode).toBe(opponentLogin.checkCode);
+        });
+
+        it("should be able to connect with opponent and share verificationUri", async () => {
+            await Promise.all([ourLogin.negotiateProtocols(), opponentLogin.negotiateProtocols()]);
+
+            mocked(client.getDevice).mockRejectedValue(new MatrixError({ errcode: "M_NOT_FOUND" }, 404));
+
+            await Promise.all([
+                expect(ourLogin.deviceAuthorizationGrant()).resolves.toEqual({
+                    verificationUri: verificationUriComplete,
+                }),
+                // We don't have the new device side of this flow implemented at this time so mock it
+                // @ts-ignore
+                opponentLogin.send({
+                    type: PayloadType.Protocol,
+                    protocol: "device_authorization_grant",
+                    device_authorization_grant: {
+                        verification_uri: verificationUri,
+                        verification_uri_complete: verificationUriComplete,
+                    },
+                    device_id: deviceId,
+                }),
+            ]);
+        });
+
+        it("should abort if device already exists", async () => {
+            await Promise.all([ourLogin.negotiateProtocols(), opponentLogin.negotiateProtocols()]);
+
+            mocked(client.getDevice).mockResolvedValue({} as IMyDevice);
+
+            await Promise.all([
+                expect(ourLogin.deviceAuthorizationGrant()).rejects.toThrow("Specified device ID already exists"),
+                // We don't have the new device side of this flow implemented at this time so mock it
+                // @ts-ignore
+                opponentLogin.send({
+                    type: PayloadType.Protocol,
+                    protocol: "device_authorization_grant",
+                    device_authorization_grant: {
+                        verification_uri: verificationUri,
+                    },
+                    device_id: deviceId,
+                }),
+            ]);
+        });
+
+        it("should abort on unsupported protocol", async () => {
+            await Promise.all([ourLogin.negotiateProtocols(), opponentLogin.negotiateProtocols()]);
+
+            await Promise.all([
+                expect(ourLogin.deviceAuthorizationGrant()).rejects.toThrow(
+                    "Received a request for an unsupported protocol",
+                ),
+                // We don't have the new device side of this flow implemented at this time so mock it
+                // @ts-ignore
+                opponentLogin.send({
+                    type: PayloadType.Protocol,
+                    protocol: "device_authorization_grant_v2",
+                    device_authorization_grant: {
+                        verification_uri: verificationUri,
+                    },
+                    device_id: deviceId,
+                }),
+            ]);
+        });
+
+        it("should be able to connect with opponent and share secrets", async () => {
+            await Promise.all([ourLogin.negotiateProtocols(), opponentLogin.negotiateProtocols()]);
+
+            // We don't have the new device side of this flow implemented at this time so mock it
+            // @ts-ignore
+            ourLogin.expectingNewDeviceId = "DEADB33F";
+
+            const ourProm = ourLogin.shareSecrets();
+
+            // Consume the ProtocolAccepted message which would normally be handled by step 4 which we do not have here
+            // @ts-ignore
+            await opponentLogin.receive();
+
+            mocked(client.getDevice).mockResolvedValue({} as IMyDevice);
+
+            const secrets = {
+                cross_signing: { master_key: "mk", user_signing_key: "usk", self_signing_key: "ssk" },
+            };
+            client.getCrypto()!.exportSecretsBundle = jest.fn().mockResolvedValue(secrets);
+
+            const payload = {
+                secrets: expect.objectContaining(secrets),
+            };
+            await Promise.all([
+                expect(ourProm).resolves.toEqual(payload),
+                expect(opponentLogin.shareSecrets()).resolves.toEqual(payload),
+            ]);
+        });
+
+        it("should abort if device doesn't come up by timeout", async () => {
+            jest.spyOn(global, "setTimeout").mockImplementation((fn) => {
+                (<Function>fn)();
+                return -1;
+            });
+            jest.spyOn(Date, "now").mockImplementation(() => {
+                return 12345678 + mocked(setTimeout).mock.calls.length * 1000;
+            });
+
+            await Promise.all([ourLogin.negotiateProtocols(), opponentLogin.negotiateProtocols()]);
+
+            // We don't have the new device side of this flow implemented at this time so mock it
+            // @ts-ignore
+            ourLogin.expectingNewDeviceId = "DEADB33F";
+
+            // @ts-ignore
+            await opponentLogin.send({
+                type: PayloadType.Success,
+            });
+            mocked(client.getDevice).mockRejectedValue(new MatrixError({ errcode: "M_NOT_FOUND" }, 404));
+
+            const ourProm = ourLogin.shareSecrets();
+            await expect(ourProm).rejects.toThrow("New device not found");
+        });
+
+        it("should abort on unexpected errors", async () => {
+            await Promise.all([ourLogin.negotiateProtocols(), opponentLogin.negotiateProtocols()]);
+
+            // We don't have the new device side of this flow implemented at this time so mock it
+            // @ts-ignore
+            ourLogin.expectingNewDeviceId = "DEADB33F";
+
+            // @ts-ignore
+            await opponentLogin.send({
+                type: PayloadType.Success,
+            });
+            mocked(client.getDevice).mockRejectedValue(
+                new MatrixError({ errcode: "M_UNKNOWN", error: "The message" }, 500),
+            );
+
+            await expect(ourLogin.shareSecrets()).rejects.toThrow("The message");
+        });
+
+        it("should abort on declined login", async () => {
+            await Promise.all([ourLogin.negotiateProtocols(), opponentLogin.negotiateProtocols()]);
+
+            await ourLogin.declineLoginOnExistingDevice();
+            await expect(opponentLogin.shareSecrets()).rejects.toThrow(
+                new RendezvousError("Failed", MSC4108FailureReason.UserCancelled),
+            );
+        });
+
+        it("should not send secrets if user cancels", async () => {
+            jest.spyOn(global, "setTimeout").mockImplementation((fn) => {
+                (<Function>fn)();
+                return -1;
+            });
+
+            await Promise.all([ourLogin.negotiateProtocols(), opponentLogin.negotiateProtocols()]);
+
+            // We don't have the new device side of this flow implemented at this time so mock it
+            // @ts-ignore
+            ourLogin.expectingNewDeviceId = "DEADB33F";
+
+            const ourProm = ourLogin.shareSecrets();
+            const opponentProm = opponentLogin.shareSecrets();
+
+            // Consume the ProtocolAccepted message which would normally be handled by step 4 which we do not have here
+            // @ts-ignore
+            await opponentLogin.receive();
+
+            const deferred = defer<IMyDevice>();
+            mocked(client.getDevice).mockReturnValue(deferred.promise);
+
+            ourLogin.cancel(MSC4108FailureReason.UserCancelled).catch(() => {});
+            deferred.resolve({} as IMyDevice);
+
+            const secrets = {
+                cross_signing: { master_key: "mk", user_signing_key: "usk", self_signing_key: "ssk" },
+            };
+            client.getCrypto()!.exportSecretsBundle = jest.fn().mockResolvedValue(secrets);
+
+            await Promise.all([
+                expect(ourProm).rejects.toThrow("User cancelled"),
+                expect(opponentProm).rejects.toThrow("Unexpected message received"),
+            ]);
+        });
+    });
+});

spec/setupTests.ts

@@ -14,10 +14,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import DOMException from "domexception";
-
-global.DOMException = DOMException as typeof global.DOMException;
-
 jest.mock("../src/http-api/utils", () => ({
     ...jest.requireActual("../src/http-api/utils"),
     // We mock timeoutSignal otherwise it causes tests to leave timers running

spec/test-utils/client.ts

@@ -88,6 +88,6 @@ export const mockClientMethodsEvents = () => ({
 export const mockClientMethodsServer = (): Partial<Record<MethodLikeKeys<MatrixClient>, unknown>> => ({
     getIdentityServerUrl: jest.fn(),
     getHomeserverUrl: jest.fn(),
-    getCapabilities: jest.fn().mockReturnValue({}),
+    getCachedCapabilities: jest.fn().mockReturnValue({}),
     doesServerSupportUnstableFeature: jest.fn().mockResolvedValue(false),
 });

spec/test-utils/oidc.ts

@@ -38,7 +38,10 @@ export const makeDelegatedAuthConfig = (issuer = "https://auth.org/"): OidcClien
  * @param issuer used as the base for all other urls
  * @returns ValidatedIssuerMetadata
  */
-export const mockOpenIdConfiguration = (issuer = "https://auth.org/"): ValidatedIssuerMetadata => ({
+export const mockOpenIdConfiguration = (
+    issuer = "https://auth.org/",
+    additionalGrantTypes: string[] = [],
+): ValidatedIssuerMetadata => ({
     issuer,
     revocation_endpoint: issuer + "revoke",
     token_endpoint: issuer + "token",
@@ -47,6 +50,6 @@ export const mockOpenIdConfiguration = (issuer = "https://auth.org/"): Validated
     device_authorization_endpoint: issuer + "device",
     jwks_uri: issuer + "jwks",
     response_types_supported: ["code"],
-    grant_types_supported: ["authorization_code", "refresh_token"],
+    grant_types_supported: ["authorization_code", "refresh_token", ...additionalGrantTypes],
     code_challenge_methods_supported: ["S256"],
 });

spec/unit/base64.spec.ts

@@ -50,17 +50,18 @@ describe.each(["browser", "node"])("Base64 encoding (%s)", (env) => {
     });
 
     it("Should encode unpadded URL-safe base64", () => {
-        const toEncode = "?????";
+        // Chosen to have padding and multiple instances of / and + in the base64
+        const toEncode = "???????⊕⊗⊗";
         const data = new TextEncoder().encode(toEncode);
 
         const encoded = encodeUnpaddedBase64Url(data);
-        expect(encoded).toEqual("Pz8_Pz8");
+        expect(encoded).toEqual("Pz8_Pz8_P-KKleKKl-KKlw");
     });
 
     it("Should decode URL-safe base64", () => {
-        const decoded = new TextDecoder().decode(decodeBase64("Pz8_Pz8="));
+        const decoded = new TextDecoder().decode(decodeBase64("Pz8_Pz8_P-KKleKKl-KKlw=="));
 
-        expect(decoded).toStrictEqual("?????");
+        expect(decoded).toStrictEqual("???????⊕⊗⊗");
     });
 
     it("Encode unpadded should not have padding", () => {

spec/unit/content-repo.spec.ts

@@ -80,24 +80,22 @@ describe("ContentRepo", function () {
         it("should return an authenticated URL when requested", function () {
             const mxcUri = "mxc://server.name/resourceid";
             expect(getHttpUriForMxc(baseUrl, mxcUri, undefined, undefined, undefined, undefined, true, true)).toEqual(
-                baseUrl +
-                    "/_matrix/client/unstable/org.matrix.msc3916/media/download/server.name/resourceid?allow_redirect=true",
+                baseUrl + "/_matrix/client/v1/media/download/server.name/resourceid?allow_redirect=true",
             );
             expect(getHttpUriForMxc(baseUrl, mxcUri, 64, 64, "scale", undefined, true, true)).toEqual(
                 baseUrl +
-                    "/_matrix/client/unstable/org.matrix.msc3916/media/thumbnail/server.name/resourceid?width=64&height=64&method=scale&allow_redirect=true",
+                    "/_matrix/client/v1/media/thumbnail/server.name/resourceid?width=64&height=64&method=scale&allow_redirect=true",
             );
         });
 
         it("should force-enable allow_redirects when useAuthentication is set true", function () {
             const mxcUri = "mxc://server.name/resourceid";
             expect(getHttpUriForMxc(baseUrl, mxcUri, undefined, undefined, undefined, undefined, false, true)).toEqual(
-                baseUrl +
-                    "/_matrix/client/unstable/org.matrix.msc3916/media/download/server.name/resourceid?allow_redirect=true",
+                baseUrl + "/_matrix/client/v1/media/download/server.name/resourceid?allow_redirect=true",
             );
             expect(getHttpUriForMxc(baseUrl, mxcUri, 64, 64, "scale", undefined, false, true)).toEqual(
                 baseUrl +
-                    "/_matrix/client/unstable/org.matrix.msc3916/media/thumbnail/server.name/resourceid?width=64&height=64&method=scale&allow_redirect=true",
+                    "/_matrix/client/v1/media/thumbnail/server.name/resourceid?width=64&height=64&method=scale&allow_redirect=true",
             );
         });
     });

spec/unit/matrixrtc/CallMembership.spec.ts

@@ -15,16 +15,7 @@ limitations under the License.
 */
 
 import { MatrixEvent } from "../../../src";
-import { CallMembership, CallMembershipData } from "../../../src/matrixrtc/CallMembership";
-
-const membershipTemplate: CallMembershipData = {
-    call_id: "",
-    scope: "m.room",
-    application: "m.call",
-    device_id: "AAAAAAA",
-    expires: 5000,
-    membershipID: "bloop",
-};
+import { CallMembership, CallMembershipDataLegacy, SessionMembershipData } from "../../../src/matrixrtc/CallMembership";
 
 function makeMockEvent(originTs = 0): MatrixEvent {
     return {
@@ -34,96 +25,175 @@ function makeMockEvent(originTs = 0): MatrixEvent {
 }
 
 describe("CallMembership", () => {
-    it("rejects membership with no expiry and no expires_ts", () => {
-        expect(() => {
-            new CallMembership(
-                makeMockEvent(),
-                Object.assign({}, membershipTemplate, { expires: undefined, expires_ts: undefined }),
+    describe("CallMembershipDataLegacy", () => {
+        const membershipTemplate: CallMembershipDataLegacy = {
+            call_id: "",
+            scope: "m.room",
+            application: "m.call",
+            device_id: "AAAAAAA",
+            expires: 5000,
+            membershipID: "bloop",
+            foci_active: [{ type: "livekit" }],
+        };
+        it("rejects membership with no expiry and no expires_ts", () => {
+            expect(() => {
+                new CallMembership(
+                    makeMockEvent(),
+                    Object.assign({}, membershipTemplate, { expires: undefined, expires_ts: undefined }),
+                );
+            }).toThrow();
+        });
+
+        it("rejects membership with no device_id", () => {
+            expect(() => {
+                new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { device_id: undefined }));
+            }).toThrow();
+        });
+
+        it("rejects membership with no call_id", () => {
+            expect(() => {
+                new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { call_id: undefined }));
+            }).toThrow();
+        });
+
+        it("allow membership with no scope", () => {
+            expect(() => {
+                new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { scope: undefined }));
+            }).not.toThrow();
+        });
+        it("rejects with malformatted expires_ts", () => {
+            expect(() => {
+                new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { expires_ts: "string" }));
+            }).toThrow();
+        });
+        it("rejects with malformatted expires", () => {
+            expect(() => {
+                new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { expires: "string" }));
+            }).toThrow();
+        });
+
+        it("uses event timestamp if no created_ts", () => {
+            const membership = new CallMembership(makeMockEvent(12345), membershipTemplate);
+            expect(membership.createdTs()).toEqual(12345);
+        });
+
+        it("uses created_ts if present", () => {
+            const membership = new CallMembership(
+                makeMockEvent(12345),
+                Object.assign({}, membershipTemplate, { created_ts: 67890 }),
             );
-        }).toThrow();
+            expect(membership.createdTs()).toEqual(67890);
+        });
+
+        it("computes absolute expiry time based on expires", () => {
+            const membership = new CallMembership(makeMockEvent(1000), membershipTemplate);
+            expect(membership.getAbsoluteExpiry()).toEqual(5000 + 1000);
+        });
+
+        it("computes absolute expiry time based on expires_ts", () => {
+            const membership = new CallMembership(
+                makeMockEvent(1000),
+                Object.assign({}, membershipTemplate, { expires_ts: 6000 }),
+            );
+            expect(membership.getAbsoluteExpiry()).toEqual(5000 + 1000);
+        });
+
+        it("considers memberships unexpired if local age low enough", () => {
+            const fakeEvent = makeMockEvent(1000);
+            fakeEvent.getLocalAge = jest.fn().mockReturnValue(3000);
+            const membership = new CallMembership(fakeEvent, membershipTemplate);
+            expect(membership.isExpired()).toEqual(false);
+        });
+
+        it("considers memberships expired when local age large", () => {
+            const fakeEvent = makeMockEvent(1000);
+            fakeEvent.localTimestamp = Date.now() - 6000;
+            const membership = new CallMembership(fakeEvent, membershipTemplate);
+            expect(membership.isExpired()).toEqual(true);
+        });
+
+        it("returns preferred foci", () => {
+            const fakeEvent = makeMockEvent();
+            const mockFocus = { type: "this_is_a_mock_focus" };
+            const membership = new CallMembership(
+                fakeEvent,
+                Object.assign({}, membershipTemplate, { foci_active: [mockFocus] }),
+            );
+            expect(membership.getPreferredFoci()).toEqual([mockFocus]);
+        });
     });
 
-    it("rejects membership with no device_id", () => {
-        expect(() => {
-            new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { device_id: undefined }));
-        }).toThrow();
-    });
+    describe("SessionMembershipData", () => {
+        const membershipTemplate: SessionMembershipData = {
+            call_id: "",
+            scope: "m.room",
+            application: "m.call",
+            device_id: "AAAAAAA",
+            focus_active: { type: "livekit" },
+            foci_preferred: [{ type: "livekit" }],
+        };
 
-    it("rejects membership with no call_id", () => {
-        expect(() => {
-            new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { call_id: undefined }));
-        }).toThrow();
-    });
+        it("rejects membership with no device_id", () => {
+            expect(() => {
+                new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { device_id: undefined }));
+            }).toThrow();
+        });
 
-    it("rejects membership with no scope", () => {
-        expect(() => {
-            new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { scope: undefined }));
-        }).toThrow();
-    });
-    it("rejects with malformatted expires_ts", () => {
-        expect(() => {
-            new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { expires_ts: "string" }));
-        }).toThrow();
-    });
-    it("rejects with malformatted expires", () => {
-        expect(() => {
-            new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { expires: "string" }));
-        }).toThrow();
-    });
+        it("rejects membership with no call_id", () => {
+            expect(() => {
+                new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { call_id: undefined }));
+            }).toThrow();
+        });
 
-    it("uses event timestamp if no created_ts", () => {
-        const membership = new CallMembership(makeMockEvent(12345), membershipTemplate);
-        expect(membership.createdTs()).toEqual(12345);
-    });
+        it("allow membership with no scope", () => {
+            expect(() => {
+                new CallMembership(makeMockEvent(), Object.assign({}, membershipTemplate, { scope: undefined }));
+            }).not.toThrow();
+        });
 
-    it("uses created_ts if present", () => {
-        const membership = new CallMembership(
-            makeMockEvent(12345),
-            Object.assign({}, membershipTemplate, { created_ts: 67890 }),
-        );
-        expect(membership.createdTs()).toEqual(67890);
-    });
+        it("uses event timestamp if no created_ts", () => {
+            const membership = new CallMembership(makeMockEvent(12345), membershipTemplate);
+            expect(membership.createdTs()).toEqual(12345);
+        });
 
-    it("computes absolute expiry time based on expires", () => {
-        const membership = new CallMembership(makeMockEvent(1000), membershipTemplate);
-        expect(membership.getAbsoluteExpiry()).toEqual(5000 + 1000);
-    });
+        it("uses created_ts if present", () => {
+            const membership = new CallMembership(
+                makeMockEvent(12345),
+                Object.assign({}, membershipTemplate, { created_ts: 67890 }),
+            );
+            expect(membership.createdTs()).toEqual(67890);
+        });
 
-    it("computes absolute expiry time based on expires_ts", () => {
-        const membership = new CallMembership(
-            makeMockEvent(1000),
-            Object.assign({}, membershipTemplate, { expires: undefined, expires_ts: 6000 }),
-        );
-        expect(membership.getAbsoluteExpiry()).toEqual(5000 + 1000);
-    });
+        it("considers memberships unexpired if local age low enough", () => {
+            const fakeEvent = makeMockEvent(1000);
+            fakeEvent.getLocalAge = jest.fn().mockReturnValue(3000);
+            const membership = new CallMembership(fakeEvent, membershipTemplate);
+            expect(membership.isExpired()).toEqual(false);
+        });
 
-    it("considers memberships unexpired if local age low enough", () => {
-        const fakeEvent = makeMockEvent(1000);
-        fakeEvent.getLocalAge = jest.fn().mockReturnValue(3000);
-        const membership = new CallMembership(fakeEvent, membershipTemplate);
-        expect(membership.isExpired()).toEqual(false);
-    });
-
-    it("considers memberships expired when local age large", () => {
-        const fakeEvent = makeMockEvent(1000);
-        fakeEvent.localTimestamp = Date.now() - 6000;
-        const membership = new CallMembership(fakeEvent, membershipTemplate);
-        expect(membership.isExpired()).toEqual(true);
-    });
-
-    it("returns active foci", () => {
-        const fakeEvent = makeMockEvent();
-        const mockFocus = { type: "this_is_a_mock_focus" };
-        const membership = new CallMembership(
-            fakeEvent,
-            Object.assign({}, membershipTemplate, { foci_active: [mockFocus] }),
-        );
-        expect(membership.getActiveFoci()).toEqual([mockFocus]);
+        it("returns preferred foci", () => {
+            const fakeEvent = makeMockEvent();
+            const mockFocus = { type: "this_is_a_mock_focus" };
+            const membership = new CallMembership(
+                fakeEvent,
+                Object.assign({}, membershipTemplate, { foci_preferred: [mockFocus] }),
+            );
+            expect(membership.getPreferredFoci()).toEqual([mockFocus]);
+        });
     });
 
     describe("expiry calculation", () => {
         let fakeEvent: MatrixEvent;
         let membership: CallMembership;
+        const membershipTemplate: CallMembershipDataLegacy = {
+            call_id: "",
+            scope: "m.room",
+            application: "m.call",
+            device_id: "AAAAAAA",
+            expires: 5000,
+            membershipID: "bloop",
+            foci_active: [{ type: "livekit" }],
+        };
 
         beforeEach(() => {
             // server origin timestamp for this event is 1000

spec/unit/matrixrtc/LivekitFocus.spec.ts

@@ -0,0 +1,60 @@
+/*
+Copyright 2023 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 { isLivekitFocus, isLivekitFocusActive, isLivekitFocusConfig } from "../../../src/matrixrtc/LivekitFocus";
+
+describe("LivekitFocus", () => {
+    it("isLivekitFocus", () => {
+        expect(
+            isLivekitFocus({
+                type: "livekit",
+                livekit_service_url: "http://test.com",
+                livekit_alias: "test",
+            }),
+        ).toBeTruthy();
+        expect(isLivekitFocus({ type: "livekit" })).toBeFalsy();
+        expect(
+            isLivekitFocus({ type: "not-livekit", livekit_service_url: "http://test.com", livekit_alias: "test" }),
+        ).toBeFalsy();
+        expect(
+            isLivekitFocus({ type: "livekit", other_service_url: "http://test.com", livekit_alias: "test" }),
+        ).toBeFalsy();
+        expect(
+            isLivekitFocus({ type: "livekit", livekit_service_url: "http://test.com", other_alias: "test" }),
+        ).toBeFalsy();
+    });
+    it("isLivekitFocusActive", () => {
+        expect(
+            isLivekitFocusActive({
+                type: "livekit",
+                focus_selection: "oldest_membership",
+            }),
+        ).toBeTruthy();
+        expect(isLivekitFocusActive({ type: "livekit" })).toBeFalsy();
+        expect(isLivekitFocusActive({ type: "not-livekit", focus_selection: "oldest_membership" })).toBeFalsy();
+    });
+    it("isLivekitFocusConfig", () => {
+        expect(
+            isLivekitFocusConfig({
+                type: "livekit",
+                livekit_service_url: "http://test.com",
+            }),
+        ).toBeTruthy();
+        expect(isLivekitFocusConfig({ type: "livekit" })).toBeFalsy();
+        expect(isLivekitFocusConfig({ type: "not-livekit", livekit_service_url: "http://test.com" })).toBeFalsy();
+        expect(isLivekitFocusConfig({ type: "livekit", other_service_url: "oldest_membership" })).toBeFalsy();
+    });
+});

spec/unit/matrixrtc/MatrixRTCSession.spec.ts

@@ -16,7 +16,11 @@ limitations under the License.
 
 import { EventTimeline, EventType, MatrixClient, MatrixError, MatrixEvent, Room } from "../../../src";
 import { KnownMembership } from "../../../src/@types/membership";
-import { CallMembershipData } from "../../../src/matrixrtc/CallMembership";
+import {
+    CallMembershipData,
+    CallMembershipDataLegacy,
+    SessionMembershipData,
+} from "../../../src/matrixrtc/CallMembership";
 import { MatrixRTCSession, MatrixRTCSessionEvent } from "../../../src/matrixrtc/MatrixRTCSession";
 import { EncryptionKeysEventContent } from "../../../src/matrixrtc/types";
 import { randomString } from "../../../src/randomstring";
@@ -29,6 +33,7 @@ const membershipTemplate: CallMembershipData = {
     device_id: "AAAAAAA",
     expires: 60 * 60 * 1000,
     membershipID: "bloop",
+    foci_active: [{ type: "livekit", livekit_service_url: "https://lk.url" }],
 };
 
 const mockFocus = { type: "mock" };
@@ -98,22 +103,33 @@ describe("MatrixRTCSession", () => {
     });
 
     it("safely ignores events with no memberships section", () => {
+        const roomId = randomString(8);
+        const event = {
+            getType: jest.fn().mockReturnValue(EventType.GroupCallMemberPrefix),
+            getContent: jest.fn().mockReturnValue({}),
+            getSender: jest.fn().mockReturnValue("@mock:user.example"),
+            getTs: jest.fn().mockReturnValue(1000),
+            getLocalAge: jest.fn().mockReturnValue(0),
+        };
         const mockRoom = {
             ...makeMockRoom([]),
-            roomId: randomString(8),
+            roomId,
             getLiveTimeline: jest.fn().mockReturnValue({
                 getState: jest.fn().mockReturnValue({
                     on: jest.fn(),
                     off: jest.fn(),
-                    getStateEvents: (_type: string, _stateKey: string) => [
-                        {
-                            getType: jest.fn().mockReturnValue(EventType.GroupCallMemberPrefix),
-                            getContent: jest.fn().mockReturnValue({}),
-                            getSender: jest.fn().mockReturnValue("@mock:user.example"),
-                            getTs: jest.fn().mockReturnValue(1000),
-                            getLocalAge: jest.fn().mockReturnValue(0),
-                        },
-                    ],
+                    getStateEvents: (_type: string, _stateKey: string) => [event],
+                    events: new Map([
+                        [
+                            EventType.GroupCallMemberPrefix,
+                            {
+                                size: () => true,
+                                has: (_stateKey: string) => true,
+                                get: (_stateKey: string) => event,
+                                values: () => [event],
+                            },
+                        ],
+                    ]),
                 }),
             }),
         };
@@ -122,22 +138,33 @@ describe("MatrixRTCSession", () => {
     });
 
     it("safely ignores events with junk memberships section", () => {
+        const roomId = randomString(8);
+        const event = {
+            getType: jest.fn().mockReturnValue(EventType.GroupCallMemberPrefix),
+            getContent: jest.fn().mockReturnValue({ memberships: ["i am a fish"] }),
+            getSender: jest.fn().mockReturnValue("@mock:user.example"),
+            getTs: jest.fn().mockReturnValue(1000),
+            getLocalAge: jest.fn().mockReturnValue(0),
+        };
         const mockRoom = {
             ...makeMockRoom([]),
-            roomId: randomString(8),
+            roomId,
             getLiveTimeline: jest.fn().mockReturnValue({
                 getState: jest.fn().mockReturnValue({
                     on: jest.fn(),
                     off: jest.fn(),
-                    getStateEvents: (_type: string, _stateKey: string) => [
-                        {
-                            getType: jest.fn().mockReturnValue(EventType.GroupCallMemberPrefix),
-                            getContent: jest.fn().mockReturnValue({ memberships: "i am a fish" }),
-                            getSender: jest.fn().mockReturnValue("@mock:user.example"),
-                            getTs: jest.fn().mockReturnValue(1000),
-                            getLocalAge: jest.fn().mockReturnValue(0),
-                        },
-                    ],
+                    getStateEvents: (_type: string, _stateKey: string) => [event],
+                    events: new Map([
+                        [
+                            EventType.GroupCallMemberPrefix,
+                            {
+                                size: () => true,
+                                has: (_stateKey: string) => true,
+                                get: (_stateKey: string) => event,
+                                values: () => [event],
+                            },
+                        ],
+                    ]),
                 }),
             }),
         };
@@ -185,6 +212,67 @@ describe("MatrixRTCSession", () => {
         expect(sess.memberships).toHaveLength(0);
     });
 
+    describe("updateCallMembershipEvent", () => {
+        const mockFocus = { type: "livekit", livekit_service_url: "https://test.org" };
+        const joinSessionConfig = { useLegacyMemberEvents: false };
+
+        const legacyMembershipData: CallMembershipDataLegacy = {
+            call_id: "",
+            scope: "m.room",
+            application: "m.call",
+            device_id: "AAAAAAA_legacy",
+            expires: 60 * 60 * 1000,
+            membershipID: "bloop",
+            foci_active: [mockFocus],
+        };
+
+        const expiredLegacyMembershipData: CallMembershipDataLegacy = {
+            ...legacyMembershipData,
+            device_id: "AAAAAAA_legacy_expired",
+            expires: 0,
+        };
+
+        const sessionMembershipData: SessionMembershipData = {
+            call_id: "",
+            scope: "m.room",
+            application: "m.call",
+            device_id: "AAAAAAA_session",
+            focus_active: mockFocus,
+            foci_preferred: [mockFocus],
+        };
+
+        function testSession(
+            membershipData: CallMembershipData[] | SessionMembershipData,
+            shouldUseLegacy: boolean,
+        ): void {
+            sess = MatrixRTCSession.roomSessionForRoom(client, makeMockRoom(membershipData));
+
+            const makeNewLegacyMembershipsMock = jest.spyOn(sess as any, "makeNewLegacyMemberships");
+            const makeNewMembershipMock = jest.spyOn(sess as any, "makeNewMembership");
+
+            sess.joinRoomSession([mockFocus], mockFocus, joinSessionConfig);
+
+            expect(makeNewLegacyMembershipsMock).toHaveBeenCalledTimes(shouldUseLegacy ? 1 : 0);
+            expect(makeNewMembershipMock).toHaveBeenCalledTimes(shouldUseLegacy ? 0 : 1);
+        }
+
+        it("uses legacy events if there are any active legacy calls", () => {
+            testSession([expiredLegacyMembershipData, legacyMembershipData, sessionMembershipData], true);
+        });
+
+        it('uses legacy events if a non-legacy call is in a "memberships" array', () => {
+            testSession([sessionMembershipData], true);
+        });
+
+        it("uses non-legacy events if all legacy calls are expired", () => {
+            testSession([expiredLegacyMembershipData], false);
+        });
+
+        it("uses non-legacy events if there are only non-legacy calls", () => {
+            testSession(sessionMembershipData, false);
+        });
+    });
+
     describe("getOldestMembership", () => {
         it("returns the oldest membership event", () => {
             const mockRoom = makeMockRoom([
@@ -198,6 +286,64 @@ describe("MatrixRTCSession", () => {
         });
     });
 
+    describe("getsActiveFocus", () => {
+        const activeFociConfig = { type: "livekit", livekit_service_url: "https://active.url" };
+        it("gets the correct active focus with oldest_membership", () => {
+            const mockRoom = makeMockRoom([
+                Object.assign({}, membershipTemplate, {
+                    device_id: "foo",
+                    created_ts: 500,
+                    foci_active: [activeFociConfig],
+                }),
+                Object.assign({}, membershipTemplate, { device_id: "old", created_ts: 1000 }),
+                Object.assign({}, membershipTemplate, { device_id: "bar", created_ts: 2000 }),
+            ]);
+
+            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+
+            sess.joinRoomSession([{ type: "livekit", livekit_service_url: "htts://test.org" }], {
+                type: "livekit",
+                focus_selection: "oldest_membership",
+            });
+            expect(sess.getActiveFocus()).toBe(activeFociConfig);
+        });
+        it("does not provide focus if the selction method is unknown", () => {
+            const mockRoom = makeMockRoom([
+                Object.assign({}, membershipTemplate, {
+                    device_id: "foo",
+                    created_ts: 500,
+                    foci_active: [activeFociConfig],
+                }),
+                Object.assign({}, membershipTemplate, { device_id: "old", created_ts: 1000 }),
+                Object.assign({}, membershipTemplate, { device_id: "bar", created_ts: 2000 }),
+            ]);
+
+            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+
+            sess.joinRoomSession([{ type: "livekit", livekit_service_url: "htts://test.org" }], {
+                type: "livekit",
+                focus_selection: "unknown",
+            });
+            expect(sess.getActiveFocus()).toBe(undefined);
+        });
+        it("gets the correct active focus legacy", () => {
+            const mockRoom = makeMockRoom([
+                Object.assign({}, membershipTemplate, {
+                    device_id: "foo",
+                    created_ts: 500,
+                    foci_active: [activeFociConfig],
+                }),
+                Object.assign({}, membershipTemplate, { device_id: "old", created_ts: 1000 }),
+                Object.assign({}, membershipTemplate, { device_id: "bar", created_ts: 2000 }),
+            ]);
+
+            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+
+            sess.joinRoomSession([{ type: "livekit", livekit_service_url: "htts://test.org" }]);
+            expect(sess.getActiveFocus()).toBe(activeFociConfig);
+        });
+    });
+
     describe("joining", () => {
         let mockRoom: Room;
         let sendStateEventMock: jest.Mock;
@@ -223,13 +369,13 @@ describe("MatrixRTCSession", () => {
         });
 
         it("shows joined once join is called", () => {
-            sess!.joinRoomSession([mockFocus]);
+            sess!.joinRoomSession([mockFocus], mockFocus);
             expect(sess!.isJoined()).toEqual(true);
         });
 
         it("sends a membership event when joining a call", () => {
             jest.useFakeTimers();
-            sess!.joinRoomSession([mockFocus]);
+            sess!.joinRoomSession([mockFocus], mockFocus);
             expect(client.sendStateEvent).toHaveBeenCalledWith(
                 mockRoom!.roomId,
                 EventType.GroupCallMemberPrefix,
@@ -242,7 +388,8 @@ describe("MatrixRTCSession", () => {
                             device_id: "AAAAAAA",
                             expires: 3600000,
                             expires_ts: Date.now() + 3600000,
-                            foci_active: [{ type: "mock" }],
+                            foci_active: [mockFocus],
+
                             membershipID: expect.stringMatching(".*"),
                         },
                     ],
@@ -252,12 +399,48 @@ describe("MatrixRTCSession", () => {
             jest.useRealTimers();
         });
 
+        describe("non-legacy calls", () => {
+            const activeFocusConfig = { type: "livekit", livekit_service_url: "https://active.url" };
+            const activeFocus = { type: "livekit", focus_selection: "oldest_membership" };
+
+            function testJoin(useOwnedStateEvents: boolean): void {
+                if (useOwnedStateEvents) {
+                    mockRoom.getVersion = jest.fn().mockReturnValue("org.matrix.msc3779.default");
+                }
+
+                jest.useFakeTimers();
+                sess!.joinRoomSession([activeFocusConfig], activeFocus, { useLegacyMemberEvents: false });
+                expect(client.sendStateEvent).toHaveBeenCalledWith(
+                    mockRoom!.roomId,
+                    EventType.GroupCallMemberPrefix,
+                    {
+                        application: "m.call",
+                        scope: "m.room",
+                        call_id: "",
+                        device_id: "AAAAAAA",
+                        foci_preferred: [activeFocusConfig],
+                        focus_active: activeFocus,
+                    } satisfies SessionMembershipData,
+                    `${!useOwnedStateEvents ? "_" : ""}@alice:example.org_AAAAAAA`,
+                );
+                jest.useRealTimers();
+            }
+
+            it("sends a membership event with session payload when joining a non-legacy call", () => {
+                testJoin(false);
+            });
+
+            it("does not prefix the state key with _ for rooms that support user-owned state events", () => {
+                testJoin(true);
+            });
+        });
+
         it("does nothing if join called when already joined", () => {
-            sess!.joinRoomSession([mockFocus]);
+            sess!.joinRoomSession([mockFocus], mockFocus);
 
             expect(client.sendStateEvent).toHaveBeenCalledTimes(1);
 
-            sess!.joinRoomSession([mockFocus]);
+            sess!.joinRoomSession([mockFocus], mockFocus);
             expect(client.sendStateEvent).toHaveBeenCalledTimes(1);
         });
 
@@ -274,15 +457,26 @@ describe("MatrixRTCSession", () => {
                 const sendStateEventMock = jest.fn().mockImplementation(resolveFn);
                 client.sendStateEvent = sendStateEventMock;
 
-                sess!.joinRoomSession([mockFocus]);
+                sess!.joinRoomSession([mockFocus], mockFocus);
 
                 const eventContent = await eventSentPromise;
 
                 // definitely should have renewed by 1 second before the expiry!
                 const timeElapsed = 60 * 60 * 1000 - 1000;
-                mockRoom.getLiveTimeline().getState(EventTimeline.FORWARDS)!.getStateEvents = jest
-                    .fn()
-                    .mockReturnValue(mockRTCEvent(eventContent.memberships, mockRoom.roomId, timeElapsed));
+                const event = mockRTCEvent(eventContent.memberships, mockRoom.roomId, timeElapsed);
+                const getState = mockRoom.getLiveTimeline().getState(EventTimeline.FORWARDS)!;
+                getState.getStateEvents = jest.fn().mockReturnValue(event);
+                getState.events = new Map([
+                    [
+                        event.getType(),
+                        {
+                            size: () => true,
+                            has: (_stateKey: string) => true,
+                            get: (_stateKey: string) => event,
+                            values: () => [event],
+                        } as unknown as Map<string, MatrixEvent>,
+                    ],
+                ]);
 
                 const eventReSentPromise = new Promise<Record<string, any>>((r) => {
                     resolveFn = (_roomId: string, _type: string, val: Record<string, any>) => {
@@ -308,7 +502,7 @@ describe("MatrixRTCSession", () => {
                                 device_id: "AAAAAAA",
                                 expires: 3600000 * 2,
                                 expires_ts: 1000 + 3600000 * 2,
-                                foci_active: [{ type: "mock" }],
+                                foci_active: [mockFocus],
                                 created_ts: 1000,
                                 membershipID: expect.stringMatching(".*"),
                             },
@@ -322,7 +516,7 @@ describe("MatrixRTCSession", () => {
         });
 
         it("creates a key when joining", () => {
-            sess!.joinRoomSession([mockFocus], true);
+            sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
             const keys = sess?.getKeysForParticipant("@alice:example.org", "AAAAAAA");
             expect(keys).toHaveLength(1);
 
@@ -336,7 +530,7 @@ describe("MatrixRTCSession", () => {
                 sendEventMock.mockImplementation(resolve);
             });
 
-            sess!.joinRoomSession([mockFocus], true);
+            sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
 
             await eventSentPromise;
 
@@ -372,7 +566,7 @@ describe("MatrixRTCSession", () => {
                     });
                 });
 
-                sess!.joinRoomSession([mockFocus], true);
+                sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 jest.advanceTimersByTime(10000);
 
                 await eventSentPromise;
@@ -394,7 +588,7 @@ describe("MatrixRTCSession", () => {
                 throw e;
             });
 
-            sess!.joinRoomSession([mockFocus], true);
+            sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
 
             expect(client.cancelPendingEvent).toHaveBeenCalledWith(eventSentinel);
         });
@@ -409,7 +603,7 @@ describe("MatrixRTCSession", () => {
                     sendEventMock.mockImplementation(resolve);
                 });
 
-                sess.joinRoomSession([mockFocus], true);
+                sess.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 await keysSentPromise1;
 
                 sendEventMock.mockClear();
@@ -462,7 +656,7 @@ describe("MatrixRTCSession", () => {
                     sendEventMock.mockImplementation((_roomId, _evType, payload) => resolve(payload));
                 });
 
-                sess.joinRoomSession([mockFocus], true);
+                sess.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 const firstKeysPayload = await keysSentPromise1;
                 expect(firstKeysPayload.keys).toHaveLength(1);
 
@@ -489,7 +683,7 @@ describe("MatrixRTCSession", () => {
         });
 
         it("Doesn't re-send key immediately", async () => {
-            const realSetImmediate = setImmediate;
+            const realSetTimeout = setTimeout;
             jest.useFakeTimers();
             try {
                 const mockRoom = makeMockRoom([membershipTemplate]);
@@ -499,7 +693,7 @@ describe("MatrixRTCSession", () => {
                     sendEventMock.mockImplementation(resolve);
                 });
 
-                sess.joinRoomSession([mockFocus], true);
+                sess.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 await keysSentPromise1;
 
                 sendEventMock.mockClear();
@@ -517,7 +711,7 @@ describe("MatrixRTCSession", () => {
                 sess.onMembershipUpdate();
 
                 await new Promise((resolve) => {
-                    realSetImmediate(resolve);
+                    realSetTimeout(resolve);
                 });
 
                 expect(sendEventMock).not.toHaveBeenCalled();
@@ -595,7 +789,7 @@ describe("MatrixRTCSession", () => {
 
             jest.advanceTimersByTime(10000);
 
-            sess.joinRoomSession([mockFocus]);
+            sess.joinRoomSession([mockFocus], mockFocus);
 
             expect(client.sendStateEvent).toHaveBeenCalledWith(
                 mockRoomNoExpired!.roomId,
@@ -631,7 +825,7 @@ describe("MatrixRTCSession", () => {
         ]);
         sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
 
-        sess.joinRoomSession([mockFocus]);
+        sess.joinRoomSession([mockFocus], mockFocus);
 
         expect(client.sendStateEvent).toHaveBeenCalledWith(
             mockRoom!.roomId,
@@ -645,6 +839,7 @@ describe("MatrixRTCSession", () => {
                         device_id: "OTHERDEVICE",
                         expires: 3600000,
                         created_ts: 1000,
+                        foci_active: [{ type: "livekit", livekit_service_url: "https://lk.url" }],
                         membershipID: expect.stringMatching(".*"),
                     },
                     {

spec/unit/matrixrtc/MatrixRTCSessionManager.spec.ts

@@ -35,6 +35,7 @@ const membershipTemplate: CallMembershipData = {
     device_id: "AAAAAAA",
     expires: 60 * 60 * 1000,
     membershipID: "bloop",
+    foci_active: [{ type: "test" }],
 };
 
 describe("MatrixRTCSessionManager", () => {

spec/unit/matrixrtc/mocks.ts

@@ -15,24 +15,27 @@ limitations under the License.
 */
 
 import { EventType, MatrixEvent, Room } from "../../../src";
-import { CallMembershipData } from "../../../src/matrixrtc/CallMembership";
+import { CallMembershipData, SessionMembershipData } from "../../../src/matrixrtc/CallMembership";
 import { randomString } from "../../../src/randomstring";
 
-export function makeMockRoom(memberships: CallMembershipData[], localAge: number | null = null): Room {
+type MembershipData = CallMembershipData[] | SessionMembershipData;
+
+export function makeMockRoom(membershipData: MembershipData, localAge: number | null = null): Room {
     const roomId = randomString(8);
     // Caching roomState here so it does not get recreated when calling `getLiveTimeline.getState()`
-    const roomState = makeMockRoomState(memberships, roomId, localAge);
+    const roomState = makeMockRoomState(membershipData, roomId, localAge);
     return {
         roomId: roomId,
         hasMembershipState: jest.fn().mockReturnValue(true),
         getLiveTimeline: jest.fn().mockReturnValue({
             getState: jest.fn().mockReturnValue(roomState),
         }),
+        getVersion: jest.fn().mockReturnValue("default"),
     } as unknown as Room;
 }
 
-export function makeMockRoomState(memberships: CallMembershipData[], roomId: string, localAge: number | null = null) {
-    const event = mockRTCEvent(memberships, roomId, localAge);
+export function makeMockRoomState(membershipData: MembershipData, roomId: string, localAge: number | null = null) {
+    const event = mockRTCEvent(membershipData, roomId, localAge);
     return {
         on: jest.fn(),
         off: jest.fn(),
@@ -40,15 +43,30 @@ export function makeMockRoomState(memberships: CallMembershipData[], roomId: str
             if (stateKey !== undefined) return event;
             return [event];
         },
+        events: new Map([
+            [
+                event.getType(),
+                {
+                    size: () => true,
+                    has: (_stateKey: string) => true,
+                    get: (_stateKey: string) => event,
+                    values: () => [event],
+                },
+            ],
+        ]),
     };
 }
 
-export function mockRTCEvent(memberships: CallMembershipData[], roomId: string, localAge: number | null): MatrixEvent {
+export function mockRTCEvent(membershipData: MembershipData, roomId: string, localAge: number | null): MatrixEvent {
     return {
         getType: jest.fn().mockReturnValue(EventType.GroupCallMemberPrefix),
-        getContent: jest.fn().mockReturnValue({
-            memberships: memberships,
-        }),
+        getContent: jest.fn().mockReturnValue(
+            !Array.isArray(membershipData)
+                ? membershipData
+                : {
+                      memberships: membershipData,
+                  },
+        ),
         getSender: jest.fn().mockReturnValue("@mock:user.example"),
         getTs: jest.fn().mockReturnValue(1000),
         localTimestamp: Date.now() - (localAge ?? 10),

spec/unit/queueToDevice.spec.ts

@@ -61,251 +61,293 @@ describe.each([[StoreType.Memory], [StoreType.IndexedDB]])("queueToDevice (%s st
     let httpBackend: MockHttpBackend;
     let client: MatrixClient;
 
-    beforeEach(async function () {
-        jest.runOnlyPendingTimers();
-        jest.useRealTimers();
-        httpBackend = new MockHttpBackend();
+    /**
+     * We need to split the tests into regular ones (these) and ones that use fake timers,
+     * because the fake indexeddb uses timers too and appears make tests cause other tests
+     * to fail if we keep enabling/disabling fake timers within the same test suite.
+     */
+    describe("non-timed tests", () => {
+        beforeEach(async function () {
+            httpBackend = new MockHttpBackend();
 
-        let store: IStore;
-        if (storeType === StoreType.IndexedDB) {
-            const idbStore = new IndexedDBStore({ indexedDB: fakeIndexedDB });
-            await idbStore.startup();
-            store = idbStore;
-        } else {
-            store = new MemoryStore();
-        }
+            let store: IStore;
+            if (storeType === StoreType.IndexedDB) {
+                const idbStore = new IndexedDBStore({ indexedDB: fakeIndexedDB });
+                await idbStore.startup();
+                store = idbStore;
+            } else {
+                store = new MemoryStore();
+            }
 
-        client = new MatrixClient({
-            baseUrl: "https://my.home.server",
-            accessToken: "my.access.token",
-            fetchFn: httpBackend.fetchFn as typeof global.fetch,
-            store,
-        });
-    });
-
-    afterEach(function () {
-        jest.useRealTimers();
-        client.stopClient();
-    });
-
-    it("sends a to-device message", async function () {
-        httpBackend
-            .when("PUT", "/sendToDevice/org.example.foo/")
-            .check((request) => {
-                expect(request.data).toEqual(EXPECTED_BODY);
-            })
-            .respond(200, {});
-
-        await client.queueToDevice({
-            eventType: "org.example.foo",
-            batch: [FAKE_MSG],
-        });
-
-        await httpBackend.flushAllExpected();
-        // let the code handle the response to the request so we don't get
-        // log output after the test has finished (apparently stopping the
-        // client in aftereach is not sufficient.)
-        await flushPromises();
-    });
-
-    it("retries on error", async function () {
-        jest.useFakeTimers();
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(500);
-
-        httpBackend
-            .when("PUT", "/sendToDevice/org.example.foo/")
-            .check((request) => {
-                expect(request.data).toEqual(EXPECTED_BODY);
-            })
-            .respond(200, {});
-
-        await client.queueToDevice({
-            eventType: "org.example.foo",
-            batch: [FAKE_MSG],
-        });
-        await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
-        expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
-
-        await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
-
-        expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
-
-        // flush, as per comment in first test
-        await flushPromises();
-    });
-
-    it("stops retrying on 4xx errors", async function () {
-        jest.useFakeTimers();
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(400);
-
-        await client.queueToDevice({
-            eventType: "org.example.foo",
-            batch: [FAKE_MSG],
-        });
-        await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
-        expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
-
-        // Asserting that another request is never made is obviously
-        // a bit tricky - we just flush the queue what should hopefully
-        // be plenty of times and assert that nothing comes through.
-        let tries = 0;
-        await flushAndRunTimersUntil(() => ++tries === 10);
-
-        expect(httpBackend.requests.length).toEqual(0);
-    });
-
-    it("honours ratelimiting", async function () {
-        jest.useFakeTimers();
-
-        // pick something obscure enough it's unlikley to clash with a
-        // retry delay the algorithm uses anyway
-        const retryDelay = 279 * 1000;
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(429, {
-            errcode: "M_LIMIT_EXCEEDED",
-            retry_after_ms: retryDelay,
-        });
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(200, {});
-
-        await client.queueToDevice({
-            eventType: "org.example.foo",
-            batch: [FAKE_MSG],
-        });
-        await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
-        expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
-        await flushPromises();
-
-        logger.info("Advancing clock to just before expected retry time...");
-
-        jest.advanceTimersByTime(retryDelay - 1000);
-        await flushPromises();
-
-        expect(httpBackend.requests.length).toEqual(0);
-
-        logger.info("Advancing clock past expected retry time...");
-
-        jest.advanceTimersByTime(2000);
-        await flushPromises();
-
-        expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
-    });
-
-    it("retries on retryImmediately()", async function () {
-        httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
-            versions: ["v1.1"],
-        });
-
-        await Promise.all([client.startClient(), httpBackend.flush(undefined, 1, 20)]);
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(500);
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(200, {});
-
-        await client.queueToDevice({
-            eventType: "org.example.foo",
-            batch: [FAKE_MSG],
-        });
-        expect(await httpBackend.flush(undefined, 1, 1)).toEqual(1);
-        await flushPromises();
-
-        client.retryImmediately();
-
-        // longer timeout here to try & avoid flakiness
-        expect(await httpBackend.flush(undefined, 1, 3000)).toEqual(1);
-    });
-
-    it("retries on when client is started", async function () {
-        httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
-            versions: ["v1.1"],
-        });
-
-        await Promise.all([client.startClient(), httpBackend.flush("/_matrix/client/versions", 1, 20)]);
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(500);
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(200, {});
-
-        await client.queueToDevice({
-            eventType: "org.example.foo",
-            batch: [FAKE_MSG],
-        });
-        expect(await httpBackend.flush(undefined, 1, 1)).toEqual(1);
-        await flushPromises();
-
-        client.stopClient();
-        await Promise.all([client.startClient(), httpBackend.flush("/_matrix/client/versions", 1, 20)]);
-
-        expect(await httpBackend.flush(undefined, 1, 20)).toEqual(1);
-    });
-
-    it("retries when a message is retried", async function () {
-        httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
-            versions: ["v1.1"],
-        });
-
-        await Promise.all([client.startClient(), httpBackend.flush(undefined, 1, 20)]);
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(500);
-
-        httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(200, {});
-
-        await client.queueToDevice({
-            eventType: "org.example.foo",
-            batch: [FAKE_MSG],
-        });
-
-        expect(await httpBackend.flush(undefined, 1, 20)).toEqual(1);
-        await flushPromises();
-
-        const dummyEvent = new MatrixEvent({
-            event_id: "!fake:example.org",
-        });
-        const mockRoom = {
-            updatePendingEvent: jest.fn(),
-            hasEncryptionStateEvent: jest.fn().mockReturnValue(false),
-        } as unknown as Room;
-        client.resendEvent(dummyEvent, mockRoom);
-
-        expect(await httpBackend.flush(undefined, 1, 20)).toEqual(1);
-    });
-
-    it("splits many messages into multiple HTTP requests", async function () {
-        const batch: ToDeviceBatch = {
-            eventType: "org.example.foo",
-            batch: [],
-        };
-
-        for (let i = 0; i <= 20; ++i) {
-            batch.batch.push({
-                userId: `@user${i}:example.org`,
-                deviceId: FAKE_DEVICE_ID,
-                payload: FAKE_PAYLOAD,
+            client = new MatrixClient({
+                baseUrl: "https://my.home.server",
+                accessToken: "my.access.token",
+                fetchFn: httpBackend.fetchFn as typeof global.fetch,
+                store,
             });
-        }
+        });
 
-        const expectedCounts = [20, 1];
-        httpBackend
-            .when("PUT", "/sendToDevice/org.example.foo/")
-            .check((request) => {
-                expect(
-                    removeElement(expectedCounts, (c) => c === Object.keys(request.data.messages).length),
-                ).toBeTruthy();
-            })
-            .respond(200, {});
-        httpBackend
-            .when("PUT", "/sendToDevice/org.example.foo/")
-            .check((request) => {
-                expect(Object.keys(request.data.messages).length).toEqual(1);
-            })
-            .respond(200, {});
+        afterEach(function () {
+            client.stopClient();
+        });
 
-        await client.queueToDevice(batch);
-        await httpBackend.flushAllExpected();
+        it("sends a to-device message", async function () {
+            httpBackend
+                .when("PUT", "/sendToDevice/org.example.foo/")
+                .check((request) => {
+                    expect(request.data).toEqual(EXPECTED_BODY);
+                })
+                .respond(200, {});
 
-        // flush, as per comment in first test
-        await flushPromises();
+            await client.queueToDevice({
+                eventType: "org.example.foo",
+                batch: [FAKE_MSG],
+            });
+
+            await httpBackend.flushAllExpected();
+            // let the code handle the response to the request so we don't get
+            // log output after the test has finished (apparently stopping the
+            // client in aftereach is not sufficient.)
+            await flushPromises();
+        });
+
+        it("retries on retryImmediately()", async function () {
+            httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
+                versions: ["v1.1"],
+            });
+
+            await Promise.all([client.startClient(), httpBackend.flush(undefined, 1, 20)]);
+
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(500);
+
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(200, {});
+
+            await client.queueToDevice({
+                eventType: "org.example.foo",
+                batch: [FAKE_MSG],
+            });
+            expect(await httpBackend.flush(undefined, 1, 1)).toEqual(1);
+            await flushPromises();
+
+            client.retryImmediately();
+
+            // longer timeout here to try & avoid flakiness
+            expect(await httpBackend.flush(undefined, 1, 3000)).toEqual(1);
+        });
+
+        it("retries on when client is started", async function () {
+            httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
+                versions: ["v1.1"],
+            });
+
+            await Promise.all([client.startClient(), httpBackend.flush("/_matrix/client/versions", 1, 20)]);
+
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(500);
+
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(200, {});
+
+            await client.queueToDevice({
+                eventType: "org.example.foo",
+                batch: [FAKE_MSG],
+            });
+            expect(await httpBackend.flush(undefined, 1, 1)).toEqual(1);
+            await flushPromises();
+
+            client.stopClient();
+            await Promise.all([client.startClient(), httpBackend.flush("/_matrix/client/versions", 1, 20)]);
+
+            expect(await httpBackend.flush(undefined, 1, 20)).toEqual(1);
+        });
+
+        it("retries when a message is retried", async function () {
+            httpBackend.when("GET", "/_matrix/client/versions").respond(200, {
+                versions: ["v1.1"],
+            });
+
+            await Promise.all([client.startClient(), httpBackend.flush(undefined, 1, 20)]);
+
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(500);
+
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(200, {});
+
+            await client.queueToDevice({
+                eventType: "org.example.foo",
+                batch: [FAKE_MSG],
+            });
+
+            expect(await httpBackend.flush(undefined, 1, 20)).toEqual(1);
+            await flushPromises();
+
+            const dummyEvent = new MatrixEvent({
+                event_id: "!fake:example.org",
+            });
+            const mockRoom = {
+                updatePendingEvent: jest.fn(),
+                hasEncryptionStateEvent: jest.fn().mockReturnValue(false),
+            } as unknown as Room;
+            client.resendEvent(dummyEvent, mockRoom);
+
+            expect(await httpBackend.flush(undefined, 1, 20)).toEqual(1);
+        });
+
+        it("splits many messages into multiple HTTP requests", async function () {
+            const batch: ToDeviceBatch = {
+                eventType: "org.example.foo",
+                batch: [],
+            };
+
+            for (let i = 0; i <= 20; ++i) {
+                batch.batch.push({
+                    userId: `@user${i}:example.org`,
+                    deviceId: FAKE_DEVICE_ID,
+                    payload: FAKE_PAYLOAD,
+                });
+            }
+
+            const expectedCounts = [20, 1];
+            httpBackend
+                .when("PUT", "/sendToDevice/org.example.foo/")
+                .check((request) => {
+                    expect(
+                        removeElement(expectedCounts, (c) => c === Object.keys(request.data.messages).length),
+                    ).toBeTruthy();
+                })
+                .respond(200, {});
+            httpBackend
+                .when("PUT", "/sendToDevice/org.example.foo/")
+                .check((request) => {
+                    expect(Object.keys(request.data.messages).length).toEqual(1);
+                })
+                .respond(200, {});
+
+            await client.queueToDevice(batch);
+            await httpBackend.flushAllExpected();
+
+            // flush, as per comment in first test
+            await flushPromises();
+        });
+    });
+
+    describe("async tests", () => {
+        beforeAll(() => {
+            jest.useFakeTimers();
+        });
+
+        afterAll(() => {
+            jest.useRealTimers();
+        });
+
+        beforeEach(async function () {
+            httpBackend = new MockHttpBackend();
+
+            let store: IStore;
+            if (storeType === StoreType.IndexedDB) {
+                const idbStore = new IndexedDBStore({ indexedDB: fakeIndexedDB });
+                let storeStarted = false;
+                idbStore.startup().then(() => {
+                    storeStarted = true;
+                });
+                await flushAndRunTimersUntil(() => storeStarted);
+                store = idbStore;
+            } else {
+                store = new MemoryStore();
+            }
+
+            client = new MatrixClient({
+                baseUrl: "https://my.home.server",
+                accessToken: "my.access.token",
+                fetchFn: httpBackend.fetchFn as typeof global.fetch,
+                store,
+            });
+        });
+
+        afterEach(function () {
+            client.stopClient();
+        });
+
+        it("retries on error", async function () {
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(500);
+
+            httpBackend
+                .when("PUT", "/sendToDevice/org.example.foo/")
+                .check((request) => {
+                    expect(request.data).toEqual(EXPECTED_BODY);
+                })
+                .respond(200, {});
+
+            client
+                .queueToDevice({
+                    eventType: "org.example.foo",
+                    batch: [FAKE_MSG],
+                })
+                .then();
+            await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
+            expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
+
+            await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
+
+            expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
+
+            // flush, as per comment in first test
+            await flushPromises();
+        });
+
+        it("stops retrying on 4xx errors", async function () {
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(400);
+
+            client
+                .queueToDevice({
+                    eventType: "org.example.foo",
+                    batch: [FAKE_MSG],
+                })
+                .then();
+            await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
+            expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
+
+            // Asserting that another request is never made is obviously
+            // a bit tricky - we just flush the queue what should hopefully
+            // be plenty of times and assert that nothing comes through.
+            let tries = 0;
+            await flushAndRunTimersUntil(() => ++tries === 10);
+
+            expect(httpBackend.requests.length).toEqual(0);
+        });
+
+        it("honours ratelimiting", async function () {
+            // pick something obscure enough it's unlikley to clash with a
+            // retry delay the algorithm uses anyway
+            const retryDelay = 279 * 1000;
+
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(429, {
+                errcode: "M_LIMIT_EXCEEDED",
+                retry_after_ms: retryDelay,
+            });
+
+            httpBackend.when("PUT", "/sendToDevice/org.example.foo/").respond(200, {});
+
+            client
+                .queueToDevice({
+                    eventType: "org.example.foo",
+                    batch: [FAKE_MSG],
+                })
+                .then();
+            await flushAndRunTimersUntil(() => httpBackend.requests.length > 0);
+            expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
+            await flushPromises();
+
+            logger.info("Advancing clock to just before expected retry time...");
+
+            jest.advanceTimersByTime(retryDelay - 1000);
+            await flushPromises();
+
+            expect(httpBackend.requests.length).toEqual(0);
+
+            logger.info("Advancing clock past expected retry time...");
+
+            jest.advanceTimersByTime(2000);
+            await flushPromises();
+
+            expect(httpBackend.flushSync(undefined, 1)).toEqual(1);
+        });
     });
 });

spec/unit/rendezvous/MSC4108RendezvousSession.spec.ts

@@ -0,0 +1,341 @@
+/*
+Copyright 2024 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 fetchMock from "fetch-mock-jest";
+
+import { ClientPrefix, IHttpOpts, MatrixClient, MatrixHttpApi } from "../../../src";
+import { ClientRendezvousFailureReason, MSC4108RendezvousSession } from "../../../src/rendezvous";
+
+function makeMockClient(opts: { userId: string; deviceId: string; msc4108Enabled: boolean }): MatrixClient {
+    const client = {
+        doesServerSupportUnstableFeature(feature: string) {
+            return Promise.resolve(opts.msc4108Enabled && feature === "org.matrix.msc4108");
+        },
+        getUserId() {
+            return opts.userId;
+        },
+        getDeviceId() {
+            return opts.deviceId;
+        },
+        baseUrl: "https://example.com",
+    } as unknown as MatrixClient;
+    client.http = new MatrixHttpApi<IHttpOpts & { onlyData: true }>(client, {
+        baseUrl: client.baseUrl,
+        prefix: ClientPrefix.Unstable,
+        onlyData: true,
+    });
+    return client;
+}
+
+fetchMock.config.overwriteRoutes = true;
+
+describe("MSC4108RendezvousSession", () => {
+    beforeEach(() => {
+        fetchMock.reset();
+    });
+
+    async function postAndCheckLocation(msc4108Enabled: boolean, fallbackRzServer: string, locationResponse: string) {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled });
+        const transport = new MSC4108RendezvousSession({ client, fallbackRzServer });
+        {
+            // initial POST
+            const expectedPostLocation = msc4108Enabled
+                ? `${client.baseUrl}/_matrix/client/unstable/org.matrix.msc4108/rendezvous`
+                : fallbackRzServer;
+
+            fetchMock.postOnce(expectedPostLocation, {
+                status: 201,
+                body: { url: locationResponse },
+            });
+            await transport.send("data");
+        }
+
+        {
+            fetchMock.get(locationResponse, {
+                status: 200,
+                body: "data",
+                headers: {
+                    "content-type": "text/plain",
+                    "etag": "aaa",
+                },
+            });
+            await expect(transport.receive()).resolves.toEqual("data");
+        }
+    }
+
+    it("should use custom fetchFn if provided", async () => {
+        const sandbox = fetchMock.sandbox();
+        const fetchFn = jest.fn().mockImplementation(sandbox);
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fetchFn,
+            fallbackRzServer: "https://fallbackserver/rz",
+        });
+        sandbox.postOnce("https://fallbackserver/rz", {
+            status: 201,
+            body: {
+                url: "https://fallbackserver/rz/123",
+            },
+        });
+        await transport.send("data");
+        await sandbox.flush(true);
+        expect(fetchFn).toHaveBeenCalledWith("https://fallbackserver/rz", expect.anything());
+    });
+
+    it("should throw an error when no server available", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({ client });
+        await expect(transport.send("data")).rejects.toThrow("Invalid rendezvous URI");
+    });
+
+    it("POST to fallback server", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+        });
+        fetchMock.postOnce("https://fallbackserver/rz", {
+            status: 201,
+            body: { url: "https://fallbackserver/rz/123" },
+        });
+        await fetchMock.flush(true);
+        await expect(transport.send("data")).resolves.toStrictEqual(undefined);
+    });
+
+    it("POST with no location", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+        });
+        fetchMock.postOnce("https://fallbackserver/rz", {
+            status: 201,
+        });
+        await Promise.all([expect(transport.send("data")).rejects.toThrow(), fetchMock.flush(true)]);
+    });
+
+    it("POST with absolute path response", async function () {
+        await postAndCheckLocation(false, "https://fallbackserver/rz", "https://fallbackserver/123");
+    });
+
+    it("POST to built-in MSC3886 implementation", async function () {
+        await postAndCheckLocation(
+            true,
+            "https://fallbackserver/rz",
+            "https://example.com/_matrix/client/unstable/org.matrix.msc4108/rendezvous/123",
+        );
+    });
+
+    it("POST with relative path response including parent", async function () {
+        await postAndCheckLocation(false, "https://fallbackserver/rz/abc", "https://fallbackserver/rz/xyz/123");
+    });
+
+    // fetch-mock doesn't handle redirects properly, so we can't test this
+    it.skip("POST to follow 307 to other server", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+        });
+        fetchMock.postOnce("https://fallbackserver/rz", {
+            status: 307,
+            redirectUrl: "https://redirected.fallbackserver/rz",
+            redirected: true,
+        });
+        fetchMock.postOnce("https://redirected.fallbackserver/rz", {
+            status: 201,
+            body: { url: "https://redirected.fallbackserver/rz/123" },
+            headers: { etag: "aaa" },
+        });
+        await fetchMock.flush(true);
+        await expect(transport.send("data")).resolves.toStrictEqual(undefined);
+    });
+
+    it("POST and GET", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+        });
+        {
+            // initial POST
+            fetchMock.postOnce("https://fallbackserver/rz", {
+                status: 201,
+                body: { url: "https://fallbackserver/rz/123" },
+            });
+            await expect(transport.send("foo=baa")).resolves.toStrictEqual(undefined);
+            await fetchMock.flush(true);
+            expect(fetchMock).toHaveFetched("https://fallbackserver/rz", {
+                method: "POST",
+                headers: { "content-type": "text/plain" },
+                functionMatcher: (_, opts): boolean => {
+                    return opts.body === "foo=baa";
+                },
+            });
+        }
+        {
+            // first GET without etag
+            fetchMock.getOnce("https://fallbackserver/rz/123", {
+                status: 200,
+                body: "foo=baa",
+                headers: { "content-type": "text/plain", "etag": "aaa" },
+            });
+            await expect(transport.receive()).resolves.toEqual("foo=baa");
+            await fetchMock.flush(true);
+        }
+        {
+            // subsequent GET which should have etag from previous request
+            fetchMock.getOnce("https://fallbackserver/rz/123", {
+                status: 200,
+                body: "foo=baa",
+                headers: { "content-type": "text/plain", "etag": "bbb" },
+            });
+            await expect(transport.receive()).resolves.toEqual("foo=baa");
+            await fetchMock.flush(true);
+            expect(fetchMock).toHaveFetched("https://fallbackserver/rz/123", {
+                method: "GET",
+                headers: { "if-none-match": "aaa" },
+            });
+        }
+    });
+
+    it("POST and PUTs", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+        });
+        {
+            // initial POST
+            fetchMock.postOnce("https://fallbackserver/rz", {
+                status: 201,
+                body: { url: "https://fallbackserver/rz/123" },
+                headers: { etag: "aaa" },
+            });
+            await transport.send("foo=baa");
+            await fetchMock.flush(true);
+            expect(fetchMock).toHaveFetched("https://fallbackserver/rz", {
+                method: "POST",
+                headers: { "content-type": "text/plain" },
+                functionMatcher: (_, opts): boolean => {
+                    return opts.body === "foo=baa";
+                },
+            });
+        }
+        {
+            // subsequent PUT which should have etag from previous request
+            fetchMock.putOnce("https://fallbackserver/rz/123", { status: 202, headers: { etag: "bbb" } });
+            await transport.send("c=d");
+            await fetchMock.flush(true);
+            expect(fetchMock).toHaveFetched("https://fallbackserver/rz/123", {
+                method: "PUT",
+                headers: { "if-match": "aaa" },
+            });
+        }
+    });
+
+    it("POST and DELETE", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+        });
+        {
+            // Create
+            fetchMock.postOnce("https://fallbackserver/rz", {
+                status: 201,
+                body: { url: "https://fallbackserver/rz/123" },
+            });
+            await expect(transport.send("foo=baa")).resolves.toStrictEqual(undefined);
+            await fetchMock.flush(true);
+            expect(fetchMock).toHaveFetched("https://fallbackserver/rz", {
+                method: "POST",
+                headers: { "content-type": "text/plain" },
+                functionMatcher: (_, opts): boolean => {
+                    return opts.body === "foo=baa";
+                },
+            });
+        }
+        {
+            // Cancel
+            fetchMock.deleteOnce("https://fallbackserver/rz/123", { status: 204 });
+            await transport.cancel(ClientRendezvousFailureReason.UserDeclined);
+            await fetchMock.flush(true);
+        }
+    });
+
+    it("send after cancelled", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+        });
+        await transport.cancel(ClientRendezvousFailureReason.UserDeclined);
+        await expect(transport.send("data")).resolves.toBeUndefined();
+    });
+
+    it("receive before ready", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+        });
+        await expect(transport.receive()).rejects.toThrow();
+    });
+
+    it("404 failure callback", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const onFailure = jest.fn();
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+            onFailure,
+        });
+
+        fetchMock.postOnce("https://fallbackserver/rz", { status: 404 });
+        await Promise.all([expect(transport.send("foo=baa")).resolves.toBeUndefined(), fetchMock.flush(true)]);
+        expect(onFailure).toHaveBeenCalledWith(ClientRendezvousFailureReason.Unknown);
+    });
+
+    it("404 failure callback mapped to expired", async function () {
+        const client = makeMockClient({ userId: "@alice:example.com", deviceId: "DEVICEID", msc4108Enabled: false });
+        const onFailure = jest.fn();
+        const transport = new MSC4108RendezvousSession({
+            client,
+            fallbackRzServer: "https://fallbackserver/rz",
+            onFailure,
+        });
+
+        {
+            // initial POST
+            fetchMock.postOnce("https://fallbackserver/rz", {
+                status: 201,
+                body: { url: "https://fallbackserver/rz/123" },
+                headers: { expires: "Thu, 01 Jan 1970 00:00:00 GMT" },
+            });
+
+            await transport.send("foo=baa");
+            await fetchMock.flush(true);
+        }
+        {
+            // GET with 404 to simulate expiry
+            fetchMock.getOnce("https://fallbackserver/rz/123", { status: 404, body: "foo=baa" });
+            await Promise.all([expect(transport.receive()).resolves.toBeUndefined(), fetchMock.flush(true)]);
+            expect(onFailure).toHaveBeenCalledWith(ClientRendezvousFailureReason.Expired);
+        }
+    });
+});

spec/unit/rendezvous/channels/MSC4108SecureChannel.spec.ts

@@ -0,0 +1,126 @@
+/*
+Copyright 2024 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 { EstablishedEcies, QrCodeData, QrCodeMode, Ecies } from "@matrix-org/matrix-sdk-crypto-wasm";
+import { mocked } from "jest-mock";
+
+import { MSC4108RendezvousSession, MSC4108SecureChannel, PayloadType } from "../../../../src/rendezvous";
+
+describe("MSC4108SecureChannel", () => {
+    const baseUrl = "https://example.com";
+    const url = "https://fallbackserver/rz/123";
+
+    it("should generate qr code data as expected", async () => {
+        const session = new MSC4108RendezvousSession({
+            url,
+        });
+        const channel = new MSC4108SecureChannel(session);
+
+        const code = await channel.generateCode(QrCodeMode.Login);
+        expect(code).toHaveLength(71);
+        const text = new TextDecoder().decode(code);
+        expect(text.startsWith("MATRIX")).toBeTruthy();
+        expect(text.endsWith(url)).toBeTruthy();
+    });
+
+    it("should throw error if attempt to connect multiple times", async () => {
+        const mockSession = {
+            send: jest.fn(),
+            receive: jest.fn(),
+            url,
+        } as unknown as MSC4108RendezvousSession;
+        const channel = new MSC4108SecureChannel(mockSession);
+
+        const qrCodeData = QrCodeData.fromBytes(await channel.generateCode(QrCodeMode.Reciprocate, baseUrl));
+        const { initial_message: ciphertext } = new Ecies().establish_outbound_channel(
+            qrCodeData.publicKey,
+            "MATRIX_QR_CODE_LOGIN_INITIATE",
+        );
+        mocked(mockSession.receive).mockResolvedValue(ciphertext);
+        await channel.connect();
+        await expect(channel.connect()).rejects.toThrow("Channel already connected");
+    });
+
+    it("should throw error on invalid initiate response", async () => {
+        const mockSession = {
+            send: jest.fn(),
+            receive: jest.fn(),
+            url,
+        } as unknown as MSC4108RendezvousSession;
+        const channel = new MSC4108SecureChannel(mockSession);
+
+        mocked(mockSession.receive).mockResolvedValue("");
+        await expect(channel.connect()).rejects.toThrow("No response from other device");
+
+        const qrCodeData = QrCodeData.fromBytes(await channel.generateCode(QrCodeMode.Reciprocate, baseUrl));
+        const { initial_message: ciphertext } = new Ecies().establish_outbound_channel(
+            qrCodeData.publicKey,
+            "NOT_REAL_MATRIX_QR_CODE_LOGIN_INITIATE",
+        );
+
+        mocked(mockSession.receive).mockResolvedValue(ciphertext);
+        await expect(channel.connect()).rejects.toThrow("Invalid response from other device");
+    });
+
+    describe("should be able to connect as a reciprocating device", () => {
+        let mockSession: MSC4108RendezvousSession;
+        let channel: MSC4108SecureChannel;
+        let opponentChannel: EstablishedEcies;
+
+        beforeEach(async () => {
+            mockSession = {
+                send: jest.fn(),
+                receive: jest.fn(),
+                url,
+            } as unknown as MSC4108RendezvousSession;
+            channel = new MSC4108SecureChannel(mockSession);
+
+            const qrCodeData = QrCodeData.fromBytes(await channel.generateCode(QrCodeMode.Reciprocate, baseUrl));
+            const { channel: _opponentChannel, initial_message: ciphertext } = new Ecies().establish_outbound_channel(
+                qrCodeData.publicKey,
+                "MATRIX_QR_CODE_LOGIN_INITIATE",
+            );
+            opponentChannel = _opponentChannel;
+
+            mocked(mockSession.receive).mockResolvedValue(ciphertext);
+            await channel.connect();
+            expect(opponentChannel.decrypt(mocked(mockSession.send).mock.calls[0][0])).toBe("MATRIX_QR_CODE_LOGIN_OK");
+            mocked(mockSession.send).mockReset();
+        });
+
+        it("should be able to securely send encrypted payloads", async () => {
+            const payload = {
+                type: PayloadType.Secrets,
+                protocols: ["a", "b", "c"],
+                homeserver: "https://example.org",
+            };
+            await channel.secureSend(payload);
+            expect(mockSession.send).toHaveBeenCalled();
+            expect(opponentChannel.decrypt(mocked(mockSession.send).mock.calls[0][0])).toBe(JSON.stringify(payload));
+        });
+
+        it("should be able to securely receive encrypted payloads", async () => {
+            const payload = {
+                type: PayloadType.Secrets,
+                protocols: ["a", "b", "c"],
+                homeserver: "https://example.org",
+            };
+            const ciphertext = opponentChannel.encrypt(JSON.stringify(payload));
+            mocked(mockSession.receive).mockResolvedValue(ciphertext);
+            await expect(channel.secureReceive()).resolves.toEqual(payload);
+        });
+    });
+});

spec/unit/rendezvous/ecdhv2.spec.ts

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import "../../olm-loader";
-import { RendezvousFailureReason, RendezvousIntent } from "../../../src/rendezvous";
+import { LegacyRendezvousFailureReason as RendezvousFailureReason, RendezvousIntent } from "../../../src/rendezvous";
 import { MSC3903ECDHPayload, MSC3903ECDHv2RendezvousChannel } from "../../../src/rendezvous/channels";
 import { decodeBase64 } from "../../../src/base64";
 import { DummyTransport } from "./DummyTransport";

spec/unit/rendezvous/rendezvous.spec.ts

@@ -17,7 +17,12 @@ limitations under the License.
 import MockHttpBackend from "matrix-mock-request";
 
 import "../../olm-loader";
-import { MSC3906Rendezvous, RendezvousCode, RendezvousFailureReason, RendezvousIntent } from "../../../src/rendezvous";
+import {
+    MSC3906Rendezvous,
+    RendezvousCode,
+    LegacyRendezvousFailureReason as RendezvousFailureReason,
+    RendezvousIntent,
+} from "../../../src/rendezvous";
 import {
     ECDHv2RendezvousCode as ECDHRendezvousCode,
     MSC3903ECDHPayload,
@@ -111,7 +116,7 @@ function makeMockClient(opts: {
                     },
                 };
             },
-            getCapabilities() {
+            getCachedCapabilities() {
                 return opts.msc3882r0Only
                     ? {}
                     : {

spec/unit/rendezvous/simpleHttpTransport.spec.ts

@@ -17,7 +17,7 @@ limitations under the License.
 import MockHttpBackend from "matrix-mock-request";
 
 import type { MatrixClient } from "../../../src";
-import { RendezvousFailureReason } from "../../../src/rendezvous";
+import { LegacyRendezvousFailureReason as RendezvousFailureReason } from "../../../src/rendezvous";
 import { MSC3886SimpleHttpRendezvousTransport } from "../../../src/rendezvous/transports";
 
 function makeMockClient(opts: { userId: string; deviceId: string; msc3886Enabled: boolean }): MatrixClient {

spec/unit/room.spec.ts

@@ -4034,4 +4034,47 @@ describe("Room", function () {
             expect(room.getLastThread()).toBe(thread2);
         });
     });
+
+    describe("getRecommendedVersion", () => {
+        it("returns the server's recommended version from capabilities", async () => {
+            const client = new TestClient(userA).client;
+            client.getCapabilities = jest.fn().mockReturnValue({
+                ["m.room_versions"]: {
+                    default: "1",
+                    available: ["1", "2"],
+                },
+            });
+            const room = new Room(roomId, client, userA);
+            expect(await room.getRecommendedVersion()).toEqual({
+                version: "1",
+                needsUpgrade: false,
+                urgent: false,
+            });
+        });
+
+        it("force-refreshes versions to make sure an upgrade is necessary", async () => {
+            const client = new TestClient(userA).client;
+            client.getCapabilities = jest.fn().mockReturnValue({
+                ["m.room_versions"]: {
+                    default: "5",
+                    available: ["5"],
+                },
+            });
+
+            client.fetchCapabilities = jest.fn().mockResolvedValue({
+                ["m.room_versions"]: {
+                    default: "1",
+                    available: ["1"],
+                },
+            });
+
+            const room = new Room(roomId, client, userA);
+            expect(await room.getRecommendedVersion()).toEqual({
+                version: "1",
+                needsUpgrade: false,
+                urgent: false,
+            });
+            expect(client.fetchCapabilities).toHaveBeenCalled();
+        });
+    });
 });

spec/unit/rust-crypto/rust-crypto.spec.ts

@@ -1515,6 +1515,44 @@ describe("RustCrypto", () => {
             expect(await rustCrypto.isDehydrationSupported()).toBe(true);
         });
     });
+
+    describe("import & export secrets bundle", () => {
+        let rustCrypto: RustCrypto;
+
+        beforeEach(async () => {
+            rustCrypto = await makeTestRustCrypto(
+                new MatrixHttpApi(new TypedEventEmitter<HttpApiEvent, HttpApiEventHandlerMap>(), {
+                    baseUrl: "http://server/",
+                    prefix: "",
+                    onlyData: true,
+                }),
+                testData.TEST_USER_ID,
+            );
+        });
+
+        it("should throw an error if there is nothing to export", async () => {
+            await expect(rustCrypto.exportSecretsBundle()).rejects.toThrow(
+                "The store doesn't contain any cross-signing keys",
+            );
+        });
+
+        it("should correctly import & export a secrets bundle", async () => {
+            const bundle = {
+                cross_signing: {
+                    master_key: "bMnVpkHI4S2wXRxy+IpaKM5PIAUUkl6DE+n0YLIW/qs",
+                    user_signing_key: "8tlgLjUrrb/zGJo4YKGhDTIDCEjtJTAS/Sh2AGNLuIo",
+                    self_signing_key: "pfDknmP5a0fVVRE54zhkUgJfzbNmvKcNfIWEW796bQs",
+                },
+                backup: {
+                    algorithm: "m.megolm_backup.v1.curve25519-aes-sha2",
+                    key: "bYYv3aFLQ49jMNcOjuTtBY9EKDby2x1m3gfX81nIKRQ",
+                    backup_version: "9",
+                },
+            };
+            await rustCrypto.importSecretsBundle(bundle);
+            await expect(rustCrypto.exportSecretsBundle()).resolves.toEqual(expect.objectContaining(bundle));
+        });
+    });
 });
 
 /** Build a MatrixHttpApi instance */

src/@types/event.ts

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { UnstableValue } from "../NamespacedValue";
+import { NamespacedValue, UnstableValue } from "../NamespacedValue";
 import {
     PolicyRuleEventContent,
     RoomAvatarEventContent,
@@ -57,6 +57,7 @@ import {
 } from "../webrtc/callEventTypes";
 import { EncryptionKeysEventContent, ICallNotifyContent } from "../matrixrtc/types";
 import { M_POLL_END, M_POLL_START, PollEndEventContent, PollStartEventContent } from "./polls";
+import { SessionMembershipData } from "../matrixrtc/CallMembership";
 
 export enum EventType {
     // Room state events
@@ -302,7 +303,7 @@ export const UNSIGNED_THREAD_ID_FIELD = new UnstableValue("thread_id", "org.matr
  *
  * @experimental
  */
-export const UNSIGNED_MEMBERSHIP_FIELD = new UnstableValue("membership", "io.element.msc4115.membership");
+export const UNSIGNED_MEMBERSHIP_FIELD = new NamespacedValue("membership", "io.element.msc4115.membership");
 
 /**
  * Mapped type from event type to content type for all specified non-state room events.
@@ -356,7 +357,10 @@ export interface StateEvents {
 
     // MSC3401
     [EventType.GroupCallPrefix]: IGroupCallRoomState;
-    [EventType.GroupCallMemberPrefix]: XOR<IGroupCallRoomMemberState, ExperimentalGroupCallRoomMemberState>;
+    [EventType.GroupCallMemberPrefix]: XOR<
+        XOR<IGroupCallRoomMemberState, ExperimentalGroupCallRoomMemberState>,
+        XOR<SessionMembershipData, {}>
+    >;
 
     // MSC3089
     [UNSTABLE_MSC3089_BRANCH.name]: MSC3089EventContent;

src/@types/matrix-sdk-crypto-wasm.d.ts

@@ -0,0 +1,44 @@
+/*
+Copyright 2024 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 type * as RustSdkCryptoJs from "@matrix-org/matrix-sdk-crypto-wasm";
+
+declare module "@matrix-org/matrix-sdk-crypto-wasm" {
+    interface OlmMachine {
+        importSecretsBundle(bundle: RustSdkCryptoJs.SecretsBundle): Promise<void>;
+        exportSecretsBundle(): Promise<RustSdkCryptoJs.SecretsBundle>;
+    }
+
+    interface SecretsBundle {
+        // eslint-disable-next-line @typescript-eslint/naming-convention
+        to_json(): Promise<{
+            cross_signing: {
+                master_key: string;
+                self_signing_key: string;
+                user_signing_key: string;
+            };
+            backup?: {
+                algorithm: string;
+                key: string;
+                backup_version: string;
+            };
+        }>;
+    }
+
+    interface Device {
+        requestVerification(methods?: any[]): [RustSdkCryptoJs.VerificationRequest, RustSdkCryptoJs.ToDeviceRequest];
+    }
+}

src/@types/search.ts

@@ -54,9 +54,9 @@ enum GroupKey {
 }
 
 export interface IResultRoomEvents {
-    count: number;
-    highlights: string[];
-    results: ISearchResult[];
+    count?: number;
+    highlights?: string[];
+    results?: ISearchResult[];
     state?: { [roomId: string]: IStateEventWithRoomId[] };
     groups?: {
         [groupKey in GroupKey]: {

src/@types/state_events.ts

@@ -95,7 +95,9 @@ export interface RoomTopicEventContent {
 
 export interface RoomAvatarEventContent {
     url?: string;
-    info?: ImageInfo;
+    // The spec says that an encrypted file can be used for the thumbnail but this isn't true
+    // https://github.com/matrix-org/matrix-spec/issues/562 so omit those fields
+    info?: Omit<ImageInfo, "thumbnail_file">;
 }
 
 export interface RoomPinnedEventsEventContent {

src/base64.ts

@@ -59,7 +59,7 @@ export function encodeUnpaddedBase64(uint8Array: ArrayBuffer | Uint8Array): stri
  * @returns The unpadded base64.
  */
 export function encodeUnpaddedBase64Url(uint8Array: ArrayBuffer | Uint8Array): string {
-    return encodeUnpaddedBase64(uint8Array).replace("+", "-").replace("/", "_");
+    return encodeUnpaddedBase64(uint8Array).replace(/\+/g, "-").replace(/\//g, "_");
 }
 
 /**
@@ -75,7 +75,7 @@ export function decodeBase64(base64: string): Uint8Array {
         const itFunc = function* (): Generator<number> {
             const decoded = atob(
                 // built-in atob doesn't support base64url: convert so we support either
-                base64.replace("-", "+").replace("_", "/"),
+                base64.replace(/-/g, "+").replace(/_/g, "/"),
             );
             for (let i = 0; i < decoded.length; ++i) {
                 yield decoded.charCodeAt(i);

src/client.ts

@@ -226,6 +226,7 @@ import { getRelationsThreadFilter } from "./thread-utils";
 import { KnownMembership, Membership } from "./@types/membership";
 import { RoomMessageEventContent, StickerEventContent } from "./@types/events";
 import { ImageInfo } from "./@types/media";
+import { Capabilities, ServerCapabilities } from "./serverCapabilities";
 
 export type Store = IStore;
 
@@ -233,7 +234,6 @@ export type ResetTimelineCallback = (roomId: string) => boolean;
 
 const SCROLLBACK_DELAY_MS = 3000;
 export const CRYPTO_ENABLED: boolean = isCryptoAvailable();
-const CAPABILITIES_CACHE_MS = 21600000; // 6 hours - an arbitrary value
 const TURN_CHECK_INTERVAL = 10 * 60 * 1000; // poll for turn credentials every 10 minutes
 
 export const UNSTABLE_MSC3852_LAST_SEEN_UA = new UnstableValue(
@@ -518,26 +518,6 @@ export interface IStartClientOpts {
 
 export interface IStoredClientOpts extends IStartClientOpts {}
 
-export enum RoomVersionStability {
-    Stable = "stable",
-    Unstable = "unstable",
-}
-
-export interface IRoomVersionsCapability {
-    default: string;
-    available: Record<string, RoomVersionStability>;
-}
-
-export interface ICapability {
-    enabled: boolean;
-}
-
-export interface IChangePasswordCapability extends ICapability {}
-
-export interface IThreadsCapability extends ICapability {}
-
-export interface IGetLoginTokenCapability extends ICapability {}
-
 export const GET_LOGIN_TOKEN_CAPABILITY = new NamespacedValue(
     "m.get_login_token",
     "org.matrix.msc3882.get_login_token",
@@ -547,19 +527,6 @@ export const UNSTABLE_MSC2666_SHARED_ROOMS = "uk.half-shot.msc2666";
 export const UNSTABLE_MSC2666_MUTUAL_ROOMS = "uk.half-shot.msc2666.mutual_rooms";
 export const UNSTABLE_MSC2666_QUERY_MUTUAL_ROOMS = "uk.half-shot.msc2666.query_mutual_rooms";
 
-/**
- * A representation of the capabilities advertised by a homeserver as defined by
- * [Capabilities negotiation](https://spec.matrix.org/v1.6/client-server-api/#get_matrixclientv3capabilities).
- */
-export interface Capabilities {
-    [key: string]: any;
-    "m.change_password"?: IChangePasswordCapability;
-    "m.room_versions"?: IRoomVersionsCapability;
-    "io.element.thread"?: IThreadsCapability;
-    "m.get_login_token"?: IGetLoginTokenCapability;
-    "org.matrix.msc3882.get_login_token"?: IGetLoginTokenCapability;
-}
-
 enum CrossSigningKeyType {
     MasterKey = "master_key",
     SelfSigningKey = "self_signing_key",
@@ -1293,10 +1260,6 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
     // TODO: This should expire: https://github.com/matrix-org/matrix-js-sdk/issues/1020
     protected serverVersionsPromise?: Promise<IServerVersions>;
 
-    public cachedCapabilities?: {
-        capabilities: Capabilities;
-        expiration: number;
-    };
     protected clientWellKnown?: IClientWellKnown;
     protected clientWellKnownPromise?: Promise<IClientWellKnown>;
     protected turnServers: ITurnServer[] = [];
@@ -1325,6 +1288,8 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
 
     public readonly matrixRTC: MatrixRTCSessionManager;
 
+    private serverCapabilitiesService: ServerCapabilities;
+
     public constructor(opts: IMatrixClientCreateOpts) {
         super();
 
@@ -1418,6 +1383,8 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
         // the underlying session management and doesn't use any actual media capabilities
         this.matrixRTC = new MatrixRTCSessionManager(this);
 
+        this.serverCapabilitiesService = new ServerCapabilities(this.http);
+
         this.on(ClientEvent.Sync, this.fixupRoomNotifications);
 
         this.timelineSupport = Boolean(opts.timelineSupport);
@@ -1540,6 +1507,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
         }
 
         this.toDeviceMessageQueue.start();
+        this.serverCapabilitiesService.start();
     }
 
     /**
@@ -1593,6 +1561,8 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
         this.toDeviceMessageQueue.stop();
 
         this.matrixRTC.stop();
+
+        this.serverCapabilitiesService.stop();
     }
 
     /**
@@ -2095,47 +2065,35 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
     }
 
     /**
-     * Gets the capabilities of the homeserver. Always returns an object of
-     * capability keys and their options, which may be empty.
-     * @param fresh - True to ignore any cached values.
-     * @returns Promise which resolves to the capabilities of the homeserver
-     * @returns Rejects: with an error response.
+     * Gets the cached capabilities of the homeserver, returning cached ones if available.
+     * If there are no cached capabilities and none can be fetched, throw an exception.
+     *
+     * @returns Promise resolving with The capabilities of the homeserver
      */
-    public getCapabilities(fresh = false): Promise<Capabilities> {
-        const now = new Date().getTime();
+    public async getCapabilities(): Promise<Capabilities> {
+        const caps = this.serverCapabilitiesService.getCachedCapabilities();
+        if (caps) return caps;
+        return this.serverCapabilitiesService.fetchCapabilities();
+    }
 
-        if (this.cachedCapabilities && !fresh) {
-            if (now < this.cachedCapabilities.expiration) {
-                this.logger.debug("Returning cached capabilities");
-                return Promise.resolve(this.cachedCapabilities.capabilities);
-            }
-        }
+    /**
+     * Gets the cached capabilities of the homeserver. If none have been fetched yet,
+     * return undefined.
+     *
+     * @returns The capabilities of the homeserver
+     */
+    public getCachedCapabilities(): Capabilities | undefined {
+        return this.serverCapabilitiesService.getCachedCapabilities();
+    }
 
-        type Response = {
-            capabilities?: Capabilities;
-        };
-        return this.http
-            .authedRequest<Response>(Method.Get, "/capabilities")
-            .catch((e: Error): Response => {
-                // We swallow errors because we need a default object anyhow
-                this.logger.error(e);
-                return {};
-            })
-            .then((r = {}) => {
-                const capabilities = r["capabilities"] || {};
-
-                // If the capabilities missed the cache, cache it for a shorter amount
-                // of time to try and refresh them later.
-                const cacheMs = Object.keys(capabilities).length ? CAPABILITIES_CACHE_MS : 60000 + Math.random() * 5000;
-
-                this.cachedCapabilities = {
-                    capabilities,
-                    expiration: now + cacheMs,
-                };
-
-                this.logger.debug("Caching capabilities: ", capabilities);
-                return capabilities;
-            });
+    /**
+     * Fetches the latest capabilities from the homeserver, ignoring any cached
+     * versions. The newly returned version is cached.
+     *
+     * @returns A promise which resolves to the capabilities of the homeserver
+     */
+    public fetchCapabilities(): Promise<Capabilities> {
+        return this.serverCapabilitiesService.fetchCapabilities();
     }
 
     /**
@@ -4319,9 +4277,13 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
             signPromise = this.http.requestOtherUrl<IThirdPartySigned>(Method.Post, url);
         }
 
-        const queryString: Record<string, string | string[]> = {};
+        let queryParams: QueryDict = {};
         if (opts.viaServers) {
-            queryString["server_name"] = opts.viaServers;
+            queryParams.server_name = opts.viaServers;
+            queryParams.via = opts.viaServers;
+            if (this.canSupport.get(Feature.MigrateServerNameToVia) === ServerSupport.Unstable) {
+                queryParams = replaceParam("via", "org.matrix.msc4156.via", queryParams);
+            }
         }
 
         const data: IJoinRequestBody = {};
@@ -4331,7 +4293,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
         }
 
         const path = utils.encodeUri("/join/$roomid", { $roomid: roomIdOrAlias });
-        const res = await this.http.authedRequest<{ room_id: string }>(Method.Post, path, queryString, data);
+        const res = await this.http.authedRequest<{ room_id: string }>(Method.Post, path, queryParams, data);
 
         const roomId = res.room_id;
         // In case we were originally given an alias, check the room cache again
@@ -4364,9 +4326,13 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
 
         const path = utils.encodeUri("/knock/$roomIdOrAlias", { $roomIdOrAlias: roomIdOrAlias });
 
-        const queryParams: Record<string, string | string[]> = {};
+        let queryParams: QueryDict = {};
         if (opts.viaServers) {
             queryParams.server_name = opts.viaServers;
+            queryParams.via = opts.viaServers;
+            if (this.canSupport.get(Feature.MigrateServerNameToVia) === ServerSupport.Unstable) {
+                queryParams = replaceParam("via", "org.matrix.msc4156.via", queryParams);
+            }
         }
 
         const body: Record<string, string> = {};
@@ -7109,7 +7075,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
         // append the new results to our existing results
         const resultsLength = roomEvents.results?.length ?? 0;
         for (let i = 0; i < resultsLength; i++) {
-            const sr = SearchResult.fromJson(roomEvents.results[i], mapper);
+            const sr = SearchResult.fromJson(roomEvents.results![i], mapper);
             const room = this.getRoom(sr.context.getEvent().getRoomId());
             if (room) {
                 // Copy over a known event sender if we can

src/content-repo.ts

@@ -62,7 +62,7 @@ export function getHttpUriForMxc(
     if (useAuthentication) {
         allowRedirects = true; // per docs (MSC3916 always expects redirects)
 
-        // Dev note: MSC3916 (as of writing) removes `allow_redirect` entirely, but
+        // Dev note: MSC3916 removes `allow_redirect` entirely, but
         // for explicitness we set it here. This makes it slightly more obvious to
         // callers, hopefully.
     }
@@ -70,8 +70,7 @@ export function getHttpUriForMxc(
     let serverAndMediaId = mxc.slice(6); // strips mxc://
     let prefix: string;
     if (useAuthentication) {
-        // TODO: Use stable once available (requires FCP on MSC3916).
-        prefix = "/_matrix/client/unstable/org.matrix.msc3916/media/download/";
+        prefix = "/_matrix/client/v1/media/download/";
     } else {
         prefix = "/_matrix/media/v3/download/";
     }
@@ -90,8 +89,7 @@ export function getHttpUriForMxc(
         // these are thumbnailing params so they probably want the
         // thumbnailing API...
         if (useAuthentication) {
-            // TODO: Use stable once available (requires FCP on MSC3916).
-            prefix = "/_matrix/client/unstable/org.matrix.msc3916/media/thumbnail/";
+            prefix = "/_matrix/client/v1/media/thumbnail/";
         } else {
             prefix = "/_matrix/media/v3/thumbnail/";
         }

src/crypto-api.ts

@@ -14,6 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import type { SecretsBundle } from "@matrix-org/matrix-sdk-crypto-wasm";
 import type { IMegolmSessionData } from "./@types/crypto";
 import { Room } from "./models/room";
 import { DeviceMap } from "./models/device";
@@ -532,6 +533,23 @@ export interface CryptoApi {
      *   to false.
      */
     startDehydration(createNewKey?: boolean): Promise<void>;
+
+    ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+    //
+    // Import/export of secret keys
+    //
+    ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+    /**
+     * Export secrets bundle for transmitting to another device as part of OIDC QR login
+     */
+    exportSecretsBundle?(): Promise<Awaited<ReturnType<SecretsBundle["to_json"]>>>;
+
+    /**
+     * Import secrets bundle transmitted from another device.
+     * @param secrets - The secrets bundle received from the other device
+     */
+    importSecretsBundle?(secrets: Awaited<ReturnType<SecretsBundle["to_json"]>>): Promise<void>;
 }
 
 /** A reason code for a failure to decrypt an event. */

src/feature.ts

@@ -33,6 +33,7 @@ export enum Feature {
     AccountDataDeletion = "AccountDataDeletion",
     RelationsRecursion = "RelationsRecursion",
     IntentionalMentions = "IntentionalMentions",
+    MigrateServerNameToVia = "MigrateServerNameToVia",
 }
 
 type FeatureSupportCondition = {
@@ -65,6 +66,9 @@ const featureSupportResolver: Record<string, FeatureSupportCondition> = {
         unstablePrefixes: ["org.matrix.msc3952_intentional_mentions"],
         matrixVersion: "v1.7",
     },
+    [Feature.MigrateServerNameToVia]: {
+        unstablePrefixes: ["org.matrix.msc4156"],
+    },
 };
 
 export async function buildFeatureSupportMap(versions: IServerVersions): Promise<Map<Feature, ServerSupport>> {

src/matrix.ts

@@ -24,6 +24,7 @@ import { RoomWidgetClient, ICapabilities } from "./embedded";
 import { CryptoStore } from "./crypto/store/base";
 
 export * from "./client";
+export * from "./serverCapabilities";
 export * from "./embedded";
 export * from "./http-api";
 export * from "./autodiscovery";

src/matrixrtc/CallMembership.ts

@@ -14,52 +14,114 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { EitherAnd } from "matrix-events-sdk/lib/types";
+
 import { MatrixEvent } from "../matrix";
 import { deepCompare } from "../utils";
 import { Focus } from "./focus";
+import { isLivekitFocusActive } from "./LivekitFocus";
 
 type CallScope = "m.room" | "m.user";
-
 // Represents an entry in the memberships section of an m.call.member event as it is on the wire
-export interface CallMembershipData {
-    application?: string;
+
+// There are two different data interfaces. One for the Legacy types and one compliant with MSC4143
+
+// MSC4143 (MatrixRTC) session membership data
+
+export type SessionMembershipData = {
+    application: string;
+    call_id: string;
+    device_id: string;
+
+    focus_active: Focus;
+    foci_preferred: Focus[];
+    created_ts?: number;
+
+    // Application specific data
+    scope?: CallScope;
+};
+
+export const isSessionMembershipData = (data: CallMembershipData): data is SessionMembershipData =>
+    "focus_active" in data;
+
+const checkSessionsMembershipData = (data: any, errors: string[]): data is SessionMembershipData => {
+    const prefix = "Malformed session membership event: ";
+    if (typeof data.device_id !== "string") errors.push(prefix + "device_id must be string");
+    if (typeof data.call_id !== "string") errors.push(prefix + "call_id must be string");
+    if (typeof data.application !== "string") errors.push(prefix + "application must be a string");
+    if (typeof data.focus_active?.type !== "string") errors.push(prefix + "focus_active.type must be a string");
+    if (!Array.isArray(data.foci_preferred)) errors.push(prefix + "foci_preferred must be an array");
+    // optional parameters
+    if (data.created_ts && typeof data.created_ts !== "number") errors.push(prefix + "created_ts must be number");
+
+    // application specific data (we first need to check if they exist)
+    if (data.scope && typeof data.scope !== "string") errors.push(prefix + "scope must be string");
+    return errors.length === 0;
+};
+
+// Legacy session membership data
+
+export type CallMembershipDataLegacy = {
+    application: string;
     call_id: string;
     scope: CallScope;
     device_id: string;
-    created_ts?: number;
-    expires?: number;
-    expires_ts?: number;
-    foci_active?: Focus[];
     membershipID: string;
-}
+    created_ts?: number;
+    foci_active?: Focus[];
+} & EitherAnd<{ expires: number }, { expires_ts: number }>;
+
+export const isLegacyCallMembershipData = (data: CallMembershipData): data is CallMembershipDataLegacy =>
+    "membershipID" in data;
+
+const checkCallMembershipDataLegacy = (data: any, errors: string[]): data is CallMembershipDataLegacy => {
+    const prefix = "Malformed legacy rtc membership event: ";
+    if (!("expires" in data || "expires_ts" in data)) {
+        errors.push(prefix + "expires_ts or expires must be present");
+    }
+    if ("expires" in data) {
+        if (typeof data.expires !== "number") {
+            errors.push(prefix + "expires must be numeric");
+        }
+    }
+    if ("expires_ts" in data) {
+        if (typeof data.expires_ts !== "number") {
+            errors.push(prefix + "expires_ts must be numeric");
+        }
+    }
+
+    if (typeof data.device_id !== "string") errors.push(prefix + "device_id must be string");
+    if (typeof data.call_id !== "string") errors.push(prefix + "call_id must be string");
+    if (typeof data.application !== "string") errors.push(prefix + "application must be a string");
+    if (typeof data.membershipID !== "string") errors.push(prefix + "membershipID must be a string");
+    // optional elements
+    if (data.created_ts && typeof data.created_ts !== "number") errors.push(prefix + "created_ts must be number");
+    // application specific data (we first need to check if they exist)
+    if (data.scope && typeof data.scope !== "string") errors.push(prefix + "scope must be string");
+    return errors.length === 0;
+};
+
+export type CallMembershipData = CallMembershipDataLegacy | SessionMembershipData;
 
 export class CallMembership {
     public static equal(a: CallMembership, b: CallMembership): boolean {
-        return deepCompare(a.data, b.data);
+        return deepCompare(a.membershipData, b.membershipData);
     }
+    private membershipData: CallMembershipData;
 
     public constructor(
         private parentEvent: MatrixEvent,
-        private data: CallMembershipData,
+        data: any,
     ) {
-        if (!(data.expires || data.expires_ts)) {
-            throw new Error("Malformed membership: expires_ts or expires must be present");
+        const sessionErrors: string[] = [];
+        const legacyErrors: string[] = [];
+        if (!checkSessionsMembershipData(data, sessionErrors) && !checkCallMembershipDataLegacy(data, legacyErrors)) {
+            throw Error(
+                `unknown CallMembership data. Does not match legacy call.member (${legacyErrors.join(" & ")}) events nor MSC4143 (${sessionErrors.join(" & ")})`,
+            );
+        } else {
+            this.membershipData = data;
         }
-        if (data.expires) {
-            if (typeof data.expires !== "number") {
-                throw new Error("Malformed membership: expires must be numeric");
-            }
-        }
-        if (data.expires_ts) {
-            if (typeof data.expires_ts !== "number") {
-                throw new Error("Malformed membership: expires_ts must be numeric");
-            }
-        }
-
-        if (typeof data.device_id !== "string") throw new Error("Malformed membership event: device_id must be string");
-        if (typeof data.call_id !== "string") throw new Error("Malformed membership event: call_id must be string");
-        if (typeof data.scope !== "string") throw new Error("Malformed membership event: scope must be string");
-        if (!parentEvent.getSender()) throw new Error("Invalid parent event: sender is null");
     }
 
     public get sender(): string | undefined {
@@ -67,62 +129,89 @@ export class CallMembership {
     }
 
     public get callId(): string {
-        return this.data.call_id;
+        return this.membershipData.call_id;
     }
 
     public get deviceId(): string {
-        return this.data.device_id;
+        return this.membershipData.device_id;
     }
 
     public get application(): string | undefined {
-        return this.data.application;
+        return this.membershipData.application;
     }
 
-    public get scope(): CallScope {
-        return this.data.scope;
+    public get scope(): CallScope | undefined {
+        return this.membershipData.scope;
     }
 
     public get membershipID(): string {
-        return this.data.membershipID;
+        if (isLegacyCallMembershipData(this.membershipData)) return this.membershipData.membershipID;
+        // the createdTs behaves equivalent to the membershipID.
+        // we only need the field for the legacy member envents where we needed to update them
+        // synapse ignores sending state events if they have the same content.
+        else return this.createdTs().toString();
     }
 
     public createdTs(): number {
-        return this.data.created_ts ?? this.parentEvent.getTs();
+        return this.membershipData.created_ts ?? this.parentEvent.getTs();
     }
 
-    public getAbsoluteExpiry(): number {
-        if (this.data.expires) {
-            return this.createdTs() + this.data.expires;
+    public getAbsoluteExpiry(): number | undefined {
+        if (!isLegacyCallMembershipData(this.membershipData)) return undefined;
+        if ("expires" in this.membershipData) {
+            // we know createdTs exists since we already do the isLegacyCallMembershipData check
+            return this.createdTs() + this.membershipData.expires;
         } else {
             // We know it exists because we checked for this in the constructor.
-            return this.data.expires_ts!;
+            return this.membershipData.expires_ts;
         }
     }
 
     // gets the expiry time of the event, converted into the device's local time
-    public getLocalExpiry(): number {
-        if (this.data.expires) {
+    public getLocalExpiry(): number | undefined {
+        if (!isLegacyCallMembershipData(this.membershipData)) return undefined;
+        if ("expires" in this.membershipData) {
+            // we know createdTs exists since we already do the isLegacyCallMembershipData check
             const relativeCreationTime = this.parentEvent.getTs() - this.createdTs();
 
             const localCreationTs = this.parentEvent.localTimestamp - relativeCreationTime;
 
-            return localCreationTs + this.data.expires;
+            return localCreationTs + this.membershipData.expires;
         } else {
             // With expires_ts we cannot convert to local time.
             // TODO: Check the server timestamp and compute a diff to local time.
-            return this.data.expires_ts!;
+            return this.membershipData.expires_ts;
         }
     }
 
-    public getMsUntilExpiry(): number {
-        return this.getLocalExpiry() - Date.now();
+    public getMsUntilExpiry(): number | undefined {
+        if (isLegacyCallMembershipData(this.membershipData)) return this.getLocalExpiry()! - Date.now();
     }
 
     public isExpired(): boolean {
-        return this.getMsUntilExpiry() <= 0;
+        if (isLegacyCallMembershipData(this.membershipData)) return this.getMsUntilExpiry()! <= 0;
+
+        // MSC4143 events expire by being updated. So if the event exists, its not expired.
+        return false;
     }
 
-    public getActiveFoci(): Focus[] {
-        return this.data.foci_active ?? [];
+    public getPreferredFoci(): Focus[] {
+        // To support both, the new and the old MatrixRTC memberships have two cases based
+        // on the availablitiy of `foci_preferred`
+        if (isLegacyCallMembershipData(this.membershipData)) return this.membershipData.foci_active ?? [];
+
+        // MSC4143 style membership
+        return this.membershipData.foci_preferred;
+    }
+
+    public getFocusSelection(): string | undefined {
+        if (isLegacyCallMembershipData(this.membershipData)) {
+            return "oldest_membership";
+        } else {
+            const focusActive = this.membershipData.focus_active;
+            if (isLivekitFocusActive(focusActive)) {
+                return focusActive.focus_selection;
+            }
+        }
     }
 }

src/matrixrtc/LivekitFocus.ts

@@ -0,0 +1,39 @@
+/*
+Copyright 2023 New Vector Ltd
+
+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 { Focus } from "./focus";
+
+export interface LivekitFocusConfig extends Focus {
+    type: "livekit";
+    livekit_service_url: string;
+}
+
+export const isLivekitFocusConfig = (object: any): object is LivekitFocusConfig =>
+    object.type === "livekit" && "livekit_service_url" in object;
+
+export interface LivekitFocus extends LivekitFocusConfig {
+    livekit_alias: string;
+}
+
+export const isLivekitFocus = (object: any): object is LivekitFocus =>
+    isLivekitFocusConfig(object) && "livekit_alias" in object;
+
+export interface LivekitFocusActive extends Focus {
+    type: "livekit";
+    focus_selection: "oldest_membership";
+}
+export const isLivekitFocusActive = (object: any): object is LivekitFocusActive =>
+    object.type === "livekit" && "focus_selection" in object;

src/matrixrtc/MatrixRTCSession.ts

@@ -20,7 +20,13 @@ import { EventTimeline } from "../models/event-timeline";
 import { Room } from "../models/room";
 import { MatrixClient } from "../client";
 import { EventType } from "../@types/event";
-import { CallMembership, CallMembershipData } from "./CallMembership";
+import {
+    CallMembership,
+    CallMembershipData,
+    CallMembershipDataLegacy,
+    SessionMembershipData,
+    isLegacyCallMembershipData,
+} from "./CallMembership";
 import { RoomStateEvent } from "../models/room-state";
 import { Focus } from "./focus";
 import { randomString, secureRandomBase64Url } from "../randomstring";
@@ -29,6 +35,8 @@ import { decodeBase64, encodeUnpaddedBase64 } from "../base64";
 import { KnownMembership } from "../@types/membership";
 import { MatrixError } from "../http-api/errors";
 import { MatrixEvent } from "../models/event";
+import { isLivekitFocusActive } from "./LivekitFocus";
+import { ExperimentalGroupCallRoomMemberState } from "../webrtc/groupCall";
 
 const MEMBERSHIP_EXPIRY_TIME = 60 * 60 * 1000;
 const MEMBER_EVENT_CHECK_PERIOD = 2 * 60 * 1000; // How often we check to see if we need to re-send our member event
@@ -57,7 +65,7 @@ export enum MatrixRTCSessionEvent {
     MembershipsChanged = "memberships_changed",
     // We joined or left the session: our own local idea of whether we are joined,
     // separate from MembershipsChanged, ie. independent of whether our member event
-    // has succesfully gone through.
+    // has successfully gone through.
     JoinStateChanged = "join_state_changed",
     // The key used to encrypt media has changed
     EncryptionKeyChanged = "encryption_key_changed",
@@ -75,7 +83,20 @@ export type MatrixRTCSessionEventHandlerMap = {
         participantId: string,
     ) => void;
 };
-
+export interface JoinSessionConfig {
+    /** If true, generate and share a media key for this participant,
+     *  and emit MatrixRTCSessionEvent.EncryptionKeyChanged when
+     *  media keys for other participants become available.
+     */
+    manageMediaKeys?: boolean;
+    /** Lets you configure how the events for the session are formatted.
+     *   - legacy: use one event with a membership array.
+     *   - MSC4143: use one event per membership (with only one membership per event)
+     * More details can be found in MSC4143 and by checking the types:
+     * `CallMembershipDataLegacy` and `SessionMembershipData`
+     */
+    useLegacyMemberEvents?: boolean;
+}
 /**
  * A MatrixRTCSession manages the membership & properties of a MatrixRTC session.
  * This class doesn't deal with media at all, just membership & properties of a session.
@@ -102,12 +123,16 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
     private makeNewKeyTimeout?: ReturnType<typeof setTimeout>;
     private setNewKeyTimeouts = new Set<ReturnType<typeof setTimeout>>();
 
-    private activeFoci: Focus[] | undefined;
+    // This is a Focus with the specified fields for an ActiveFocus (e.g. LivekitFocusActive for type="livekit")
+    private ownFocusActive?: Focus;
+    // This is a Foci array that contains the Focus objects this user is aware of and proposes to use.
+    private ownFociPreferred?: Focus[];
 
     private updateCallMembershipRunning = false;
     private needCallMembershipUpdate = false;
 
     private manageMediaKeys = false;
+    private useLegacyMemberEvents = true;
     // userId:deviceId => array of keys
     private encryptionKeys = new Map<string, Array<Uint8Array>>();
     private lastEncryptionKeyUpdateRequest?: number;
@@ -134,21 +159,33 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
 
         const callMemberships: CallMembership[] = [];
         for (const memberEvent of callMemberEvents) {
-            const eventMemberships: CallMembershipData[] = memberEvent.getContent()["memberships"];
-            if (eventMemberships === undefined) {
-                continue;
+            const content = memberEvent.getContent();
+            let membershipContents: any[] = [];
+            // We first decide if its a MSC4143 event (per device state key)
+            if ("memberships" in content) {
+                // we have a legacy (one event for all devices) event
+                if (!Array.isArray(content["memberships"])) {
+                    logger.warn(`Malformed member event from ${memberEvent.getSender()}: memberships is not an array`);
+                    continue;
+                }
+                membershipContents = content["memberships"];
+            } else {
+                // We have a MSC4143 event membership event
+                if (Object.keys(content).length !== 0) {
+                    // We checked for empty content to not try to construct CallMembership's with {}.
+                    membershipContents.push(content);
+                }
             }
-            if (!Array.isArray(eventMemberships)) {
-                logger.warn(`Malformed member event from ${memberEvent.getSender()}: memberships is not an array`);
+            if (membershipContents.length === 0) {
                 continue;
             }
 
-            for (const membershipData of eventMemberships) {
+            for (const membershipData of membershipContents) {
                 try {
                     const membership = new CallMembership(memberEvent, membershipData);
 
                     if (membership.callId !== "" || membership.scope !== "m.room") {
-                        // for now, just ignore anything that isn't the a room scope call
+                        // for now, just ignore anything that isn't a room scope call
                         logger.info(`Ignoring user-scoped call`);
                         continue;
                     }
@@ -202,6 +239,7 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
 
     /*
      * Returns true if we intend to be participating in the MatrixRTC session.
+     * This is determined by checking if the relativeExpiry has been set.
      */
     public isJoined(): boolean {
         return this.relativeExpiry !== undefined;
@@ -232,30 +270,34 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
      * desired.
      * This method will return immediately and the session will be joined in the background.
      *
-     * @param activeFoci - The list of foci to set as currently active in the call member event
-     * @param manageMediaKeys - If true, generate and share a a media key for this participant,
-     *                          and emit MatrixRTCSessionEvent.EncryptionKeyChanged when
-     *                          media keys for other participants become available.
+     * @param fociActive - The object representing the active focus. (This depends on the focus type.)
+     * @param fociPreferred - The list of preferred foci this member proposes to use/knows/has access to.
+     *                        For the livekit case this is a list of foci generated from the homeserver well-known, the current rtc session,
+     *                        or optionally other room members homeserver well known.
+     * @param joinConfig - Additional configuration for the joined session.
      */
-    public joinRoomSession(activeFoci: Focus[], manageMediaKeys?: boolean): void {
+    public joinRoomSession(fociPreferred: Focus[], fociActive?: Focus, joinConfig?: JoinSessionConfig): void {
         if (this.isJoined()) {
             logger.info(`Already joined to session in room ${this.room.roomId}: ignoring join call`);
             return;
         }
 
-        logger.info(`Joining call session in room ${this.room.roomId} with manageMediaKeys=${manageMediaKeys}`);
-        this.activeFoci = activeFoci;
+        this.ownFocusActive = fociActive;
+        this.ownFociPreferred = fociPreferred;
         this.relativeExpiry = MEMBERSHIP_EXPIRY_TIME;
-        this.manageMediaKeys = manageMediaKeys ?? false;
+        this.manageMediaKeys = joinConfig?.manageMediaKeys ?? this.manageMediaKeys;
+        this.useLegacyMemberEvents = joinConfig?.useLegacyMemberEvents ?? this.useLegacyMemberEvents;
         this.membershipId = randomString(5);
-        this.emit(MatrixRTCSessionEvent.JoinStateChanged, true);
-        if (manageMediaKeys) {
+
+        logger.info(`Joining call session in room ${this.room.roomId} with manageMediaKeys=${this.manageMediaKeys}`);
+        if (joinConfig?.manageMediaKeys) {
             this.makeNewSenderKey();
             this.requestKeyEventSend();
         }
         // We don't wait for this, mostly because it may fail and schedule a retry, so this
         // function returning doesn't really mean anything at all.
         this.triggerCallMembershipEventUpdate();
+        this.emit(MatrixRTCSessionEvent.JoinStateChanged, true);
     }
 
     /**
@@ -295,7 +337,7 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
 
         logger.info(`Leaving call session in room ${this.room.roomId}`);
         this.relativeExpiry = undefined;
-        this.activeFoci = undefined;
+        this.ownFocusActive = undefined;
         this.manageMediaKeys = false;
         this.membershipId = undefined;
         this.emit(MatrixRTCSessionEvent.JoinStateChanged, false);
@@ -315,6 +357,21 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
         });
     }
 
+    public getActiveFocus(): Focus | undefined {
+        if (this.ownFocusActive && isLivekitFocusActive(this.ownFocusActive)) {
+            // A livekit active focus
+            if (this.ownFocusActive.focus_selection === "oldest_membership") {
+                const oldestMembership = this.getOldestMembership();
+                return oldestMembership?.getPreferredFoci()[0];
+            }
+        }
+        if (!this.ownFocusActive) {
+            // we use the legacy call.member events so default to oldest member
+            const oldestMembership = this.getOldestMembership();
+            return oldestMembership?.getPreferredFoci()[0];
+        }
+    }
+
     public getKeysForParticipant(userId: string, deviceId: string): Array<Uint8Array> | undefined {
         return this.encryptionKeys.get(getParticipantId(userId, deviceId));
     }
@@ -344,7 +401,7 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
      * @param userId - The user ID of the participant
      * @param deviceId - Device ID of the participant
      * @param encryptionKeyIndex - The index of the key to set
-     * @param encryptionKeyString - The string represenation of the key to set in base64
+     * @param encryptionKeyString - The string representation of the key to set in base64
      * @param delayBeforeuse - If true, delay before emitting a key changed event. Useful when setting
      *                         encryption keys for the local participant to allow time for the key to
      *                         be distributed.
@@ -379,7 +436,7 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
 
     /**
      * Generate a new sender key and add it at the next available index
-     * @param delayBeforeUse - If true, wait for a short period before settign the key for the
+     * @param delayBeforeUse - If true, wait for a short period before setting the key for the
      *                         media encryptor to use. If false, set the key immediately.
      */
     private makeNewSenderKey(delayBeforeUse = false): void {
@@ -488,7 +545,9 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
         let soonestExpiry;
         for (const membership of this.memberships) {
             const thisExpiry = membership.getMsUntilExpiry();
-            if (soonestExpiry === undefined || thisExpiry < soonestExpiry) {
+            // If getMsUntilExpiry is undefined we have a MSC4143 (MatrixRTC) compliant event - it never expires
+            // but will be reliably resent on disconnect.
+            if (thisExpiry !== undefined && (soonestExpiry === undefined || thisExpiry < soonestExpiry)) {
                 soonestExpiry = thisExpiry;
             }
         }
@@ -502,6 +561,13 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
         return this.memberships[0];
     }
 
+    public getFocusInUse(): Focus | undefined {
+        const oldestMembership = this.getOldestMembership();
+        if (oldestMembership?.getFocusSelection() === "oldest_membership") {
+            return oldestMembership.getPreferredFoci()[0];
+        }
+    }
+
     public onCallEncryption = (event: MatrixEvent): void => {
         const userId = event.getSender();
         const content = event.getContent<EncryptionKeysEventContent>();
@@ -613,30 +679,41 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
      * Constructs our own membership
      * @param prevMembership - The previous value of our call membership, if any
      */
-    private makeMyMembership(prevMembership?: CallMembership): CallMembershipData {
+    private makeMyMembershipLegacy(deviceId: string, prevMembership?: CallMembership): CallMembershipDataLegacy {
         if (this.relativeExpiry === undefined) {
             throw new Error("Tried to create our own membership event when we're not joined!");
         }
         if (this.membershipId === undefined) {
             throw new Error("Tried to create our own membership event when we have no membership ID!");
         }
-
-        const m: CallMembershipData = {
+        const createdTs = prevMembership?.createdTs();
+        return {
             call_id: "",
             scope: "m.room",
             application: "m.call",
-            device_id: this.client.getDeviceId()!,
+            device_id: deviceId,
             expires: this.relativeExpiry,
-            foci_active: this.activeFoci,
+            // TODO: Date.now() should be the origin_server_ts (now).
+            expires_ts: this.relativeExpiry + (createdTs ?? Date.now()),
+            // we use the fociPreferred since this is the list of foci.
+            // it is named wrong in the Legacy events.
+            foci_active: this.ownFociPreferred,
             membershipID: this.membershipId,
+            ...(createdTs ? { created_ts: createdTs } : {}),
+        };
+    }
+    /**
+     * Constructs our own membership
+     */
+    private makeMyMembership(deviceId: string): SessionMembershipData {
+        return {
+            call_id: "",
+            scope: "m.room",
+            application: "m.call",
+            device_id: deviceId,
+            focus_active: { type: "livekit", focus_selection: "oldest_membership" },
+            foci_preferred: this.ownFociPreferred ?? [],
         };
-
-        if (prevMembership) m.created_ts = prevMembership.createdTs();
-        if (m.created_ts) m.expires_ts = m.created_ts + (m.expires ?? 0);
-        // TODO: Date.now() should be the origin_server_ts (now).
-        else m.expires_ts = Date.now() + (m.expires ?? 0);
-
-        return m;
     }
 
     /**
@@ -646,36 +723,41 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
         myPrevMembershipData?: CallMembershipData,
         myPrevMembership?: CallMembership,
     ): boolean {
-        // work out if we need to update our membership event
-        let needsUpdate = false;
+        if (myPrevMembership && myPrevMembership.getMsUntilExpiry() === undefined) return false;
+
         // Need to update if there's a membership for us but we're not joined (valid or otherwise)
-        if (!this.isJoined() && myPrevMembershipData) needsUpdate = true;
-        if (this.isJoined()) {
-            // ...or if we are joined, but there's no valid membership event
-            if (!myPrevMembership) {
-                needsUpdate = true;
-            } else if (myPrevMembership.getMsUntilExpiry() < MEMBERSHIP_EXPIRY_TIME / 2) {
-                // ...or if the expiry time needs bumping
-                needsUpdate = true;
-                this.relativeExpiry! += MEMBERSHIP_EXPIRY_TIME;
-            }
+        if (!this.isJoined()) return !!myPrevMembershipData;
+
+        // ...or if we are joined, but there's no valid membership event
+        if (!myPrevMembership) return true;
+
+        const expiryTime = myPrevMembership.getMsUntilExpiry();
+        if (expiryTime !== undefined && expiryTime < MEMBERSHIP_EXPIRY_TIME / 2) {
+            // ...or if the expiry time needs bumping
+            this.relativeExpiry! += MEMBERSHIP_EXPIRY_TIME;
+            return true;
         }
 
-        return needsUpdate;
+        return false;
     }
 
+    private makeNewMembership(deviceId: string): SessionMembershipData | {} {
+        // If we're joined, add our own
+        if (this.isJoined()) {
+            return this.makeMyMembership(deviceId);
+        }
+        return {};
+    }
     /**
      * Makes a new membership list given the old list alonng with this user's previous membership event
      * (if any) and this device's previous membership (if any)
      */
-    private makeNewMemberships(
+    private makeNewLegacyMemberships(
         oldMemberships: CallMembershipData[],
+        localDeviceId: string,
         myCallMemberEvent?: MatrixEvent,
         myPrevMembership?: CallMembership,
-    ): CallMembershipData[] {
-        const localDeviceId = this.client.getDeviceId();
-        if (!localDeviceId) throw new Error("Local device ID is null!");
-
+    ): ExperimentalGroupCallRoomMemberState {
         const filterExpired = (m: CallMembershipData): boolean => {
             let membershipObj;
             try {
@@ -704,10 +786,10 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
 
         // If we're joined, add our own
         if (this.isJoined()) {
-            newMemberships.push(this.makeMyMembership(myPrevMembership));
+            newMemberships.push(this.makeMyMembershipLegacy(localDeviceId, myPrevMembership));
         }
 
-        return newMemberships;
+        return { memberships: newMemberships };
     }
 
     private triggerCallMembershipEventUpdate = async (): Promise<void> => {
@@ -741,47 +823,58 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
         const localDeviceId = this.client.getDeviceId();
         if (!localUserId || !localDeviceId) throw new Error("User ID or device ID was null!");
 
-        const myCallMemberEvent = roomState.getStateEvents(EventType.GroupCallMemberPrefix, localUserId) ?? undefined;
-        const content = myCallMemberEvent?.getContent<Record<any, unknown>>() ?? {};
-        const memberships: CallMembershipData[] = Array.isArray(content["memberships"]) ? content["memberships"] : [];
-
-        const myPrevMembershipData = memberships.find((m) => m.device_id === localDeviceId);
-        let myPrevMembership;
-        try {
-            if (myCallMemberEvent && myPrevMembershipData && myPrevMembershipData.membershipID === this.membershipId) {
-                myPrevMembership = new CallMembership(myCallMemberEvent, myPrevMembershipData);
+        const callMemberEvents = roomState.events.get(EventType.GroupCallMemberPrefix);
+        const legacy =
+            !!this.useLegacyMemberEvents ||
+            (callMemberEvents?.size && this.stateEventsContainOngoingLegacySession(callMemberEvents));
+        let newContent: {} | ExperimentalGroupCallRoomMemberState | SessionMembershipData = {};
+        if (legacy) {
+            const myCallMemberEvent = callMemberEvents?.get(localUserId);
+            const content = myCallMemberEvent?.getContent() ?? {};
+            let myPrevMembership: CallMembership | undefined;
+            // We know its CallMembershipDataLegacy
+            const memberships: CallMembershipDataLegacy[] = Array.isArray(content["memberships"])
+                ? content["memberships"]
+                : [];
+            const myPrevMembershipData = memberships.find((m) => m.device_id === localDeviceId);
+            try {
+                if (
+                    myCallMemberEvent &&
+                    myPrevMembershipData &&
+                    isLegacyCallMembershipData(myPrevMembershipData) &&
+                    myPrevMembershipData.membershipID === this.membershipId
+                ) {
+                    myPrevMembership = new CallMembership(myCallMemberEvent, myPrevMembershipData);
+                }
+            } catch (e) {
+                // This would indicate a bug or something weird if our own call membership
+                // wasn't valid
+                logger.warn("Our previous call membership was invalid - this shouldn't happen.", e);
             }
-        } catch (e) {
-            // This would indicate a bug or something weird if our own call membership
-            // wasn't valid
-            logger.warn("Our previous call membership was invalid - this shouldn't happen.", e);
+            if (myPrevMembership) {
+                logger.debug(`${myPrevMembership.getMsUntilExpiry()} until our membership expires`);
+            }
+            if (!this.membershipEventNeedsUpdate(myPrevMembershipData, myPrevMembership)) {
+                // nothing to do - reschedule the check again
+                this.memberEventTimeout = setTimeout(this.triggerCallMembershipEventUpdate, MEMBER_EVENT_CHECK_PERIOD);
+                return;
+            }
+            newContent = this.makeNewLegacyMemberships(memberships, localDeviceId, myCallMemberEvent, myPrevMembership);
+        } else {
+            newContent = this.makeNewMembership(localDeviceId);
         }
 
-        if (myPrevMembership) {
-            logger.debug(`${myPrevMembership.getMsUntilExpiry()} until our membership expires`);
-        }
-
-        if (!this.membershipEventNeedsUpdate(myPrevMembershipData, myPrevMembership)) {
-            // nothing to do - reschedule the check again
-            this.memberEventTimeout = setTimeout(this.triggerCallMembershipEventUpdate, MEMBER_EVENT_CHECK_PERIOD);
-            return;
-        }
-
-        const newContent = {
-            memberships: this.makeNewMemberships(memberships, myCallMemberEvent, myPrevMembership),
-        };
-
         try {
             await this.client.sendStateEvent(
                 this.room.roomId,
                 EventType.GroupCallMemberPrefix,
                 newContent,
-                localUserId,
+                legacy ? localUserId : this.makeMembershipStateKey(localUserId, localDeviceId),
             );
             logger.info(`Sent updated call member event.`);
 
             // check periodically to see if we need to refresh our member event
-            if (this.isJoined()) {
+            if (this.isJoined() && legacy) {
                 this.memberEventTimeout = setTimeout(this.triggerCallMembershipEventUpdate, MEMBER_EVENT_CHECK_PERIOD);
             }
         } catch (e) {
@@ -792,6 +885,29 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
         }
     }
 
+    private stateEventsContainOngoingLegacySession(callMemberEvents: Map<string, MatrixEvent>): boolean {
+        for (const callMemberEvent of callMemberEvents.values()) {
+            const content = callMemberEvent.getContent();
+            if (Array.isArray(content["memberships"])) {
+                for (const membership of content.memberships) {
+                    if (!new CallMembership(callMemberEvent, membership).isExpired()) {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
+
+    private makeMembershipStateKey(localUserId: string, localDeviceId: string): string {
+        const stateKey = `${localUserId}_${localDeviceId}`;
+        if (/^org\.matrix\.msc3779\b/.exec(this.room.getVersion())) {
+            return stateKey;
+        } else {
+            return `_${stateKey}`;
+        }
+    }
+
     private onRotateKeyTimeout = (): void => {
         if (!this.manageMediaKeys) return;
 

src/matrixrtc/MatrixRTCSessionManager.ts

@@ -73,9 +73,9 @@ export class MatrixRTCSessionManager extends TypedEventEmitter<MatrixRTCSessionM
         }
         this.roomSessions.clear();
 
-        this.client.removeListener(ClientEvent.Room, this.onRoom);
-        this.client.removeListener(RoomEvent.Timeline, this.onTimeline);
-        this.client.removeListener(RoomStateEvent.Events, this.onRoomState);
+        this.client.off(ClientEvent.Room, this.onRoom);
+        this.client.off(RoomEvent.Timeline, this.onTimeline);
+        this.client.off(RoomStateEvent.Events, this.onRoomState);
     }
 
     /**

src/matrixrtc/focus.ts

@@ -21,4 +21,5 @@ limitations under the License.
  */
 export interface Focus {
     type: string;
+    [key: string]: unknown;
 }

src/models/event.ts

@@ -77,7 +77,6 @@ export interface IUnsigned {
     "invite_room_state"?: StrippedState[];
     "m.relations"?: Record<RelationType | string, any>; // No common pattern for aggregated relations
     [UNSIGNED_THREAD_ID_FIELD.name]?: string;
-    [UNSIGNED_MEMBERSHIP_FIELD.name]?: Membership | string;
 }
 
 export interface IThreadBundledRelationship {
@@ -717,13 +716,9 @@ export class MatrixEvent extends TypedEventEmitter<MatrixEventEmittedEvents, Mat
      * @returns The user's room membership, or `undefined` if the server does
      *   not report it.
      */
-    public getMembershipAtEvent(): Membership | string | undefined {
+    public getMembershipAtEvent(): Optional<Membership | string> {
         const unsigned = this.getUnsigned();
-        if (typeof unsigned[UNSIGNED_MEMBERSHIP_FIELD.name] === "string") {
-            return unsigned[UNSIGNED_MEMBERSHIP_FIELD.name];
-        } else {
-            return undefined;
-        }
+        return UNSIGNED_MEMBERSHIP_FIELD.findIn<Membership | string>(unsigned);
     }
 
     /**

src/models/room.ts

@@ -41,7 +41,7 @@ import {
     RelationType,
     UNSIGNED_THREAD_ID_FIELD,
 } from "../@types/event";
-import { IRoomVersionsCapability, MatrixClient, PendingEventOrdering, RoomVersionStability } from "../client";
+import { MatrixClient, PendingEventOrdering } from "../client";
 import { GuestAccess, HistoryVisibility, JoinRule, ResizeMethod } from "../@types/partials";
 import { Filter, IFilterDefinition } from "../filter";
 import { RoomState, RoomStateEvent, RoomStateEventHandlerMap } from "./room-state";
@@ -70,6 +70,7 @@ import { RoomReceipts } from "./room-receipts";
 import { compareEventOrdering } from "./compare-event-ordering";
 import * as utils from "../utils";
 import { KnownMembership, Membership } from "../@types/membership";
+import { Capabilities, IRoomVersionsCapability, RoomVersionStability } from "../serverCapabilities";
 
 // These constants are used as sane defaults when the homeserver doesn't support
 // the m.room_versions capability. In practice, KNOWN_SAFE_ROOM_VERSION should be
@@ -397,7 +398,8 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
      *             Use getLiveTimeline().getState(EventTimeline.FORWARDS) instead.
      */
     public currentState!: RoomState;
-    public readonly relations = new RelationsContainer(this.client, this);
+
+    public readonly relations;
 
     /**
      * A collection of events known by the client
@@ -459,6 +461,7 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
         private readonly opts: IOpts = {},
     ) {
         super();
+
         // In some cases, we add listeners for every displayed Matrix event, so it's
         // common to have quite a few more than the default limit.
         this.setMaxListeners(100);
@@ -469,6 +472,8 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
         this.name = roomId;
         this.normalizedName = roomId;
 
+        this.relations = new RelationsContainer(this.client, this);
+
         // Listen to our own receipt event as a more modular way of processing our own
         // receipts. No need to remove the listener: it's on ourself anyway.
         this.on(RoomEvent.Receipt, this.onReceipt);
@@ -611,7 +616,10 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
      * Resolves to the version the room should be upgraded to.
      */
     public async getRecommendedVersion(): Promise<IRecommendedVersion> {
-        const capabilities = await this.client.getCapabilities();
+        let capabilities: Capabilities = {};
+        try {
+            capabilities = await this.client.getCapabilities();
+        } catch (e) {}
         let versionCap = capabilities["m.room_versions"];
         if (!versionCap) {
             versionCap = {
@@ -636,8 +644,12 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
                     "to be supporting a newer room version we don't know about.",
             );
 
-            const caps = await this.client.getCapabilities(true);
-            versionCap = caps["m.room_versions"];
+            try {
+                capabilities = await this.client.fetchCapabilities();
+            } catch (e) {
+                logger.warn("Failed to refresh room version capabilities", e);
+            }
+            versionCap = capabilities["m.room_versions"];
             if (!versionCap) {
                 logger.warn("No room version capability - assuming upgrade required.");
                 return result;

src/oidc/register.ts

@@ -49,6 +49,8 @@ interface OidcRegistrationRequestBody {
     application_type: "web" | "native";
 }
 
+export const DEVICE_CODE_SCOPE = "urn:ietf:params:oauth:grant-type:device_code";
+
 /**
  * Attempts dynamic registration against the configured registration endpoint
  * @param delegatedAuthConfig - Auth config from {@link discoverAndValidateOIDCIssuerWellKnown}

src/rendezvous/MSC3906Rendezvous.ts

@@ -16,13 +16,18 @@ limitations under the License.
 
 import { UnstableValue } from "matrix-events-sdk";
 
-import { RendezvousChannel, RendezvousFailureListener, RendezvousFailureReason, RendezvousIntent } from ".";
-import { IGetLoginTokenCapability, MatrixClient, GET_LOGIN_TOKEN_CAPABILITY } from "../client";
+import {
+    RendezvousChannel,
+    RendezvousFailureListener,
+    LegacyRendezvousFailureReason as RendezvousFailureReason,
+    RendezvousIntent,
+} from ".";
+import { MatrixClient, GET_LOGIN_TOKEN_CAPABILITY } from "../client";
 import { buildFeatureSupportMap, Feature, ServerSupport } from "../feature";
 import { logger } from "../logger";
 import { sleep } from "../utils";
 import { CrossSigningKey } from "../crypto-api";
-import { Device } from "../matrix";
+import { Capabilities, Device, IGetLoginTokenCapability } from "../matrix";
 
 enum PayloadType {
     Start = "m.login.start",
@@ -59,6 +64,9 @@ const LOGIN_TOKEN_PROTOCOL = new UnstableValue("login_token", "org.matrix.msc390
  * Implements MSC3906 to allow a user to sign in on a new device using QR code.
  * This implementation only supports generating a QR code on a device that is already signed in.
  * Note that this is UNSTABLE and may have breaking changes without notice.
+ * MSC3886/MSC3903/MSC3906 are now closed and so this functionality will be removed in future.
+ * However, we want to keep this implementation around for some time.
+ * TODO: define an end-of-life date for this implementation.
  */
 export class MSC3906Rendezvous {
     private newDeviceId?: string;
@@ -101,7 +109,10 @@ export class MSC3906Rendezvous {
         logger.info(`Connected to secure channel with checksum: ${checksum} our intent is ${this.ourIntent}`);
 
         // in stable and unstable r1 the availability is exposed as a capability
-        const capabilities = await this.client.getCapabilities();
+        let capabilities: Capabilities = {};
+        try {
+            capabilities = await this.client.getCapabilities();
+        } catch (e) {}
         // in r0 of MSC3882 the availability is exposed as a feature flag
         const features = await buildFeatureSupportMap(await this.client.getVersions());
         const capability = GET_LOGIN_TOKEN_CAPABILITY.findIn<IGetLoginTokenCapability>(capabilities);

src/rendezvous/MSC4108SignInWithQR.ts

@@ -0,0 +1,439 @@
+/*
+Copyright 2024 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 { QrCodeMode } from "@matrix-org/matrix-sdk-crypto-wasm";
+
+import { ClientRendezvousFailureReason, MSC4108FailureReason, RendezvousError, RendezvousFailureListener } from ".";
+import { MatrixClient } from "../client";
+import { logger } from "../logger";
+import { MSC4108SecureChannel } from "./channels/MSC4108SecureChannel";
+import { MatrixError } from "../http-api";
+import { sleep } from "../utils";
+import { DEVICE_CODE_SCOPE, discoverAndValidateOIDCIssuerWellKnown, OidcClientConfig } from "../oidc";
+import { CryptoApi } from "../crypto-api";
+
+/**
+ * Enum representing the payload types transmissible over [MSC4108](https://github.com/matrix-org/matrix-spec-proposals/pull/4108)
+ * secure channels.
+ * @experimental Note that this is UNSTABLE and may have breaking changes without notice.
+ */
+export enum PayloadType {
+    Protocols = "m.login.protocols",
+    Protocol = "m.login.protocol",
+    Failure = "m.login.failure",
+    Success = "m.login.success",
+    Secrets = "m.login.secrets",
+    ProtocolAccepted = "m.login.protocol_accepted",
+    Declined = "m.login.declined",
+}
+
+/**
+ * Type representing the base payload format for [MSC4108](https://github.com/matrix-org/matrix-spec-proposals/pull/4108)
+ * messages sent over the secure channel.
+ * @experimental Note that this is UNSTABLE and may have breaking changes without notice.
+ */
+export interface MSC4108Payload {
+    type: PayloadType;
+}
+
+interface ProtocolsPayload extends MSC4108Payload {
+    type: PayloadType.Protocols;
+    protocols: string[];
+    homeserver: string;
+}
+
+interface ProtocolPayload extends MSC4108Payload {
+    type: PayloadType.Protocol;
+    protocol: Exclude<string, "device_authorization_grant">;
+    device_id: string;
+}
+
+interface DeviceAuthorizationGrantProtocolPayload extends ProtocolPayload {
+    protocol: "device_authorization_grant";
+    device_authorization_grant: {
+        verification_uri: string;
+        verification_uri_complete?: string;
+    };
+}
+
+function isDeviceAuthorizationGrantProtocolPayload(
+    payload: ProtocolPayload,
+): payload is DeviceAuthorizationGrantProtocolPayload {
+    return payload.protocol === "device_authorization_grant";
+}
+
+interface FailurePayload extends MSC4108Payload {
+    type: PayloadType.Failure;
+    reason: MSC4108FailureReason;
+    homeserver?: string;
+}
+
+interface DeclinedPayload extends MSC4108Payload {
+    type: PayloadType.Declined;
+}
+
+interface SuccessPayload extends MSC4108Payload {
+    type: PayloadType.Success;
+}
+
+interface AcceptedPayload extends MSC4108Payload {
+    type: PayloadType.ProtocolAccepted;
+}
+
+interface SecretsPayload extends MSC4108Payload, Awaited<ReturnType<NonNullable<CryptoApi["exportSecretsBundle"]>>> {
+    type: PayloadType.Secrets;
+}
+
+/**
+ * Prototype of the unstable [MSC4108](https://github.com/matrix-org/matrix-spec-proposals/pull/4108)
+ * sign in with QR + OIDC flow.
+ * @experimental Note that this is UNSTABLE and may have breaking changes without notice.
+ */
+export class MSC4108SignInWithQR {
+    private readonly ourIntent: QrCodeMode;
+    private _code?: Uint8Array;
+    private expectingNewDeviceId?: string;
+
+    /**
+     * Returns the check code for the secure channel or undefined if not generated yet.
+     */
+    public get checkCode(): string | undefined {
+        return this.channel?.getCheckCode();
+    }
+
+    /**
+     * @param channel - The secure channel used for communication
+     * @param client - The Matrix client in used on the device already logged in
+     * @param didScanCode - Whether this side of the channel scanned the QR code from the other party
+     * @param onFailure - Callback for when the rendezvous fails
+     */
+    public constructor(
+        private readonly channel: MSC4108SecureChannel,
+        private readonly didScanCode: boolean,
+        private readonly client?: MatrixClient,
+        public onFailure?: RendezvousFailureListener,
+    ) {
+        this.ourIntent = client ? QrCodeMode.Reciprocate : QrCodeMode.Login;
+    }
+
+    /**
+     * Returns the code representing the rendezvous suitable for rendering in a QR code or undefined if not generated yet.
+     */
+    public get code(): Uint8Array | undefined {
+        return this._code;
+    }
+
+    /**
+     * Generate the code including doing partial set up of the channel where required.
+     */
+    public async generateCode(): Promise<void> {
+        if (this._code) {
+            return;
+        }
+
+        if (this.ourIntent === QrCodeMode.Reciprocate && this.client) {
+            this._code = await this.channel.generateCode(this.ourIntent, this.client.getDomain()!);
+        } else if (this.ourIntent === QrCodeMode.Login) {
+            this._code = await this.channel.generateCode(this.ourIntent);
+        }
+    }
+
+    /**
+     * Returns true if the device is the already logged in device reciprocating a new login on the other side of the channel.
+     */
+    public get isExistingDevice(): boolean {
+        return this.ourIntent === QrCodeMode.Reciprocate;
+    }
+
+    /**
+     * Returns true if the device is the new device logging in being reciprocated by the device on the other side of the channel.
+     */
+    public get isNewDevice(): boolean {
+        return !this.isExistingDevice;
+    }
+
+    /**
+     * The first step in the OIDC QR login process.
+     * To be called after the QR code has been rendered or scanned.
+     * The scanning device has to discover the homeserver details, if they scanned the code then they already have it.
+     * If the new device is the one rendering the QR code then it has to wait be sent the homeserver details via the rendezvous channel.
+     */
+    public async negotiateProtocols(): Promise<{ serverName?: string }> {
+        logger.info(`negotiateProtocols(isNewDevice=${this.isNewDevice} didScanCode=${this.didScanCode})`);
+        await this.channel.connect();
+
+        if (this.didScanCode) {
+            // Secure Channel step 6 completed, we trust the channel
+
+            if (this.isNewDevice) {
+                // MSC4108-Flow: ExistingScanned - take homeserver from QR code which should already be set
+            } else {
+                // MSC4108-Flow: NewScanned -send protocols message
+                let oidcClientConfig: OidcClientConfig | undefined;
+                try {
+                    const { issuer } = await this.client!.getAuthIssuer();
+                    oidcClientConfig = await discoverAndValidateOIDCIssuerWellKnown(issuer);
+                } catch (e) {
+                    logger.error("Failed to discover OIDC metadata", e);
+                }
+
+                if (oidcClientConfig?.metadata.grant_types_supported.includes(DEVICE_CODE_SCOPE)) {
+                    await this.send<ProtocolsPayload>({
+                        type: PayloadType.Protocols,
+                        protocols: ["device_authorization_grant"],
+                        homeserver: this.client!.getDomain()!,
+                    });
+                } else {
+                    await this.send<FailurePayload>({
+                        type: PayloadType.Failure,
+                        reason: MSC4108FailureReason.UnsupportedProtocol,
+                    });
+                    throw new RendezvousError(
+                        "Device code grant unsupported",
+                        MSC4108FailureReason.UnsupportedProtocol,
+                    );
+                }
+            }
+        } else if (this.isNewDevice) {
+            // MSC4108-Flow: ExistingScanned - wait for protocols message
+            logger.info("Waiting for protocols message");
+            const payload = await this.receive<ProtocolsPayload>();
+
+            if (payload?.type === PayloadType.Failure) {
+                throw new RendezvousError("Failed", payload.reason);
+            }
+
+            if (payload?.type !== PayloadType.Protocols) {
+                await this.send<FailurePayload>({
+                    type: PayloadType.Failure,
+                    reason: MSC4108FailureReason.UnexpectedMessageReceived,
+                });
+                throw new RendezvousError(
+                    "Unexpected message received",
+                    MSC4108FailureReason.UnexpectedMessageReceived,
+                );
+            }
+
+            return { serverName: payload.homeserver };
+        } else {
+            // MSC4108-Flow: NewScanned - nothing to do
+        }
+        return {};
+    }
+
+    /**
+     * The second & third step in the OIDC QR login process.
+     * To be called after `negotiateProtocols` for the existing device.
+     * To be called after OIDC negotiation for the new device. (Currently unsupported)
+     */
+    public async deviceAuthorizationGrant(): Promise<{
+        verificationUri?: string;
+        userCode?: string;
+    }> {
+        if (this.isNewDevice) {
+            throw new Error("New device flows around OIDC are not yet implemented");
+        } else {
+            // The user needs to do step 7 for the out-of-band confirmation
+            // but, first we receive the protocol chosen by the other device so that
+            // the confirmation_uri is ready to go
+            logger.info("Waiting for protocol message");
+            const payload = await this.receive<ProtocolPayload | DeviceAuthorizationGrantProtocolPayload>();
+
+            if (payload?.type === PayloadType.Failure) {
+                throw new RendezvousError("Failed", payload.reason);
+            }
+
+            if (payload?.type !== PayloadType.Protocol) {
+                await this.send<FailurePayload>({
+                    type: PayloadType.Failure,
+                    reason: MSC4108FailureReason.UnexpectedMessageReceived,
+                });
+                throw new RendezvousError(
+                    "Unexpected message received",
+                    MSC4108FailureReason.UnexpectedMessageReceived,
+                );
+            }
+
+            if (isDeviceAuthorizationGrantProtocolPayload(payload)) {
+                const { device_authorization_grant: dag, device_id: expectingNewDeviceId } = payload;
+                const { verification_uri: verificationUri, verification_uri_complete: verificationUriComplete } = dag;
+
+                let deviceAlreadyExists = true;
+                try {
+                    await this.client?.getDevice(expectingNewDeviceId);
+                } catch (err: MatrixError | unknown) {
+                    if (err instanceof MatrixError && err.httpStatus === 404) {
+                        deviceAlreadyExists = false;
+                    }
+                }
+
+                if (deviceAlreadyExists) {
+                    await this.send<FailurePayload>({
+                        type: PayloadType.Failure,
+                        reason: MSC4108FailureReason.DeviceAlreadyExists,
+                    });
+                    throw new RendezvousError(
+                        "Specified device ID already exists",
+                        MSC4108FailureReason.DeviceAlreadyExists,
+                    );
+                }
+
+                this.expectingNewDeviceId = expectingNewDeviceId;
+
+                return { verificationUri: verificationUriComplete ?? verificationUri };
+            }
+
+            await this.send<FailurePayload>({
+                type: PayloadType.Failure,
+                reason: MSC4108FailureReason.UnsupportedProtocol,
+            });
+            throw new RendezvousError(
+                "Received a request for an unsupported protocol",
+                MSC4108FailureReason.UnsupportedProtocol,
+            );
+        }
+    }
+
+    /**
+     * The fifth (and final) step in the OIDC QR login process.
+     * To be called after the new device has completed authentication.
+     */
+    public async shareSecrets(): Promise<{ secrets?: Omit<SecretsPayload, "type"> }> {
+        if (this.isNewDevice) {
+            await this.send<SuccessPayload>({
+                type: PayloadType.Success,
+            });
+            // then wait for secrets
+            logger.info("Waiting for secrets message");
+            const payload = await this.receive<SecretsPayload>();
+            if (payload?.type === PayloadType.Failure) {
+                throw new RendezvousError("Failed", payload.reason);
+            }
+
+            if (payload?.type !== PayloadType.Secrets) {
+                await this.send<FailurePayload>({
+                    type: PayloadType.Failure,
+                    reason: MSC4108FailureReason.UnexpectedMessageReceived,
+                });
+                throw new RendezvousError(
+                    "Unexpected message received",
+                    MSC4108FailureReason.UnexpectedMessageReceived,
+                );
+            }
+            return { secrets: payload };
+            // then done?
+        } else {
+            if (!this.expectingNewDeviceId) {
+                throw new Error("No new device ID expected");
+            }
+            await this.send<AcceptedPayload>({
+                type: PayloadType.ProtocolAccepted,
+            });
+
+            logger.info("Waiting for outcome message");
+            const payload = await this.receive<SuccessPayload | DeclinedPayload>();
+
+            if (payload?.type === PayloadType.Failure) {
+                throw new RendezvousError("Failed", payload.reason);
+            }
+
+            if (payload?.type === PayloadType.Declined) {
+                throw new RendezvousError("User declined", ClientRendezvousFailureReason.UserDeclined);
+            }
+
+            if (payload?.type !== PayloadType.Success) {
+                await this.send<FailurePayload>({
+                    type: PayloadType.Failure,
+                    reason: MSC4108FailureReason.UnexpectedMessageReceived,
+                });
+                throw new RendezvousError("Unexpected message", MSC4108FailureReason.UnexpectedMessageReceived);
+            }
+
+            const timeout = Date.now() + 10000; // wait up to 10 seconds
+            do {
+                // is the device visible via the Homeserver?
+                try {
+                    const device = await this.client?.getDevice(this.expectingNewDeviceId);
+
+                    if (device) {
+                        // if so, return the secrets
+                        const secretsBundle = await this.client!.getCrypto()!.exportSecretsBundle!();
+                        if (this.channel.cancelled) {
+                            throw new RendezvousError("User cancelled", MSC4108FailureReason.UserCancelled);
+                        }
+                        // send secrets
+                        await this.send<SecretsPayload>({
+                            type: PayloadType.Secrets,
+                            ...secretsBundle,
+                        });
+                        return { secrets: secretsBundle };
+                        // let the other side close the rendezvous session
+                    }
+                } catch (err: MatrixError | unknown) {
+                    if (err instanceof MatrixError && err.httpStatus === 404) {
+                        // not found, so keep waiting until timeout
+                    } else {
+                        throw err;
+                    }
+                }
+                await sleep(1000);
+            } while (Date.now() < timeout);
+
+            await this.send<FailurePayload>({
+                type: PayloadType.Failure,
+                reason: MSC4108FailureReason.DeviceNotFound,
+            });
+            throw new RendezvousError("New device not found", MSC4108FailureReason.DeviceNotFound);
+        }
+    }
+
+    private async receive<T extends MSC4108Payload>(): Promise<T | FailurePayload | undefined> {
+        return (await this.channel.secureReceive()) as T | undefined;
+    }
+
+    private async send<T extends MSC4108Payload>(payload: T): Promise<void> {
+        await this.channel.secureSend(payload);
+    }
+
+    /**
+     * Decline the login on the existing device.
+     */
+    public async declineLoginOnExistingDevice(): Promise<void> {
+        if (!this.isExistingDevice) {
+            throw new Error("Can only decline login on existing device");
+        }
+        await this.send<FailurePayload>({
+            type: PayloadType.Failure,
+            reason: MSC4108FailureReason.UserCancelled,
+        });
+    }
+
+    /**
+     * Cancels the rendezvous session.
+     * @param reason the reason for the cancellation
+     */
+    public async cancel(reason: MSC4108FailureReason | ClientRendezvousFailureReason): Promise<void> {
+        this.onFailure?.(reason);
+        await this.channel.cancel(reason);
+    }
+
+    /**
+     * Closes the rendezvous session.
+     */
+    public async close(): Promise<void> {
+        await this.channel.close();
+    }
+}

src/rendezvous/RendezvousFailureReason.ts

@@ -16,16 +16,47 @@ limitations under the License.
 
 export type RendezvousFailureListener = (reason: RendezvousFailureReason) => void;
 
-export enum RendezvousFailureReason {
+export type RendezvousFailureReason =
+    | LegacyRendezvousFailureReason
+    | MSC4108FailureReason
+    | ClientRendezvousFailureReason;
+
+export enum LegacyRendezvousFailureReason {
     UserDeclined = "user_declined",
-    OtherDeviceNotSignedIn = "other_device_not_signed_in",
-    OtherDeviceAlreadySignedIn = "other_device_already_signed_in",
     Unknown = "unknown",
     Expired = "expired",
     UserCancelled = "user_cancelled",
-    InvalidCode = "invalid_code",
     UnsupportedAlgorithm = "unsupported_algorithm",
-    DataMismatch = "data_mismatch",
-    UnsupportedTransport = "unsupported_transport",
+    UnsupportedProtocol = "unsupported_protocol",
     HomeserverLacksSupport = "homeserver_lacks_support",
 }
+
+export enum MSC4108FailureReason {
+    AuthorizationExpired = "authorization_expired",
+    DeviceAlreadyExists = "device_already_exists",
+    DeviceNotFound = "device_not_found",
+    UnexpectedMessageReceived = "unexpected_message_received",
+    UnsupportedProtocol = "unsupported_protocol",
+    UserCancelled = "user_cancelled",
+}
+
+export enum ClientRendezvousFailureReason {
+    /** The sign in request has expired */
+    Expired = "expired",
+    /** The homeserver is lacking support for the required features */
+    HomeserverLacksSupport = "homeserver_lacks_support",
+    /** The secure channel verification failed meaning that it might be compromised */
+    InsecureChannelDetected = "insecure_channel_detected",
+    /** An invalid/incompatible QR code was scanned */
+    InvalidCode = "invalid_code",
+    /** The other device is not signed in */
+    OtherDeviceNotSignedIn = "other_device_not_signed_in",
+    /** The other device is already signed in */
+    OtherDeviceAlreadySignedIn = "other_device_already_signed_in",
+    /** Other */
+    Unknown = "unknown",
+    /** The user declined the sign in request */
+    UserDeclined = "user_declined",
+    /** The rendezvous request is missing an ETag header */
+    ETagMissing = "etag_missing",
+}

src/rendezvous/channels/MSC3903ECDHv2RendezvousChannel.ts

@@ -23,7 +23,7 @@ import {
     RendezvousChannel,
     RendezvousTransportDetails,
     RendezvousTransport,
-    RendezvousFailureReason,
+    LegacyRendezvousFailureReason as RendezvousFailureReason,
 } from "..";
 import { encodeUnpaddedBase64, decodeBase64 } from "../../base64";
 import { crypto, subtleCrypto, TextEncoder } from "../../crypto/crypto";
@@ -69,6 +69,9 @@ async function importKey(key: Uint8Array): Promise<CryptoKey> {
  * Implementation of the unstable [MSC3903](https://github.com/matrix-org/matrix-spec-proposals/pull/3903)
  * X25519/ECDH key agreement based secure rendezvous channel.
  * Note that this is UNSTABLE and may have breaking changes without notice.
+ * MSC3886/MSC3903/MSC3906 are now closed and so this functionality will be removed in future.
+ * However, we want to keep this implementation around for some time.
+ * TODO: define an end-of-life date for this implementation.
  */
 export class MSC3903ECDHv2RendezvousChannel<T> implements RendezvousChannel<T> {
     private olmSAS?: SAS;

src/rendezvous/channels/MSC4108SecureChannel.ts

@@ -0,0 +1,270 @@
+/*
+Copyright 2024 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 {
+    Curve25519PublicKey,
+    Ecies,
+    EstablishedEcies,
+    QrCodeData,
+    QrCodeMode,
+} from "@matrix-org/matrix-sdk-crypto-wasm";
+
+import {
+    ClientRendezvousFailureReason,
+    MSC4108FailureReason,
+    MSC4108Payload,
+    RendezvousError,
+    RendezvousFailureListener,
+} from "..";
+import { MSC4108RendezvousSession } from "../transports/MSC4108RendezvousSession";
+import { logger } from "../../logger";
+
+/**
+ * Prototype of the unstable [MSC4108](https://github.com/matrix-org/matrix-spec-proposals/pull/4108)
+ * secure rendezvous session protocol.
+ * @experimental Note that this is UNSTABLE and may have breaking changes without notice.
+ * Imports @matrix-org/matrix-sdk-crypto-wasm so should be async-imported to avoid bundling the WASM into the main bundle.
+ */
+export class MSC4108SecureChannel {
+    private readonly secureChannel: Ecies;
+    private establishedChannel?: EstablishedEcies;
+    private connected = false;
+
+    public constructor(
+        private rendezvousSession: MSC4108RendezvousSession,
+        private theirPublicKey?: Curve25519PublicKey,
+        public onFailure?: RendezvousFailureListener,
+    ) {
+        this.secureChannel = new Ecies();
+    }
+
+    /**
+     * Generate a QR code for the current session.
+     * @param mode the mode to generate the QR code in, either `Login` or `Reciprocate`.
+     * @param serverName the name of the homeserver to connect to, as defined by server discovery in the spec, required for `Reciprocate` mode.
+     */
+    public async generateCode(mode: QrCodeMode.Login): Promise<Uint8Array>;
+    public async generateCode(mode: QrCodeMode.Reciprocate, serverName: string): Promise<Uint8Array>;
+    public async generateCode(mode: QrCodeMode, serverName?: string): Promise<Uint8Array> {
+        const { url } = this.rendezvousSession;
+
+        if (!url) {
+            throw new Error("No rendezvous session URL");
+        }
+
+        return new QrCodeData(
+            this.secureChannel.public_key(),
+            url,
+            mode === QrCodeMode.Reciprocate ? serverName : undefined,
+        ).toBytes();
+    }
+
+    /**
+     * Returns the check code for the secure channel or undefined if not generated yet.
+     */
+    public getCheckCode(): string | undefined {
+        const x = this.establishedChannel?.check_code();
+
+        if (!x) {
+            return undefined;
+        }
+        return Array.from(x.as_bytes())
+            .map((b) => `${b % 10}`)
+            .join("");
+    }
+
+    /**
+     * Connects and establishes a secure channel with the other device.
+     */
+    public async connect(): Promise<void> {
+        if (this.connected) {
+            throw new Error("Channel already connected");
+        }
+
+        if (this.theirPublicKey) {
+            // We are the scanning device
+            const result = this.secureChannel.establish_outbound_channel(
+                this.theirPublicKey,
+                "MATRIX_QR_CODE_LOGIN_INITIATE",
+            );
+            this.establishedChannel = result.channel;
+
+            /*
+             Secure Channel step 4. Device S sends the initial message
+
+             Nonce := 0
+             SH := ECDH(Ss, Gp)
+             EncKey := HKDF_SHA256(SH, "MATRIX_QR_CODE_LOGIN|" || Gp || "|" || Sp, 0, 32)
+             TaggedCiphertext := ChaCha20Poly1305_Encrypt(EncKey, Nonce, "MATRIX_QR_CODE_LOGIN_INITIATE")
+             Nonce := Nonce + 2
+             LoginInitiateMessage := UnpaddedBase64(TaggedCiphertext) || "|" || UnpaddedBase64(Sp)
+             */
+            {
+                logger.info("Sending LoginInitiateMessage");
+                await this.rendezvousSession.send(result.initial_message);
+            }
+
+            /*
+            Secure Channel step 6. Verification by Device S
+
+            Nonce_G := 1
+            (TaggedCiphertext, Sp) := Unpack(Message)
+            Plaintext := ChaCha20Poly1305_Decrypt(EncKey, Nonce_G, TaggedCiphertext)
+            Nonce_G := Nonce_G + 2
+
+            unless Plaintext == "MATRIX_QR_CODE_LOGIN_OK":
+                FAIL
+             */
+            {
+                logger.info("Waiting for LoginOkMessage");
+                const ciphertext = await this.rendezvousSession.receive();
+
+                if (!ciphertext) {
+                    throw new RendezvousError(
+                        "No response from other device",
+                        MSC4108FailureReason.UnexpectedMessageReceived,
+                    );
+                }
+                const candidateLoginOkMessage = await this.decrypt(ciphertext);
+
+                if (candidateLoginOkMessage !== "MATRIX_QR_CODE_LOGIN_OK") {
+                    throw new RendezvousError(
+                        "Invalid response from other device",
+                        ClientRendezvousFailureReason.InsecureChannelDetected,
+                    );
+                }
+
+                // Step 6 is now complete. We trust the channel
+            }
+        } else {
+            /*
+            Secure Channel step 5. Device G confirms
+
+            Nonce_S := 0
+            (TaggedCiphertext, Sp) := Unpack(LoginInitiateMessage)
+            SH := ECDH(Gs, Sp)
+            EncKey := HKDF_SHA256(SH, "MATRIX_QR_CODE_LOGIN|" || Gp || "|" || Sp, 0, 32)
+            Plaintext := ChaCha20Poly1305_Decrypt(EncKey, Nonce_S, TaggedCiphertext)
+            Nonce_S := Nonce_S + 2
+             */
+            // wait for the other side to send us their public key
+            logger.info("Waiting for LoginInitiateMessage");
+            const loginInitiateMessage = await this.rendezvousSession.receive();
+            if (!loginInitiateMessage) {
+                throw new Error("No response from other device");
+            }
+
+            const { channel, message: candidateLoginInitiateMessage } =
+                this.secureChannel.establish_inbound_channel(loginInitiateMessage);
+            this.establishedChannel = channel;
+
+            if (candidateLoginInitiateMessage !== "MATRIX_QR_CODE_LOGIN_INITIATE") {
+                throw new RendezvousError(
+                    "Invalid response from other device",
+                    ClientRendezvousFailureReason.InsecureChannelDetected,
+                );
+            }
+            logger.info("LoginInitiateMessage received");
+
+            logger.info("Sending LoginOkMessage");
+            const loginOkMessage = await this.encrypt("MATRIX_QR_CODE_LOGIN_OK");
+            await this.rendezvousSession.send(loginOkMessage);
+
+            // Step 5 is complete. We don't yet trust the channel
+
+            // next step will be for the user to confirm the check code on the other device
+        }
+
+        this.connected = true;
+    }
+
+    private async decrypt(ciphertext: string): Promise<string> {
+        if (!this.establishedChannel) {
+            throw new Error("Channel closed");
+        }
+
+        return this.establishedChannel.decrypt(ciphertext);
+    }
+
+    private async encrypt(plaintext: string): Promise<string> {
+        if (!this.establishedChannel) {
+            throw new Error("Channel closed");
+        }
+
+        return this.establishedChannel.encrypt(plaintext);
+    }
+
+    /**
+     * Sends a payload securely to the other device.
+     * @param payload the payload to encrypt and send
+     */
+    public async secureSend<T extends MSC4108Payload>(payload: T): Promise<void> {
+        if (!this.connected) {
+            throw new Error("Channel closed");
+        }
+
+        const stringifiedPayload = JSON.stringify(payload);
+        logger.debug(`=> {"type": ${JSON.stringify(payload.type)}, ...}`);
+
+        await this.rendezvousSession.send(await this.encrypt(stringifiedPayload));
+    }
+
+    /**
+     * Receives an encrypted payload from the other device and decrypts it.
+     */
+    public async secureReceive<T extends MSC4108Payload>(): Promise<Partial<T> | undefined> {
+        if (!this.establishedChannel) {
+            throw new Error("Channel closed");
+        }
+
+        const ciphertext = await this.rendezvousSession.receive();
+        if (!ciphertext) {
+            return undefined;
+        }
+        const plaintext = await this.decrypt(ciphertext);
+        const json = JSON.parse(plaintext);
+
+        logger.debug(`<= {"type": ${JSON.stringify(json.type)}, ...}`);
+        return json as Partial<T> | undefined;
+    }
+
+    /**
+     * Closes the secure channel.
+     */
+    public async close(): Promise<void> {
+        await this.rendezvousSession.close();
+    }
+
+    /**
+     * Cancels the secure channel.
+     * @param reason the reason for the cancellation
+     */
+    public async cancel(reason: MSC4108FailureReason | ClientRendezvousFailureReason): Promise<void> {
+        try {
+            await this.rendezvousSession.cancel(reason);
+            this.onFailure?.(reason);
+        } finally {
+            await this.close();
+        }
+    }
+
+    /**
+     * Returns whether the rendezvous session has been cancelled.
+     */
+    public get cancelled(): boolean {
+        return this.rendezvousSession.cancelled;
+    }
+}

src/rendezvous/channels/index.ts

@@ -14,4 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+/**
+ * @deprecated in favour of MSC4108-based implementation
+ */
 export * from "./MSC3903ECDHv2RendezvousChannel";
+export * from "./MSC4108SecureChannel";

src/rendezvous/index.ts

@@ -14,10 +14,16 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+/**
+ * @deprecated in favour of MSC4108-based implementation
+ */
 export * from "./MSC3906Rendezvous";
+export * from "./MSC4108SignInWithQR";
 export * from "./RendezvousChannel";
 export * from "./RendezvousCode";
 export * from "./RendezvousError";
 export * from "./RendezvousFailureReason";
 export * from "./RendezvousIntent";
 export * from "./RendezvousTransport";
+export * from "./transports";
+export * from "./channels";

src/rendezvous/transports/MSC3886SimpleHttpRendezvousTransport.ts

@@ -20,7 +20,7 @@ import { logger } from "../../logger";
 import { sleep } from "../../utils";
 import {
     RendezvousFailureListener,
-    RendezvousFailureReason,
+    LegacyRendezvousFailureReason as RendezvousFailureReason,
     RendezvousTransport,
     RendezvousTransportDetails,
 } from "..";
@@ -37,6 +37,9 @@ export interface MSC3886SimpleHttpRendezvousTransportDetails extends RendezvousT
  * Implementation of the unstable [MSC3886](https://github.com/matrix-org/matrix-spec-proposals/pull/3886)
  * simple HTTP rendezvous protocol.
  * Note that this is UNSTABLE and may have breaking changes without notice.
+ * MSC3886/MSC3903/MSC3906 are now closed and so this functionality will be removed in future.
+ * However, we want to keep this implementation around for some time.
+ * TODO: define an end-of-life date for this implementation.
  */
 export class MSC3886SimpleHttpRendezvousTransport<T extends {}> implements RendezvousTransport<T> {
     private uri?: string;

src/rendezvous/transports/MSC4108RendezvousSession.ts

@@ -0,0 +1,270 @@
+/*
+Copyright 2024 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 { logger } from "../../logger";
+import { sleep } from "../../utils";
+import { ClientRendezvousFailureReason, MSC4108FailureReason, RendezvousFailureListener } from "..";
+import { MatrixClient, Method } from "../../matrix";
+import { ClientPrefix } from "../../http-api";
+
+/**
+ * Prototype of the unstable [MSC4108](https://github.com/matrix-org/matrix-spec-proposals/pull/4108)
+ * insecure rendezvous session protocol.
+ * @experimental Note that this is UNSTABLE and may have breaking changes without notice.
+ */
+export class MSC4108RendezvousSession {
+    public url?: string;
+    private readonly client?: MatrixClient;
+    private readonly fallbackRzServer?: string;
+    private readonly fetchFn?: typeof global.fetch;
+    private readonly onFailure?: RendezvousFailureListener;
+    private etag?: string;
+    private expiresAt?: Date;
+    private expiresTimer?: ReturnType<typeof setTimeout>;
+    private _cancelled = false;
+    private _ready = false;
+
+    public constructor({
+        onFailure,
+        url,
+        fetchFn,
+    }: {
+        fetchFn?: typeof global.fetch;
+        onFailure?: RendezvousFailureListener;
+        url: string;
+    });
+    public constructor({
+        onFailure,
+        client,
+        fallbackRzServer,
+        fetchFn,
+    }: {
+        fetchFn?: typeof global.fetch;
+        onFailure?: RendezvousFailureListener;
+        client?: MatrixClient;
+        fallbackRzServer?: string;
+    });
+    public constructor({
+        fetchFn,
+        onFailure,
+        url,
+        client,
+        fallbackRzServer,
+    }: {
+        fetchFn?: typeof global.fetch;
+        onFailure?: RendezvousFailureListener;
+        url?: string;
+        client?: MatrixClient;
+        fallbackRzServer?: string;
+    }) {
+        this.fetchFn = fetchFn;
+        this.onFailure = onFailure;
+        this.client = client;
+        this.fallbackRzServer = fallbackRzServer;
+        this.url = url;
+    }
+
+    /**
+     * Returns whether the channel is ready to be used.
+     */
+    public get ready(): boolean {
+        return this._ready;
+    }
+
+    /**
+     * Returns whether the channel has been cancelled.
+     */
+    public get cancelled(): boolean {
+        return this._cancelled;
+    }
+
+    private fetch(resource: URL | string, options?: RequestInit): ReturnType<typeof global.fetch> {
+        if (this.fetchFn) {
+            return this.fetchFn(resource, options);
+        }
+        return global.fetch(resource, options);
+    }
+
+    private async getPostEndpoint(): Promise<string | undefined> {
+        if (this.client) {
+            try {
+                if (await this.client.doesServerSupportUnstableFeature("org.matrix.msc4108")) {
+                    return this.client.http
+                        .getUrl("/org.matrix.msc4108/rendezvous", undefined, ClientPrefix.Unstable)
+                        .toString();
+                }
+            } catch (err) {
+                logger.warn("Failed to get unstable features", err);
+            }
+        }
+
+        return this.fallbackRzServer;
+    }
+
+    /**
+     * Sends data via the rendezvous channel.
+     * @param data the payload to send
+     */
+    public async send(data: string): Promise<void> {
+        if (this._cancelled) {
+            return;
+        }
+        const method = this.url ? Method.Put : Method.Post;
+        const uri = this.url ?? (await this.getPostEndpoint());
+
+        if (!uri) {
+            throw new Error("Invalid rendezvous URI");
+        }
+
+        const headers: Record<string, string> = { "content-type": "text/plain" };
+
+        // if we didn't create the rendezvous channel, we need to fetch the first etag if needed
+        if (!this.etag && this.url) {
+            await this.receive();
+        }
+
+        if (this.etag) {
+            headers["if-match"] = this.etag;
+        }
+
+        logger.info(`=> ${method} ${uri} with ${data} if-match: ${this.etag}`);
+
+        const res = await this.fetch(uri, { method, headers, body: data, redirect: "follow" });
+        if (res.status === 404) {
+            return this.cancel(ClientRendezvousFailureReason.Unknown);
+        }
+        this.etag = res.headers.get("etag") ?? undefined;
+
+        logger.info(`Received etag: ${this.etag}`);
+
+        if (method === Method.Post) {
+            const expires = res.headers.get("expires");
+            if (expires) {
+                if (this.expiresTimer) {
+                    clearTimeout(this.expiresTimer);
+                    this.expiresTimer = undefined;
+                }
+                this.expiresAt = new Date(expires);
+                this.expiresTimer = setTimeout(() => {
+                    this.expiresTimer = undefined;
+                    this.cancel(ClientRendezvousFailureReason.Expired);
+                }, this.expiresAt.getTime() - Date.now());
+            }
+            // MSC4108: we expect a JSON response with a rendezvous URL
+            const json = await res.json();
+            if (typeof json.url !== "string") {
+                throw new Error("No rendezvous URL given");
+            }
+            this.url = json.url;
+            this._ready = true;
+        }
+    }
+
+    /**
+     * Receives data from the rendezvous channel.
+     * @return the returned promise won't resolve until new data is acquired or the channel is closed either by the server or the other party.
+     */
+    public async receive(): Promise<string | undefined> {
+        if (!this.url) {
+            throw new Error("Rendezvous not set up");
+        }
+        // eslint-disable-next-line no-constant-condition
+        while (true) {
+            if (this._cancelled) {
+                return undefined;
+            }
+
+            const headers: Record<string, string> = {};
+            if (this.etag) {
+                headers["if-none-match"] = this.etag;
+            }
+
+            logger.info(`=> GET ${this.url} if-none-match: ${this.etag}`);
+            const poll = await this.fetch(this.url, { method: Method.Get, headers });
+
+            if (poll.status === 404) {
+                await this.cancel(ClientRendezvousFailureReason.Unknown);
+                return undefined;
+            }
+
+            // rely on server expiring the channel rather than checking ourselves
+
+            const etag = poll.headers.get("etag") ?? undefined;
+            if (poll.headers.get("content-type") !== "text/plain") {
+                this.etag = etag;
+            } else if (poll.status === 200) {
+                if (!etag) {
+                    // Some browsers & extensions block the ETag header for anti-tracking purposes
+                    // We try and detect this so the client can give the user a somewhat helpful message
+                    await this.cancel(ClientRendezvousFailureReason.ETagMissing);
+                    return undefined;
+                }
+
+                this.etag = etag;
+                const text = await poll.text();
+                logger.info(`Received: ${text} with etag ${this.etag}`);
+                return text;
+            }
+            await sleep(1000);
+        }
+    }
+
+    /**
+     * Cancels the rendezvous channel.
+     * If the reason is user_declined or user_cancelled then the channel will also be closed.
+     * @param reason the reason to cancel with
+     */
+    public async cancel(reason: MSC4108FailureReason | ClientRendezvousFailureReason): Promise<void> {
+        if (this._cancelled) return;
+        if (this.expiresTimer) {
+            clearTimeout(this.expiresTimer);
+            this.expiresTimer = undefined;
+        }
+
+        if (
+            reason === ClientRendezvousFailureReason.Unknown &&
+            this.expiresAt &&
+            this.expiresAt.getTime() < Date.now()
+        ) {
+            reason = ClientRendezvousFailureReason.Expired;
+        }
+
+        this._cancelled = true;
+        this._ready = false;
+        this.onFailure?.(reason);
+
+        if (reason === ClientRendezvousFailureReason.UserDeclined || reason === MSC4108FailureReason.UserCancelled) {
+            await this.close();
+        }
+    }
+
+    /**
+     * Closes the rendezvous channel.
+     */
+    public async close(): Promise<void> {
+        if (this.expiresTimer) {
+            clearTimeout(this.expiresTimer);
+            this.expiresTimer = undefined;
+        }
+
+        if (!this.url) return;
+        try {
+            await this.fetch(this.url, { method: Method.Delete });
+        } catch (e) {
+            logger.warn(e);
+        }
+    }
+}

src/rendezvous/transports/index.ts

@@ -14,4 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+/**
+ * @deprecated in favour of MSC4108-based implementation
+ */
 export * from "./MSC3886SimpleHttpRendezvousTransport";
+export * from "./MSC4108RendezvousSession";

src/rust-crypto/rust-crypto.ts

@@ -38,6 +38,7 @@ import {
     CrossSigningKey,
     CrossSigningKeyInfo,
     CrossSigningStatus,
+    CryptoApi,
     CryptoCallbacks,
     Curve25519AuthData,
     DecryptionFailureCode,
@@ -308,6 +309,40 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
         return;
     }
 
+    /**
+     * Implementation of {@link CryptoBackend#getBackupDecryptor}.
+     */
+    public async getBackupDecryptor(backupInfo: KeyBackupInfo, privKey: ArrayLike<number>): Promise<BackupDecryptor> {
+        if (backupInfo.algorithm != "m.megolm_backup.v1.curve25519-aes-sha2") {
+            throw new Error(`getBackupDecryptor Unsupported algorithm ${backupInfo.algorithm}`);
+        }
+
+        const authData = <Curve25519AuthData>backupInfo.auth_data;
+
+        if (!(privKey instanceof Uint8Array)) {
+            throw new Error(`getBackupDecryptor expects Uint8Array`);
+        }
+
+        const backupDecryptionKey = RustSdkCryptoJs.BackupDecryptionKey.fromBase64(encodeBase64(privKey));
+
+        if (authData.public_key != backupDecryptionKey.megolmV1PublicKey.publicKeyBase64) {
+            throw new Error(`getBackupDecryptor key mismatch error`);
+        }
+
+        return this.backupManager.createBackupDecryptor(backupDecryptionKey);
+    }
+
+    /**
+     * Implementation of {@link CryptoBackend#importBackedUpRoomKeys}.
+     */
+    public async importBackedUpRoomKeys(
+        keys: IMegolmSessionData[],
+        backupVersion: string,
+        opts?: ImportRoomKeysOpts,
+    ): Promise<void> {
+        return await this.backupManager.importBackedUpRoomKeys(keys, backupVersion, opts);
+    }
+
     ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     //
     // CryptoApi implementation
@@ -1065,10 +1100,9 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
         }
 
         try {
-            const [request, outgoingRequest]: [RustSdkCryptoJs.VerificationRequest, RustSdkCryptoJs.ToDeviceRequest] =
-                await device.requestVerification(
-                    this._supportedVerificationMethods.map(verificationMethodIdentifierToMethod),
-                );
+            const [request, outgoingRequest] = device.requestVerification(
+                this._supportedVerificationMethods.map(verificationMethodIdentifierToMethod),
+            );
             await this.outgoingRequestProcessor.makeOutgoingRequest(outgoingRequest);
             return new RustVerificationRequest(
                 this.olmMachine,
@@ -1169,6 +1203,8 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
      * Signs the given object with the current device and current identity (if available).
      * As defined in {@link https://spec.matrix.org/v1.8/appendices/#signing-json | Signing JSON}.
      *
+     * Helper for {@link RustCrypto#resetKeyBackup}.
+     *
      * @param obj - The object to sign
      */
     private async signObject<T extends ISignableObject & object>(obj: T): Promise<void> {
@@ -1192,48 +1228,14 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
     }
 
     /**
-     * Implementation of {@link CryptoBackend#getBackupDecryptor}.
-     */
-    public async getBackupDecryptor(backupInfo: KeyBackupInfo, privKey: ArrayLike<number>): Promise<BackupDecryptor> {
-        if (backupInfo.algorithm != "m.megolm_backup.v1.curve25519-aes-sha2") {
-            throw new Error(`getBackupDecryptor Unsupported algorithm ${backupInfo.algorithm}`);
-        }
-
-        const authData = <Curve25519AuthData>backupInfo.auth_data;
-
-        if (!(privKey instanceof Uint8Array)) {
-            throw new Error(`getBackupDecryptor expects Uint8Array`);
-        }
-
-        const backupDecryptionKey = RustSdkCryptoJs.BackupDecryptionKey.fromBase64(encodeBase64(privKey));
-
-        if (authData.public_key != backupDecryptionKey.megolmV1PublicKey.publicKeyBase64) {
-            throw new Error(`getBackupDecryptor key mismatch error`);
-        }
-
-        return this.backupManager.createBackupDecryptor(backupDecryptionKey);
-    }
-
-    /**
-     * Implementation of {@link CryptoBackend#importBackedUpRoomKeys}.
-     */
-    public async importBackedUpRoomKeys(
-        keys: IMegolmSessionData[],
-        backupVersion: string,
-        opts?: ImportRoomKeysOpts,
-    ): Promise<void> {
-        return await this.backupManager.importBackedUpRoomKeys(keys, backupVersion, opts);
-    }
-
-    /**
-     * Implementation of {@link CryptoBackend#isDehydrationSupported}.
+     * Implementation of {@link CryptoApi#isDehydrationSupported}.
      */
     public async isDehydrationSupported(): Promise<boolean> {
         return await this.dehydratedDeviceManager.isSupported();
     }
 
     /**
-     * Implementation of {@link CryptoBackend#startDehydration}.
+     * Implementation of {@link CryptoApi#startDehydration}.
      */
     public async startDehydration(createNewKey?: boolean): Promise<void> {
         if (!(await this.isCrossSigningReady()) || !(await this.isSecretStorageReady())) {
@@ -1242,6 +1244,26 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
         return await this.dehydratedDeviceManager.start(createNewKey);
     }
 
+    /**
+     * Implementation of {@link CryptoApi#importSecretsBundle}.
+     */
+    public async importSecretsBundle(
+        secrets: Parameters<NonNullable<CryptoApi["importSecretsBundle"]>>[0],
+    ): Promise<void> {
+        const secretsBundle = RustSdkCryptoJs.SecretsBundle.from_json(secrets);
+        await this.getOlmMachineOrThrow().importSecretsBundle(secretsBundle); // this method frees the SecretsBundle
+    }
+
+    /**
+     * Implementation of {@link CryptoApi#exportSecretsBundle}.
+     */
+    public async exportSecretsBundle(): ReturnType<NonNullable<CryptoApi["exportSecretsBundle"]>> {
+        const secretsBundle = await this.getOlmMachineOrThrow().exportSecretsBundle();
+        const secrets = secretsBundle.to_json();
+        secretsBundle.free();
+        return secrets;
+    }
+
     ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     //
     // SyncCryptoCallbacks implementation

src/rust-crypto/verification.ts

@@ -72,30 +72,40 @@ export class RustVerificationRequest
         private readonly supportedVerificationMethods: string[],
     ) {
         super();
-
         this.reEmitter = new TypedReEmitter(this);
 
-        const onChange = async (): Promise<void> => {
-            const verification: RustSdkCryptoJs.Qr | RustSdkCryptoJs.Sas | undefined = this.inner.getVerification();
+        // Obviously, the Rust object maintains a reference to the callback function. If the callback function maintains
+        // a reference to the Rust object, then we have a reference cycle which means that `RustVerificationRequest`
+        // will never be garbage-collected, and hence the underlying rust object will never be freed.
+        //
+        // To avoid this reference cycle, use a weak reference in the callback function. If the `RustVerificationRequest`
+        // gets garbage-collected, then there is nothing to update!
+        const weakThis = new WeakRef(this);
+        inner.registerChangesCallback(async () => weakThis.deref()?.onChange());
+    }
 
-            // Set the _verifier object (wrapping the rust `Verification` as a js-sdk Verifier) if:
-            // - we now have a `Verification` where we lacked one before
-            // - we have transitioned from QR to SAS
-            // - we are verifying with SAS, but we need to replace our verifier with a new one because both parties
-            //   tried to start verification at the same time, and we lost the tie breaking
-            if (verification instanceof RustSdkCryptoJs.Sas) {
-                if (this._verifier === undefined || this._verifier instanceof RustQrCodeVerifier) {
-                    this.setVerifier(new RustSASVerifier(verification, this, outgoingRequestProcessor));
-                } else if (this._verifier instanceof RustSASVerifier) {
-                    this._verifier.replaceInner(verification);
-                }
-            } else if (verification instanceof RustSdkCryptoJs.Qr && this._verifier === undefined) {
-                this.setVerifier(new RustQrCodeVerifier(verification, outgoingRequestProcessor));
+    /**
+     * Hook which is called when the underlying rust class notifies us that there has been a change.
+     */
+    private onChange(): void {
+        const verification: RustSdkCryptoJs.Qr | RustSdkCryptoJs.Sas | undefined = this.inner.getVerification();
+
+        // Set the _verifier object (wrapping the rust `Verification` as a js-sdk Verifier) if:
+        // - we now have a `Verification` where we lacked one before
+        // - we have transitioned from QR to SAS
+        // - we are verifying with SAS, but we need to replace our verifier with a new one because both parties
+        //   tried to start verification at the same time, and we lost the tie breaking
+        if (verification instanceof RustSdkCryptoJs.Sas) {
+            if (this._verifier === undefined || this._verifier instanceof RustQrCodeVerifier) {
+                this.setVerifier(new RustSASVerifier(verification, this, this.outgoingRequestProcessor));
+            } else if (this._verifier instanceof RustSASVerifier) {
+                this._verifier.replaceInner(verification);
             }
+        } else if (verification instanceof RustSdkCryptoJs.Qr && this._verifier === undefined) {
+            this.setVerifier(new RustQrCodeVerifier(verification, this.outgoingRequestProcessor));
+        }
 
-            this.emit(VerificationRequestEvent.Change);
-        };
-        inner.registerChangesCallback(onChange);
+        this.emit(VerificationRequestEvent.Change);
     }
 
     private setVerifier(verifier: RustSASVerifier | RustQrCodeVerifier): void {
@@ -473,9 +483,12 @@ abstract class BaseRustVerifer<InnerType extends RustSdkCryptoJs.Qr | RustSdkCry
         super();
 
         this.completionDeferred = defer();
-        inner.registerChangesCallback(async () => {
-            this.onChange();
-        });
+
+        // As with RustVerificationRequest, we need to avoid a reference cycle.
+        // See the comments in RustVerificationRequest.
+        const weakThis = new WeakRef(this);
+        inner.registerChangesCallback(async () => weakThis.deref()?.onChange());
+
         // stop the runtime complaining if nobody catches a failure
         this.completionDeferred.promise.catch(() => null);
     }
@@ -752,9 +765,12 @@ export class RustSASVerifier extends BaseRustVerifer<RustSdkCryptoJs.Sas> implem
     public replaceInner(inner: RustSdkCryptoJs.Sas): void {
         if (this.inner != inner) {
             this.inner = inner;
-            inner.registerChangesCallback(async () => {
-                this.onChange();
-            });
+
+            // As with RustVerificationRequest, we need to avoid a reference cycle.
+            // See the comments in RustVerificationRequest.
+            const weakThis = new WeakRef(this);
+            inner.registerChangesCallback(async () => weakThis.deref()?.onChange());
+
             // replaceInner will only get called if we started the verification at the same time as the other side, and we lost
             // the tie breaker.  So we need to re-accept their verification.
             this.sendAccept();

src/serverCapabilities.ts

@@ -0,0 +1,136 @@
+/*
+Copyright 2024 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 { IHttpOpts, MatrixHttpApi, Method } from "./http-api";
+import { logger } from "./logger";
+
+// How often we update the server capabilities.
+// 6 hours - an arbitrary value, but they should change very infrequently.
+const CAPABILITIES_CACHE_MS = 6 * 60 * 60 * 1000;
+
+// How long we want before retrying if we couldn't fetch
+const CAPABILITIES_RETRY_MS = 30 * 1000;
+
+export interface ICapability {
+    enabled: boolean;
+}
+
+export interface IChangePasswordCapability extends ICapability {}
+
+export interface IThreadsCapability extends ICapability {}
+
+export interface IGetLoginTokenCapability extends ICapability {}
+
+export interface ISetDisplayNameCapability extends ICapability {}
+
+export interface ISetAvatarUrlCapability extends ICapability {}
+
+export enum RoomVersionStability {
+    Stable = "stable",
+    Unstable = "unstable",
+}
+
+export interface IRoomVersionsCapability {
+    default: string;
+    available: Record<string, RoomVersionStability>;
+}
+
+/**
+ * A representation of the capabilities advertised by a homeserver as defined by
+ * [Capabilities negotiation](https://spec.matrix.org/v1.6/client-server-api/#get_matrixclientv3capabilities).
+ */
+export interface Capabilities {
+    [key: string]: any;
+    "m.change_password"?: IChangePasswordCapability;
+    "m.room_versions"?: IRoomVersionsCapability;
+    "io.element.thread"?: IThreadsCapability;
+    "m.get_login_token"?: IGetLoginTokenCapability;
+    "org.matrix.msc3882.get_login_token"?: IGetLoginTokenCapability;
+    "m.set_displayname"?: ISetDisplayNameCapability;
+    "m.set_avatar_url"?: ISetAvatarUrlCapability;
+}
+
+type CapabilitiesResponse = {
+    capabilities: Capabilities;
+};
+
+/**
+ * Manages storing and periodically refreshing the server capabilities.
+ */
+export class ServerCapabilities {
+    private capabilities?: Capabilities;
+    private retryTimeout?: ReturnType<typeof setTimeout>;
+    private refreshTimeout?: ReturnType<typeof setInterval>;
+
+    public constructor(private readonly http: MatrixHttpApi<IHttpOpts & { onlyData: true }>) {}
+
+    /**
+     * Starts periodically fetching the server capabilities.
+     */
+    public start(): void {
+        this.poll().then();
+    }
+
+    /**
+     * Stops the service
+     */
+    public stop(): void {
+        this.clearTimeouts();
+    }
+
+    /**
+     * Returns the cached capabilities, or undefined if none are cached.
+     * @returns the current capabilities, if any.
+     */
+    public getCachedCapabilities(): Capabilities | undefined {
+        return this.capabilities;
+    }
+
+    /**
+     * Fetches the latest server capabilities from the homeserver and returns them, or rejects
+     * on failure.
+     */
+    public fetchCapabilities = async (): Promise<Capabilities> => {
+        const resp = await this.http.authedRequest<CapabilitiesResponse>(Method.Get, "/capabilities");
+        this.capabilities = resp["capabilities"];
+        return this.capabilities;
+    };
+
+    private poll = async (): Promise<void> => {
+        try {
+            await this.fetchCapabilities();
+            this.clearTimeouts();
+            this.refreshTimeout = setTimeout(this.poll, CAPABILITIES_CACHE_MS);
+            logger.debug("Fetched new server capabilities");
+        } catch (e) {
+            this.clearTimeouts();
+            const howLong = Math.floor(CAPABILITIES_RETRY_MS + Math.random() * 5000);
+            this.retryTimeout = setTimeout(this.poll, howLong);
+            logger.warn(`Failed to refresh capabilities: retrying in ${howLong}ms`, e);
+        }
+    };
+
+    private clearTimeouts(): void {
+        if (this.refreshTimeout) {
+            clearInterval(this.refreshTimeout);
+            this.refreshTimeout = undefined;
+        }
+        if (this.retryTimeout) {
+            clearTimeout(this.retryTimeout);
+            this.retryTimeout = undefined;
+        }
+    }
+}

src/utils.ts

@@ -407,9 +407,12 @@ export async function logDuration<T>(logger: BaseLogger, name: string, block: ()
 
 /**
  * Promise/async version of {@link setImmediate}.
+ *
+ * Implementation is based on `setTimeout` for wider compatibility.
+ * @deprecated Use {@link sleep} instead.
  */
 export function immediate(): Promise<void> {
-    return new Promise(setImmediate);
+    return new Promise((resolve) => setTimeout(resolve));
 }
 
 export function isNullOrUndefined(val: any): boolean {

src/webrtc/call.ts

@@ -2381,22 +2381,40 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
         // RTCRtpReceiver.getCapabilities and RTCRtpSender.getCapabilities don't seem to be supported on FF before v113
         if (!RTCRtpReceiver.getCapabilities || !RTCRtpSender.getCapabilities) return;
 
-        const recvCodecs = RTCRtpReceiver.getCapabilities("video")!.codecs;
-        const sendCodecs = RTCRtpSender.getCapabilities("video")!.codecs;
-        const codecs = [...sendCodecs, ...recvCodecs];
-
-        for (const codec of codecs) {
-            if (codec.mimeType === "video/rtx") {
-                const rtxCodecIndex = codecs.indexOf(codec);
-                codecs.splice(rtxCodecIndex, 1);
-            }
-        }
-
         const screenshareVideoTransceiver = this.transceivers.get(
             getTransceiverKey(SDPStreamMetadataPurpose.Screenshare, "video"),
         );
+
         // setCodecPreferences isn't supported on FF (as of v113)
-        screenshareVideoTransceiver?.setCodecPreferences?.(codecs);
+        if (!screenshareVideoTransceiver || !screenshareVideoTransceiver.setCodecPreferences) return;
+
+        const recvCodecs = RTCRtpReceiver.getCapabilities("video")!.codecs;
+        const sendCodecs = RTCRtpSender.getCapabilities("video")!.codecs;
+        const codecs = [];
+
+        for (const codec of [...recvCodecs, ...sendCodecs]) {
+            if (codec.mimeType !== "video/rtx") {
+                codecs.push(codec);
+                try {
+                    screenshareVideoTransceiver.setCodecPreferences(codecs);
+                } catch (e) {
+                    // Specifically, Chrome around version 125 and Electron 30 (which is Chromium 124) return an H.264 codec in
+                    // the sender's capabilities but throw when you try to set it. Hence... this mess.
+                    // Specifically, that codec is:
+                    // {
+                    //   clockRate: 90000,
+                    //   mimeType: "video/H264",
+                    //   sdpFmtpLine: "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=640034",
+                    // }
+                    logger.info(
+                        "Working around buggy WebRTC impl: claimed to support codec but threw when setting codec preferences",
+                        codec,
+                        e,
+                    );
+                    codecs.pop();
+                }
+            }
+        }
     }
 
     private onNegotiationNeeded = async (): Promise<void> => {

tsconfig.json

@@ -1,6 +1,6 @@
 {
     "compilerOptions": {
-        "target": "es2016",
+        "target": "es2022",
         "experimentalDecorators": true,
         "esModuleInterop": true,
         "module": "commonjs",