Fetch capabilities in the background

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

@@ -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,
+            });
+
+            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,
             });
-            const prom = httpBackend.flushAllExpected();
-            const capabilities1 = await client.getCapabilities();
-            const capabilities2 = await client.getCapabilities();
+        });
+
+        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

@@ -105,20 +105,21 @@ 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);
     });
 
     it("should stop sync keep alive when client is stopped.", async () => {
         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/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/unit/rendezvous/rendezvous.spec.ts

@@ -116,7 +116,7 @@ function makeMockClient(opts: {
                     },
                 };
             },
-            getCapabilities() {
+            getCachedCapabilities() {
                 return opts.msc3882r0Only
                     ? {}
                     : {

src/client.ts

@@ -226,14 +226,14 @@ 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;
 
 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();
-
-        if (this.cachedCapabilities && !fresh) {
-            if (now < this.cachedCapabilities.expiration) {
-                this.logger.debug("Returning cached capabilities");
-                return Promise.resolve(this.cachedCapabilities.capabilities);
-            }
-        }
-
-        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;
+    public async getCapabilities(): Promise<Capabilities> {
+        const caps = this.serverCapabilitiesService.getCachedCapabilities();
+        if (caps) return caps;
+        return this.serverCapabilitiesService.fetchCapabilities();
+    }
 
-                this.cachedCapabilities = {
-                    capabilities,
-                    expiration: now + cacheMs,
-                };
+    /**
+     * 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();
+    }
 
-                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();
     }
 
     /**

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";