Remove well-known proxy URL lookup; always use native

This is actually required for SSS because otherwise it would use
the proxy over native support.

src/SlidingSyncManager.ts

@@ -322,44 +322,12 @@ export class SlidingSyncManager {
      * @returns A working Sliding Sync or undefined
      */
     public async setup(client: MatrixClient): Promise<SlidingSync | undefined> {
-        const baseUrl = client.baseUrl;
+        this.configure(client, client.baseUrl);
-        const proxyUrl = SettingsStore.getValue("feature_sliding_sync_proxy_url");
+        logger.info("Simplified Sliding Sync activated at", client.baseUrl);
-        const wellKnownProxyUrl = await this.getProxyFromWellKnown(client);
-
-        const slidingSyncEndpoint = proxyUrl || wellKnownProxyUrl || baseUrl;
-
-        this.configure(client, slidingSyncEndpoint);
-        logger.info("Sliding sync activated at", slidingSyncEndpoint);
         this.startSpidering(100, 50); // 100 rooms at a time, 50ms apart
-
         return this.slidingSync;
     }
 
-    /**
-     * Get the sliding sync proxy URL from the client well known
-     * @param client The MatrixClient to use
-     * @return The proxy url
-     */
-    public async getProxyFromWellKnown(client: MatrixClient): Promise<string | undefined> {
-        let proxyUrl: string | undefined;
-
-        try {
-            const clientDomain = await client.getDomain();
-            if (clientDomain === null) {
-                throw new RangeError("Homeserver domain is null");
-            }
-            const clientWellKnown = await AutoDiscovery.findClientConfig(clientDomain);
-            proxyUrl = clientWellKnown?.["org.matrix.msc3575.proxy"]?.url;
-        } catch (e) {
-            // Either client.getDomain() is null so we've shorted out, or is invalid so `AutoDiscovery.findClientConfig` has thrown
-        }
-
-        if (proxyUrl != undefined) {
-            logger.log("getProxyFromWellKnown: client well-known declares sliding sync proxy at", proxyUrl);
-        }
-        return proxyUrl;
-    }
-
     /**
      * Check if the server "natively" supports sliding sync (with an unstable endpoint).
      * @param client The MatrixClient to use
@@ -370,7 +338,7 @@ export class SlidingSyncManager {
         // `client` can be undefined/null in tests for some reason.
         const support = await client?.doesServerSupportUnstableFeature("org.matrix.simplified_msc3575");
         if (support) {
-            logger.log("nativeSlidingSyncSupport: sliding sync advertised as unstable");
+            logger.log("nativeSlidingSyncSupport: org.matrix.simplified_msc3575 sliding sync advertised as unstable");
         }
         return support;
     }
@@ -387,17 +355,6 @@ export class SlidingSyncManager {
             SlidingSyncController.serverSupportsSlidingSync = true;
             return;
         }
-
+        SlidingSyncController.serverSupportsSlidingSync = false;
-        const proxyUrl = await this.getProxyFromWellKnown(client);
-        if (proxyUrl != undefined) {
-            const response = await fetch(new URL("/client/server.json", proxyUrl), {
-                method: Method.Get,
-                signal: timeoutSignal(10 * 1000), // 10s
-            });
-            if (response.status === 200) {
-                logger.log("checkSupport: well-known sliding sync proxy is up at", proxyUrl);
-                SlidingSyncController.serverSupportsSlidingSync = true;
-            }
-        }
     }
 }

src/i18n/strings/en_EN.json

@@ -1470,7 +1470,7 @@
         "render_reaction_images_description": "Sometimes referred to as \"custom emojis\".",
         "report_to_moderators": "Report to moderators",
         "report_to_moderators_description": "In rooms that support moderation, the “Report” button will let you report abuse to room moderators.",
-        "sliding_sync": "Sliding Sync mode",
+        "sliding_sync": "Simplified Sliding Sync mode",
         "sliding_sync_description": "Under active development, cannot be disabled.",
         "sliding_sync_disabled_notice": "Log out and back in to disable",
         "sliding_sync_server_no_support": "Your server lacks support",

src/settings/Settings.tsx

@@ -388,11 +388,6 @@ export const SETTINGS: { [setting: string]: ISetting } = {
         default: false,
         controller: new SlidingSyncController(),
     },
-    "feature_sliding_sync_proxy_url": {
-        // This is not a distinct feature, it is a legacy setting for feature_sliding_sync above
-        supportedLevels: LEVELS_DEVICE_ONLY_SETTINGS_WITH_CONFIG,
-        default: "",
-    },
     "feature_element_call_video_rooms": {
         isFeature: true,
         labsGroup: LabGroup.VoiceAndVideo,

test/SlidingSyncManager-test.ts

@@ -14,7 +14,6 @@ import fetchMockJest from "fetch-mock-jest";
 import { SlidingSyncManager } from "../src/SlidingSyncManager";
 import { stubClient } from "./test-utils";
 import SlidingSyncController from "../src/settings/controllers/SlidingSyncController";
-import SettingsStore from "../src/settings/SettingsStore";
 
 jest.mock("matrix-js-sdk/src/sliding-sync");
 const MockSlidingSync = <jest.Mock<SlidingSync>>(<unknown>SlidingSync);
@@ -41,7 +40,6 @@ describe("SlidingSyncManager", () => {
             const roomId = "!room:id";
             const subs = new Set<string>();
             mocked(slidingSync.getRoomSubscriptions).mockReturnValue(subs);
-            mocked(slidingSync.modifyRoomSubscriptions).mockResolvedValue("yep");
             await manager.setRoomVisible(roomId, true);
             expect(slidingSync.modifyRoomSubscriptions).toHaveBeenCalledWith(new Set<string>([roomId]));
         });
@@ -67,7 +65,6 @@ describe("SlidingSyncManager", () => {
             });
             const subs = new Set<string>();
             mocked(slidingSync.getRoomSubscriptions).mockReturnValue(subs);
-            mocked(slidingSync.modifyRoomSubscriptions).mockResolvedValue("yep");
             await manager.setRoomVisible(roomId, true);
             expect(slidingSync.modifyRoomSubscriptions).toHaveBeenCalledWith(new Set<string>([roomId]));
             // we aren't prescriptive about what the sub name is.
@@ -95,7 +92,6 @@ describe("SlidingSyncManager", () => {
             mocked(slidingSync.getListParams).mockReturnValue({
                 ranges: [[0, 42]],
             });
-            mocked(slidingSync.setList).mockResolvedValue("yep");
             await manager.ensureListRegistered(listKey, {
                 sort: ["by_recency"],
             });
@@ -201,61 +197,11 @@ describe("SlidingSyncManager", () => {
     describe("checkSupport", () => {
         beforeEach(() => {
             SlidingSyncController.serverSupportsSlidingSync = false;
-            jest.spyOn(manager, "getProxyFromWellKnown").mockResolvedValue("https://proxy/");
         });
         it("shorts out if the server has 'native' sliding sync support", async () => {
             jest.spyOn(manager, "nativeSlidingSyncSupport").mockResolvedValue(true);
             expect(SlidingSyncController.serverSupportsSlidingSync).toBeFalsy();
             await manager.checkSupport(client);
-            expect(manager.getProxyFromWellKnown).not.toHaveBeenCalled(); // We return earlier
-            expect(SlidingSyncController.serverSupportsSlidingSync).toBeTruthy();
-        });
-        it("tries to find a sliding sync proxy url from the client well-known if there's no 'native' support", async () => {
-            jest.spyOn(manager, "nativeSlidingSyncSupport").mockResolvedValue(false);
-            expect(SlidingSyncController.serverSupportsSlidingSync).toBeFalsy();
-            await manager.checkSupport(client);
-            expect(manager.getProxyFromWellKnown).toHaveBeenCalled();
-            expect(SlidingSyncController.serverSupportsSlidingSync).toBeTruthy();
-        });
-        it("should query well-known on server_name not baseUrl", async () => {
-            fetchMockJest.get("https://matrix.org/.well-known/matrix/client", {
-                "m.homeserver": {
-                    base_url: "https://matrix-client.matrix.org",
-                    server: "matrix.org",
-                },
-                "org.matrix.msc3575.proxy": {
-                    url: "https://proxy/",
-                },
-            });
-            fetchMockJest.get("https://matrix-client.matrix.org/_matrix/client/versions", { versions: ["v1.4"] });
-
-            mocked(manager.getProxyFromWellKnown).mockRestore();
-            jest.spyOn(manager, "nativeSlidingSyncSupport").mockResolvedValue(false);
-            expect(SlidingSyncController.serverSupportsSlidingSync).toBeFalsy();
-            await manager.checkSupport(client);
-            expect(SlidingSyncController.serverSupportsSlidingSync).toBeTruthy();
-            expect(fetchMockJest).not.toHaveFetched("https://matrix-client.matrix.org/.well-known/matrix/client");
-        });
-    });
-    describe("nativeSlidingSyncSupport", () => {
-        beforeEach(() => {
-            SlidingSyncController.serverSupportsSlidingSync = false;
-        });
-        it("should make an OPTIONS request to avoid unintended side effects", async () => {
-            // See https://github.com/element-hq/element-web/issues/27426
-
-            const unstableSpy = jest
-                .spyOn(client, "doesServerSupportUnstableFeature")
-                .mockImplementation(async (feature: string) => {
-                    expect(feature).toBe("org.matrix.simplified_msc3575");
-                    return true;
-                });
-            const proxySpy = jest.spyOn(manager, "getProxyFromWellKnown").mockResolvedValue("https://proxy/");
-
-            expect(SlidingSyncController.serverSupportsSlidingSync).toBeFalsy();
-            await manager.checkSupport(client); // first thing it does is call nativeSlidingSyncSupport
-            expect(proxySpy).not.toHaveBeenCalled();
-            expect(unstableSpy).toHaveBeenCalled();
             expect(SlidingSyncController.serverSupportsSlidingSync).toBeTruthy();
         });
     });
@@ -264,28 +210,11 @@ describe("SlidingSyncManager", () => {
             jest.spyOn(manager, "configure");
             jest.spyOn(manager, "startSpidering");
         });
-        it("uses the baseUrl as a proxy if no proxy is set in the client well-known and the server has no native support", async () => {
+        it("uses the baseUrl", async () => {
             await manager.setup(client);
             expect(manager.configure).toHaveBeenCalled();
             expect(manager.configure).toHaveBeenCalledWith(client, client.baseUrl);
             expect(manager.startSpidering).toHaveBeenCalled();
         });
-        it("uses the proxy declared in the client well-known", async () => {
-            jest.spyOn(manager, "getProxyFromWellKnown").mockResolvedValue("https://proxy/");
-            await manager.setup(client);
-            expect(manager.configure).toHaveBeenCalled();
-            expect(manager.configure).toHaveBeenCalledWith(client, "https://proxy/");
-            expect(manager.startSpidering).toHaveBeenCalled();
-        });
-        it("uses the legacy `feature_sliding_sync_proxy_url` if it was set", async () => {
-            jest.spyOn(manager, "getProxyFromWellKnown").mockResolvedValue("https://proxy/");
-            jest.spyOn(SettingsStore, "getValue").mockImplementation((name: string) => {
-                if (name === "feature_sliding_sync_proxy_url") return "legacy-proxy";
-            });
-            await manager.setup(client);
-            expect(manager.configure).toHaveBeenCalled();
-            expect(manager.configure).toHaveBeenCalledWith(client, "legacy-proxy");
-            expect(manager.startSpidering).toHaveBeenCalled();
-        });
     });
 });